دانشگاه تهران پژوهش های جغرافیای طبیعی 2008-630X 55 4 2023 12 23 Synoptic analysis of extreme and exteremly Wet Period in southern Iran تحلیل همدیدی ترسالی های شدید و فوق شدید در جنوب ایران 1 25 96004 10.22059/jphgr.2024.356775.1007755 FA فرناز مشایخ گروه آب و هواشناسی، دانشکده جغرافیا، واحد علوم تحقیقات، دانشگاه آزاد اسلامی، تهران، ایران حسن لشکری گروه جغرافیای طبیعی، دانشکده علوم زمین، دانشگاه شهید بهشتی، تهران 0000-0002-6007-7275 Journal Article 2023 08 01 ABSTRACT Aridity and drought are inseparable features of every climate. But in arid and semi-arid climates, tarsal is an ideal opportunity to restore or compensate for the lack of water in the region. The southern part of Iran has a dry climate despite access to the huge moisture resources of the warm southern seas. To conduct the research, first, the daily rainfall data of all the synoptic stations of the southern provinces of the country, which had complete statistics in the 33-year statistical period (1986-2019), were extracted. Then, using ZCI, ZSI, and SPI indicators, droughts and droughts were identified. Finally, the years that were in extreme poverty in all three above indicators were selected as samples. In the next step, the data of specific humidity, orbital and meridional wind, geopotential height and omega for all atmospheric levels in the lower and middle layers of the Verdosphere were received from the NCEP/NCAR site for all rainy days. Examining the maps of subsurface levels of the Verdspehr (sea, 1000 and 925 hectopascals) showed that three main systems control the pattern of the subsurface layer of the Verdspehr. The Siberian, Tibetan and Mohajer high-pressure fronts spread over the warm waters of the Oman and Arabian seas from 3 to 7 days before the start of the system's rainfall and spread the necessary moisture into the Sudanese system. It plays a very important role in determining the entry path of the system, the expansion pattern of the Mediterranean trough and the duration of the activity of the precipitation system in the middle layer of the Arabian Wardspehr Extended abstract Introduction The southern part of Iran is one of the strategic regions in terms of industry, trade, port, population and agriculture. Any disturbance in any of the above sectors will result in irreparable economic, social, environmental and political damages. In the south of Iran, due to the thermodynamic nature of precipitation systems and the topographical conditions of the region, precipitation is generally very intense. As a result, most heavy rains are accompanied by heavy floods. This region has a arid and semi-arid climate due to its geographical location in relation to the general and regional circulation of the atmosphere. As a result, wet years are an opportunity to compensate for water shortages. This area is one of the cores of agricultural products production, especially in the field of grains, vegetables and fruits. All the country's need for vegetables and fruits in the cold period of the year, which cannot be cultivated in other places, is provided from this region. Also, only in the southern provinces, the cultivation period and the rainy season coincide, and the winter rains can be directly used for agriculture. Understanding the mechanism of rainfall in heavy wet years, in addition to improving the level of preparedness of managers to control and reduce the destructive effects of floods resulting from heavy rains, will help to manage excess water resources in heavy wet years. Materials and methods In this research, all the synoptic stations of the southern provinces of the country, which had complete statistics in the statistical period of 1986 to 2019 (corresponding to three solar cycles 22 to 24), have been selected. With this criterion, 17 stations were selected from the synoptic stations of southern Iran with appropriate distribution over the region. Then, the daily rainfall statistics of these stations during the region's predominant rainfall period (November to May) were extracted from Iranian meteorological data. These data, after sorting in the Excel environment, have been statistically reconstructed using conventional statistical methods. Then the data were averaged and using the annual rainfall of the stations and using the three indexes ZCI, SPI, and ZSI, the periods of wet and dray years were calculated. Finally, the years in which severe wet year occurred in more than half of the stations based on all three above indicators were selected as severe wet years. In the next step, the sea levels, 1000 and 925 hPa data were obtained from the NCEP/NCAR website. At this stage, using these data and the maps drawn for these levels, the dominant pattern in the lower layer of the troposphere was extracted. Then, based on the selected patterns and the entry path of precipitation systems, synoptic patterns were extracted. For these pattern, specific humidity, orbital wind and meridional wind, height and omega data for 1000, 850, 700 and 500 hPa levels were obtained from the NCEP/NCAR site. In the final step, with appropriate scripting, composite maps for selected synoptic patterns have been drawn and analyzed. Results and Discussion. The results of the assessment of wet and arid years showed that the frequency of droughts in the last three decades was much higher than droughts. This phenomenon has increased in the last decade. The results of this research also showed that, due to the diversity of topography and the extent of the region in terms of longitude, wet years are not widespread. This heterogeneity can be seen even in severe and ultra-extreme wet years. The results of the analysis of synoptic patterns in the lower levels of the troposphere showed that in all precipitation samples, regardless of the duration of the precipitation system and its entry path, from three to 7 days before the onset of the precipitation system activity, a tab of one of the high pressure systems of Migrant, Tibet or Siberia extends over the warm waters of the Oman and Arabian seas. With the expansion of this ridge over these warm waters, while intensifying the temperature gradient, with the advection of the moisture from the warm Arabian and Oman seas inside the Sudanese low pressure, it provides considerable energy and moisture for the formation of convection currents in the region. This high-pressure ridge is still active over the Arabian and Oman seas during the whole period of the activity of the rainfall system in the region. In the middle levelsof troposphere, regardless of the path of Sudan's low pressure, from three to four days before the start of the rainfall activity of the system, a deep trough should spread over the African Sahara within the borders of the countries of Libya and Algeria. One to two days before the start of rain in the south of Iran, this trough was located over Egypt, and with the southward expansion and suitable vorticity advection over the sudan thermal low pressure, the necessary conditions are provided to strengthen the system. These troughs have had a significant southward expansion in all rainfall samples. So, the southern end of trough has extended to southern Sudan and northern Ethiopia. In all cases, the southern end of the trough extended below the 15° orbit at the 700 hPa level. The movement path of the sudan low pressure and its eastward movement trough is closely related to the location and eastward movement of the Arabian subtropical high-pressure. Precipitation systems with Sudanese origin enter southern Iran from three main routes. In long-term rainfall systems, this system gradually enters the region from the southwest and gradually moves to the east with the displacement of the Arabian subtropical high-pressure, and the entire southern region of Iran benefits from the rains of this system. Conclusion Despite the access to the huge sources of moisture of the warm waters of the southern seas, due to the prevailing circulation pattern in the region, especially the proximity to the strong dynamic Arabian subtropical high-pressure system on the one hand and the vast deserts of Arabia and Lut in the southeast of Iran, the south of Iran has a dry and semi-arid climate. As a result, water scarcity and poverty of surface and underground water resources are the characteristics of this region. Due to the strategic importance of this region, water scarcity can be a great risk for economic, social and industrial activities in the region. As a result, wet years are an opportunity to compensate for the lack of water and to store excess water resulting from heavy rains and floods, which are currently causing destruction and damage to infrastructure, soil and vegetation in the form of torrential flows. Due to the fact that the synoptic pattern leading to flooding rains is formed from three to 7 days before the start of rain, especially in the lower levels of the troposphere and can be estimated, by creating infrastructure and proper planning, most of these rains can be controlled and With surface storage and infiltration in the underground layers, it provided a suitable storage for droughts. Funding There is no funding support. Authors’ Contribution All of the authors approved the content of the manuscript and agreed on all aspects of the work. Conflict of Interest Authors declared no conflict of interest. Acknowledgments We are grateful to all the scientific consultants of this paper. ترسالی و خشک‌سالی ویژگی جدایی‌ناپذیر هر اقلیمی می‌باشد. ولی در اقلیم‌های خشک و نیمه‌خشک، ترسالی یک فرصت ایده آل برای ترمیم یا جبران کم‌آبی‌های منطقه می‌باشد. بخش جنوبی کشور ایران علیرغم دسترسی به منابع عظیم رطوبتی دریاهای گرم جنوبی، اقلیمی خشک دارد. برای انجام تحقیق، ابتدا داده‌های بارش روزانه تمام ایستگاه‌های سینوپتیک استان‌های جنوبی کشور که در دوره آماری 33 ساله (1986-2019) دارای آمار کامل بوده‌اند، استخراج گردید. سپس با استفاده از شاخص‌های ZCI،ZSI،SPI ترسالی‌ها و خشک‌سالی‌ها شناسایی گردید. در نهایت سال‌هایی که در هر سه شاخص فوق در شرایط ترسالی شدید قرار داشتند، به‌عنوان نمونه انتخاب گردید. در گام بعد داده‌های نم ویژه، باد مداری و نصف‌النهاری، ارتفاع ژئوپتانسیل و امگا برای تمام ترازهای جوی در لایه زیرین و میانی وردسپهر از سایت NCEP/NCAR برای تمام روزهای بارشی دریافت شد. بررسی نقشه‌های ترازهای زیرین وردسپهر (دریا،1000 و 925 هکتوپاسکال) نشان داد که سه سامانه اصلی الگوی لایه زیرین وردسپهر را کنترل می‌کنند. زبانه‌های پرفشارهای سیبری، تبت و مهاجر از سه تا 7 روز قبل از شروع فعالیت بارشی سامانه، با گسترش بر روی آب‌های گرم دریاهای عمان و عرب رطوبت لازم را به درون سامانه سودانی فرا رفت می‌نمایند. در لایه میانی وردسپهر واچرخند عربستان نقش بسیار مهمی در تعیین مسیر ورود سامانه، الگوی گسترش ناوه مدیترانه‌ای و طول دوام فعالیت سامانه بارشی بر روی منطقه ‌ایفا می‌کند

