@article { author = {Azizi, Gh and Akbari, T and Davudi, M and Akbari, M}, title = {A Synoptic Analysis of January 2008 Sever Cold in Iran}, journal = {Physical Geography Research}, volume = {41}, number = {70}, pages = {-}, year = {2010}, publisher = {University of Tehran}, issn = {2008-630X}, eissn = {2423-7760}, doi = {}, abstract = {Introduction January 2008 was one of the coldest days during the history of registering data in Iran. In this month an unusual cold air mass covered the most part of Iran particularly the north area of the country. As this air mass shifted southward, it produced very cold condition in all of the country and dry snowfall in the north parts and mountain area. Materials and methods In this paper in order to investigation of unusual cold event on Jan 2008 in Iran, a dataset includes daily minimum temperature of Jan 2008 has been gathered from synoptic stations all over the country. Then, by using cluster analysis extracted 21 stations as selected stations; the final stations almost covered all of the country area. Z score index used for calculated minimum daily temperature anomalies. Then the calculated Z scores applied as an indicator in order to compared January 2008 minimum temperature with the long-term average minimum temperatures of January. Also extracted the four hourly temperature, sea level pressure, geopotential height, and the wind speed components (U&V components) for synoptic analysis of Frost events in the period of study from NCEP/NCAR. Position and movement of the atmospheric systems such as cyclones, anticyclones, fronts and wind fields were identified using synoptic maps. Also the daily temperature data and the wind speed components are used for plotting the composite maps of temperature advection, thickness, temperature gradient’s vectors, and thermal wind. Results and discussion The result shown that the Z scores index of January 2008 has been more than (-5) Celsius degrees in majority of selected stations except 6 stations in south regions of Iran consist of Ahwaz, Bushehr, BandarAbbas, Shiraz, Kerman, and Iranshahr. The analysis of minimum temperature in case of 6 quintuple periods (consist of 5days periods) showed that the fourth period (16th -20th days of Jan 2008) have had the coldest temperatures. Almost during the study period the most observed prevailing event has been a Blocking system. The blocking situation created a suitable condition for cold advection to Iran during the period study. The sea level pressure field map in the forth quintuple (16th -20th January 2008) depicted that there is a high system that is closed by isobar 1025hPa over the north of Aral Sea and it is extended over the north of Caspian Sea. The existence of severe cold in the most stations verifies this result. Isobar 1024hPa is located over most of southern region simultaneously. An intensive decease of temperature has been seen during the fourth quintuple in stations contains Saghez. Shahrekord, Birjand, Tehran, Gorgan, and Ramsar. These stations are as preventatives of northern regions of country that is exposed blowing of westerlies. In order to investigate the causes of severe cold we used the thickness map. The investigation of thermal wind in thickness map of 1000 up to 500 gpm levels presents an intense cold advection over the northern regions of Iran. This cold mass air is originated from arctic region and by passing cold territories such as Siberia it becomes colder and colder. Passing from the colder paths will create a colder advection and colder weather as a result. It transmitted the dry and cold air masses into the country in such a way that the maximum decrease of air thickness over latitude 32?N is between longitude 69E and 62E. It contains the north and north eastern part of Iran. Following intensive lessening of temperature we can observe frost in forth quintuple. So the advectional frost outbreak in the east north and northern half of country could be explained by this intensive cold advection in the 4th quintuple period of study. Conclusion Cold advection to Iran during the study period has originated from north and North West area of the country as two main sources for cool advection. From other side it is evident that there is an active center for warm advection that it is located on Arabian Peninsula region and western neighboring area of Iran. The analysis of maps showed that the speed of thermal wind over south of Iran and Persian Gulf is over 30 m/s and it decreases the intense of frost and sever cold over south region by warm advection. Also another conclusion of this investigation is that the thermal wind over the southern region of country, Persian Gulf, and Oman Sea with velocity over than 30m.s-1 has decreased the intense of cold events in southern regions of Iran. It seems that the higher minimum temperature of some southern stations such as Ahwaz, Bushehr, BandarAbbas, Shiraz, Kerman, and Chabahar is because of warm advection.}, keywords = {Blocking System,Cold advection,Frost,synoptic patterns,Thermal wind}, title_fa = {تحلیل همدیدی موج سرمای شدید دی‌ماه 1386 ایران}, abstract_fa = {سرمای شدید و یخبندان‌ها از مخاطرات مهم جوی به‌شمار می‌آیند که معمولاً در ایران سالانه خسارات فراوانی را به محصولات کشاورزی و تأسیسات وارد می‌کنند. تحلیل سینوپتیکی آماری این یخبندان‌ها به پیش‌بینی وقوع آنها و اتخاذ تصمیمات صحیح پیش از وقوع و البته مقابله با آنها کمک می‌کند. در پژوهش حاضر به بررسی و تحلیل موج سرمای شدید و فراگیر در ژانویه 2008 پرداخته شده است. در این تحقیق به‌منظور بررسی و تحلیل رویداد سرمای غیرمعمول دی‌ماه 1386 (ژانویه 2008) اقدام به جمع‌آوری آمار و اطلاعات دمای حداقل روزانة ماه ژانویه در ایستگاه‌های سینوپتیک سراسر کشور شد. سپس با مطالعه 21 ایستگاه منتخب، ناهنجاری دمای ژانویه 2008 در مقایسه با میانگین درازمدت دمای حداقل ژانویة کشور مورد بررسی قرار گرفت. با بررسی ناهنجاری‌ها و شاخص‌ بی‌بُعد نمرة استاندارد، مشاهده شد که دمای حداقل ژانویه 2008 به جز در 6 ایستگاه در نیمه جنوبی کشور (اهواز، بوشهر، بندرعباس، شیراز، کرمان، ایرانشهر)، در سایر ایستگاه‌ها دارای ناهنجاری بیش از 5- درجه سلسیوس در مقایسه با دوره آماری 30 ساله بوده است. با تحلیل دمای حداقل ژانویه 2008 در قالب 6 دورة 5 روزه، مشخص شد که ایستگاه‌های مورد بررسی در دورة چهارم (روزهای شانزدهم تا بیستم) سردترین دماها را داشته‌اند. به‌منظور تحلیل شرایط همدیدی مؤثر در وقوع یخبندان ژانویه 2008 و تعیین علل آن، داده‌های مربوط به دما، فشار سطح دریا، ارتفاع ژئوپتانسیل، مؤلفه باد نصف‌النهاری و مداری (U و V) در ترازهای متفاوت و در چهار ساعت، از سایت NCEP/NCAR برای روزهای ژانویه 2008 استخراج گردید. به‌وسیله داده‌های ارتفاع ژئوپتانسیل و فشار سطح دریا، وضعیت شکل‌گیری سامانه بندالی مورد بررسی قرار گرفت. از داده‌های دما، مؤلفه باد نصف‌النهاری و مداری (U و V) نیز برای ترسیم نقشه‌های ترکیبی فرارفت دما، ضخامت جوّ، بردارهای شیو دما و باد گرمایی استفاده شد. با مشاهدة نقشه‌های تراز میانی جوّ مشاهده شد که در سراسر ژانویه 2008 به طور مداوم سامانه بندالی حاکمیت داشته است، به‌طوری‌که تشکیل سامانه بندالی زوجی در پنجه چهارم (روزهای شانزدهم تا بیستم) و پنجه دوم (روزهای ششم تا دهم) به‌خوبی مشاهده می‌شود. با بررسی باد گرمایی در لایه ضخامت 1000 تا 500 هکتوپاسکال، مشاهده می‌شود که نیمة شمالی کشور در معرض فرارفت شدید هوای سردی است که از مناطق قطبی و شمال منطقه سرد سیبری می‌گذرد و با خود هوای سرد و خشک را به داخل کشور منتقل می‌کند. بنابراین، بروز یخبندان فرارفتی در نواحی شمال شرقی و نیمة شمالی کشور در روزهای پنجه چهارم توجیه می‌شود. همچنین باد گرمایی در جنوب کشور و بر روی خلیج فارس و دریای عمان و کرانه‌های آن با سرعتی بیش از 30 متر بر ثانیه از شدت سرمای مناطق جنوبی کشور کاسته است. به‌نظر می‌رسد که بالاتر بودن دمای حداقل ایستگاه‌های اهواز، بوشهر، بندرعباس، شیراز، کرمان‌ و چابهار به همین علت باشد.