فصلنامه پژوهش های جغرافیای طبیعی
پیاپی 95 (بهار 1395)

Snow is a kind of precipitation that is formed by the condensation of moist air mass and in the condition that temperature is below freezing. Although small areas of the world are mountainous regions but these small territories play an important role in the hydrological context of river basins. And in many areas snow covers and glaciers supply drinking water. Monitoring and forecasting of snow cover areas is essential for the promotion of climatic predictions and water-related decisions particularly in mountainous regions that a great share of needed water is provided. Some works have been conducted regarding the influence of altitude, slope and aspect on the distribution of snow-covered days. In this part some of these works have been reviewed here as follow. Endrizzi et al (2006) have indicated that there is a relation between snow water equivalent, altitude and aspect. They found that the dependence of snow water equivalent to altitude is weaker in fall and stronger in the spring. Gurung et al (2011) have shown that in Bhutan the accumulation of snow is varied based on aspect. North-east and north-west facing slopes are favored to be accumulated by snow in the seasons of winter, summer and fall.
In the present paper MODIS Terra and MODIS Aqua data were used to explore the relation of snow-covered days with altitude, slope and aspect. The selected study period covers the years from 1382 to 1393. As MODIS Aqua data are missing before the year 1382, we had to limit the study period only to the aforementioned years. The data of these products were downloaded in daily time scale. Before the analysis of the data, we applied two different algorithms to minimize cloud contamination that is a big hindrance against snow cover monitoring. One of the applied algorithms is based on three days filtering and the second is made on the combination of the two products. By exploiting these algorithms we managed to reduce cloud cover considerably. In the second step we started analyzing the data by creating different codes in Matlab. As the spatial resolution of the data was in 500 meters, we needed a Digital Elevation Model to be consistent with snow data both in spatial resolution and projection system. So a DEM with the aforementioned attributes was provided from NASA. In the applied Digital Elevation Model the information of aspect and slope for each of the grids was available. In the next step we developed some codes in Matlab to explore the relation between altitude, aspect and slope.
The considered relation between the number of snow-covered days and altitude indicated that there are three patterns in this way. Up to the elevations of 700 meters the number of snow-covered days does not increase by the increase of elevations. In the elevations between 700-1700 the number of snow-covered days shows a gradual increase, but in the elevations between 1700-3200 the number of snow-covered days experiences a significant increase by the changes of the elevations. Above the elevation of 3200 meters the behavior of snow-covered days does not show a clear pattern. So it can be concluded that the number of snow-covered days does not show a linear pattern. The analysis of slope indicated that the snow-covered is the most frequent in the slope of 25 degree. And above this slope the snow-covered days become less frequent. And the analysis of aspect indicated that the numbers of snow-covered days are observed frequently in the north facing slopes and in the south and south-west facing slopes the snow-covered days become less frequent. In another part of this paper, the profile of snow-covered days and other parameters like aspect and altitude was investigated over three mountains of Sahand, Karkas and Lale zar. The obtained results confirmed that in the eastern and northern facing slopes the numbers of snow-covered days are more frequent than their western and southern counterparts respectively.
In this study MODIS Terra and MODIS Aqua data were exploited in order to investigate the relation between snow-covered days with altitude, slope and aspect. The study period of the present study covers the period from 1382 to 1393. Before using the daily raw data, two fundamental algorithms were performed on the initial data to minimize cloud cover. After reducing cloud cover in the raw data, we started analyzing by creating some codes in Matlab. The obtained results show that in Iran the relation between snow-covered days and altitude does not depict a linear relation and in each of the elevation zones the behaviors are completely different. The most direct direction of snow-covered days and altitude was seen in the elevations between 1700 to 3200. The analysis of aspect show that north facing slopes has a good potential to be snow covered during the year. The analysis of slope indicated that in slope of 25 degree, the numbers of snow-covered days are the most frequent in comparison to the other slopes. So the slope of 25 degree is indeed the critical slope in this country.