https://jphgr.ut.ac.ir/article_96004_41beda93de132628dbc0478c89adcde0.pdf

دانشگاه تهران پژوهش های جغرافیای طبیعی 2008-630X 55 4 2023 12 23 Examining Trends of the Intensity of Mediterranean-Red Sea Cyclones واکاوی روند تغییرات شدت چرخندهای توأمان مدیترانه-دریای سرخ 27 44 96238 10.22059/jphgr.2024.363162.1007785 FA حسین عساکره گروه جغرافیا، دانشکده علوم انسانی، دانشگاه زنجان، زنجان، ایران 0000-0001-7699-0547 رویا پورکریم گروه جغرافیا، دانشکده علوم انسانی، دانشگاه زنجان، زنجان، ایران عبدالله فرجی گروه جغرافیا، دانشکده علوم انسانی، دانشگاه زنجان، زنجان، ایران محمود خسروی گروه جغرافیای طبیعی، دانشکده جغرافیا و برنامه‌ریزی محیطی، دانشگاه سیستان و بلوچستان، زاهدان، ایران Journal Article 2023 08 01 ABSTRACT Among the cyclones that affect the sometimes-widespread rainfall in Iran are the merging systems of the Mediterranean and Red Seas. Therefore, it is very important to obtain the changes in the intensity of the geopotential height and the geopotential height shift of the Mediterranean-Red Sea convection patterns as one of the factors of the manifestations of these gyres, as well as the precipitation in some areas of Iran. To carry out this research, the data of geopotential height level of 1000 hectopascals related to the European Center for Medium-term Atmospheric Forecasting and ERA-Entrim version were used as a six-hour observation during the period of 1979-2018. To investigate the presence of jumps and fluctuations in the intensity of the Mediterranean-Red Sea cyclone centers during the statistical period, the Alexanderson index, known as the Standard Normal Homogeneity Test (SNHT) index, was used. A non-parametric chi-square statistic was exerted to verify and investigate the significance of the trend between geopotential height data and geopotential height tilt data. The parametric linear regression method was used to analyze and model the long-term trend. The findings of the present research indicate the increase of geopotential height in the place of the formation of the circulation centers of the Mediterranean Sea, as well as the decrease of the pressure gradient in the average annual values, which will probably lead to a decrease in instability and precipitation in the affected areas. The geopotential height shift data of the Mediterranean Sea had a significant jump in 1996, which divided the time series into two periods before and after the jump. The results indicate an upward trend in these two time periods, but the second period, with a gentler slope, has increased compared to the previous period Extended Abstract Introduction Mediterranean Sea and Red Sea cyclones are a type of extratropical-tropical merge system that can influence precipitation over Iran. These combined Mediterranean-Red Sea cyclones form concurrently over the Mediterranean and Red Sea basins. They may sometimes merge as they track eastward, bringing precipitation to Iran (particularly southern and southwestern Iran). Changes in these merged cyclone systems are likely linked to shifts in Iran's precipitation climatology. Examining trends in the intensity of Mediterranean-Red Sea cyclones can thus provide insights into changes in Iran's precipitation patterns. This study investigates trends in the intensity of combined Mediterranean-Red Sea cyclonic systems and their relationship to precipitation over Iran. Cyclone intensity is assessed using geopotential height data at the 1000 hPa level over 40 years. Statistical tests, including chi-square and linear regression analysis, are applied to the geopotential height time series to detect significant trends. The focus is on examining changes in geopotential height slopes and trends that may indicate cyclone intensity changes. This research aims to improve understanding of how Mediterranean-Red Sea cyclones change and identify their impacts on Iran's precipitation climatology. The results can aid in tracking precipitation changes and projecting future climate scenarios for the region. The intensity trends may also provide broader insights into how climate change influences global cyclone behavior. Materials and methods To examine the changes in intensity of atmospheric systems and geopotential height, as well as the geopotential height shift of Mediterranean-Red Sea cyclones from 1979 to 2018, geopotential height data at the 1000 hPa level were utilized. The study area encompassed coordinates ranging from -10° E to 120° E and 0° N to 80° N, with a spatial resolution of 0.25° x 0.25°. This area consisted of 321 x 521 pixels, totaling 167,241 pixels. The Mediterranean and Red Sea cyclones, which are extratropical-tropical systems that occasionally merge and influence precipitation in Iran, were investigated. Statistical tests, such as chi-square and linear regression analysis, were conducted on the geopotential height time series for each pixel within the studied region to identify significant trends. The primary focus was analyzing changes in geopotential height slopes and trends, which could indicate cyclone intensity alterations. Results and Discussion This section presents the findings and discussion on the changes observed in monthly geopotential height intensity and geopotential height gradient of Mediterranean-Red Sea cyclones. In the Mediterranean Sea, an upward trend was observed in the geopotential height intensity, while a downward trend was observed in the geopotential height gradient. The increase in geopotential height over the circulation centers of the Mediterranean Sea and the decrease in pressure gradient are likely to result in reduced atmospheric instability and precipitation in the region. These results align with Darende's (2013) and Skleris et al. (2012) findings. Contrasting the Mediterranean Sea, the analysis of the Red Sea data revealed a downward trend in geopotential height and an upward trend in geopotential height intensity, indicating an increase in instability. This finding is consistent with the results of Asakereh and Khani (2021). No statistically significant trends were observed in the annual averages of geopotential height and geopotential height gradient in the Red Sea. However, the annual averages of both geopotential height and its gradient in the Mediterranean Sea exhibited a decreasing trend. A notable shift in the Mediterranean geopotential height occurred in 1996, dividing it into two distinct phases. Both phases showed an upward trend, albeit with a gentler slope in the second phase. The annual trend of geopotential height in the Mediterranean Sea revealed a decreasing pattern, which has been previously documented in studies by Alpert (1994, 2004). Conclusion These studies suggest that while this reduction in geopotential height has taken place, cyclone tracks have shifted towards northern latitudes, resulting in increased drought and decreased precipitation in regions influenced by these cyclones, including Iran. The studies also acknowledge that changes in high-pressure systems near the tropics and alterations in cyclone direction contribute to variations in dry seasons and reduced precipitation. Further investigation of long-term changes in the geopotential height of the Mediterranean Sea identified three distinct phases in the time series: 1988-1979, 2005-1989, and 2006-2018. The decreasing trend in Mediterranean Sea cyclones persists until the final years of the period, indicating a potential cause for the reduction in atmospheric instability. The Kolmogorov-Smirnov statistical test was employed to determine the appropriate statistical test (parametric or non-parametric) for comparing means and variances across different periods. The parametric tests (one-sample t-test) and the one-way variance test confirmed the normal distribution of the data. Furthermore, no statistically significant trends were observed when examining the geopotential height intensity and gradient of two-day continuities of Mediterranean-Red Sea cyclones. Funding There is no funding support. Authors’ Contribution All of the authors approved the content of the manuscript and agreed on all aspects of the work. Conflict of Interest Authors declared no conflict of interest. Acknowledgments We are grateful to all the scientific consultants of this paper. از چرخندهای مؤثر بر بارش‌های بعضاً فراگیر ایران‌زمین، سامانه‌های ادغامی دریای مدیترانه و دریای سرخ می‌باشند. ازاین‌رو دستیابی به روند تغییرات شدت ارتفاع ژئوپتانسیل و شیو ارتفاع ژئوپتانسیل هم‌زمان با الگوهای توأم مدیترانه- دریای سرخ به‌عنوان یکی از عوامل نمودهای این چرخندها و نیز بارش برخی نواحی ایران‌زمین، از اهمیت شایان توجهی برخوردار است. برای انجام این پژوهش از داده‌های ارتفاع ژئوپتانسیل تراز 1000 هکتوپاسکال مربوط به مرکز پیش‌بینی میان‌مدت جوی اروپایی و نسخه ERA-Entrim به‌صورت دیده‌بانی شش‌ساعته طی بازه زمانی 1979-2018 استفاده شد. برای بررسی وجود جهش و نوسانات در شدت مراکز چرخندی توأمان مدیترانه – دریای سرخ در طی دوره آماری از نمایه الکساندرسون موسوم به نمایه آزمون همگنی استاندارد نرمال (SNHT) استفاده گردید. به‌منظور وارسی و بررسی معنی‌داری روند بین داده‌های ارتفاع ژئوپتانسیل و داده‌های شیو ارتفاع ژئوپتانسیل، آماره ناپارامتری خی‌دو به‌کار گرفته شد. به‌منظور تحلیل و الگوسازی روند بلندمدت از روش پارامتری رگرسیون خطی بهره گرفته شد. یافته‌های پژوهش حاضر بیان‌گر افزایش ارتفـاع ژئوپتانسیل در محل شکل‌گیری مراکز چرخندی دریای مدیترانه و همچنین کاهش شیو فشار در مقادیر متوسط سالانه می‌باشد که احتمالاً منجر به کاهش ناپایداری و بارش در مناطق تحت تأثیر خواهد شد. داده‌های شیو ارتفاع ژئوپتانسیل دریای مدیترانه در سال 1996 یک جهش معنی‌دار داشت که سری زمانی را به دو مقطع زمانی قبل و بعد از جهش تقسیم کرد، نتایج نمایانگر روند صعودی در این دو مقطع زمانی است، امّا دوره دوم نسبت به دوره قبل با شیب ملایم‌تری افزایش پیداکرده است