}, keywords_fa = {ایران.,باد گرمایی,ژانویه 2008,سامانه بندالی,فرارفت سرد,موج سرما}, url = {https://jphgr.ut.ac.ir/article_21518.html}, eprint = {https://jphgr.ut.ac.ir/article_21518_d6ae253e62151ed2ac4a1604baee1e1b.pdf} } @article { author = {Zolfaghari, H}, title = {A Study of Cooling and Heating Requrements in Northwest of Iran}, journal = {Physical Geography Research}, volume = {41}, number = {70}, pages = {-}, year = {2010}, publisher = {University of Tehran}, issn = {2008-630X}, eissn = {2423-7760}, doi = {}, abstract = {Introduction If the human comfort temperature (threshold temperature) is defined as X, the average deviation of daily temperature from the comfort level is termed a degree-day, which represents the need to cool the environment from temperatures above the threshold temperature and the need to warm the environment from temperatures below the threshold temperature (i.e., cooling and heating needs, respectively). Heating degree day and cooling degree day values for a given area indicate the harshness of the climate and bear a direct relation to an area’s population and size of residential areas. HDD and CDD values are also related to climatic change. Materials and Methods The area considered in this research is northwest Iran (44–50?E and 34–40?N), including the provinces of Gilan, Ardebil, Eastern and Western Azarbaijan, Ghazvin, Hamedan, Kurdestan, Kermanshah, and Markazi. We analyzed daily amounts of HDD and CDD recorded at 28 meteorological stations in northwest Iran for the period 1984–2003, using data provided by the Information and Statistics Center of the Meteorology Organization of Iran. In choosing the meteorological stations to include in our analysis, we took account of data availability and connectivity. Because of the influence of altitude on climate, we also selected stations located close to each other but with contrasting altitudes (e.g., the stations at Hamedan (airport) and Hamedan (Nojeh) occur in the same geographical area, but are located at altitudes of 1749 and 1679 m above sea level, respectively). The selected stations are also those with appropriate data for our analysis. Some stations lacked data for certain years; consequently, we reconstructed the data required to calculate HDD and CDD values using the method of differences, as temperature series show little variability. In this approach, missing data were replaced based on data from the closest stations with similar climate. Before analyzing the data, we assessed the data quality using the Run Test method. The tests demonstrated the congruency of annual HDD and CDD data for all stations. Maps of cooling and heating needs were compiled using SURFER software, and regionalization maps were compiled using ARCVIEW software. Results and Discussion We used statistical methods to calculate and examine the cooling and heating needs of the areas represented by 28 meteorology stations in northwest Iran, and analyzed the spatial distribution of the needs. The study area was divided into sub-regions via a climatic classification scheme based on environmental cooling and heating needs, and we compiled a GIS-based map of cooling and heating needs throughout the study area. The average monthly cooling and heating needs of the stations revealed the greatest need of heating energy during January and the greatest need of cooling during July. Ardebil is the coldest site, requiring heating energy throughout the year; Sarpolzahab is the warmest. A comparison of the spatial distribution of annual average cooling and heating degree-days with altitude reveals that areas at 1600–1700 m elevation have heating needs of 3300–3500 degree-days (the highest values among the stations) and cooling needs of 50–150 degree-days (the lowest among the stations). Also, a comparison of cooling and heating needs revealed that the mountainous nature and high altitude of the stations means that heating needs are dominant; i.e., most of the energy consumed in the region is used for providing heat. A regression analysis revealed that with increasing altitude, heating needs increase and cooling needs decrease. Although coastal stations benefit from their proximity to the Caspian Sea, according to the hierarchical classification (which assigns the stations of Rasht, Bandar Anzali, Astara, and Parsabad in the same climatic class), the sea has relatively little effect on the cooling and heating needs of the region overall. During the second decade of the study period, the heating needs of high-altitude stations decreased by an average of 317 degree-days compared with the first decade. The effect of latitude on cooling needs was examined by cubic (bivariate regression). To limit the influence of altitude, stations located above 1500 m were excluded from analysis. The heating needs of the region increased by 0.622 degree-days for each degree increase in latitude, and cooling needs decreased by 0.651 degree-days for each degree increase in latitude. The same trends are apparent in the spatial distribution of heating and cooling needs relative to latitude. The combined data demonstrate that cooling needs in northwest Iran are reduced with increasing latitude. Conclusion An analysis of the effects of independent factors on the cooling and heating needs of the area revealed that the Caspian Sea influences only the coastal land adjacent to the sea; latitude and altitude affect the cooling and heating needs throughout the region. For each degree of increase in latitude, the heating needs increase by 0.662 degree-days and the cooling needs decrease by 0.651 degree-days. Over the second decade of the study period, the heating needs of highland regions decreased by an average of 317 degree-days relative to the first decade. The conditions that affect cooling and heating needs throughout the study region are heterogeneous. Our regionalization analysis demonstrates the existence of 11 different climatic classes in terms of cooling and heating needs.}, keywords = {Cooling,Degree-day,Heating,Northwest Iran,Regionalization}, title_fa = {تحلیلی بر نیازهای سرمایشی و گرمایشی در شمال غرب ایران}, abstract_fa = {در پژوهش حاضر، داده‌های ماهانة نیازهای سرمایشی و گرمایشی 28 ایستگاه هواشناسی شمال غرب کشور طی دوره آماری 20 ساله از سال 1984 تا 2003 با استفاده از روش‌های آماری، ابزارهای مشاهداتی نقشه و نمودار،‌ مورد بررسی قرار گرفت و توزیع فضایی و مکانی این مقادیر تحلیل گردید. همچنین با استفاده از سامانة جدید پهنه‌بندی اقلیمی از دیدگاه نیازهای سرمایشی ـ گرمایشی محیط، منطقة مورد مطالعه پهنه‌بندی شد و نقشة پهنه‌بندی اقلیمی شمال غرب ایران بر پایة طبقه‌بندی‌های فوق، در محیط GIS ارائه گردید. در بررسی تأثیر عوامل مستقل بر نیازهای سرمایشی و گرمایشی در منطقه، معلوم گردید که دریای خزر به‌جز بر باریکه ساحلی این پهنة آبی تأثیری ندارد، ولی عرض جغرافیایی و ارتفاع بر نیازهای گرمایشی و سرمایشی مؤثرند. نتیجة‌ مطالعه نشان داد که به ازای افزایش هر درجه عرض جغرافیایی 622/0 درجه ـ‌ روز، نیازهای گرمایشی افزایش می‌یابد و 651/0 درجه ـ روز از میزان نیازهای سرمایشی کاسته می‌شود. همچنین معلوم شد که در دهه دوم آماری در نقاط مرتفع منطقه، به‌طور متوسط 317 درجه ـ روز از میزان نیازهای گرمایشی کاسته شده است. به‌طور کلی می‌توان گفت که شرایط یکسانی از نظر نیازهای سرمایشی و گرمایشی در منطقة مورد مطالعه حاکم نیست، به‌طوری‌که نتیجة پهنه‌بندی، وجود 11 طبقة متفاوت اقلیمی از دیدگاه نیازهای گرمایشی و سرمایشی را نشان می‌دهد.