Interaction between of internal and external processes of the earth during time epoch have an important role in formation and deformation and landforms transformation, we can identify course of their processes changes with landform survey. In the inner parts of Iran is apparent several geomorphological evidence of dry and rainy climate changes. Playaes and lakes or generally internal holes had an important role in climate balance and ecological changes in the quaternary in its surrounding areas. Because of this their study has been considered always to determine past climate.Morphology and alluvial fan deposits, contains traces of past enviromental changes. The key issue is that be determined changes in alluvial fan processes, isthe result of which of tectonic factors, climatic and or geomorphological conditions of alluvial fans.
To conduct this research from fieldwork, are used sediment core data of wells and further satellite imagery and digital elevation data with different scales in different software enviroment.In this research with comparing the sediment core of wells in surrounding area of Mighan hole and interpolation of their common areas was determined maximum spread of the lake.after was tend to extraction of alluvial fans, then according to region morphology, are compared and analyzed geological structure and location, region drainage basins, base level changes and alluvial fans sequence in northern part of pit (Ashtian’s alluvial fan) and the southern part of the pit (alluvial fans of Arak, Tamar Abad, Mehr Abad).
Discussion and findngs: Finding from this research are presented as follows: Investigation of evidence of clay deposits of region and interpolation of core wells of Velashjerd, Taremozd and Mashhad Mighan, show about 57 meter water forasmuch as the same formation area for clay layers 90, 80, 120 meter this cores for Mighan lake in the quaternary.
Evidence of sediment of cores and clay sediments abundant in the western and southern proves that maximum deep of lake has been in western and southern slopes of craters and about 8000 to 16000 last year extent of clay sediments indicate wetter climate conditions and reflects the development and progression of the lake at that time.With study of region geological conditions and tectonic it should be state that clearly visible function of Talkhab and Tabrateh faults and also effect of craters subsidence on the drainage basin and alluvial fans surrounding the hole and that has been caused asymmetry on the northern slopes and should be stated that this region has been affected by the impact of Neotectonics.
Also with existance of same climate conditions for sedimentary basin Mighan we determined five base level changeson the northern slopes of the well (hole) for the Ashtian cone that 3 base level related to river redirection has been in effect of neotectonics activities and is not sensible for the next two levels detection of impact of climate and neotectonics function.
Including evidence of base level changes available evidence on the Ashtian alluvial fans indicates considerable activity of neotectonics processes during quaternary are:1) Creation of mound hills on the formations of quaternary epochthat are represented tectonic movements.
2) The effect of Talkhab fault line on quaternary sediments and quaternary landforms.
3) Existence of thick alluvial deposits that starts from 50 meter to 100 meter at the bottom of the cone. But base level change in southern slopes has not been caused alluvial fans sequence, existence large mound hills, fraction of alluvial fans and being abandoned cones level.
The result of the study show that the sequence of fine-grained sediments of silt and clay and sand and gravel in thecore of exploratory wells indicate enviromental changes particularly climate changes in the quaternary.Likewise the cause of climate change on morphology change of alluvial fans surrounding Mighan hole (Ashtian, Arak and etc) has been a major role, but was more effective neotectonics rule on deformation and development of Ashtian alluvial fan than the other alluvial fans.Because it is measurable in the northern part of five old cones to newcones with about 700 meters height difference while this sequence is not found in the alluvial fans of southern part.Base level changes of Mighan hole and hole gradual subsidence with rising marginal part of hole that indicate existence of asymmetry and morphotectonic for this hole, are effected on the morphology of around alluvial fans. In other words, neotectonics effects has been more effective than climate change in base level changes of Mighan hole at this region and this effects is caused asymmetry in North domain. According to the geomorphological evidence can be concluded that this Playa has been placed in dynamic tectonically. And climate change, especially neo-tectonic has been caused base level changes in Mighan playa.

There are significant differences in the spatial distribution of the Iran’s annual precipitation, resulting from spatial behavior of precipitation on the one hand and variation in the sources of precipitation at the other. The lack of adequate distribution of meteorological stations and the unavailability of long-term statistics of precipitation makes analysis of precipitation more complicated. Precipitation data are constant inputs of research and models related to water resources (eg, climate, agriculture, hydrology, environment). Most of research institutions are used to record the data and present it to different users. Different ways of interpolation of the data will cause different results; so it is a critical step to select the appropriate data based on research design. This study evaluates APHRODIATE, GPCC and Delaware University precipitation data (UDel) based on precipitation data stations using RMSE, R2 and Taylor diagram techniques.