https://jphgr.ut.ac.ir/article_96238_41855e03cc3902ca9f71ef4039642e38.pdf

دانشگاه تهران پژوهش های جغرافیای طبیعی 2008-630X 55 4 2023 12 24 Identifying the Types of Air in Abu Musa Island for the Planning and Implementation of Amphibious Operation شناسایی تیپ‌های هوای جزیره ابوموسی جهت طرح‌ریزی و اجرای عملیات آب‌خاکی 45 60 93285 10.22059/jphgr.2023.353820.1007740 FA محمد محمدی گروه جغرافیا، دانشکده علوم اجتماعی، دانشگاه فرماندهی و ستاد ارتش، تهران، ایران مسعود مصدق گروه جغرافیا، دانشکده علوم اجتماعی، دانشگاه فرماندهی و ستاد ارتش، تهران، ایران Journal Article 2023 08 02 ABSTRACT Having sufficient information about the operation area is one of the most important and key success factors in planning, directing and successfully implementing operations, and this issue is of double importance, especially regarding the weather conditions of the area, in water and soil operations. In order to conduct research and identify the weather types of Abu Musa Island, in order to plan and implement hydrological operations, the data related to 18 weather variables in a period of 30 years (1991-2021) as well as the average and maximum strength of the sea in one day have been used. In order to statistically analyze the data and obtain the statistical characteristics of each weather type, MATLAB software was used and to identify the weather types, weather elements were subjected to cluster analysis by integration method. After conducting trial and error operations to select the number of air brigade groups, four air brigades were finally identified for this island. Hierarchical analysis has been used to determine the most suitable and worst type of weather. The results showed that based on the pairwise comparison of weather elements to determine the priority of the air force to carry out soil dredging operations, the elements of wind speed and horizontal visibility were assigned the highest weight and the most effective weather elements in soil dredging operations were identified. After forming the decision matrix, the weight of each of the specific weather types and the moderate weather type with the maximum sea power with a weight of 0.343 with the activity period in the late winter and early spring season was estimated as the worst weather type for carrying out dredging operations in Abu Musi Island Extended Abstract Introduction Atmospheric conditions and characteristics are components of investigating the operation area in military units; its results lead to the estimation of intelligence plans and are examined in all types of activities and military operations in each area. The investigation of the operation area is more critical in amphibious operations due to the simultaneous implementation in the sea and on land and the involvement of naval and ground forces. An amphibious operation is a planned attack from the sea, carried out by the navy and the disembarking force stationed in ships to the enemy's coast or the coast occupied by the enemy. This type of operation leads to the disembarkation of the force on the coast. This operation is highly sensitive, and any mistake in planning will lead to its failure. Abu Musa Island is the southernmost land of Iran in the Persian Gulf, and due to its strategic location, it is of high military, economic, and political importance. Any amphibious operation on this island requires accurate knowledge of the weather conditions. Materials and Methods In order to carry out this research, first, an exploratory study was conducted regarding the subject of the research, and the field manuals related to seafaring and the subject of the research were reviewed, as well as the opinion of experts in this field. In the following, 18 climatic elements have been applied in 30 years (1991-2021), as well as the average and maximum sea strength in one day, to identify the weather types of Abu Musa Island. The data relating to climatic elements were received from the Meteorological Organization. MATLAB software was exerted to ensure the correctness of the received data and for the statistical analysis. The maximum and average daily wind speed was used to identify the strength of the sea. In order to identify whether types and elements of maximum and minimum wind speed were subjected to cluster analysis, after extracting the air types in Abu Musa Island, a hierarchical analysis method was used to prioritize them for planning and implementing amphibious operations. Results and discussion Four types of weather affect Abu Musa Island throughout the year, and the frequency of hot, cloudy, and foggy weather types has turned out to be the highest. On the other hand, clear and calm air type has the lowest frequency throughout the year by examining the average climatic elements for each. From the weather types in Abu Musa Island, it can be seen that temperature, humidity, sea power, and precipitation have the most significant influence on the development of the air types of this island, and the average of each of these elements in the air types is a good indicator of this. The high speed of the wind and the high level of sea power are the essential characteristics of this type 1, which may disturb the evacuation in the ports and make the conditions of the beach unsuitable for disembarkation and the possibility of paratroopers to disembark. These conditions make it difficult to guide vessels. In addition, the possibility of naval fire support reduces the accuracy of weapons fire, affects the implementation of smoke operations to disembark forces on the beach, and increases the number of human casualties during the disembarkation. The highest amount of precipitation occurs in type 2. During the rain, the visibility decreases, making it difficult for helicopters and airplanes to fly, and despite providing cover and surprise, it does not provide suitable conditions for close air support of ground troops. Rainfall has negatively affected radio communications, disrupting reconnaissance flights and radar, image, and infrared data collection systems. During the rainy season, the disembarkation forces on the beach face problems, and capturing the bridgehead in the first stage of the operation becomes complicated. This, in turn, increases the human loss of lives in friendly troops. In Type 3, humidity and high air temperature reduce the efficiency of the crew, equipment, and vessels and severely reduce the endurance of the disembarking force on the beach. The number of fog occurrences, is suitable for surprising the enemy and creating concealment and cover. However, it is not suitable for air support and guiding vessels. This condition reduces direct vision and targeting for vessels. Moreover, the effectiveness of radars reduces the detection of targets. In type 4, the temperature and humidity of the air are still high, and this issue has a negative effect on the endurance of the landing forces and the crew of the vessels. Despite this disadvantage, the sea is calm, and sea power and wind are suitable for carrying out amphibious operations. It was found that wind speed and horizontal visibility are essential in amphibious operations and decisive for the operation's success. Conclusion Any amphibious operation in types 1 and 2 requires a detailed investigation of the weather during the exercise or operation. At this time, the changes in sea strength, cloudiness, and rainfall are high. Also, the fog created on the sea reduces visibility. In Type 4, both the air temperature and the rainy conditions have dropped a bit, and the amount of rainfall and wind speed and, accordingly, the power of the sea is also low. Thus, it creates suitable conditions for this operation compared to other types of weather and in case of proper planning. It will also bring a favorable result. Based on the paired comparison of climatic elements to determine the priority of the air type for carrying out amphibious operations, the element of wind speed and horizontal visibility was given the highest weight. The most effective climatic elements in amphibious operations and the moderate weather type with the maximum sea power were identified. Type 1 is the worst in late winter and early spring, and clear and calm weather type (Type 4) is the best. The suitable time for planning and implementing amphibious operations was determined in October and November. Funding There is no funding support. Authors’ Contribution All of the authors approved the content of the manuscript and agreed on all aspects of the work. Conflict of Interest Authors declared no conflict of interest. Acknowledgments We are grateful to all the scientific consultants of this paper. داشتن اطلاعات کافی از منطقه عملیات از مهم‌ترین و کلیدی‌ترین عوامل موفقیت در طرح‌ریزی، هدایت و اجرای موفقیت‌آمیز عملیات‌هاست و این مسئله به‌خصوص در مورد شرایط جوی منطقه، در عملیات آب‌خاکی از اهمیت دوچندان برخوردار می‌باشد. جهت انجام پژوهش و شناسایی تیپ‌های هوای جزیره ابوموسی جهت طرح‌ریزی و اجرای عملیات آب‌خاکی از داده‌های مربوط به 18 متغیر آب‌وهوایی در بازه زمانی 30 ساله (2021-1991) و همچنین از میانگین و حداکثر قدرت دریا در یک روز استفاده‌شده است. به‌منظور تجزیه‌وتحلیل آماری داده‌ها و به دست آوردن ویژگی‌های آماری هریک از تیپ‌های هوا، از نرم‌افزار متلب استفاده و جهت شناسایی تیپ‌های هوا، عناصر آب و هوایی در معرض تحلیل خوشه‌ای به روش ادغام وارد قرار گرفتند. پس از انجام عملیات آزمون‌وخطا برای گزینش شمار گروه‌های تشکیل‌دهنده تیپ‌های هوا، درنهایت چهار تیپ هوا، برای این جزیره شناسایی شد. برای تعیین مناسب‌ترین و بدترین تیپ هوا، از تحلیل سلسله‌مراتبی استفاده‌شده است. نتایج نشان داد که بر اساس مقایسه زوجی عناصر آب و هوایی برای تعیین اولویت تیپ هوا برای انجام عملیات آب‌خاکی عنصر سرعت باد و دید افقی بالاترین وزن را به خود اختصاص داده و مؤثرترین عناصر آب و هوایی در عملیات آب‌خاکی شناخته شدند. پس از تشکیل ماتریس تصمیم، وزن هریک از تیپ‌های هوا مشخص و تیپ هوای معتدل با بیشینه قدرت دریا با وزن 0.343 با دوره فعالیت در اواخر فصل زمستان و اویل فصل بهار بدترین تیپ هوا برای اجرای عملیات آب‌خاکی در جزیره ابوموسی برآورد شد.

