ORIGINAL_ARTICLE
Spatial Analysis of Long Duration Droughts in Iran
Extended AbstractIntroductionDrought is one of the devastating hazards of human history. It can occur in all times and anyplaces. Drought is a regional event that its occurrence in many world zones cannot be avoided.It is more important than other natural misfortunes due to loss of life and property and socialfactors. This event is more display in arid zones such as Iran for the sake of regionalcharacteristics like small precipitation, intensity in oscillations of rainfall in different years,inappropriate distribution of the rainfall in a period of years and the great fluctuations inplaceand time of the rainfall. For this reason this research has studied the severity and spatialorganization of these droughts over the country.MethodologyImportant parameters that influences drought are temperature and precipitation. In this research,in order to make a spatial analysis of the long duration droughts in Iran, the precipitation datawere used. For this reason the monthly precipitation of 70 long period stations during 1976-2005 were obtained from the Meteorological Organization of Iran.Researchers all over the world offer different methods for study of the droughts. One ofthese is Standardized Precipitation Index (SPI). This method was developed by McKee,Doesken, and Kleist (1993) to analyze the impact of precipitation deficit on groundwater,reservoir storage, soil moisture, snowpack, and stream flow in different time scales for definingand monitoring the phenomenon. These time scales reflect the impact of drought on theavailability of different water resources. Soil moisture conditions respond to precipitation
anomalies in a relatively short time scale. Groundwater, stream flow, and reservoir storagereflect the longer-period precipitation anomalies. For these reasons, McKee et al. (1993)originally calculated the SPI for 3, 6, 12, 24, and 48 months time scales. The SPI computes thetemporal frequency and anomalies of droughts. It can also be used to determine periods ofanomalously wet events. The SPI is recognized as a better quality model compared to othermodels. The advantage of this index is that allows the analyzer to determine the number ofoccurrences of droughts in different stages of time. In the other words, it is, because of the nondistance of this index that we could use of it to compare information of different zones andmake carefully anextent of drought maps. The other advantage of this index is that it ismeasuring the drought function of probable density so that you can perform more analysis aboutthat. The study has used the SPI method for a period of12 and 24 months during the 1976-2005.The spatial distribution of the drought was interpolatedvia ordinary kringingin the ArcGISenvironment.Results and DiscussionIn this study SPI time series were calculated in time scales of 12 and 24 months. Then, thefrequency and spatial distribution of droughts were prepared and analyzed using theGeostatistics methods (Ordinary Kringing). These results have showed that the intensive 12-months period droughts were frequent in the east, southwest, central, and western parts of thecountry ( for example Birjand Station 8%, Ramhormoze Station 6% Ilam Station 5% and SirjanStation 5%), while the southeast and northern parts experienced moderate and weak droughts.But the 24- months droughts were intensive in the eastern parts of the country(for example,Tabass Station 6%,Ramhormoze Station 6%,Iranshahr Station 6%, and Sirjan Station 5%). Thismeans that the longer droughts are common in the east, where they affect the underground waterresources.ConclusionDrought is one of the devastating hazards inhuman histories. The occurrence of the phenomenonis possible in any time and places. Iran as an arid country with fragile climate is prone tofrequent droughts. For this reason this research has studied the severity and spatial organizationof these droughts over the country. The study has used SPI method with the 12 and 24 monthsscales during the 1976-2005 periods. The spatial distribution of the drought was performed viaOrdinary Kringingin the Arc GIS software.The results have indicated that the 12-month period droughts were intensive in the east,southwest, central, and western parts of the country while the southeast and northern partsexperienced moderate and weak droughts. But, the 24- months scale droughts were intensive onthe eastern parts of the country. This indicates that the longer droughts are common in the east,where they affect the underground water resources.