DATA APHRODITE APHRODITE’s (Asian Precipitation - Highly-Resolved Observational Data Integration Towards Evaluation) daily gridded precipitation is the only long-term (1951 onward) continental-scale daily product that contains a dense network of daily precipitation-gauge data for Asia including the Himalayas, South and Southeast Asia and mountainous areas in the Middle East. The number of valid stations was between 5000 and 12,000, representing 2.3 to 4.5 times the data available through the Global Telecommunication System network, which were used for most daily grid precipitation products. The products are available on a regional basis.
Key Strengths: High density and quality station network.
Key Limitations: Station network changes with time and season.
GPCC
The Global Precipitation Climatology Centre (GPCC) has been established in 1989 on request of the World Meteorological Organization (WMO). It is operated by Deutscher Wetterdienst (DWD, National Meteorological Service of Germany) as a German contribution to the World Climate Research Programme (WCRP). The GPCC provides gridded gauge-analysis products derived from quality controlled station data. Two products are for climate: (a) the Full Data Reanalysis Product (1901-2010) is recommended for global and regional water balance studies, calibration/validation of remote sensing based precipitation estimations and verification of numerical models, and (b) the VASClimO 50-Year Data Set which is for climate variability and trend studies.
Key Strengths: Large number of stations used; gauge network extends beyond GHCN
Key Limitations: Variable number of stations per grid over time can be a major inhomogeneity source. Monitoring products are frequently updated but climate products are not.
Global (land) precipitation, University of Delaware (UDel)
A series of gridded temperature and precipitation data sets. Station records that served as bases for the Terrestrial Air Temperature: 1900-2010 Gridded Monthly Time Series (Version 3.01) and Terrestrial Precipitation: 1900-2010 Gridded Monthly Time Series (Version 3.02) archives are used here to help create new gridded climatologies of monthly and annual average air temperature (T) and total precipitation (P). These two sets of station time series were drawn primarily from recent versions of the Global Historical Climatology Network (GHCN version 2) and the Global Surface Summary of Day (GSOD) archive. Selected averages from Legates and Willmott’s (1990a and b) long-term station averages of monthly and annual T and P also were used to help produce this new gridded archive.
Key Strengths: Provides a relatively detailed global land surface temperature climatology. Higher spatial resolution than comparable data sets
Key Limitations: Infrequent updates.
In order to evaluate the data, the closest point from the mentioned precipitation data to meteorological stations (max 40 km) were identified for the period 1961-2007. Then we used RMSE, the coefficient of determination (R2) and Taylor diagram to evaluate precipitation data. These methods are formulated as below:〖RMSD〗^2=σ_est^2σ_obs^2-2σ_est σ_obs R
R=(1/N ∑_(n=1)^N▒(〖P_est^((i))〗_n-(P_est^((i)) ) )(〖P_obs^((i))〗_n-P_obs^((i)) ) )/(σ_f σ_r )
σ_est^2=1/N ∑_(n=1)^N▒(〖P_est^((i))〗_n-(P_est^((i)) ) )^2
σ_obs^2=1/N ∑_(n=1)^N▒(〖P_obs^((i))〗_n-(P_obs^((i)) ) )^2
RMSE=√((∑_(i=1)^n▒(P_obs^((i))-P_est^((i)) )^2 )/n)
R^2=(n(∑_(i=1)^n▒P_est^((i)) P_obs^((i)) )-(∑_(i=1)^n▒〖P_est^((i)) ∑_(i=1)^n▒P_obs^((i)) 〗))/√([n∑_(i=1)^n▒〖〖P_est^((i))〗^2-(∑_(i=1)^n▒P_est^((i)) )^2 〗][n∑_(i=1)^n▒〖〖P_obs^((i))〗^2-(∑_(i=1)^n▒P_obs^((i)) )^2 〗] )
Where P_obs^((i)) and P_est^((i)) are the precipitation value provided by instrumental data and precipitation data respectively, σ_obs^2 and σ_est^2 are the variance values of instrumental data and precipitation data respectively, n indicate the number of stations.