https://jphgr.ut.ac.ir/article_93285_71f2d016c99885d0a2740443a081d9d7.pdf

دانشگاه تهران پژوهش های جغرافیای طبیعی 2008-630X 55 4 2023 12 24 Evaluation of Desertification Intensity using Spectral Indices Resulting from Satellite Images the Case Study of Bandar Mahshahr County ارزیابی شدت بیابان‎زایی با استفاده از شاخص‌های طیفی منتج از تصاویر ماهواره‌ای مطالعه موردی: شهرستان بندر ماهشهر 61 81 95315 10.22059/jphgr.2023.355751.1007753 FA محمد عبیات گروه علوم و مهندسی خاک، دانشکده کشاورزی، دانشگاه شهید چمران اهواز، اهواز، ایران مرتضی عبیات گروه جغرافیا و برنامه‌ریزی روستایی، دانشکده علوم جغرافیایی و برنامه‌ریزی، دانشگاه اصفهان، اصفهان، ایران مصطفی عبیات گروه جغرافیا و برنامه‌ریزی روستایی، دانشکده علوم جغرافیایی و برنامه‌ریزی، دانشگاه اصفهان، اصفهان، ایران Journal Article 2023 08 02 ABSTRACT Desertification is one of the factors in the destruction of natural ecosystems in arid regions of the world. Knowing the areas exposed to desertification is very important to combat this phenomenon. Remote sensing is a practical tool for evaluating and monitoring land degradation and desertification. The current research aims at the desertification intensity evaluation in Bandar Mahshahr County based on the spectral indices derived from satellite images. To begin with, utilized the ENVI software to extract several indices, such as NDVI, SAVI, RVI, TGSI, and Albedo, from the satellite image captured by the Landsat 8 OLI in the region. Then, Linear regression was utilized to determine correlations of spectral indices in the region, and the desertification intensity in the region was classified. The results showed that the correlation coefficient between NDVI and Albedo indices was -0.83, between SAVI and Albedo indices was -0.78, and between RVI and Albedo indices was -0.77. The correlation coefficient between TGSI and Albedo indices was 0.86. The higher correlation between TGSI and Albedo indicates that the Albedo-TGSI model is more appropriate for evaluating the desertification intensity in the region. The desertification map of the Albedo-TGSI model showed that the areas with less desertification intensity are located mainly in the northern and eastern parts, and the areas with more desertification intensity were situated in the southern and southwestern parts of the region Extended abstract Introduction Many arid and semi-arid regions of the world are affected by land degradation and desertification. Climate changes, environmental hazards, and human activities cause desertification. Desertification causes a decrease in land potential due to factors such as loss of vegetation and destruction of soil resources. Controlling desertification is one of the necessities and priorities of natural resources management. Due to spatial and temporal information, remote sensing (RS) and satellite images play an essential role in evaluating and monitoring land degradation and desertification at local, regional, and global scales. Over the last few years, spectral indices have been increasingly utilized to determine land cover. These indicators are particularly beneficial in identifying areas susceptible to environmental hazards. Using spectral indices in creating desertification intensity maps can be an effective tool. By visualizing the areas susceptible to desertification, decision-makers and land managers can prioritize their efforts and resources more effectively. The detailed information provided by these intensity maps allows for targeted interventions and the implementation of appropriate land management and conservation practices to mitigate the effects of desertification. Additionally, by utilizing spectral indices to create intensity maps, stakeholders can better understand the spatial distribution and severity of desertification, leading to more informed decision-making in natural resources management. This, in turn, can facilitate the development and implementation of sustainable land use policies and programs aimed at controlling and reversing the process of desertification. Therefore, these maps serve as effective tools for reducing the impact of land degradation and implementing strategic desertification control measures. This research aims to assess and classify the severity of desertification in Bandar Mahshahr County, located in the southwest of Iran and south of Khuzestan province, by utilizing spectral indices derived from satellite images. Materials and Methods In this research, all the processes were performed on the OLI sensor image of the Landsat satellite 8 of the region on June 18, 2021, in row 39 and pass 165. The dark Subtraction method was used for the atmospheric corrections of the image. Then, spectral indices of NDVI, SAVI, RVI, TGSI, and Albedo were extracted from the region's image using ENVI 5.6 software. SPSS 22 software was used for statistical analysis, and ArcGIS 10.8 software was used to prepare desertification intensity maps. After extracting the spectral indices, the correlation between them was evaluated. To investigate the relationship between the four indices NDVI, SAVI, RVI, and TGSI with the Albedo index, a linear regression model based on 40 random pixels was used. In order to obtain desertification intensity equations, the slope coefficient of the regression line between the spectral indices was calculated. The natural breaks (Jenks) method in ArcGIS software was used to classify the data value into five degrees of desertification (areas without impact, low intensity, medium intensity, high intensity, and very high intensity). The map of spectral indices was validated using the error matrix and two parameters as Overall Accuracy and Kappa Coefficient. Results and Discussion Numerical values for the NDVI index, -0.45 to 0.51; for the SAVI index, from -0.91 to 1.03; for the RVI index, from 0.36 to 3.14; and for the TGSI index, from -0.09 to 0.17 were obtained. An Albedo index map was created to assess the relationship between the NDVI, SAVI, RVI, and TGSI indices and the Albedo index. Based on the obtained results, the minimum and maximum values of the Albedo index were 0.127 and 0.415, respectively. The lowest values of the Albedo index were estimated in the northern and eastern regions, and the highest values were estimated in the southern and southwestern regions. The results showed that with an increase in vegetation in the region, the number of the Albedo decreases. The linear regression model results between the indices showed that the three indices, NDVI, SAVI, and RVI, have a negative correlation with the Albedo index. Thus, the Albedo index decreases as the NDVI, SAVI, and RVI indices increase. The correlation coefficient between the two indices NDVI and Albedo is -0.83, between SAVI and Albedo, is .78, and between RVI and Albedo is -0.77. The linear regression model results between the TGSI and Albedo indices showed that these indices have a strong correlation relationship. The correlation coefficient between the TGSI and Albedo indices was 0.86. The study findings indicated that as the TGSI index increases, the Albedo also increases. Previous studies have also shown a significant relationship between desertification processes and Albedo and TGSI indices. Thus, the amount of Albedo is a function of the size of the surface soil particles, and with an increase in the size of the surface soil particles, the amount of Albedo increases. The study of desertification intensity maps in this region showed that the areas with less desertification intensity are located mainly in the northern and eastern parts, and the areas with higher desertification intensity are situated in the southern and southwestern parts of the region. For spectral index map validation, 231 pixels were selected as the ground reality of the study area. More samples were taken from the classes that had more desertified lands. Validation results of the spectral indices showed that the NDVI index had the least accuracy, and the TGSI index had the most accuracy in zoning the desertification intensity in the region. Conclusion This