}, keywords_fa = {پهنه‌بندی.,درجه ـ روز,شمال غرب ایران,نیازهای سرمایشی,نیازهای گرمایشی}, url = {https://jphgr.ut.ac.ir/article_21519.html}, eprint = {https://jphgr.ut.ac.ir/article_21519_d9b5d1c04bcc282d8de7b621c0735a83.pdf} } @article { author = {Khoshhal Dastjerdi, J and Baratian, A}, title = {Thermal Requirements Estimation of the Phenological Stages of Autumn Colza SLM046, Okapi in Iranian Cold Climatic Conditions (ShahreKord Case Study)}, journal = {Physical Geography Research}, volume = {41}, number = {70}, pages = {-}, year = {2010}, publisher = {University of Tehran}, issn = {2008-630X}, eissn = {2423-7760}, doi = {}, abstract = {Introduction In recent years, characteristics of Canola and its suitable amenity with all climates and weather conditions invarious points of country , had result in expanding implantation of this plant as a good source of meal oil. This is considered in the general perspectives. Continental amenity of this plant and time difference of its growth period and in its capacity for using agronomy frequency, are the positive points of this plant in Iran. Expanded implantation of this kind with other kinds of corps has started since 1997-98 with the surface of 2893 Hectares. According to the last reports, the implantation of this plant in Iran in 2005-06, was about 119321. The average performance of Canola in that period was about 2035 kilograms a hectare. Materials and methods The study on Okapi and SLM046 Canola has began since 2000 in research farm of Farokhshahr in the research centre of Chaharmahal Va Bakhtiari. For the possibility of expanding these results to farms, we have tried to set real farm situation for the experiment. These steps were done in 7 periods in 2000-2001 to 2006-2007 continuously. The implantation to cropping the products , has longed about 10 months. Beside the research farm, there was a climatology station to measure weather parameters in standard conditions. Details of observation of phonology is directed according to Canola association of Canada. Look at the following: First stage - Germination: the soil was pulled aside from 4 directions of the farm and according to the amount of germination, the percentage of germination was measured until the end of this phase. Second stage - Green: at first , we based 4 small 1*1 plot with the standard procedure and by appearing first 2 leave , we counted the leaves and we established the number in each plot. After formation of rows, in every parts, we chosen 10 plants and we continued our observation on them. Third stage – Rosette. in this level , we have some real leaves. The rise of the leaves will continue until hibernation. 4th stage – Bud Returns: At this stage, the main flower can be observed at the center of rosette. Then , rising of the stem will continue and other stems will be formed. 5th stage - Flowering: The first flower will be opened ( about 10% of purses will be opened) and pods will rise and they will start to grain. At the end of this period , the flowering of the most of the plots will finish in this period. 6th stage - Reach: In this stage , pods will reach the maximum size and will begin to change brown. The number of plates in each plots was recorded each day. Results and discussion According to the number one result of this study , average needed heat for rising of Okapi and SlM 046 are 2340 and 2383 respectfully (degree day). we observed that in the beginning of spring. also , in comparison between these 2 kinds , the maximum difference was calculated about 13% in green and about 8% in rosettet. the mentioned plant , can adjust itself to every environment and climate and in suitable conditions , it can grow very well. The effective heat is calculated about 1548 and 1559 degree day. From other results we can mention the suitable heat for 6 parts of autumn cycle of Canola. Germination: 160.9, Green: 216.4, Rosette: 522.3,Bud Returns:279.7, Flowering: 402.1, Reach: 780.2. Also , the heat per day for effective growth is calculated : Germination: 117.5, Green: 151.4, Rosette: 309, Bud Returns: 136.4, Flowering: 258.7, Reach 580.2. Conclusion The live cycle of Canola is divided to 6 periods that are illustrated with 6 codes form 0 to 5. These periods are consisted of: Germination, Green, Rosette, Bud Returns, Flowering and Reach. The goal of this study is to find the heat needs of Canola in the climate of ShahreKord. We want to recognize its needs and build a base for the agronomy calendar of Iran. Canola is a plant for cold climates. It reacts to the heat changes and its very sensitive to the temperature. Our studies show that different kinds of this plant have various kinds of reactions to their original climate.}, keywords = {Canola,Climate,Growing degree day,Phenological stages,ShahreKord.}, title_fa = {برآورد نیازهای حرارتی مراحل فنولوژیکی کلزای پاییزه (ارقام Okapi SLM046,) در شرایط اقلیمی سرد ایران (مطالعه موردی شهرکرد)}, abstract_fa = {هر گیاه برحسب شرایط اقلیمی برای دوره حیات خود نیاز به کسب مقدار معینی حرارت دارد. در پژوهش حاضر، نیازهای حرارتی دو رقم از کلزای پاییزه برای مناطق سرد بررسی شده است. به این منظور به‌مدت 7 سال پیاپی این ارقام در مزرعه آزمایشی مرکز تحقیقات هواشناسی کشاورزی فرخ‌شهر کشت گردید و اقدام به برداشت اطلاعات فنولوژیکی آن شد. نتایج نشان داد که میانگین کل دوره حیاتی ارقام SLM046, Okapi به ترتیب برابر 161 و 163 روز است و به این ترتیب اختلاف زیادی با یکدیگر ندارند. میانگین مجموع نیازهای حرارتی این دو رقم نیز به ترتیب برمبنای دمای پایه صفر درجه (دمای فعال) برابر با 2340 و 2383 درجه بوده است و براساس دمای 5 درجه سانتی‌گراد (دمای مؤثر) به‌ترتیب برابر 1548 و 1559 محاسبه شد. مقایسه میانگین مجموع طول کل دوره حیاتی این دو رقم با دیگر ارقام پاییزه که بین 83 تا 126 روز در سایر نقاط دنیا گزارش شده است، نشان می‌دهد که این دوره در منطقه سردسیر کشور ایران در حدود 35 تا 40 روز بلندتر است. این امر می‌تواند به دو علت باشد یا تفاوت ژنتیکی ـ که کمتر به‌نظر می‌رسد چنین اهمیتی داشته باشد ـ یا تفاوت اقلیمی محل کشت ـ که محتمل‌تر به‌نظر می‌رسد ـ زیرا طول روز و عرض جغرافیایی مناطق کشت، میزان انرژی کسب‌شده به‌وسیلة گیاه را تغییر می‌دهد.