https://jphgr.ut.ac.ir/article_35831_077ad630608521ab35f862e2327aee11.pdf
2013-11-22
1
12
10.22059/jphgr.2013.35831
Droughts
Iran
Medium and Long Droughts
Spatial Analysis of Droughts
SPI
Drought Index
omolsalameh
Babaee
o.babaee43@gmail.com
1
Assistant Prof., Dep. of Geography, Payame Noor University
LEAD_AUTHOR
Bohlool
Alijani
bralijani@gmail.com
2
Prof. of Climatology and Director of the Center of Excellence for Spatial Analysis of Environmental Hazards, Dep of Geography, Kharazmi University
AUTHOR
ORIGINAL_ARTICLE
Detection of the Snow Cover Area Using NOAA-AVHRR in Shahcheraghi Dam Basin
Extended AbstractIntroductionSnow, as one of the basic factors of water supply, plays an important role in water resourcesmanagement, especially in areas with cold winters and warm summers. The data obtained fromsnow gauges as well as temperature and precipitation time series data are generally being usedto develop experimental models in order to estimate the spatial and temporal distribution ofsnow in watersheds. However, when reliable snow or other necessary climatic data records donot exist, using proper substitutes becomes essential. Hence, the snow cover area (SCA) derivedfrom satellite images can be used as a representative of the amount of snow in a basin.Moreover, Remote Sensing (RS) is a useful tool in identifying snow and calculating SCA inmountainous regions with low accessibility and deficiency of snow gauges. Accordingly, theSCA time series data can then be used as input dataset in flow forecasting by hydrologicmodels.This paper aims to study the snow cover area of Shahcheraghi Dam basin in order to collectthe necessary input data for developing dam inflow forecasting models. The basin is located inthe north of Semnan province, Iran. The area of the basin is 1373km2 and the annualprecipitation and mean temperature of the basin are 124mm and 12°c, respectively. Since there
is no active snow gauges within the basin and also there is only one weather station with reliabletemperature records in the region, NOAA satellite images have been used for defining the SCA.MethodologyIn this paper snow cover area detection in Shahcheraghi dam basin has been studied usingNOAA-AVHRR images in a 22-year period from 1986 to 2007. In order to improve theprecision of calculated monthly SCAs, an image per 10 days was processed (3 images permonth). The highest value of SCA among the three calculated values in each month is selectedas the final SCA data of the month. Since during this period of time two different sensors ofAVHRR-2 and AVHRR-3 have recorded data in different spectral bands, it is necessary to usedifferent algorithms in separating snow from other phenomena including cloud and land cover.By employing the differences between the spectral characteristics of snow compared with otherphenomena, the snow covered area can be separated. Therefore, two threshold algorithms areused to separate SCAs. These algorithms are based on grouped conditions of comparing albedoof bands 1 and 2 and brightness temperature values of thermal bands. The most significantdifference between the conditions in these methods is using the albedo of band 3A (1.6μm) inAVHRR-3.On the other hand, it is necessary to evaluate the numerical difference among the snowseparation methods as they may significantly affect the statistic parameters of the time series.Moreover, two trend detection methods are used to examine whether significant trends in thetime series exist. The hypothesis-based linear regression and non-parametric Mann-Kendallmethods are applied to the maximum annual SCA data.Results and DiscussionBased on the NOAA-AVHRR image properties, snow cover area is detected by theaforementioned threshold algorithms. The results show that the maximum amount of SCAoccurs in January. Generally the snow settlement in the basin is from December to April whilethere is no record of snow from May to September, which is due to the abrupt air temperaturerise in spring. Furthermore, the difference between the snow separation methods is analyzed bycomparing two successive images of the basin, taken by different sensors on 5th November2003. One of the images contains channel 3B which includes thermal infrared band and theother contains channel 3A that scans near infrared wavelengths. Accordingly, the SCA ofAVHRR-3 sensor which contains channels 3A has been calculated 4% more than the SCA ofAVHRR-2 which records channel 3B. Moreover, the result of applying trend detection testsshows that the SCA time series has no evident linear or monotonic trend.ConclusionThe trend analysis on the SCA dataset has demonstrated that no significant statistic trend existsin the SCA time series. Moreover, the difference between calculated values of the SCA derivedfrom two different AVHRR-2 and AVHRR-3 sensors does not affect the reliability of the SCAdataset, considering the area of the basin. Hence, as a representative of the snow in Shahcheraghi basin, it is possible to consider the calculated snow cover area data as an appropriate input for hydrologic flow forecasting models.
https://jphgr.ut.ac.ir/article_35832_fdb196bb2844c79863e8bc05222a6775.pdf
2013-11-22
13
29
10.22059/jphgr.2013.35832
Brightness Temperature
NOAA-AVHRR
remote sensing
Shahcheraghi Reservoir
Snow Cover Area Trend
Mohammad Ebrahim
Banihabib
banihabib@ut.ac.ir
1
Associate Prof., Dep. of Irrigation and Drainage Engineering, College of Abureihan, University of Tehran
LEAD_AUTHOR
Farimah Sadat
Jamali
f336jamali@gmail.com
2
M.Sc. Water Resources Engineering Graduate, Dep. of Irrigation and Drainage Engineering, College of Abureihan, University of Tehran
AUTHOR
Bahram
Saghafian
saghafian@scwmri.ac.ir
3
Prof. of Soil Conservation and Watershed Management Research Institute (SCWMRI)
AUTHOR
ORIGINAL_ARTICLE
A Comparative Study on Empirical Methods for Estimating Effective Rainfall for Rainfed Wheat Crop in Different Climates of Iran
Extended AbstractIntroductionAmong factors affecting crop production, especially rainfed crops, the rainfall and itsdistribution during crop season have a significant role. In addition, all the precipitation that fallsduring the growing season does not have the same effect on crop yield, and is not used inagriculture. So, quantification of Effective Rainfall (ER), as a portion of the precipitation whichis stored in plant root zone and meets the needs of evapotranspiration requirements in differentclimatic zones is an essential component of water resources in rainfed wheat areas. Effectiverainfall used in this study is “That portion of the total precipitation on the cropped area, during aspecific time period, which is available to meet the potential evapotranspiration requirements inthe cropped area. A precise estimation of effective rainfall is still needed not only for planningand management of rainfed wheat production, but also for risk management strategies in farms.Since a precise estimation of effective rainfall is necessary for increasing agriculturalproduction, major challenge is to design a soil-water balance model that provides more accuratecalculation of effective rainfall. The main goal of this study was to compare different effectiverainfall estimation methods for rainfed wheat.