research used Landsat satellite images to extract spectral indices and prepare a desertification intensity map in Bandar Mahshahr County. The overall accuracy criteria and Kappa coefficient of the produced maps show the reliability of the desertification intensity zoning results. The TGSI index map has been the most accurate in zoning the desertification intensity in the region. The linear regression model results showed that the three spectral indices NDVI, SAVI, and RVI have a negative correlation with the Albedo index, and the TGSI index has a positive and strong correlation with the Albedo index. The strong correlation between TGSI and Albedo indices showed that the Albedo-TGSI model is suitable for evaluating the desertification intensity in the study area according to its climatic conditions. This model can be used in regions with similar climates to determine the desertification intensity. According to the obtained maps of desertification, the southern and southwestern parts of the region have the highest intensity of desertification. Funding There is no funding support. Authors’ Contribution All of the authors approved the content of the manuscript and agreed on all aspects of the work. Conflict of Interest Authors declared no conflict of interest. Acknowledgments We are grateful to all the scientific consultants of this paper. بیابان‌زایی از عوامل تخریب اکوسیستم‌های طبیعی در مناطق خشک جهان به شمار می‌آید. شناخت مناطق در معرض بیابان‌زایی، جهت مبارزه با این پدیده اهمیت فراوانی دارد. سنجش از دور، ابزاری مهم در ارزیابی و پایش تخریب سرزمین و بیابانزایی است. هدف پژوهش حاضر، ارزیابی شدت بیابان‌زایی در شهرستان بندر ماهشهر براساس شاخص‌های طیفی منتج از تصاویر ماهوارهای است. ابتدا شاخص‌های NDVI، SAVI، RVI، TGSI و Albedo با کمک نرم‌افزار ENVI از تصویر OLI لندست 8 منطقه استخراج شدند. سپس، برای ارزیابی رابطه همبستگی بین شاخص‌های طیفی از رگرسیون خطی استفاده شد و شدت بیابان‌زایی در منطقه طبقه‌بندی گردید. نتایج نشان داد که ضریب همبستگی بین دو شاخص NDVI و Albedo برابر با 83/0-، بین دو شاخص SAVI و Albedo برابر با 78/0- و بین دو شاخص RVI و Albedo برابر با 77/0- بوده است. ضریب همبستگی بین دو شاخص TGSI و Albedo برابر 86/0 بوده است. همبستگی بیشتر بین دو شاخص TGSI و Albedo، بیانگر مناسبتر بودن مدل Albedo-TGSI جهت ارزیابی شدت بیابانزایی در منطقه است. نقشه‌ بیابان‌زایی مدل Albedo-TGSI نشان داد که نواحی دارای شدت بیابان‌زایی کمتر، عمدتاً در قسمت‌های شمالی و شرقی و نواحی دارای شدت بیابان‌زایی بیشتر، عمدتاً در قسمت‌های جنوبی و جنوب غربی منطقه واقع شده‌اند.

https://jphgr.ut.ac.ir/article_95315_0788a6af8f3aee48ec0d33e0ee1bc19a.pdf

دانشگاه تهران پژوهش های جغرافیای طبیعی 2008-630X 55 4 2023 12 24 Application of Support Vector Machine (SVM) and Boosted Regression Tree (BRT) to Model the Sensitivity of Gully Erosion in the Watershed of Shore River Moher City کاربرد ماشین بردار پشتیبان (SVM) و درخت رگرسیون تقویت‌شده (BRT) جهت مدل‌سازی حساسیت فرسایش خندقی درحوضه آبخیز رودخانه شور (شهرستان مُهر) 83 101 95567 10.22059/jphgr.2023.360424.1007775 FA عقیل مددی گروه جغرافیای طبیعی، دانشکدة علوم اجتماعی، دانشگاه محقق اردبیلی، اردبیل، ایران 0000-0002-1036-4292 صیاد اصغری سراسکانرود گروه جغرافیای طبیعی، دانشکدة علوم اجتماعی، دانشگاه محقق اردبیلی، اردبیل، ایران سعید نگهبان گروه جغرافیا، دانشکده اقتصاد، مدیریت و علوم اجتماعی، دانشگاه شیراز، ایران مهری مرحمت گروه جغرافیای طبیعی، دانشکدة علوم اجتماعی، دانشگاه محقق اردبیلی، اردبیل، ایران Journal Article 2023 08 02 ABSTRACT The aim of this study is to develop sensitive gully erosion models by implementing a machine learning algorithm (Support Vector Machine and Boosted Regression Tree) in the Moher basin. First, gully areas are identified, and then 13 variables predisposing to gully erosion (Slope, Slope Direction, Topographic Wetness Index, Streem Power Index, Terrain Ruggedness Index, Distance from Waterway, Drainage Density, Distance from Road, Land use, NDVI, Avera annual Rainfall, Geology, and Soil Texture) were selected. The variance inflation coefficient was used to evaluate multicollinearity between variables. Finally, a gully erosion sensitivity map was prepared in the environment (R). Also, the effect of physical and chemical characteristics of soil on gully erosion was investigated using Multivariate Regression. Regarding the importance of variables, Geology has the most significant effect on gully erosion in the SVM model, Land use, and the BRT model. The predicted sensitivity map was validated with the help of the receiver operating characteristic (ROC) curve. The results showed that the area under the curve (AUC) in the Support Vector Machine and Boosted Regression Tree models were calculated as 0.92 and 0.94, respectively, which led to accurate prediction. Also, the results showed that the sand variable (9.299), sodium absorption ratio (7.967), and TNV (6.185) have the most significant effect on gully erosion Extended abstract Introduction Currently, many countries are facing severe land degradation and soil erosion. Soil erosion caused by water is a major environmental concern, affecting approximately one billion hectares of land worldwide. Gully erosion is one of the most essential factors in land degradation in dry and semi-arid regions, causing significant soil losses and the transfer of sediments to low-altitude areas. Many researchers investigated gully erosion sensitivity using remote sensing (RS) and geographic information systems (GIS) techniques. Traditional data mining methods cannot establish the relationship between geoenvironmental factors and gully erosion processes. Therefore, machine learning models are highly efficient for evaluating areas sensitive to gully erosion. Support vector machines (SVM) and boosted regression trees (BRT) are machine-learning techniques to model gully erosion. In the lower reaches of a watershed or near agricultural lands, gully erosion caused sediment production and desertification of the region. Using SVM and BRT models, it is possible to prepare a map of gully erosion sensitivity and use zoning to reduce potential damage and manage crises. Materials and methods The study area covers approximately 101350 hectares and is located in southern Iran, with an elevation range of 387 to 1672 meters above sea level. The basin is situated between longitude 52°24'52" to 52°59'52"E and latitude 27°22'27" to 41°49'27"N. Initially, a gully erosion points map was created based on 200 gully and non-gully points, identified through field visits and data obtained from the Natural Resources Department of Fars province. Random non-gully points were also selected throughout the basin using a Geographic Information System (GIS). Furthermore, 13 variables were chosen for modeling based on the approach utilized by previous researchers. These variables encompassed slope, slope aspect, drainage density, distance from the stream, land use, geology, soil texture, stream power index (SPI), topographic wetness index (TWI), topographic roughness index (TRI), average precipitation, distance from the road, and vegetation cover. Multicollinearity analysis employing the variance inflation factor (VIF) was conducted to determine the linear correlation between variables. Subsequently, machine learning algorithms, including Support Vector Machine (SVM) and Boosted Regression Trees (BRT), were employed for modeling. Finally, the accuracy of the models was evaluated using the ROC curve. Moreover, the effect of physical and chemical characteristics of soil on gully erosion was investigated using multivariate regression. Results and discussion Investigating the collinearity between the selected variables is crucial in creating gully erosion sensitivity maps. Among the 13 selected variables, no significant collinearity was observed in the SVM and BRT models. The areas with low sensitivity to gully erosion are mainly concentrated in the region's northern, northwestern, and southwestern parts. The moderately susceptible areas are in the middle of the basin, while the highly susceptible areas are in the southern and southeastern parts. The SVM model had an AUC value of 92.0% for the training dataset