Fig.1, shows the Taylor diagram, plotted by considering spatially averaged precipitation values, The diagram summarizes the relationship between testing and reference series standard deviations, correlation coefficient, and the RMSD (root mean square difference) computed considering series centered pattern, by means of a trigonometric similitude.
Fig.1: Taylor diagram obtained from spatial averaged values plotted on the basis of standard deviation values, correlation coefficients between products and reference dataset, and root mean square differences of series-centered pattern, indicated as RMSD in the plot. Aphrodite data are more accurate at, Khoi, Babolsar, Tehran and Yazd stations. GPCC data has better performance than other data at Zahedan and Bandar Abbas stations. For Shahr e Kord, Mashhad and Zanjan stations, Aphrodite and GPCC data have similar RMSD but according to the stronger correlations between GPCC and instrumental data, the GPCC data is more appropriate than Aphrodite data.
Based on the long-term average annual precipitation, Aphrodite and GPCC data are more accurate than UDel data. Taylor diagram is based on the geometrical relationship between correlation coefficient, series standard deviation and centered mean square error. It is useful than other uni-variable methods as RMSE and R2. Aphrodite data is better to use for the North West, the southern Alborz and internal areas and GPCC data will lead to better results in the West, South, South East and North East of Iran. As UDel data considers spatial association of data with dependent variable, it estimates precipitation time series better than other data. This type of data is useful to analyse characteristics of precipitation in the areas with short-term time series.

Rainfall erosivity, the propulsion or power of causing erosion in separation and transport of soil particles, is in relation to water erosion. Rainfall erosion is causing loss of soil, damage to agriculture and infrastructures which is followed by water pollution. Changes in rainfall patterns exacerbate risk of erosion globally. Rainfall erosovity has an effective role in soil erosion and can shows potential erosion in its study areas. Following the rainfall erosion, all type of water erosion can be occurred. Consequently, not only make soil to be eroded but also lead to filling of dam reservoirs, channels, water pollution and ecological changes. Regarding above mentioned problems, it is necessary to investigate various aspects of water erosion. Under the same condition, rate of soil loss is directly proportional with the rainfall erosivity. This can be expressed as erosivity factors which are based rainfall characteristics. Various researchers have attempted to provide factors that are based on rainfall characteristics using simultaneous measurement of soil splash (or soil loss) and rainfall characteristics and determining relationships between them. Various factors have been proposed throughout world. These factors are different because of geographical location, scale, local conditions and type of instruments. The concept of rainfall erosivity was proposed by wischmeier and smith (1958) in order to consider the effects of climate on soil erosion. Rainfall erosivity can be determined either using direct measurements or factors. Direct measurement method, is a suitable method for determining rainfall erosivity which is done by measuring amount of splashed soil. Event-based measurement of erosivity of rainfall for broad area is difficult and time-consuming, therefore researchers have attempted to provide factors that are based on rainfall characteristics using simultaneous measurement of soil loss and rainfall characteristics and determining relationships between them. For different areas, Rainfall erosivity can be determined using these characteristics without direct measurement. In general, rainfall erosivity factors can be divided into two groups: 1) factors based on energy and intensity of rainfall; 2) factors based on readily available data. One of the most famous factors is EI30 which is based on kinetic energy and intensity of rainfall. One limitation on using this factor and also other factors which are based on rainfall erosivity is that they need long-term data (>20 years) recorded with shorts intervals. Such data are recorded in stations equipped with rain gauge. Therefore, due to lack of these long-term data, researchers have proposed factors that use available rainfall data (i.e. daily and monthly data). This recent factors are computed based on regional sediment analysis or its relationship with EI30. The purpose of this study is to prepare rainfall erosivity map for Kerman province with semi-arid climate, and to determine the most suitable interpolation method. Although such a map has been produced by Nicknami (2014) for Iran, it's not available for Kerman specifically.
Maerial and This study was carried out in Kerman province. Kerman province has an area of 181,714 square kilometers and is located in the southeastern of Iran. Kerman covers more than 11 percent of the area of Iran, it is the largest province in terms of land which is located in the southeast of the Central Plateau. In order to estimate EI30 index for areas without rain gauge, the regression analysis were used between this index and some readily available indices form 17 stations equipped with rainfall stations. Based on average maximum monthly rainfall index, the most fitted regression has R2=0.882. Twenty years data (rainfall intensity & daily rainfall) form all stations (include: Synoptic, Climatology, Evaporation and Rain gauge stations) were used for this study. Outliers were removed by visual surveying of all collected data. Normality of the data distributions was tested using Kolmogorov-Smirnov in SPSS version 22. Finally, 135 meteorological stations and 17 rain gauge stations were chosen.