MethodologyIn this study, we adopted a two-layer soil–water balance (SWB) model. In the model,not onlythe portion of precipitation retained on root zone in current day is included, but a portion of theprevious day’s precipitation saved between the previous and current root-zone development isalso added to the effective rainfall of the current day. In the model, the soil reservoir is dividedinto two layers;1) an active layer in which roots are presented at any given time, t, and from which bothmoisture extraction and drainage could occur;2) immediately below the active layer, there is a passive layer of depth (maximum root depthrootdepth attained any day after sowing) from which only drainage would occur.Because of a high cost associated with direct measurements, estimate of effective rainfallcomponent is often based on empirical models. The aim of this study is to compare empiricalmethods of effective rainfall estimation with a proposed method based on soil-water balanceequation. Following, six methods have been used to calculate effective rainfall for 21 agrometeorologicalstations of Iran:• Renfro Equation method• U.S. Bureau of Reclamation method• Potential Evapotranspiration/Precipitation Ratio method• USDA-SCS method• FAO method• TR21/SCS methodFor this purpose, four groups of data (including weather data, phenological data, soilcharacteristics, and wheat yield data) were used relevant to the 21 agro-meteorological stationsrepresenting arid, semi-arid, semi-humid, and humid regions of the country. Before using theweather data for estimating effective rainfall, data reconstruction was performed using Normalratiomethod (where required).Results and DiscussionThe results of calculating the effective rainfall for rainfed wheat crop at the 21 agrometeorologicalstations, using selected methods and comparing the different methods ofestimating effective rainfall, showed that: 1) in spite of data limitations, the new procedure hadappropriate performance in estimation of that part of wheat yield which could only be explainedby effective rainfall. Therefore, this method can be used as an efficient tool in computer-basedprograms developed for agricultural risk management of rainfed area. 2) It has been observedthat the higher the values of de Martonne Aridity Index, the lower is value of “effectiverainfall/rainfall during the cropping season”. 3) The best result for arid and semi-arid climateswas obtained by PET/P method (d-index= 0.8), and for semi-humid and humid climates by FAOmethod (respectively 0.9 and 0.8), and USDA-SCS method (respectively 0.8 and 0.7).ConclusionA soil water balance model for estimating effective rainfall is applied for evaluating theaccuracy of six established effective rainfall estimation methods.
Renfro Equation provides an initial approximation based on aridity factor. The accuracy ofthis method is very low and it is exclusively empirical. USBR method considers only the runoff.The accuracy of this method is low and is not suitable for wide application. PET/PrecipitationRatio method takes the first approximation by runoff, soil and aridity factor. This method issuitable for preliminary plans, and is more effective than other methods, nearly in all regions.USDA- SCS method takes the first approximation of soil and crop beside aridity factor. Thismethod is suitable for those areas that have low intensity of rainfall and high infiltration rate.
https://jphgr.ut.ac.ir/article_35833_b7dc3c3b81e86772f9107222fdc416fd.pdf
2013-11-22
31
46
10.22059/jphgr.2013.35833
Effective Rainfall
Empirical Methods
Iran
Rainfed Wheat Crop
Two-layer soil-water balance model
Jaber
Rahimi
jaberrahimy@ut.ac.ir
1
Ph.D. Student of Agrometeorology, Meteorological Division, Dept. of Irrigation and Reclamation Engineering, College of Soil and Water Engineering, University of Tehran
LEAD_AUTHOR
Javad
Bazrafshan
jbazr@ut.ac.ir
2
Associate Prof., Meteorological Division, Dept. of Irrigation and Reclamation Engineering, College of Soil and Water Engineering, University of Tehran
AUTHOR
Ali
Khalili
akhalili@ut.ac.ir
3
Prof. in Meteorological Division, Dept. of Irrigation and Reclamation Engineering, College of Soil and Water Engineering, University of Tehran
AUTHOR
ORIGINAL_ARTICLE
An Assessment on the Spatial-Temporal Patterns of Songhor’s Archaeological Sites in GIS
Extended AbstractIntroductionDespite academic advances in spatial analysis within archaeology, primary uses of computerbased GIS in archaeology were initiated by Cultural Resource Management (CRM) needs in theworld. In conjunction with the development of environmental GIS data within severalorganizations, other federal agencies saw its potential for the management and spatialrepresentation of archaeological data. Therefore, in other ways, developing methods of analysisand visual representation of data, previously impossible, were started. New methods ofexploratory data analysis became possible and the efficiency within GIS environments formanipulation and analysis of spatial data contributed to exploratory and experimental use of data.Developed in catchment analysis of the 1970 in archaeology was a byproduct of settlementpattern and cultural ecological studies in which archaeologists became interested in the typesand spatial distribution of resources exploited by a given settlement. The concept is based on theassumption that resource use around a settlement is distance dependant and that sites will belocated so that to maximize exploitation of resource. Typically, the area associated with thesettlement was calculated through Euclidian boundary techniques. Yet Euclidian distancemeasures do not take into account aspects of the topography in consideration of distance. Today,