and 93.0% for the test dataset. The BRT model had an AUC value of 96.0% for the training dataset and 94.0% for the test dataset. Both models demonstrated high accuracy. Soil erosion can cause severe environmental and human damage through natural or human-induced gully formation. In dry and semi-dry areas, the formation and development of gullies are mainly problematic and lead to a decrease in soil quantity and quality and a reduction in agricultural productivity. Additionally, the sediment resulting from soil erosion can accumulate at the basin outlet and create problems for the environment and humans. Therefore, it is essential to investigate the formation and development of gullies and determine their importance in environmental modeling and management. In the Mohr watershed, gully erosion has become a problem, and identifying vulnerable areas using SVM and BRT models is useful for sustainable land management. Topography, slope, surface runoff, drainage density, soil erosion, soil moisture, vegetation cover, and geomorphological processes affect the formation and expansion of gullies. Most gullies are formed and expanded in the north, northeast, east, and northwest directions. Gully erosion has a positive relationship with drainage density, and gullies are formed in areas with low slopes and high moisture. Soil texture and land use are also important for controlling gully erosion. The type of relationship between erosion factors and surface cover of the region is determined based on land use. The presence of vegetation cover in this area is highly important and effective in controlling erosion. The absence of vegetation cover creates runoff and causes erosion and sedimentation on a large scale. Additionally, the impact of road networks is crucial in soil erosion. The results of geological variables show that Quaternary sediments play an important role in the formation of gully erosion. Quaternary sediments are effective in gully erosion formation due to high levels of gypsum and salt, fine-grained sediment deposits, loess instability, soil structure weakening, and lack of organic matter. Soil texture is also used as a controlling mechanism in gully erosion. The results of physical and chemical characteristics showed that the sand variable (9.299), sodium absorption ratio (7.967), and TNV (6.185) have the most significant effect on gully erosion. Conclusion A study was conducted to prepare a gully erosion sensitivity prediction map using machine learning algorithms (SVM and BRT) in the Shoor River watershed (Mohr county). This research investigated 13 gully erosion-sensitive variables and their performance in gully development. The entire dataset was randomly divided into 70/30 for training and validation. The area under the curve (AUC) values for SVM and BRT were 0.92 and 0.94, respectively. In both models, more than half of the watershed was classified as low to very low sensitivity (SVM: 89.22%, BRT: 92.84%), while 2.62% and 3.58% of the area were classified as highly sensitive in SVM and BRT models, respectively. Also, the results of the physical and chemical characteristics of the soil showed that sand (9.299), sodium absorption ratio (7.967), and TNV (6.185) have the most significant effect on the expansion of gully erosion in the study area. Finally, the results showed that machine learning models can determine gully erosion boundaries, and the resulting susceptibility maps can be used as essential tools for protecting and sustainably managing gully erosion-prone areas in the study area. Funding There is no funding support. Authors’ Contribution All of the authors approved the content of the manuscript and agreed on all aspects of the work. Conflict of Interest Authors declared no conflict of interest. Acknowledgments We are grateful to all the scientific consultants of this paper. هدف از این مطالعه توسعه مدل‌های حساس فرسایش خندقی با اجرای الگوریتم یادگیری ماشینی (ماشین بردار پشتیبان و درخت رگرسیون تقویت‌شده) در حوضه مُهر است. ابتدا، مناطق خندقی شناسایی و پس ‌از آن 13 متغیر مستعد کننده فرسایش خندقی (شیب، جهت شیب، شاخص رطوبت توپوگرافی، شاخص قدرت جریان، شاخص زبری سطح، فاصله از آبراهه، تراکم زهکشی، فاصله از جاده، کاربری اراضی، پوشش گیاهی، متوسط بارندگی سالانه، زمین‌شناسی و بافت خاک) انتخاب شد. ضریب تورم واریانس برای ارزیابی چندخطی بین متغیرها استفاده شد. در نهایت نقشه حساسیت فرسایش خندقی در محیط (R) تهیه شد. همچنین تأثیر ویژگیهای فیزیکی و شیمیایی خاک بر فرسایش خندقی با استفاده از رگرسیون چند متغیره بررسی شد. از نظر اهمیت متغییرها، در مدل SVM کاربری اراضی و در مدل BRT زمین شناسی بیشترین تأثیر را بر فرسایش خندقی دارد. نقشه حساسیت پیش‌بینی‌شده با کمک منحنی مشخصه عملکرد گیرنده (ROC) اعتبارسنجی شد. نتایج نشان داد که مساحت زیر منحنی (AUC) در مدل‌های ماشین بردار پشتیبان و درخت رگرسیون تقویت‌شده به ترتیب 92/0 و 94/0 محاسبه شد که منجر به پیشبینی دقیقی شد. همچنین نتایج نشان داد متغیر ماسه (299/9)، نسبت جذب سدیم (967/7) و مواد خنثی شونده (185/6) بیشترین تأثیر را بر فرسایش خندقی دارد

https://jphgr.ut.ac.ir/article_95567_0c7eb8c9d4a40503f25ad9409fb4a941.pdf

دانشگاه تهران پژوهش های جغرافیای طبیعی 2008-630X 55 4 2023 12 25 Evaluation of the Effects of Extensive Recreation on Vegetation and Soil Ecotone of Hormozgan Province ارزیابی اثرات تفرج گسترده بر ویژگی‌های محیطی اکوتون‌های هرمزگان 103 121 96240 10.22059/jphgr.2024.357063.1007756 FA خدیجه پورحسینی گروه علوم جغرافیا، دانشکده علوم انسانی، دانشگاه هرمزگان، بندرعباس، ایران مرضیه رضائی گروه مهندسی منابع طبیعی، دانشکده کشاورزی و منابع طبیعی، دانشگاه هرمزگان، بندرعباس، ایران محمد اکبریان گروه علوم جغرافیا، دانشکده علوم انسانی، دانشگاه هرمزگان، بندرعباس، ایران Journal Article 2023 08 03 ABSTRACT The aim of this study is to develop sensitive gully erosion models by implementing a machine learning algorithm (Support Vector Machine and Boosted Regression Tree) in the Moher basin. First, gully areas are identified, and then 13 variables predisposing to gully erosion (Slope, Slope Direction, Topographic Wetness Index, Streem Power Index, Terrain Ruggedness Index, Distance from Waterway, Drainage Density, Distance from Road, Land use, NDVI, Avera annual Rainfall, Geology, and Soil Texture) were selected. The variance inflation coefficient was used to evaluate multicollinearity between variables. Finally, a gully erosion sensitivity map was prepared in the environment (R). Also, the effect of physical and chemical characteristics of soil on gully erosion was investigated using Multivariate Regression. Regarding the importance of variables, Geology has the most significant effect on gully erosion in the SVM model, Land use, and the BRT model. The predicted sensitivity map was validated with the help of the receiver operating characteristic (ROC) curve. The results showed that the area under the curve (AUC) in the Support Vector Machine and Boosted Regression Tree models were calculated as 0.92 and 0.94, respectively, which led to accurate prediction. Also, the results showed that the sand variable (9.299), sodium absorption ratio (7.967), and TNV (6.185) have the most significant effect on gully erosion Extended abstract Introduction Tourism means voluntarily spending a part of free time with the intention of having fun in a place other than permanent residence (Asadpoor Kordi et all, 2023). The tourism industry has various types and every year, millions of people travel to other parts of the world to visit historical areas, have fun, relax, etc. (Fetres et al, 2022). This industry is one of the fundamental factors of sustainable development (Papali et al, 2006), its impact on the social, economic and cultural development of countries is not hidden from anyone (Godovykh & Ridderstaat, 2020; Gursoy et al., 2019). The development of the tourism industry, in addition to the prosperity of related businesses, such as the prosperity of places of residence, restaurants, the management of resorts and travel agencies, has also caused the attraction of foreign capital and, in other words, foreign exchange, after industrial production, with a share of 3.9 percent, the largest share. In the growth