}, keywords_fa = {اقلیم,درجه ـ روز,شهرکرد.,کلزا,‌ مراحل فنولوژیکی}, url = {https://jphgr.ut.ac.ir/article_21520.html}, eprint = {https://jphgr.ut.ac.ir/article_21520_c6ee869e52bc9f97d584017902567839.pdf} } @article { author = {Tablebi, A and Nafarzadegan, A.R and Malekinezhad, H}, title = {A Review on Empirical and Physically Based Modelling of Rainfall Triggered Landslides}, journal = {Physical Geography Research}, volume = {41}, number = {70}, pages = {-}, year = {2010}, publisher = {University of Tehran}, issn = {2008-630X}, eissn = {2423-7760}, doi = {}, abstract = {Introduction Emergence of landslide phenomena can be due to the different factors like geology, geomorphology, hydrology, biology and human activities but main role in landslide initiation only is created by triggered factor. Intense rainfall, rapid snowmelt, water-level change, seismic loading and rapid erosion are the most important landslide triggering mechanisms. Rainfall has been known as the most common factor in occurring landslides. In general, infiltration of rainfall in soil causes to increase soil water pressure, reduce matric suction and increase the weight of soil mass and finally, soil strength is decreases and landslide occurs. Moreover, groundwater conditions responsible for slope failures are related to rainfall through infiltration, soil characteristics, antecedent moisture content, and rainfall history. Thus, the most important section of landslide modeling (empirical, statistical or physically-based) is hydrological part. In this study, it has been tried to present the obtained results and the applied idioms in most cited researches about hydrological modeling of landslides. With respect to the human and financial damages due to occurring landslides in our country, designing and applying a landslide warning system is necessary and doing study in this background is huge step for decreasing damages and sustainable managing of natural hazards. Authors hope to witness of creating the advance warning systems for landslides in our country by using obtained experiences around the world and motivations of internal researchers. Materials and Methods We investigated many researches about hydrological modeling of landslides. Then, we selected those researches that have been presented in some highly cited books and papers. Based on our literature review, the time period between 1975 (presenting rainfall threshold for initiation of landslide by Campbell) and 2008 (presenting a physically-based model (HSB-SM) by Telabi et al.) was considered for our studies. Results and Discussion The consideration that some storms produce failures and others do not, could induce scientific research to analyze the relationship between rainfall amount and landslide initiation. This is aimed at identifying the rainfall thresholds. A threshold is the minimum or maximum level of some quantity needed for a process to take place or a state to change. For rainfall-induced landslides a threshold may define the rainfall, soil moisture, or hydrological conditions that, when reached or exceeded, are likely to trigger landslides. Rainfall thresholds can be defined on physical (process based, conceptual) or empirical (historical, statistical) bases. Empirical thresholds for the initiation of landslides can be loosely defined as global, regional, or local thresholds. Review of the literature reveals that no unique set of measurements exists to characterize the rainfall conditions that are likely (or not likely) to trigger slope failures. Based on the considered rainfall measurements, empirical rainfall thresholds can be grouped in three broad categories: (i) thresholds that use event rainfall measurements, (ii) thresholds that employ antecedent conditions, and (iii) thresholds that consider other conditions (for instance antecedent discharge, storms with different frequencies and relative parameters). First category can be further subdivided in four subcategories: (i) intensity-duration (ID) thresholds, (ii) thresholds based on the total event rainfall, (iii) rainfall event-duration (ED) thresholds, and (iv) rainfall event-intensity (EI) thresholds. Intensity-duration thresholds are the most common type of thresholds proposed in the literature. Physically-based models attempt to extend spatially the slope stability models (e.g., the ‘‘infinite slope stability method’’) widely adopted in geotechnical engineering (Wu and Sidle, 1995; Iverson, 2000). To link rainfall pattern and its history to slope stability/instability conditions, physically-based models incorporate infiltration models (e.g., Green and Ampt, 1911; Philip, 1954; Salvucci and Entekabi, 1994). Various approaches have been proposed to predict the accumulation of the infiltrated water into the ground. Crosta and Frattini (2003) compared three infiltration models, including a steady-state model (Montgomery and Dietrich, 1994), a transient “piston-flow’’ model (Green and Ampt, 1911; Salvucci and Entekabi, 1994), and a transient diffusive model (Iverson, 2000), to predict the location and time of debris flows. In this paper, some physically-based models (ASWS, SHALSTAB, SINMAP, dSLAM, IDSSM) and recently developed model (HSB-SM) have been studied. The HSB-SM model is composed of three parts: a topography model conceptualizing three-dimensional soil mantled landscapes, a dynamic hydrology model for shallow subsurface flow and water table depth (HSB model) and an infinite slope stability method based on the Mohr-Coulomb failure law. The model (HSB-SM) is able to simulate rain-induced shallow landsliding on hillslopes with non-constant bedrock slope and non-parallel plan shape. Review of the literature reveals that physically based models perform best when attempting to predict shallow landslides (soil slides and debris flows). Conclusion Process-based models can determine the amount of precipitation needed to trigger slope failures, and the location and time of the expected landslides, making them of interest for landslide warning systems. However, limitations exist. physical models require detailed spatial information on the hydrological, lithological, morphological, and soil characteristics that control the initiation of landslides. This information is difficult to collect precisely over large areas, and is rarely available outside specifically equipped test fields. Process based models are calibrated using rainfall events for which precipitation measurements and the location and the time of slope failures are known. This information is not commonly available and is costly to obtain. Therefore, with respect to the availability of rainfall data in most regions of Iran, empirical-statistical models can be used for determination of a confidence relation between rainfall characteristics and landslide occurrence in each region. The inputs of these models are mainly the rainfall data with different time intervals which makes their applications to be simple. On the other hand, with respect to the applied researches in different sites of the world and also in Iran (by authors), the obtained results have appropriate accuracy that has been studied in this paper.