more sophisticated models utilize cost distance to establish distance in the development ofcatchment areas.Other improvements in spatial analysis can also be seen in settlement pattern analysis. WithGIS, archaeologists are now able to explore and analyze multiple variables across a givenlandscape such as distance between archaeological site locations and particular types ofarchitecture and/or artifacts. These variables can be used to discuss issues related to, forinstance, mobility and socio-political development through time. At more micro-scales, GIS hasbeen used to manage and analyze the distribution of artifact types at a given site. This type ofanalysis is useful for understanding the behavioral patterns at a given site and identifyingspecific activity areas within a site through time.MethodologyThis study has tried to analyze the spatial-temporal patterns of Songhor’s archaeological sites inGIS. To conduct the research, the techniques applied for gathering data will be pervasivesurface survey. Accordingly, all archaeological and historical evidence will be identified andthen recorded, in details. The collected data, including 286 sites and monuments from Neolithicto late Islamic period, was reported in 2 volumes. Dating of the sites has been carried out basedon sample recognition and comparing the studies of collected surface data. The materialgathered were divided into six general groups, which are Neolithic, Chalcolithic, Bronze, Iron,Historic and late Islamic period. According to current research, from the total 286 sites, two ofthem belong to Neolithic periods, 32 of them belong to Chalcolithic period, 25 of them belongto Bronze period, 46 of them belong to Iron Age and 147 of sites present the culture of theAchaemanid, Parthian and Sassanian era. Finally, 214 sites and monuments have shown thetraces of the Islamic period which some of them show only a particular time of Islamic era andmostly present the monuments and architecture of this period. Then these archeological sites arechosen as our materials and statistical population.For achieving the research goals, we have used and analyzed geographical information,using Arc GIS 10 Software. By establishing a data bank, as Geodatabase, for the studywecarried out an analysis on spatial distribution of the sites. Thus, we focused on natural factorslike height, slope, Landform, climate, flowing waters, rivers, flora (pasture), and rainfall tounderstand the role and efficacy of each factor in appearance of the sites. Our study made itclear that the ancient settlement patterns of Songhor was highly affected by natural factors suchas flora, water sources, rainfall, and height.Results and DiscussionIn addition, according to this research it has been specified that each of the natural factors haveplayed different roles in the distribution of the ancient sites and there is no same precept for all.Thus, it is necessary that the role of each natural factor to be studied separately. The analysisshows that the area under study is affected by Zagros mountain ranges, height, distance to theriver and dense pasture cover.
ConclusionThis area has a cool climate and height and these factors have created special and differentconditions in forming human settlements relative to other areas in central Zagros. Our studymade it clear that the ancient settlement patterns of Songhor were highly affected by naturalfactors such as height and distance to the river.
https://jphgr.ut.ac.ir/article_35834_2ab21922714ef318c14e1a5dc5ad2d8d.pdf
2013-11-22
47
64
10.22059/jphgr.2013.35834
Ancient Sites
GIS
Songhor
Spatial-temporal Patterns
Mahmood
Heydarian
heydarianm@yahoo.com
1
Assistant Prof., Dept. of Archaeology, Shahrekord University
LEAD_AUTHOR
Alireza
Khosrowzadeh
2
Assistant Prof., Dept. of Archaeology, Shahrekord University
AUTHOR
Majid
Sarikhani
3
Assistant Prof., Dept. of Archaeology, Shahrekord University
AUTHOR
Aman-Allah
Fathnia
4
Assistant Prof., Dept. of Geography, Razi University
AUTHOR
ORIGINAL_ARTICLE
Impact of Different Land-use / Land Cover Types on Soil Quality in Alandan Forest, Sari
Extended AbstractIntroductionSoil is the main source for human basic needs and land utilization. It makes a linkage betweenclimatic and biogeochemical systems and meets a variety of human requirements (Young et al.,2004). An unsuitable land- use change may lead to a decrease in areas of pastures and forests,soil and water pollution, soil quality reduction and lossing land productivity (Islam et al., 1999).Forest destruction and its conversion into agricultural lands and reforestation by broad-leavedand coniferous species are the common forms of forest land-uses in the mountainous Hyrcanianforests in north of Iran. Soil quality as the combination of physical, chemical and biologicalproperties of soil may be altered by changing in soil conditions affected by land use type(Brejda et al., 2000). Impact of different land – uses on soil quality was evaluated by measuringseveral soil properties. The present study aimed to investigate the effect of land use change onsoil physical, chemical and biological properties and soil quality index in managed Beech stand,destructed forest stand, Pine plantation, Ash plantation, and agriculture land in Alandan forests.MethodologyOur study was conducted in Alandan forest, a part of Hyrcanian region in the north of Iran