of global gross production (Jordan et al., 2019). In addition to economic, cultural and social benefits, tourism also leaves effects on the natural environment of target areas, which can be positive or negative (Akbarian et al, 2021). The amount of changes and the impact of tourism activities on natural environments is a direct function of the intensity of use and the amount of tourist presence, the stability of the region and the variability of the place (Atic, 2009). Tourism activities have caused a 50% increase in soil compaction, which has resulted in a decrease in the intensity of water infiltration in the soil (Webb & Wilshire, 1983) and finally increases the amount of runoff and leaching of soil minerals (Zhongdong, 2010). Soil washing causes a decrease in the number and activity of soil microorganisms, which in turn will result in a decrease in soil fertility. Materials and methods GNU Protected Area with an area of 44,598 hectares is located 30 kilometers north of Bandar Abbas in the geographical coordinates of 49, 18, 27 to 28, 29, 27 north latitude and 18, 18, 56 to 5, 57 and 56 (Figure 1). This region has a lot of plant diversity due to its special geographical location and the unique feature of being on the border of the transformation of the vegetation of the Iranian-Turanian region to the Sindhi desert (Rezai et al, 2019). Data collection The research data includes density and percentage of plant species cover, percentage of litter and soil data of the region. For field studies of vegetation and soil profile digging, three representative areas of 5 hectares, a) without tourism pressure, b) with moderate tourism pressure and c) with high tourism pressure, were selected after GNU circulation forest. These areas were almost similar in terms of geological features, direction and slope percentage, but they were different in terms of the type of tourist presence. The method of estimating vegetative parameters The variables included plant characteristics recorded in the sampling plots (percentage of the total vegetation canopy, canopy cover of each species in the plot, percentage of bare soil, percentage of pebbles and percentage of litter) as well as soil profile characteristics of all three representative areas. - Percentage of canopy cover After the precise determination of the number of plots and the location of the samples, the desired vegetation factors were collected and measured and recorded in the preliminary forms. For this purpose, gridded plots were used to measure the percentage of vegetation cover. In order to estimate the percentage of plant crown coverage, it is assumed that there is no discontinuity in the inside or umbrella of the plant and the plant space around the crown is in the shape of an umbrella. If the root of the plant is outside the plot and the crown of that plant is inside the plot, the percentage of its coverage will be calculated inside the plot (Zerehi et al, 2022). With this calculation, gridded plots of four-square meters were used, which were divided into four hundred houses of 100 square centimeters and each house represented 0.25% (Figure 4b). - Number of bases per hectare (density) Density is defined as the number of individuals of each species per unit area and is one of the best numerical indicators to express the quantitative values of a plant community, especially for evaluating tree and shrub communities (Zerehi et al, 2021). In order to estimate the density, all the bases of plant species in the plots were counted and finally the density per hectare of the species was calculated. Also, the presence and absence of the species (abundance) in the recorded plots, the composition percentage of each species was calculated. In order to obtain the average diameter of tree and shrub species, assuming that their canopy is spherical, two perpendicular diameters of the plant were measured and then the average diameter of the species was calculated (Figure 4c). - Methods of measuring physical and chemical properties of soil In order to investigate the impact of ecotourism pressure on the soil, 10 soil profiles were dug to a depth of 40 cm in each tourism representative area (Figure 4d). Results and discussion The results of vegetation and soil measurements. The findings of soil surface cover characteristics, density and height of plant species in low, medium and high-pressure tourism areas are shown in Tables 1 and 2. The measurement of land surface cover in the three representative areas under investigation showed that the total amount of vegetation cover in the representative area of low-pressure tourism is 70%, medium pressure tourism is 45.3% and high-pressure tourism is 23.1%. Accordingly, the percentage of bare soil in these sites is 6.5, 17.3, and 25.6 respectively, the percentage of litter is 4.5, 2.2, and 1.1, respectively, and the amount of stone and gravel in these three sites is 19, respectively. 35.2 percent (Table 1). The total density of these species in low pressure tourism area is 16,500, medium pressure tourism is 12,000 and high-pressure tourism is 10,750 plants per hectare. The results of the research show a significant deterioration of all the characteristics of the vegetation in the GNU region, including the density, canopy percentage and height of tree, shrub and bush species with increasing tourism pressure. Most of the researches have confirmed that plants are affected by recreational activities and it has been proven that there is a negative correlation between the intensity of tourism and the percentage of vegetation cover, plant height and species diversity (Cakir et al., 2010). Some researchers have reported that increasing the number of recreational activities even leads to a decrease in the height of plant species and also reduces the percentage of foliage cover of plant species (Turton, 2005). Conclusion In the current research, in terms of height, there is a statistically significant difference between all three tourist areas. The height of different vegetation forms of bushes, trees and shrubs has an inverse relationship with the increase in the intensity of tourism activities, and its average in the low tourism zone is higher than the average of this feature in the medium tourism zone, and it is higher than the height of the vegetation forms in the high tourism zone. Funding There is no funding support. Authors’ Contribution All of the authors approved the content of the manuscript and agreed on all aspects of the work. Conflict of Interest Authors declared no conflict of interest. Acknowledgments We are grateful to all the scientific consultants of this paper. هدف از این پژوهش ارزیابی اثرات گردشگری غیرمسئولانه بر ویژگی‌های محیطی اکوتونهای هرمزگان است. به این منظور پس از جنگل گردشی، سه منطقه معرف پنج هکتاری با شرایط بدون فشار توریسم، با فشار متوسط و با فشار زیاد توریسم، انتخاب و شاخصه‌های مختلف محیطی اندازه‌گیری شد. در هر منطقه معرف، ده ترانسکت خطی، هر یک شامل دوازده پلات، قرار داده شد. برای اندازه‌گیری فانروفیت‌ها از پلات 20*20 و برای اندازه‌گیری کریپتوفیت‌ها و بوته‌ای‌ها پلات 2*2 مترمربعی، استفاده شد. ده پروفیل خاک نیز بر روی هر ترانسکت، حفر و مقایسه میانگین داده‌ها با آزمون LSD با استفاده از نرم‌افزار SAS 9.1 انجام شد. نتایج نشان داد وزن مخصوص خاک در منطقه گردشگری شدید، افزایش و درصد تخلخل خاک کاهش‌یافته است. همچنین میانگین تاج پوشش گیاهی مربوط به منطقه گردشگری کم (70 درصد) و کمترین آن مربوط به منطقه گردشگری زیاد (1/23 درصد) است. بیشترین وزن مخصوص ظاهری مربوط به منطقه با فشار زیاد گردشگری (79/1 گرم بر سانتی‌متر مکعب) و کمترین آن، مربوط به منطقه گردشگری با فشار کم (24/1 گرم بر سانتی‌متر مکعب) است. بیشترین درصد تخلخل خاک، در منطقه با فشار گردشگری کم، به ترتیب 93/50 و کمترین میزان، در منطقه با فشار گردشگری زیاد 19/32 درصد است. در نهایت افزایش شدت فعالیت‌های گردشگری، باعث تخریب خاک شده و تمامی ویژگی‌های پوشش گیاهی منطقه، شامل تراکم، درصد تاج پوشش گیاهی در بازه زمانی یک سال و ارتفاع گونه‌های درختی، درختچه‌ای و بوته‌ای نیز در اثر افزایش فشار گردشگری زوال یافته است. پیشنهاد می‌گردد ظرفیت برد گردشگری رعایت و فرهنگ‌سازی و آموزش گردشگران انجام گیرد.