}, keywords = {landslide,Physically-based modeling,Rainfall threshold,Safety factor}, title_fa = {مروری بر مدل‌سازی تجربی و فیزیکی زمین‌لغزش‌های ناشی از بارندگی}, abstract_fa = {بروز پدیدة زمین‌لغزش می‌تواند ناشی از عوامل متعدد زمین‌شناسی، ژئومورفولوژیکی، هیدرولوژیکی، بیولوژیکی و انسانی باشد. با وجود این، نقش اساسی در شروع زمین‌لغزش را عمدتاً عاملی ماشه‌ای ایفا می‌کند. بارندگی، به‌عنوان متداول‌ترین عامل ماشه‌ای وقوع زمین‌لغزش‌ها شناخته شده است. از این رو، مهمترین بخش در مدل‌سازی تجربی، آماری و یا فیزیکی زمین‌لغزش، بخش هیدرولوژیکی آن خواهد بود. در پژوهش حاضر کوشش شده است با بررسی پژوهش‌های صورت گرفته (کتاب‌ها و مقالات پُراستناد از پژوهشگران شناخته شده در زمینه مدل‌سازی هیدرولوژیکی زمین‌لغزش)، در بازه زمانی 1975 (معرفی مفهومی به نام آستانه بارندگی برای شروع زمین‌لغزش به‌وسیله کمبل) تا 2008 میلادی (ارائه مدل فیزیکی HSB-SM از سوی طالبی و همکاران)، مفاهیم به‌کار رفته در این پژوهش‌ها معرفی و دستاوردهای حاصل از آنها بررسی شود. اغلب مدل‌های فیزیکی، مقدار بارندگی مورد نیاز برای وقوع زمین‌لغزش را به صورت دینامیک (در هر لحظه از رخداد بارندگی) برآورد می‌کنند، اما محدودیت بزرگ مدل‌های فیزیکی (به خصوص در کشورهایی مانند ایران) نیاز آنها به اطلاعات مفصل و دقیق از خصوصیات خاک، هیدرولوژی و مورفولوژی دامنه است، که البته جمع‌آوری آنها معمولاً دشوار و پرهزینه است. بنابراین با توجه به در دسترس بودن داده‌های بارندگی در اغلب مناطق کشور، پیشنهاد می‌شود برای تعیین آستانه بارندگی وقوع لغزش در مناطق مستعد کشور، مدل‌های تجربی ـ آماری در نظر گرفته شود و برای هر منطقه رابطة قابل اطمینانی بین خصوصیات بارش و وقوع زمین‌لغزش ارائه گردد. ورودی این مدل‌ها اغلب داده‌های بارندگی در پایه‌های زمانی مختلف است که باعث سهولت استفاده از آنها می‌گردد. از طرفی با توجه به تحقیقات انجام شده در نقاط مختلف جهان و نمونه‌ای در ایران (به‌وسیلة نگارندگان)، نتایج این مدل‌ها از دقت مناسبی برخوردار است.}, keywords_fa = {آستانه بارندگی,زمین‌لغزش,ضریب پایداری.,مدل‌سازی فیزیکی}, url = {https://jphgr.ut.ac.ir/article_21521.html}, eprint = {https://jphgr.ut.ac.ir/article_21521_c6756120e0d49e21e8643c28a7164fe1.pdf} } @article { author = {Darvishi Bollorani, A and Gholami, I and Mirzapour, F}, title = {The Evaluation of Multi-Temporal ENVISAT-ASAR for Temporal and Spatial Discrimination of Rice Fields}, journal = {Physical Geography Research}, volume = {41}, number = {70}, pages = {-}, year = {2010}, publisher = {University of Tehran}, issn = {2008-630X}, eissn = {2423-7760}, doi = {}, abstract = {Introduction Rice is one of the most important crops in tropical areas, specifically in Southeast Asia. The specific climatology with always cloudy conditions; temporal variability in sowing, growing, and harvesting of rice crops and also different cultivation timetables, make the necessity of using multi-temporal RADAR and Synthetic Aperture Radar (SAR) images for obtaining quantitative and qualitative information from rice fields in tropical areas. The objective of this research is the evaluation of the ability of multi-temporal ENVISAT-ASAR datasets for temporal and spatial discrimination of rice fields, therefore, Palolo Valley, Central Sulawesi, Indonesia as the area of study was selected. The evaluated images were acquired in multi-polarimetric mode (HH, HV or VV, VH) from 4th February to 28th July 2004. These datasets includes two raw or primary datasets: Co-Polarized (HH, VV) and Cross-Polarized (HV, VH) and five derivative or secondary datasets: Mean Texture Co-Polarized, Mean Texture Cross-Polarized, Monthly Subtraction, Polarized Subtraction and Normalized Polarized Subtractions. Here the advantages of the relationship between rice growth process and the changes in the SAR backscatter coefficients using the multi-temporal ENVISAT-ASAR datasets are taken. After doing the preprocessing and the processing stages, the obtained results were evaluated using high resolution Quickbird/MS satellite imagery and available field works information. The obtained results for spatial discrimination of rice fields show the highest accuracy for Co-Polarized dataset with an overall accuracy (88.05%) and Kappa coefficient (0.867), while Normalized Polarization Subtraction dataset offered the lowest amount of accuracy with an overall accuracy (80.23%) and Kappa coefficient (0.781). The results of temporal discrimination of rice fields show a good correspondence between the rice growth and SAR backscatter coefficients. Materials and methods: This study is carried out in one of the most important rice growing areas in Sulawesi, Indonesia where is located within the Sunda Islands The Lore-Lindu National Park, covering an area of 229.000 hectares. This area is placed in the centre of the study region of the STORMA project. For the purpose of the study, the area is divided into two classes, where 28% is rice and 72% is non-rice fields. ENVISAT/ASAR satellites images for six months, from 4th February to 28th July 2004 have been utilized. All polarization modes of the imagery (HH, HV, VV, VH) have been investigated. Due to the lack of precise information about the timetable planting of paddy patches we only used the backscatter change responses of different rice fields during the six months for this work. Data analysis procedures are included in two main pre-processing and processing stages. As the original SAR data has many radiometric and geometric distortions, the basic and elementary pre-processing steps are carried out. Here, after visual comparison of four de-speckling techniques included Frost filter, Lee filter, Lee filter and Time Series filter in different polarizations (HH, VV, VH, HV), the Time Series filter as the best one has been selected. Geometric correction and radiometric calibration using 1:50,000 DEM have been done which is based on the SARscape algorithm with backward geocoding methodology. In order to discriminate the rice fields, seven separate data sets have been evaluated.Two of them are directly from the original imagery; two of them are based on mean texture parameters obtained from two original data sets; other two data sets are computed based on polarization subtraction; the monthly subtraction; and normalized polarization subtracted. Result and discussion: By the help of Quickbird/MS satellite imagery nine training areas from nine visual separable rice fields have been chosen and using maximum likelihood classifier the whole data sets were classified separately. Finally, the overall accuracy and kappa coefficients are calculated. The final results show the co-polarization with discrimination accuracy about 88% could give the best results and the normalized co-polarization with the accuracy around 80% gave the weakest results. Conclusion The main ambition for this work was based on the multi-temporal Envisat/ASAR satellite imagery to discriminate rice fields. Despite the fact that all data sets used show somewhat similar results, the original Co-Polarized (HH, VV) data set gave the best results. Having the border of rice fields, Multi-temporal SAR data can help to get better results of temporal rice changes. Another result from this work is that texture derivatives of polarized SAR data do not significantly improve the results for the discrimination of rice fields from other crops. Multi-temporal SAR observations are able to characterize the phenological development of rice crops but for enhanced detection of growth stages and better mapping and monitoring of cropping systems, a higher temporal resolution would be desirable.