(latitude, 36° 13´ N; longitude, 36° 10´ E). The experimental area was situated in 1000 m abovesea level and average annual rainfall and temperature were 858 mm and 11.9 °C, respectively.Soil type is Brown forest soil. Five land-use types, here, are including managed Beech stand(Fagus orientalis Lipsky.), destructed forest stand (Carpinus betulus L., Parrotia persica C. A.Meyer) Pine plantation (Pinuse nigra Arnold.), Ash plantation (Fraxinus excelsior L.) andagriculture land (as rainfed farming with wheat and barley). Soil samples were taken in all sitesin August 2010 using 8 cm core based on systematic random sampling design (n=6 in each land– use). The soil samples were transported to laboratory and their physical and chemicalproperties were measured. Calculation of soil quality index involves three main steps:1) definition of a Minimum Data Set (MDS) by expert opinion method,2) score assignation to each indicator by liner mathematical functions,3) data integration in an index.The data were analyzed using one-way analysis of variance (ANOVA) after checking theassumption for parametric test in SPSS v.16 software.Results and DiscussionResults showed that soil moisture were significantly (P<0.05) higher in managed Beech standand destructed stand than other sites. Adding organic matter to soil may lead to increase inconservation of water in soil via reduction of evaporation and transpiration and increase in waterinfiltration rate. Ash plantation showed significantly greater pH compared with managed Beechstand. Ash litter has been shown to be easily decomposable and rich in nutrients and cause highbase cation return to the soil (Norden, 1994b). The lower pH in beech forest compared withother land uses can be explained by slower litter decomposition of this species, which leads toproduction of organic acids and also delays the return of base cations to the soil (Hagen–Thornet al., 2004a). The highest total nitrogen was found in Ash plantation and its lowest amount wasobserved in Pine plantation. The easily decomposable and nutrient-rich litter of ash may supportlarge population of micro-organisms, which could contribute to an increase in soil N (Fried etal., 1989). The low amount of total nitrogen in pine monoculture may be related to slow litterdecomposition in pine species (Neirynck, 2000). Agriculture land showed significantly greaterK compared with other sites. The fertilizer application may result in increasing of Kconcentration in arable soil. The highest Ca concentration was observed in Ash plantation. Ahigh content of base cations in the Ash foliage and its high susceptibility to leaching led toincreased base cation input through fall to the soil (Hagen-Thorn et al., 2004b). Beech stand anddestructed stand showed significantly higher ammonium concentrations compared with otherland uses. The higher ammonium concentrations may be related to higher rates of Net Nmineralization (Garten, 1993). Increasing N mineralization rates and microbial activity havebeen reported as an effect of transient increase in temperature, water content, pH, and labilesources of C and N for microbes (Rutigliano et al., 2007). The highest soil quality was found inAsh plantation and destructed stand and its lowest amount were observed in pine plantation. Thelower value of nutrient and organic C, total nitrogen and soil moisture caused reduction of soil
quality in Pine plantation (Zhaoet al., 2005). In Ash plantation, the presence of herbaceousvegetation may be one of the reasons for better soil quality.ConclusionResults of our study showed that different land – uses can significantly affect soil quality. Soilquality in Ash plantation and destructed forest were the best whereas in Pine plantation was theworst. According to our findings it can be suggested that Ash trees should be admixed withinPine monocultures in order to cause an appropriate soil quality. In that destructed forest showedthe highest soil quality compared with other sites. Thus, those areas should be fenced becausethey are capable to regeneration and forest reconstruction.
https://jphgr.ut.ac.ir/article_35835_f4410fb54510b0bb3e849a2fd889fb4d.pdf
2013-11-22
65
76
10.22059/jphgr.2013.35835
Alandan
Land – use Change
Physical and Chemical Properties of Soil
Soil quality
Maryam
Asadiyan
maryam.asadiyan23@gmail.com
1
Master of Forestry, Sari Agricultural Sciences and Natural Resources University
AUTHOR
Seyed Mohammad
Hojjati
s.hojati@sanru.ac.ir
2
Assistant Prof. in Forestry, Sari Agricultural Sciences and Natural Resources University
LEAD_AUTHOR
Mohammad Reza
Pourmajidian
m.pourmajidian@umz.ac.ir
3
Associate Prof. in Forestry, Sari Agricultural Sciences and Natural Resources University
AUTHOR
Asghar
Fallah
fallah@sanru.ac.ir
4
Associate Prof. in Forestry, Sari Agricultural Sciences and Natural Resources University
AUTHOR
ORIGINAL_ARTICLE
Analysis of Ripple Mark Forms and Nebkha Barriers in Sirjan Playa
Extended AbstractIntroductionStudy about quality and characteristics of wind erosion forms and also relationship betweenthese forms with other environmental landforms is an important criterion in the assessment ofnatural resources. When wind blows on sandy beds, sand grains hop and roll into downwindshaping sand ripples. Morphometry is quantitative analysis of geomorphic characteristics of aregion of landforms (Bayati Khatibi, 2010, 2). Study of surface sand grain size shows that largerripples wavelength are created in the sands and coarse wavelength ripples in finer grain sands(Chorley et al 1985: 434). Ripples are common forms of roughness in desert areas. Ripples arecreated when the wind blows on the sand beds and sands move in the wind direction. In the factripples are gathering sand flows into waves on different landforms surface. Ripple marks arealso the smallest and the most common forms of deserts, which are perpendicular to thedirection of the storm winds and their cross-section is asymmetric (Mehrshahy and Nekounam,2010, 8). Ripple scale is proportional to the wind speed (Tian-De Miao et al, 2001, 1). The windvelocity decrease in leeward of nebkha and this decrease in the wind velocityaffectmorphometric characteristics of current ripple marks in leeward of nebkha (Danin, 1996,7). This research tries to survey effects of nebkha morphometric characteristics onmorphometric properties of ripple marks in Sirjan salt desert.