https://jphgr.ut.ac.ir/article_96240_50404ae310c98902f01a3b5c705c3c43.pdf

دانشگاه تهران پژوهش های جغرافیای طبیعی 2008-630X 55 4 2023 12 26 Morphology, mobility and grain size characteristics in new sand dunes (Case study: young Erg of Abshirin) مورفولوژی، تحرک و ویژگی‌های اندازه ذرات رسوب در تپه‌های ماسه‌ای جدید مطالعه موردی: ارگ جوان آب‌شیرین 123 145 96681 10.22059/jphgr.2024.361806.1007780 FA فرهاد حسنی درآباد گروه مدیریت مناطق بیابانی، مرکز تحقیقات بین المللی بیابان، دانشگاه تهران، تهران، ایران ناصر مشهدی گروه علوم زمین، مرکز تحقیقات بین المللی بیابان، دانشگاه تهران، تهران، ایران امیر رضا کشتکار گروه مدیریت مناطق بیابانی، مرکز تحقیقات بین المللی بیابان، دانشگاه تهران، تهران، ایران Journal Article 2023 08 04 ABSTRACT The aim of the paper is to assess the morphological characteristics, mobility, and distribution of sediment particle size as maturity indicators of young dunes. The results indicated that according to the Equivalent Sand Thickness (EST) parameter and the wind direction variability parameter, the morphology of the sand dunes was determined as linear. The climatic index of sand dune mobility using meteorological data of Qom, Kashan, and Ardestan synoptic stations in a 27-year period showed that the sand mobility index (M) for sand dunes is 210, which is in the range of fully active dunes. The Grain Size Distribution and the scatterplots diagrams of sorting, skewness, and kurtosis versus the mean size of particles in differentiating the types of sand dunes showed that the relationship of sorting and skewness versus the mean size is effective in showing the dune's mobility. Sediment grain size parameters can be used as an indicator for transport environment and spatial changes. The studies of this research showed that based on grain size characteristics and climatic index, the sand dunes are the simple linear type with full activity. The transport environment in the dune sediments of the upwind sector is more energetic than the dune sediments of the downwind sector Extended Abstract Introduction Dune fields in arid and semi-arid regions typically form part of local to regional scale sand transport systems, which comprise source areas, transport pathways, and depositional sinks. The range of states of new sand dunes morphology and mobility generally follows the ratio between wind energy for sand transport, aeolian depositions characteristics, and many other environmental factors such as vegetation cover, humidity, and topography. Several parameters have been proposed to account for the morphology and mobility of the sand dunes. Wasson and Hyde considered dune forms as a function of the equivalent sand thickness (EST) parameter and wind direction change (RDP/DP) parameter. The range of states of dune mobility generally follows a climatic gradient. The climatic index of dune mobility developed by Lancaster has been applied to various environments. This index provides a measure of sand mobility (M) as a function of the ratio between the annual percentage of the time the wind is above the threshold for sand transport (W) and the effective annual precipitation (P/PE), where PE is potential evapotranspiration calculated using the Thornthwaite method. The grain size characteristics of the dune sands are closely related to factors such as the dynamic processes of the dunes, sand availability, vegetation, mode and distance of transportation from the source zones, and the energy conditions of the transporting medium. Textural and compositional variables widely used in grain-scale studies are the grain-size parameters (mean size, sorting, skewness, and kurtosis), and the specific gravity mean grain size is widely employed in dynamic interpretations, transport equations and sedimentary environment differentiation. Sorting is very useful in studies of sedimentary environments and aeolian dynamics. Dune sands tend to be better sorted than river sands. Skewness is likewise used to describe grain size distributions in aeolian environments and models to pattern the sediment transport trends. The distinction between the sand types can be numerically stated by computing the distribution curve's skewness (the third moment). On the phi scale, the skewness of dune sands is generally positive, whereas that of beach sands is generally negative. Finally, kurtosis is the less employed grain size parameter, and even Friedman (1961) affirms that it is not an environment-sensitive parameter. An aeolian sedimentary environment dominates the studied area and includes Active depositional dunes that have been formed in the last few decades. This research aims to analyze the characteristics of new sand dunes, including morphology, sediment physics, dunes mobility, and the relationship evaluation between factors to understand the nature of new sand dunes as one of the indicators of dry environments. Methodology The characteristics of new sand dunes were evaluated based on meteorological, remote sensing data, observations, and field sampling. MODIS remote sensing data is used to study the sand dunes' morphology. The meteorological data were derived from two stations of Qom and Kashan. The analysis of the elongation and form of the dunes as the wind direction indicator showed that the area is affected by the winds region of the Qom. The samples were collected from linear sand dunes within varying morphologies. A total of 16 dune sites were studied. Grain size analysis of all samples was carried out using standard dry sieving and sedimentation techniques. Graphic grain-size parameters were estimated following Folk and Ward and using GRADISTAT software. The four size parameters were calculated, namely, mean size, sorting, skewness, and kurtosis. Scatter plot diagrams of mean size versus sorting, skewness, and kurtosis were plotted as scatter diagrams to evaluate their interrelationship and effectiveness in differentiating between the various sand dunes. Results and Discussion Anemometry analysis shows that the wind in the region blows from three directions as westerly, north-westerly, and easterly, respectively, based on frequency and speed. Sand-moving winds in the area are strongly controlled from two primary directional sectors, westerly and north-westerly. Total potential sand transport (drift potential, DP) ranges from 202 (Qom station) to 87 (Kashan station) vector units (VU). Different types of sand dunes were identified in Erg Absherin; (a) prebarchanic dunes, (b) wedge-shaped dunes, and (c) simple immaturity linear dunes to silk dunes. The grain size distribution of the samples showed that the sand dunes have an average size range of medium to fine sand. The histograms of the size distribution indicated that they are all unimodal, with a modal class varying between medium to fine sand size. The sands of the studied dunes are poorly sorted; they range in size from 0.46 to 1.12 phi. The young and immature dunes of the northern area are relatively less sorted than the mature dunes. The interrelationship between mean size and skewness shows a general trend of skewness from medium to fine particles. Positivity of skewness increases with the increase in the mean grain size. In the same way, a general decreasing trend is recognized in the interrelationship between mean size and kurtosis, so sediments with a smaller mean size (larger phi) have leptokurtic. The state of dune mobility was determined based on the Lancaster dune mobility index test. The data showed that the sand mobility index (M) for sand dunes is 210, which is in the range of fully active dunes. Conclusion The landscape of Kashan deserts is dominated by desert sand dunes, which occupy a considerable area of this region. Many of these new dunes have been formed and developed in the last few decades. Therefore, they provide the form and aeolian deposits with special features. The immaturity of crescent-shaped sand dunes (prebarchanic) to Seif dunes, lack of vegetation cover, and topographical characteristics indicate that the Erg is active. The spatial distribution of sand dunes showed that the linear morphology is consistent with the behavior of Qom station's wind and sand flux patterns. The harmony of the wind and storm rose patterns indicated that both effectively shape the dunes. The value of the dune mobility index exhibits that the dunes are fully active. The Aeolian Sediment Availability was compared with Glaser's diagram. Most of the samples were located in the aeolian mobility sector according to Gläser criteria. In terms of grain size distribution, there are differences in the grain size distributions for different dune types. The dunes are mostly composed of medium to magnificent sands. The sorting parameter indicates that the sands on the southern dunes (downwind) are better sorted than on the northern dunes (upwind). Under the conditions of low wind activity in the south of Erg, the frequency of finer particles and better sorting will increase. In general, the study of the analysis of this new and young Erg indicates that the dunes are characterized by linear or elongated, active, and mobile in an Aoelaian high-energy environment with sands of medium to fine, poorly to moderately well-sorted and finely skewed. Funding There is no funding support. Authors’ Contribution All of the authors approved the content of the manuscript and agreed on all aspects of the work. Conflict of Interest Authors declared no conflict of interest. Acknowledgments We are grateful to all the scientific consultants of this paper. هدف مقاله ارزیابی ویژگی‌هایی مورفولوژی، تحرک‌پذیری و توزیع اندازه ذرات رسوب به عنوان شاخص‌های تکامل تپه‌های جوان می‌باشد. با این هدف و بر پایه عکس‌ه‌ای هوایی، تصاویر ماهواره، نقشه‌ها و بازدیدهای صحرایی مطالعه انجام شد. نتایج نشان داد که بر پایه پارامتر ضخامت ماسه معادل و پارامتر تغییرپذیری جهت باد، نوع مرفولوژی تپه‌های ماسه‌ای، خطی مشخص شد. شاخص آب و هوایی تحرک تپه‌های ماسه‌ای، توسعه یافته توسط لنکستر، با استفاده از داده‌های هواشناسی ایستگاه سینوپتیک قم، کاشان و اردستان، در یک دوره 27 ساله برای تپه‌های ماسه‌ای آزمایش شد و نشان داد که رابطه خوبی بین میانگین شاخص تحرک، فعالیت و مرفولوژی تپه‌های ماسه‌ای وجود دارد. داده‌های این تحقیق نشان می‌دهد که شاخص تحرک ماسه (M) برای تپه های ماسه‌ای 210 است که در محدوده تپه‌های ماسه‌ای کاملا فعال قرار دارند. توزیع اندازه دانه و چهار پارامتر اندازه یعنی میانگین اندازه، جورشدگی، چولگی و کشیدگی منحنی محاسبه شد. نمودارهای طرح پراکندگی جورشدگی، چولگی و کشیدگی در مقابل اندازه متوسط ذرات، در تمایز انواع تپه‌های ماسه‌ای نشان داد که رابطه جورشدگی و چولگی در مقابل میانگین اندازه ذرات، در نشان‌دادن تحرک تپه‌ها موثر هستند. پارامترهای اندازه دانه رسوبات بدون توجه به نوع مورفولوژی تپه‌های ماسه‌ای دارای تغییرات مکانی هستند. مشخصه‌های اندازه دانه می‌تواند به عنوان شاخصی برای محیط انتقال استفاده شود. مطالعات این تحقیق نشان داد که بر اساس ویژگی‌های اندازه دانه و شاخص‌ اقلیمی، تپه‌های ماسه‌ای از نوع خطی ساده با فعالیت زیاد می‌باشند. محیط انتقال رسوبات تپه‌ها در بالا دست باد نسبت به رسوبات تپه‌ها در پایین دست پرانرژی‌تر است

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