}, keywords = {ENVISAT-ASAR,Multi-temporal SAR images,rice field discrimination}, title_fa = {بررسی قابلیت داده‌های چندزمانة ENVISAT-ASAR به‌منظور تفکیک زمانی و مکانی مزارع برنج}, abstract_fa = {شرایط اقلیمی و جوّی گرم و مرطوب در مناطق زیر کشت برنج در جنوب شرق آسیا منجر به عدم تطابق زمانی در مراحل کاشت، داشت و برداشت در مناطق مختلف از یک ناحیه زراعی و حتی در مزارع مجاور گردیده است. علاوه بر تفاوت‌های ناشی از دوره‌های زمانی کشت، که ضرورت استفاده از داده‌های ماهواره‌ای چندزمانه را دوچندان کرده است، مناطق زیر کشت برنج در جنوب شرق آسیا غالباً مناطقی ابری هستند که ضرورت استفاده از فناوری تصویربرداری ماهواره‌ای فعال، نظیر رادار (RADAR) و سار (SAR)، را در این مناطق کاملاً آشکار می‌سازند. هدف از پژوهش حاضر، بررسی قابلیت داده‌های ماهواره‌ای چندزمانه ENVISAT-ASAR به‌منظور پایش و تفکیک مکانی و زمانی مزارع برنج است. درة پالولو، سولاوزی مرکزی، در اندونزی به‌عنوان منطقة مورد مطالعه انتخاب گردیده است. تصاویر مورد بررسی در مُد چند ـ پلاریمتریک به‌وسیلة ماهوارة ENVISAT در یک بازة زمانی از چهارم فوریه تا بیست‌وهشتم ژوئیه سال 2004 میلادی گرفته شده‌اند. داده‌های مورد بررسی شامل دو مجموعة داده‌ایِ اولیه و پنج مجموعة داده‌ای ثانویه (داده‌های حاصل از عملیات جبری بر روی داده‌های اولیه) است. داده‌های اولیه یا خام شامل اینهاست: 1) Co-Polarized HH, VV و 2) Cross-Polarized HV, VH و داده‌های مشتقی یا ثانویه شامل: 1) میانگین بافت داده‌های Co-Polarized ، 2) میانگین بافت داده‌های Cross-Polarized، 3) تفریق زمانی داده‌ها، 4) تفریق Polarization و 5) تفریق Polarization نرمال‌شده. در پژوهش حاضر، رابطة مشاهده شده بین تغییرات ناشی از رشد گیاه و میزان بازخوردی ثبت‌شدة سنجنده به‌عنوان اطلاعاتی مفید برای تفکیک مزارع برنج با استفاده از تصاویر چندزمانه مورد بهره‌برداری قرار گرفته‌اند. به‌منظور بررسی دقت نتایج به‌دست آمده،‌تصاویر ماهواره‌ای Quickbird چندطیفی با قدرت تفکیک فضایی بالا (4/2 متر) که تقریباً همزمان با داده‌های ENVISAT-ASAR برداشت گردیده است، در کنار اطلاعات حاصل از کار میدانی، مورد استفاده قرار گرفت. بررسی نتایج به‌دست آمده از تفکیک مکانی مزارع برنج حاکی از بالاترین میزان دقت کلی (88 درصد) برای مجموعه دادة اولیة Co-Polarized بوده در حالی‌که مجموعه دادة ثانویه Co-Polarized نرمال‌شده کمترین میزان دقت کلی (80 درصد) را ارائه کرده است.}, keywords_fa = {تفکیک زمانی و مکانی مزارع برنج.,داده‌های چندزمانة SAR}, url = {https://jphgr.ut.ac.ir/article_21522.html}, eprint = {https://jphgr.ut.ac.ir/article_21522_ff6fb856d20aadcf541ad5c6b38e7c3e.pdf} } @article { author = {Shafiee, E and Alavi, A and Naderi Mighan, N}, title = {Active Tectonic in Binalud Mountain with Respect to Morphotectonic}, journal = {Physical Geography Research}, volume = {41}, number = {70}, pages = {-}, year = {2010}, publisher = {University of Tehran}, issn = {2008-630X}, eissn = {2423-7760}, doi = {}, abstract = {Introduction Tectonic of Binaloud mountain ranges is controled by thrust faults system and folds related to these faults. Parts of this mountain ranges and Neyshabour plain is as study area in north eastern Iran and between latitudes 36° 11´ 00 to 36° 30´ 00 and longitudes 58° 35´ 00 to 59° 00´ 00. In this paper we first study morphometric indices in this area then analyze drainages and allovial fans to identify activity of Binaloud mountain. Materials and Methods In order to identify activities in Binaloud mountain, studing morphometric indices and analysis of drainage network together be done. The first step for calculating morphometric analysis in the region is to digitize topographical maps with the scale 1:50000 by ArcGIS software to extract required data and then morphometrical data is formulized and calculated exactly and the results is interpreted. Results and Discussion A:Morphometry Some morphometric indices that calculated in this paper are: 1&2:Mountain-front Sinuosity(smf), Relic Mountain Fronts ( Facet % ) To determine relative activity in mountain front of the area has been divided in to three parts along Bozhan, Miraabad and Damanjan rivers and elevation 1500 m is assumed as mountain front. In part 1, Smf index is obtained 1.51 , in part 2 ,2.6 and in part 3,1.69. Also in part 1,2,3 Facet% index is equal with 85%,64% and 79% respectively, And reveal that relativly activities is not the same in Binaloud and part 1 is more active than the other parts ( Figure 2 ). 3:Drainage Basin Asymmetry(AF) To this aim , we consider three drainage –basine ( figure 3 ). Values of AF are calculated for basine 1,2 and 3 are 29%,66% and 20% respectively that basine 3 shows more asymmetry than other basines. 4:Topographic Symmetry Factor (T) Values of T for basines 1,2 and 3 are 46%,40% and 58% respectively that basine 3 represents more asymmetry than other basines. 5: Ratio of Valley-floor Width to Valley Height ( Vf ) For calculating this index, 25 stations in this area are considered, that stations numbers 25,24,23,22,21,2,17,16 and 15 indicate less uplift than other stations (table 1). Vf index analysis indicates that the gradual forwarding towards the north and interior parts of Binaloud mountains , we encounter reduction in the relative uplift and tectonic activities ( figure 4 ). B. Analysis of Drainage Network 1: Quantitative Analysis Relationship between Drainage Pattern and Trend of Faults Fractures wich are occured in the area have been suffering erosion gradually and have created parallel and perpendicular valleys to faults. In order to study this research carefully, lineament map was prepared based on the drainage patterns. (Figure 5). To comparison and interpretation of changing the direction drainage, according to drainage basins, study area has been divided into 8 parts and then for each part is drawing a Rose diagram (Fig. 6). The dominant trend of streams in all the area under study is perpendicular to the thrust fronts that is both due to the topographical slop caused by thrust movements and topographical uplifts and crossed structures with faults from NW-SE. 2:Analysis of the Iso- ase Lines The iso- base lines analysis generally consists of two consecutive stages: 1 –determin order of river -2 The iso-base lines mapping (Iso-base map) interception between order 1 that is the youngest category of a erosional category system with topography lines, provid a map that indicates erosion surface (Iso-base map). analysis of iso –base lines may be a useful method to discover young tectonic processes. Because abnormalities in these surfaces in study area are approximately coincided to structural lineament. The study of iso base maps indicates that even the youngest streams ( quaternery) are influenced by tectonic movements and not erosion! It means that tectonic movements and uplifts of the area prevail over erosion. 3: Alluvial Fans In a great part of the area, the young alluvial fans have been created at the nose of the older alluvial fans and in some points being more advanced and have covered the older alluvial fans that is an evidence to the severe uplifts along with the young faults adjacent the valley indicating the continuation of recent tectonic activities in the area. (Figure 8 ). Conclusion Morphometric indices that are calculated, analysis of drainage network and alluvial fans indicate active tectonic in the area and important role of faults in development of dranaige. The study alluvial fans, Confirm active uplifting in the region affected by young faults between mountains and plain.