The study areaSirjan salt desert is in the south west of Sirjan City (located geographical coordinates 28° 46 and29° 59 north latitude and 54° 57 and 56° 27 east longitude). Sirjan salt desert is one of the mostimportant deserts in Kerman. This wilderness area with 1,625 square kilometers of the basin islargest basin in deserts of Isfahan. The basin has a triangular shape of fovea in the southwesterncity of Sirjan. The study area is elongated from south western Sirjan to west of the cityin greenbelt (Klinsli D, 2002, 220).Wind characteristics in the study areaDominant wind in the area during the year is mainly from south west and its average occurrenceis two times per year and its average speed is 5 meters per second. The weakest wind is eastwind with occurrence of 8.8 times, that its average speeds is 3.8 meters per second. Anotherimportant wind flow in the study area is tropical windsMethodologyThe study was designed by randomly tested for 60 samples of five species of nebkhas in Sirjansalt desert. At first, morphometry characterization of the five species of nebkhas includingtamarixmascatensis, Seidlitzia Florida and Reaumeriaturcestanica, plant height, plant canopycover, nebkha height, nebkha diameter, height barrier (total nebkha height and plant height) andalso height and wave length of ripple marks and were measured. Then, regression analysis usedto examine the correlation between morphometric parameters of nebkha and ripple marks.Results and DiscussionThe results about different nebkhas showed that barrier height has the most impact in lengthparameter of the area affected and plant canopy cover diameter has the most impact on a wideparameter of the area. There is also a strong correlation between the morphometric parametersof ripple marks and distance of barrier. These results indicate that the effect of distance ofbarrier on the ripple wavelength is stronger than the effect of that on the ripple wave heightparameter.ConclusionRipple wavelength and height is strongly related to the distance barrier. As the distance is slightand near to the barrier,the wind speed has dropped, and the height and the ripple wavelength isincreased. But with increase in distance of barrier, the height and the ripple wavelengthdecreases. Moreover, nebkhas affectthe ripples in a domain. The domain is more dependantsupon the plant canopy cover diameter and height of barrier. Almost length of the area is triplethan height barrier and its width depends on canopy cover diameter and further more on nebkhadiameter.
https://jphgr.ut.ac.ir/article_35836_e22e91d72928216838b9686c87c75dd1.pdf
2013-11-22
77
94
10.22059/jphgr.2013.35836
Morphometry
Nebkha
Ripple Mark
Sirjan Desert
Wave Height
Wave Length
Mohsen
Pourkhosravani
mohsen_pourkhosravani_2007@yahoo.com
1
Assistant Prof., Dep. of Geography, Shahid Bahonar University of Kerman
LEAD_AUTHOR
Abbas
Vali
vali@kashanu.ac.ir
2
Assistant Prof., Faculty of Geomorphology, Dep. of Geography, University of Kashan
AUTHOR
Tayabeh
Mahmoudi Mohamadabadi
tayebeh.mahmoodi@gmail.com
3
Ph. D. Student of Geomorphology, College of Geography, University of Isfahan
AUTHOR
Narjes
Salari
narjes.salari@yahoo.com
4
M. Sc. Student of Geomorphology, College of Geography, University of Isfahan
AUTHOR
ORIGINAL_ARTICLE
Evaluation of Dust Effect on the Quantitative and Qualitative Growth of Sugarcane Varieties CP57-614
Extended AbstractIntroductionOne of the natural disasters that affected Khozestan province's is the phenomenon undesirableof dust due to its geographical location and its neighborhood with a large expanse of desertregions. When dust sits on leaf crops, it can reduce the amount of light absorption andphotosynthesis and the growth and production will suffer loss consequently (Abdali Dehdezi1390: 19). The effects of dust on leaf surfaces are done in different ways:a) Impact on the process of photosynthesis in plants; Reduction in photosynthetic leafsurface is a function of light intensity reduction. Hirano Takashi (2003: 275) studies in Japanshow that plants exposed to dust are the major sources of risk facing chronic photosynthesis andconsequently reduce the growth face. The 10-5g of dust particles per square meter of leaf areacan reduce photosynthesis significantly.b) The effects of dust on leaf stomata: Dust reduces stomata conductance due to stomataclosure. The effect of dust on reduce the stomata conductance would be greater at time that thesize of dust particles is smaller. Dust particles with a diameter less than (0.05mm) causeddisruption of the mechanisms and functions of the openings leaves.c) The effects of dust on leaf temperature: Dust increase leaf temperature of 4-2°C.Because of dust on the leaf surface will absorb more short waves. Increase in temperature of 3-2°C increase in light respiration of leaf in plants.