Results showed the maximum and minimum index equal to 74.213 and 91.24 (MJ-mm acres per hour) for Soltani and Dolatabad Esfandagheh stations, respectively. Simple kriging method was selected as the most appropriate interpolation method using cross-validation techniques, and zoning map of rainfall erosivity factor was prepared in ArcGIS software. Results also showed the highest rainfall erosivity values for Baft, Bardsir and Sirjan cities (located in southwest of province), and the lowest values for Bam, Jiroft, Kahnouj and Ravar cities (located in east, south and north of province), respectively.

The most notable of convective systems are Mesoscale Convective Systems (MCSs) that develop when clouds occurring in response to convective instability amalgamate and organize upscale into a single cloud system with a very large cirriform cloud structure and rainfall covering large contiguous areas (Houz, 2004). Detection and monitoring of MCSs is very important in southwest Iran because they produce hazardous weather, such as lightning, heavy rainfall, hail and strong winds. Several factors influence the development of MCSs such as the flow generated by a weak midlevel trough and the occurrence of low level jets (LLJs). LLJs transport moisture at the jet level, increase the low-level convergence and are responsible for sustaining convection especially at night.
The aim of this study was to assess the influence of low level jets on MCSs formation across the southwest of Iran over the period from 2001 to 2005. The months of January, Mars, April and December was selected because of more MCSs occurrence. Event days were selected using synoptic station data (a set of storm reports such as thunderstorm, lightning, and shower and precipitation) across the study area. IR brightness temperature data from Meteosat 5 were utilized for detecting MCSs. It has a resolution of 4 km with temporal resolution of 30 min. Detection of MCSs was performed on the basis of brightness temperature and areal extent thresholds. In this approach ‘convective cells’ are connected zones of pixels below the temperature threshold that exceed the areal extent threshold (Woodley et al., 1980). The best threshold for detection of area characterized by deep moist convection was determined 228 K. Based on Morel and Senesi (2002), area threshold selected 1000 km2. Those systems have considered as a MCS which reached at least an area of 10000 km2 during its mature stage and lasted at least 3 h.
To determine the influence of low level jet on MCSs development, the occurrence percent, maximum extension and duration of MCSs was analyzed in both LLJ and NOLLJ condition. The detection of low level jet events is based on Bonner (Bonner, 1968). According to this classical definition, a low level jet event is detected when the wind speed is equal to or higher than 12 m/s. In addition, the wind speed should decrease by at least 6 m/s to the next higher minimum. Furthermore the moisture fluxes at 850 hPa are analyzed to identify low level jets role in moist air advection. Moisture flux (MF850) is calculated by multiplying the specific humidity and wind speed (Remedio, 2013). The regions with intense moisture transport are identified during the mean monthly conditions as well as during the composite of low level jet events.
The result of this study showed that the most of MCSs has triggered and developed during low level jet event in all months. So that, 85% of MCSs in January, 96% of MCSs in Mars, 84% of MCSs in April and 88% of MCSs in December has formed during Low Level Jet event. Thus MCSs triggering without low level jets assist was rare. Analyzing of the 850-mb isotachs showed that there was the Low Level Jet many hours before the organized convective systems is established in most of cases. The center of Low Level Jets was in Persian Gulf vicinity mostly. Its speed was equal to 14 - 18 m/s approximately and its axis was in north to south direction. The high wind speeds generally advect the warm and moist air from the Arab and red sea towards the southwest of Iran. These conditions induced to the release of latent heat and increase the low-level convergence which was favorable for the development of convection and MCSs formation.
Westerly wind whit low speed prevailed during the mean monthly conditions at 850 hPa. But it was southwesterly during the composite of low level jet events which transmitted heat and moisture to the study area. The result of this research revealed the biggest and most lasting formed MCSs in days whit low level jet event was bigger and more lasting in contrast whit the biggest and most lasting formed MCSs in days whit no low level jet event. But the mean extension and duration of MCSs in two different condition showed no significant difference.