}, keywords = {Alluvial fans.,Binalud mountain,Drainage,Iso-base line,Morphotectonic,Neyshabour,rose diagram}, title_fa = {تکتونیک فعال در رشته‌کوه بینالود با تکیه بر بررسی‌های مورفوتکتونیکی}, abstract_fa = {منطقة مورد مطالعه، بخشی از رشته‌کوه بینالود است که بین عرض‌های جغرافیایی´11 ْ36 و´30 ?36 شمالی و طول‌های جغرافیایی´35 ?58 و ?59 شرقی واقع شده است. هدف این پژوهش بررسی دقیق نقش تکتونیک فعال در توسعة ساختارها، براساس بررسی‌های مورفوتکتونیکی و مورفومتری است. اولین گام به‌منظور انجام مطالعات مورفوتکتونیکی در منطقة مورد مطالعه، تهیه اطلاعات لازم و موجود از قبیل نقشه‌هاست. در این راستا، نقشه‌های توپوگرافی با مقیاس 50000/1 تهیه گردید و به‌وسیلة نرم‌افزار ArcGIS دیجیتایز شد. سپس محاسبات مورفومتری به‌طور دقیق و کامل به‌وسیلة این نرم‌افزار انجام گرفت و نتایج حاصل تفسیر شد. با توجه به اندیس‌های مورفومتری محاسبه‌شده (نامتقارن بودن حوضه آبریز، سینوسیتی پیشانی کوه، درصد مسطح‌شدگی پیشانی کوهستان، و نسبت پهنای کف دره به ارتفاع آن) منطقة مورد مطالعه به‌طور کلی از نظر تکتونیکی فعال است، ولی با توجه به تقسیم‌بندی انجام‌شده، فعالیت نسبی در همه جا یکسان نیست. وجود آبراهه‌های گسلی (تأثیر زمین‌ساخت بر ایجاد شبکة آبراهه‌ها) و مخروط‌افکنه‌های جوان در رأس مخروط‌افکنه‌های قدیمی، گواه بالاآمدگی شدید در امتداد گسل‌های جوان مجاور دشت است، و این نظر را تحکیم و تقویت می‌کند که بینالود به خاطر موقعیت خاص زمین‌ساختی که دارد (محل برخورد صفحات ایران و توران و زمین‌درز پالئوتتیس) از لحاظ تکتونیکی فعال و در حال بالا آمدن است.}, keywords_fa = {آبراهه‌های گسلی,بینالود,تکتونیک,مخروط‌افکنه.,مورفومتری}, url = {https://jphgr.ut.ac.ir/article_21523.html}, eprint = {https://jphgr.ut.ac.ir/article_21523_3a6e7c4b5c0ac251f186e961399867c7.pdf} } @article { author = {Mokhtari, S and Soltani Fard, Soltani Fard H and Yavari, A}, title = {Consideration of the Changing and Self-Organizing Trend in Hur-Al-Azim Wetland by Using Image Processing to Refer Landscape Ecology Approach-Khuzestan-Iran}, journal = {Physical Geography Research}, volume = {41}, number = {70}, pages = {-}, year = {2010}, publisher = {University of Tehran}, issn = {2008-630X}, eissn = {2423-7760}, doi = {}, abstract = {Introduction Hoor-al-azim wetland is one of the most important wildlife refuges and marine ecosystems in the south-west of Iran where structure and function has been significantly affected by different changes during the 2 recent decades. Changes in water regime of Hoor-al-azim wetland and human activities are some of the most important factors. Changes in water regime and anthropogenic activities in the region are the most important factors that affected the wetland. nevertheless the foundation of our concerns must be put on the assessment of ecosystem’s ability and determining the system’s self-organizing level for reaching the balance which helps the system to diminish impacts of disturbances. Reviewing and determining self-organizing potential of the system not only can recognize existing mechanisms and indicate a true image of them, but also can show convenient amendatory strategies for reduction or elimination of their impacts. In fact, reviewing self-organizing mechanism in a specific period can give a rather precise image of the progressive and developing or declining process of the system. Materials & Methods Considering the importance of scale in ecology, particularly landscape ecology, the process of degradation was studied in three different scales: patch, zone, and landscape. The basis is maintenance of more valuable patches, relating suitable patches to the Hour (water and habitat patches) for better function of wetland. Using satellite images and interpreting them is fundamental approach in the ecology of wetlands. So in the process of environmental planning for preparing base line studies in areas where sensitive wetlands are subject to local changes this approach is widely used (UNEP, 2001). GIS and RS are some others tools which have been used in this study. In this process and in the first step after field visits some points were chosen as bench marks using GPS for later use in satellite images analysis. ER Mapper6.4 and GIS part Arc view 3.1 software were used for analysis of satellite images. Results and discussion The result of this study from analysis and landscape ecology principles using metrics indicate was showed that the size of disturbance and natural patches have significantly changed between 1991 & 2002 the size of saline, dried and vegetation patches haves increased while the size of matrix and water patches have significantly decreased. Generally based on the findings of this study the trend of metrics in different years and zones. Change of dominant matrix of the area from an area whit both water and vegetation in 1991 to disturbance dried matrix in 2002 spatially in zones 1 & 3 indicates the structural and functional changes in these zones. The amount of disturbance patches in 1991 was lower than in 2002. Amongst disturbance patches have had highest growth and zone 3 has had the highest descending trend. Conclusion The results along with observations show that factors such as road construction, oil digging, lack of criterion and efficient protecting rules causes easy degeneration of the wetland and transforming it in this section. In addition to searing the wetland and transforming it to dry land, building dams on the mouth of wetland also causes acceleration and decrease in the area and water-depth. Another important factor in the downtrend process in Hoor-al azim wetland is dam construction in superior position. Regarding the wetland need for water and the direct relation of this amount of water with wetland size, continuing the current process will endanger the growth and reproduction of unique nautical species. According to study of the region structure in two periods, road construction is developed around the wetland and consequently patched the wetland and led in an increase in dryness and salinity of blobs and drainage of the wetland. And this is indicative of human interference in wetland destruction. It is anticipated that continuing this process will lead in the inability of the system in reviving and consequently self organizing of the wetland and of course continuing this process will destroy the wetland.}, keywords = {Changes,Hur-Al-Azim wetland,Landscape ecology,Metric,self-organization}, title_fa = {خودسازماندهی در تالاب هورالعظیم / هورالهویزه با تأکید بر اکولوژی سیمای سرزمین}, abstract_fa = {تالاب هورالعظیم / هورالهویزه یکی از مهمترین پناهگاه‌های حیات‌وحش و اکوسیستم‌های آبی مشترک بین کشور ایران (جنوب غرب) و کشور عراق و بخشی از تالاب‌های بزرگ بین‌النهرین است که تغییرات مختلف در دو دهه اخیر تأثیرات مهمی بر ساختار و کارکرد این مجموعه گذاشته است. مساحت این تالاب در فاصلة‌ زمانی حدود 20 سال (1367-1345) بین 560000 تا 450000 هکتار گزارش شده است (UNEP, 2001). به دلایل مختلف به مرور زمان بخش وسیعی از آن خشک شده و در سال 1991 وسعتی معادل 310000 هکتار داشته است. روند تحولات هور بر اساس تغییرات در عناصر ساختاری تعریف‌شده در 3 مقیاس (لکه‌، پهنه همگن و کل سیمای سرزمین) و در دو دوره زمانی 1991 و 2002 به کمک متریک‌ها مورد ارزیابی قرار گرفته است. نتایج نشان می‌دهد که روند تغییرات مشابه (خرد شدن و ...) به تفکیک مکان، متفاوت و در برخی پهنه‌ها شدیدتر است. بخش مهمی از این تغییرات بیشتر به علت فعالیت‌های توسعه ضمن نادیده گرفتن تأثیرات پایین‌دست آنان در مقیاس کل سیمای سرزمین است، که کلیه کشورهای مرتبط در بروز عوارض و تأثیرات توسعه سهیم‌اند و از این رو انجام اقدامات اصلاحی به‌منظور جلوگیری از روند تخریب تالاب هورالعظیم مستلزم اقدامات مشترک دو یا چندجانبه و در برخی موارد با قبول مسئولیت یک کشور اولویت می‌یابد.}, keywords_fa = {تالاب هورالعظیم / هورالهویزه,تصاویر ماهواره‌ای,تغییرات,خودسازماندهی,سیمای سرزمین,متریک.