d) The effect of dust on the amount of light hitting the plant: The light intensity and daylength effect on the growth and production. Water absorption and evaporation is proportional tothe light intensity completely. Mvchv and colleagues (1993) showed that during the lineargrowth phase, the accumulation of biomass per hectare is linearly correlated with solar radiationreceived.Khozestan as one of the major poles of agricultural province, the epicenter of the injury isthe loss of natural plants. Damage to the agricultural sector in this province, will account for amajor share. Sugarcane crop with a cover nearly 80 thousand hectares of land under cultivationin this province are one of the vulnerable sectors. Thus the objectives of this study are:1. Survey of relationship between quantities of sugarcane yield (weight of single, stemdensity per unit area and product yield) and dust.2. Survey of relationship between the quality of sugarcane (Pol, Brix, purity, recovery andquality of white sugar cane) and dust.3. Survey of relationship between leaf chlorophyll amount and dust density.4. Survey on interactions between nitrogen and chlorophyll.MethodologyThe location of field experiment was Da'bal Khazaei Agro Industry Co. The experiment carriedon varieties 614 CP57-L09-06. Soil type was Silt loam. The test community consists of washingthe leaves and failure to wash the leaves that carried out after dust occurrence each with 21repetitions on each community. Each plot had 7 Farrow. To eliminate the side effects caused bydusts from car traffic on the farm road and irrigation, farm plots was at a distance of 20 m fromthe edge of farm. Plot size was segmentation 200 sqm for each treatment. Chlorophyll leaveswere by chlorophyll meter by 502-Spad Minolta models. This process is performed after eachdust. The plots should be washed. This process carried out after each wash. Plots in each phasewere washed with car wash tank. Cane growth and Lamina sheaths nitrogen and moisture wasmeasured each time after vigorous dust at an intervals period time.Results and DiscussionResults on quality performance show that there are significant different on level of %1 forpurity and on level of %5 for getting amount of sugar and straw quality for test treatments thatindicate on excellence of treatments wash. On the other hand survey of treatment means alsoshow that washing treatment is superior. Based on the results of treatments, there are nosignificant differences on quantitative factors. Student t-test showed that there is no effect of thewashing operation factors on increased performance. Survey of relationship between amount ofchlorophyll and dust density show that student t-test were significant at 1% for both treatments.This means that the presence of dust on the leaves is effective on chlorophyll readings. Theamount of chlorophyll in treatments wash the leaves are higher than failure to wash the leavesconsistently that it due to impaired gas exchange system, carbon dioxide and water vapor andoxygen respectively. The stomata closure with decreasing in sunshine hours has slowing the rateof photosynthesis. This process disturbances the gas exchange and download of sun light that
lead to reduce in photosynthesis and yellow leaves. Finally, it shows as the poor quality of canejuice.The relationship was examined between nitrogen and chlorophyll content of flag leaves.According to the requirements of sugarcane to nitrogen during the growing season, the amountof nitrogen fertilizer is very important. So, we can by measuring of chlorophyll in the plant toestimate the nitrogen concentration. In table and graph, the correlation between chlorophyll andnitrogen lamina clearly shows that this correlation is statistically significant at the 5% level.Using the linear equation and only by reading chlorophyll Machine, we able to achieve nitrogenlevels in each stage of growth.ConclusionThe results of experiments on wash the leaves and failure to wash the leaves treatments showthat washing treatments had higher purity and higher concentration of sugar and straw quality isbetter. Thus, dust has a negative effect on cane quality (yield and quality of sugar cane). Dusthad been affected on the amount of sunlight received by the leaves. Chlorophyll content inleaves has been decreased in the occurrence of dust. So, absorbed nitrogen also has beendecreased. Finally, yield quality is reduced consequently. However, dust has no negative effecton quantitative growth of sugarcane because many factors affect quantitative performance ofsugarcane.
https://jphgr.ut.ac.ir/article_35837_59b97d03521dfff415cdcece70598ec4.pdf
2013-11-22
95
106
10.22059/jphgr.2013.35837
Dust
Qualitative Performance
Quantitative Performance
Sugarcane
Abbas Ali
Arvin(spanani)
a_arvin@pnu.ac.ir
1
Assistant Prof. in Geography, Dep. of Payame Noor University
LEAD_AUTHOR
Sedigheh
Cheraghi
se_cheraghi@yahoo.com
2
Instructor in Dep. of Architecture, Islamic Azad University, Masjed Soleiman Branch
AUTHOR
Shahram
Cheraghi
cheraghishahram@gmail.com
3
Student of Climatology, Payame Noor University, Isfahan
AUTHOR
ORIGINAL_ARTICLE
Investigation about the Effective factors on Pressure Drop in Hydraulic Data in Guilan Plain
Extended AbstractIntroductionGroundwater is one of the essential resources for supplying requirements of drinking water,agriculture and industry. This resulted in establishment of civilization in plains and lands whereare far from rivers of freshwater.Regarding low amount annual rainfall in Iran and loss of water as a result of evaporation,volume of water production is about 128 billion cubic meters. From this volume about 83billion cubic meters form surface water resources and 45 billion cubic meters join thegroundwater by penetration. In recent decades, the growth of population and the need for waterresources have led to an increase in exploitation to these essential sources hidden in the heart ofthe earth.Study area of this research is located in southern coast of Caspian Sea in Guilan Province.The research problem is that in some wells the coefficient of pressure drop shows negativefigures whereas in some other wells these figures are positive. It is not clear that what is theeffect of these changes on exploitation of water resources of the aquifer and how much thiseffect is and in what field it may be. This research tries to recognize the factors that affect thisphenomenon besides recognizing the effective reason in negative coefficient of pressure drop inaquifer and lining of wells and determining scientific results and its applied effects.