Iran forms a relatively compact zone of active continental deformation resulting from the northward collision of Arabia with Eurasia during late Cenozoic times, and which continues to the present‐day at a rate of 25 mm/yrs. (from GPS data). Evidences of active tectonic in different parts of Iran, has been studied and identified. The arid climate, low rates of erosion, and minimal vegetation cover across the majority of the country result in excellent preservation and exposure of surface deformation produced by active faults. Geomorphic indexes are useful tools in the evaluation of active tectonics because they can provide rapid insight concerning specific areas within a region which is undergoing adjustment to relatively rapid, and even slow, rates of active tectonics. Alluvial fans, river terraces, runoff anomaly and horizontal and vertical displacement of faults are the most important landforms that indicate active tectonics and active faults. Active tectonics have a very important role on the alluvial fans deformations. Without continued tectonics, fans may become minor or short-lived features. Morphological evidences of different types of faults such as thrust faults and strike-slip faults can be determined in surface of quaternary landforms. For example Late Quaternary activity on strike-slip faults can be determined from the lateral displacement of young landforms such as river terraces and alluvial fans, or from scarps introduced by slight dip-slip components of motion. In this study, the evidences and impacts of the active faults have investigated in quaternary landforms such as river terraces, stream displacements and spatially alluvial fans morphometry and morphology located at the south part of the MishoDagh maountain north west of Iran.
The method is based on the obtained qualitative and quantitative data. The quantitative data includes satellite image interpretation and digital elevation models, alluvial fan morphometry, channel displacement and rate of sediments uplift. Longitudinal and cross profile and gradient analysis used to interpret the active fault effects on alluvial fans. Topography maps (1:25000), ETM, SPOT and Quickbird satellite image with 30, 15 and less than 3 m spatial resolution, geology maps (1:100000) and digital elevation models (10m pixel resolution) were utilized in this study. For such interpretation, ArcGIS, ENVI and Freehand software were utilized. All of the maps were produced using freehand and ArcGIS software. Also, field work for investigation of evidences of faults activities were performed. Field studies was performed for the identification and measurement of parameters such as the uplift of sediments, displacements of river, alluvial fans, and channel avulsion and river terraces. Finally, the data obtained during field studies are compared and analyzed through quantitative and descriptive methods and amount and effectiveness of active tectonic on Quaternary landforms spatially, alluvial fans was estimated.
study area located in south part of MishoDagh maountains, northwest of Iran (north of Lake Urmia). Tabriz fault is located in east part of study area. There are three main Faults in this area. South Misho Fault (SMF) is located in mountain front and affects the apex of alluvial fans and river terraces. Whereas Shabestar, Daryan-Heris-Shanlan and Sharafkhane faults are located far from mountain front. South Misho Fault has caused the displacement of the main channel in fan apex, and alluvial terrace sequence. This fault have elevated river terraces about 150m from river bed. while evidences of the two other faults activities are more, and has caused uplifting surfaces, derelict of fan surface, change of intersection point, uplift of fan sediment and lateral change of fan surface channels. The slope of most alluvial fans is 3-5 percent. The Sis fan is the largest fan in the study area. This fan combined from several quaternary surface that elevated in response to fault activity. Sis fan are affected by faults more than the others and reformate to present landform since quaternary. Shabestar, Sharafkhane and Heris-Daryan-Shanjan faults are strike-slip faults that have been changed rivers and runoff laterally.
The findings show that Shabester, Sharafkhane, Heris-Daryan-Shanjan and South Misho faults were active in quaternary epoch and position and forms of alluvial fans is affected by activities of these faults. Faults have had either lateral or vertical displacements. Findings show that the alluvial fan forms and their longitudinal and lateral profiles are affected by Shabester, Sharafkhane, Heris-Daryan-Shanjan faults. Investigations show that there is no statistical correlation among the variables that affect the alluvial fans. Generally, tectonic activities disrupt natural evolution of alluvial fans. Each fault has a different effect on alluvial fan evolution. South Misho fault has caused the displacement of the main channel and the formation of river terraces. And therefore has increased slope of this part. Other fault have caused uplift of fan deposits, change the intersection point and reconstruction of new alluvial fans in the lower of this point. Remote sensing studies can provide a valuable first step in the identification and analysis of active faulting in actively deforming regions.