}, url = {https://jphgr.ut.ac.ir/article_21524.html}, eprint = {https://jphgr.ut.ac.ir/article_21524_fadb559111c8aff4e61f3469524974cc.pdf} } @article { author = {Modirian, R and Babaeian, I and Karimian, M}, title = {The Optimum Configuration of RegCM3 Model for Simulation of Precipitation and Temperature at Autumn Seasonal over Khorasan Region in 1991-2000}, journal = {Physical Geography Research}, volume = {41}, number = {70}, pages = {-}, year = {2010}, publisher = {University of Tehran}, issn = {2008-630X}, eissn = {2423-7760}, doi = {}, abstract = {Introduction New meteorological numerical methods are developed into general circulation climate models since 1970, therefore. And different climatic models have been developed. Regional Climate Model (RegCM3) is used for climate studies and dynamic downscaling of atmosphere general circulation models output. Until now, many studies have been done using this model. Sensitivity of RegCM Model to different cumulus scheme for winter precipitation 1997 and 2000 are demonstrated by Babaeian and et al (2007). Result showed That Grell scheme with approximately 20% errors have good ability for winter precipitation simulation of Iran. Onol and et al (2009) have been investigated RegCM skill over Mediterranean region countries by using Kuo scheme. They found that annual mean simulated temperature is greater than CRU data. In this paper according to the role of autumn precipitation in water resource providing of the Khorasan area and for calibration and validation of RegCM3 as a research and seasonal prediction tool, a ten years Climate of Khorasan has been modeled for autumns 19991-2000. Materials and methods In this article, RegCM3 model is used for simulation of autumn precipitation and temperature over Khorasan. RegCM was originally developed by Giorgi et al (1993a, 1993b) and then improved and new generation released by Giorgi and Mearns (1999) and Pal et al. (2000). Dynamical core of the RegCM3 is fundamentally equivalent to the hydrostatic version of the NCAR/Pennsylvania State University mesoscale model MM5 (Grell et al., 1994). Surface processes are represented in the model using the Biosphere-Atmosphere Transfer Scheme, BATS. The non-local vertical diffusion scheme of Holtslag et al. (1990) is used to calculate the boundary layer physics. In addition, the physical parametrization is mostly based on the comprehensive radiative transfer package of the NCAR Community Climate Model, CCM3 (Kiehl et al., 1996). The mass flux cumulus cloud scheme of Grell (1993) is used to represent the convective precipitation with two possible closures: Arakawa and Schubert (1974) and Fristch and Chappell (1980). The Configuration of RegCM3 Model Optimize for Simulation of Precipitation and Temperature at Autumn Seasonal (September, October & November) in 1991-2000 The model domain covers whole of Iran and centered at 35°N, 57°E. Model is ran with a horizontal resolution of 15 * 15 km. The domain is roughly stretched over the latitude 55 to 61.5?N and longitude 30 to 40?E. RegCM may use initial and lateral boundary conditions from global analysis dataset, the output of a GCM or the output of a previous RegCM simulation. In our experiments these driving datasets are compiled from the Abdus Salam International Centre for Theoretical Physics. Modeled precipitations have been compared by both observed and CMAP data and modeled temperatures have been compared by observed and NCEP reanalysis data. Result and discussion Autumn precipitation in 1991-2000 simulated by RegCM3 and their seasonal bias is calculated for Grell-AS, Grell-FC, Kuo and Emanuel scheme relative to CMAP and observation data from equation 1: Bias = (1) Table 1 show Comparison between simulated and observed precipitation bias. According to table, bias maximum are found -209.9 mm in Grell-AS scheme at 1993. Table1. Comparison between simulated and observed precipitation bias over khorasan province (mm) Kuo Grell-FC Emanuel Grell-AS OBS year -39.1 -39.5 -39.1 -148.7 149.2 1991 -37.1 -38.5 -39.5 -64.1 65.3 1992 20.2 16.5 19.2 -209.9 260.8 1993 38.5 28.5 28.2 27.4 505.6 1994 -12.4 -17.3 -24.2 -19.7 224.4 1995 -12.3 -12.5 -16.2 -16.7 233.9 1996 18 -3.2 2.2 -8.2 752.5 1997 -32.9 -34.4 -33.2 -35.6 68.9 1998 -1.4 8.3 5.5 6.8 421.5 1999 -13.6 -13.2 -13.8 -16.4 595.1 2000 -7.1 -10.4 -11.1 -51.8 327.7 mean Comparison between simulated and observed temperature bias show that Grell-FC and Emanuel are better than cumulus scheme (see table 2). Table2. Comparison between simulated and observed temperature bias over khorasan province (°C) Kuo Grell-FC Emanuel Grell-AS OBS year -5.4 -5.4 -5.02 -4.6 16.2 1991 -5.0 -4.7 -5.3 -4.7 16.1 1992 0.1 0.2 0.5 0.1 9.2 1993 -0.6 -0.3 0.2 -0.3 13.4 1994 -0.8 -0.5 -0.2 -0.6 12.1 1995 -1.0 -0.7 -0.6 -0.7 9.1 1996 -2.2 0.4 0.6 0.4 9.7 1997 -0.7 -0.6 -0.4 -0.6 12.9 1998 -2.0 2.3 -0.1 -0.6 9.8 1999 -0.4 -2.0 -0.6 -0.7 8.9 2000 -1.8 -1.1 -1.1 -1.2 11.7 mean Conclusion Comparing to the observed precipitation, minimum mean monthly and seasonal bias are found in Kuo parameterization scheme by -0.9 and -7.1 mm, respectively and minimum mean absolute errors are found in Grell-FC scheme by 19.3 and 21.3 mm. relating to the CMAP precipitation data minimum seasonal bias are found to be in Emanuel scheme by 9.3 mm. Comparison the modeled temperature shows that the minimum monthly and seasonal biases are found in Grell-FC scheme by -1.1 °C. Minimum error was -3.4°C in Grell-FC scheme by comparing the modeled data to NCEP reanalysis data. Overally, it can be conduced that Grell-AS has no suitable skill for modeling monthly to seasonal precipitation and temperature of the Khorasan province. The results of this paper can be used in operational seasonal predictions and research purposes as well.}, keywords = {autumn,Climate Modeling,Khorasan,precipitation,RegCM3,temperature}, title_fa = {پیکربندی بهینه مدل RegCM3 برای شبیه‌سازی بارش و دما در فصل پاییز منطقه خراسان در دوره 2000-1991}, abstract_fa = {با توجه به اهمیت بارش‌های پاییزه و دما در تأمین منابع، و نیاز آبی محصولات کشاورزی و با هدف ارزیابی و واسنجی مدل اقلیمی RegCM3 برای دستیابی به مدل اقلیمی متناسب با شرایط اقلیمی استان به‌منظور انجام مطالعات و پیش‌بینی‌های اقلیمی، بارش و دمای فصول پاییز استان خراسان در یک دوره ده‌ساله به‌وسیلة مدل مذکور شبیه‌سازی شد. در این مطالعه از مدل اقلیمی RegCM3 با قدرت تفکیک افقی 15 کیلومتر و چهار طرح‌وارة مختلف گرل FC، گرل AS، کو و امانوئل برای دورة ده‌سالة 1991 تا 2000 استفاده شد. نتایج مدل‌سازی بارش با داده‌های واقعی و CMAP و نتایج دمای مدل‌سازی شده با داده‌های دیده‌بانی شدة ایستگاه‌های هواشناسی استان و داده‌های دمای مرکز NCEP مقایسه شدند و خطای مطلق میانگین و اریبی آنها محاسبه شدند. کمترین میانگین اریبی فصلی نسبت به بارش واقعی به میزان 1/7- میلی‌متر در طرح‌وارة کو، و کمترین اریبی میانگین فصلی نسبت به داده‌های CMAP به میزان 3/9 میلی‌متر در طرح‌وارة امانوئل مشاهده گردید. در مدل‌سازی دمای فصل پاییز، ‌کمترین اریبی فصلی در مقایسه با داده‌های دیده‌بانی شده به میزان 1/1- درجه سانتی‌گراد در طرح‌وارة گرل FC رخ داد. در مقایسه با داده‌های دمای مرکز NCEP نیز طرح‌وارة‌ گرل FC با اریبی سرد oC4/3- دارای کمترین خطا بود. در تحلیلی کلی می‌توان گفت که طرح‌وارة گرل AS توانمندی مناسبی برای مدل‌سازی بارش و دمای استان ندارد. نتایج این تحقیق می‌تواند در مراکز پیش‌بینی عملیاتی اقلیمی برای صدور پیش‌بینی‌های فصلی مورد استفاده قرار گیرد.}, keywords_fa = {بارش,پاییز,خراسان,دما,مدل RegCM,مدل‌سازی اقلیمی}, url = {https://jphgr.ut.ac.ir/article_21525.html}, eprint = {https://jphgr.ut.ac.ir/article_21525_ac95f5e827a44f576016da5e2489e93f.pdf} }