MethodologyIn this research, field method and using step back test has been applied to find the reason of thenegativeness of pressure coefficient in available wells in the plain. Thus, through providingnecessary conditions, digging operation and pumping of more than 600 deep wells have beensupervised and controlled. More than 300 regions were directly controlled. Geographicalfeatures in some of sample wells in the region were taken and the selected points were specifiedon the map by using ArcGIS. Statistics and information related to geographical andgeomorphologic conditions and geology of location of the wells and testing scope of pumpingin the selected wells were collected and was analyzed in the form of graphs by SPSS program.Then, the results were analyzed and all wells were classified in separate groups and those withsimilar situation in the view of pressure drop coefficient were assigned in the same groups.Finally, the selected wells have been classified in three different groups.In the next step, the features of wells in each level such as geographical andgeomorphological conditions, geology of constituting sediment layers in location of the wells,texture of surface water and layers in location of them, technical and expert characteristics ofthe company, the quality of digging and supervising system were all evaluated and compared.Common aspects of well was distinguished in each group. Then, after recognition and regardingthe common aspects of the wells belonging to each group it had been concentrated on the wellswhich had negative coefficient of pressure drop.. Being sure about the result, besides repeatingconsiderations on the ground, they have been controlled and evaluated and in some cases thetest has been performed again.Results and DiscussionDoing pumping test for determination of hydraulic features of groundwater aquifer and well isone of the usual methods. In this case, the pumping test has been done in two different methods:one is pumping by fixed rate (shuttle test) for determining aquifer coefficient and pumping byvarying rate (step pumping) for determining well's coefficients. Therefore, the well's coefficientspecification has been possible just by using the result of pumping with varying rate (steppumping). So, in this research by paying attention to the importance of the coefficients, the dataof step pumping is used for determining features and situations of well and aquifer. Beforestarting test first the water level in the wells has been measured. Then, by doing the operationsof digging and tubing of a well, washing and exiting of the fine-grained materials remained in ithas been done by pure water and pumping method. After providing suitable condition for waterarrival from aquifer layers into the well, water pumping operations has been continued withdifferent engine turn until the water level became fixed. During this period water level wasmeasured based on a predetermined timetable. The process of water level changes and itsconstancy was distinguished and from the results (result related to the first step of the test) thecoefficient related to aquifer has been computed. After being sure about the constancy of thewater level (reaching the water level to the dynamic level), well's rate and in another wordengine's turn has been increased and the act of measuring water depth from the surface up to theconstancy of water level in well has been continued as before. This plan has been implemented
at least in four steps with 4 different rates as 4 engine's turns. In the next step, the result of steppumping was analyzed and after finishing field operations and recording figures it wasabstracted in related table.After designing the mentioned table, the coefficient of pressure drop in aquifer (B) has beenobtained by using the curve of especial drop to the rate that the mentioned crossing point of thecurve connect with the widths axis with drawing the related curve. From obtaining pressuredrop in aquifer, the pressure drop in lining network of well (C) was obtained by using y2-y1 (x2-x1) that is, in fact, the slope of especial drop curve to the rate. Finally, after calculating B and C,the table of brief result of pumping is provided.ConclusionConsiderations show that available problems in taking groundwater in Guilan Plain is related tothe nature of the region in terms of sediment texture and hydrologic characteristics of the plain,humanistic factor, the performance of feeding, unsuitable quality of digging and alsoexploitation methods. The groundwater feeding is through different sources such as rivers andnetworks of irrigation channels, floodgate and pools of growing fish that are extensively in theplains, and also free aquifers situated on semi-confined aquifer that have hydraulic balancestate. These sources were useful and can have positive function at increasing the age ofeconomic exploitation of a well. However, due to unfamiliarity of most experts with thementioned phenomenon and varying performance of this phenomenon in different seasons, thewells affected by the mentioned elements will be faced with damages and sometimes it is sosevere that may destroy the well.Considering the effective factors on the pressure drop of hydraulic data in Guilan's Plain bypumping method indicates that the step back method is better for determining hydrauliccoefficient of well. It is suggested that to use this pumping method instead of step pressure.Because for determining the features and real situation of wells and aquifers especially in plainsand coast region, implementing step pumping through step drop is suitable. The data gainedfrom pumping which has been done on more than 600 wells were tested by step drop andapproved these results. The lack of observing technical principles for digging leads to theincrease of pressure drop in well's lining network and causes a speed at the entrance of water tothe wells. Therefore, this will change the physical conditions of water. This may lead totransformation of sodium bicarbonate soluble in water to insoluble carbonate which bysedimentation on the well's lining and general pack of the back of lining's tube and tracks oflining network (shell investing) will increase pressure drop of lining network. Moreover, itdecreases discharge of the wells and intensifies shell investing action which leads to a decreasein economic life time of exploitation.
https://jphgr.ut.ac.ir/article_35838_33db7dade69ccd8e87f942cfee41f8f5.pdf
2013-11-22
107
124
10.22059/jphgr.2013.35838
Aquifer
Feeding
groundwater
Guilan's Plain
hydrology
Pressure Drop
Mohamad Reza
Afshariazad
mafshariazad@gmail.com
1
Assistant Prof. Dep. of Geography, Islamic Azad University, Rasht Branch
LEAD_AUTHOR
Mohammad
Poorhoshiar
2
MA Student in Geomorphology, Islamic Azad University, Rasht Branch
AUTHOR
ORIGINAL_ARTICLE
English Abstracts
https://jphgr.ut.ac.ir/article_36230_620594408a49f3214d4d6b88657b08fe.pdf
2013-11-22
1
22
10.22059/jphgr.2013.36230