Numerous studies have proved the relationship between the amount of co2 in the atmosphere and climate change. In this respect, developed countries have a undeniable role and they cause serious damages in the throughout the world. IPCC’ forth evaluation report implies that adding greenhouse gases to the atmosphere during recent decades prevents the heat rays to emit which, in turn, cause atmospheric temperature to increase. During the past centuries, the temperature has increased by 3 to 6 Degrees Centigrade, with a rapid speed in recent decades. It is believed that if greenhouse gases continue to increase at the present rate, an average increase in temperature, from 1c to 3.5c is expected by the year 2100. Therefore, it is necessary to study and evaluate climate changes in the future decades so as to plan a proper environmental program corresponding to future climate conditions, consequently reduce its unfavorable effects. The uncertainty in Atmospheric Circulation Models being taken into account, the present study investigates the temperature and precipitation changes in Eastern South of Iran during the following periods: 2011-30, 2044-65, and 2080-99.
Material and Two datum groups; namely, observed data and model data, including maximum and minimum temperature, precipitation and solar radiation were used. The period, 1983-2007, was chosen as the observed period; data from weather synoptic stations were gathered. The required data for General Circulation Models including IPCM4, NCCCM3, HADCH3, and INCM3 with three scenario A1B, A2, B1 were gathered from the two Reference Networks, Canada Climate Change Reference and data bank of LARS-WG5.1. The most upgraded version of LARS-WG5.1 was used to evaluate climate change in Eastern South of Iran. This version observes the forth report on IPCC. Therefore, it uses the outputs of 15 General Circulation Models with A1B, A2, and B1 Scenarios. Four climate models having three shared Scenarios were used in this study.
Time series of observed data from synoptic stations in Eastern South of Iran were compared with those of IPCM4, NCCCM3, HADCH3, and INCM3 in similar periods with A1B, A2, and B1scenarioes. To do so, first, average time series of each station were computed using temperature and precipitation data from synoptic stations, then , monthly thermal data and those of GCM fall amount during the study period from CCCSN (Canada) were received. Finally the mentioned data were compared with the average temperature and precipitation during the study period. And to investigate the uncertainty resulted from employing various GCM models, weighting method of averages of observed temperature and precipitation was used.
General circulating models don’t have equal results in estimating long – term temperature and precipitation which indicate the existing uncertainty in their outputs. Analyzing using T-test and K square statics result for all stations, revealed no significant difference between modeled and observed values at P This study investigated the effects of climate change on the two weather parameters, temperature and precipitation, using the data gathered by Atmospheric General Circulation from synoptic stations located in Eastern South of Iran. The obtained results showed that LAR-WG Model is capable of modeling precipitation and temperature values. According to the results, it was shown that NCCCM3, HADCH3, IPSLM4, and INCM3 models have a good performance in simulating precipitation. Regarding temperature, HADCH3 Model proved a good capability in most months. The obtained weights having been applied on model values, an increasing temperature trend was shown in all the stations. Furthermore, it was shown that thermal increasing amount in coastal stations is higher than that of dry ones, the most amount of increase in temperature belongs to Kerman, Zahedan, Bam, Zabol, and Iranshahr, respectively. Accordingly all coastal stations would experience a thermal increase less than 3c, while the value for dry stations would exceed 3c. It seems that temperature follows a steady increasing trend, whereas precipitation in various stations fluctuates during different seasons.

Iran’s Kaluts which are considered as special models in term of magnitude and extension, have been shaped in the west of the central Lut desert. Although these Kaluts now are influenced by the selective windy erosion, they can be shaped through the process of wind and water erosion. The suitable environment for shaping of these Kaluts are the arid region together with little raining and the intensive and continuous wind. The Lut desert Kaluts are shaped in the grounds with finer structure and wind and water erosion. This erosion can be produced when the water is accumulated in the small pit and holes in the humid season after temporary precipitation in the desert. Then a doughy substance is made and wakened. After drying and as the result of the predominate wind of the district, these pit and holes gradually become enlarged and the long silts are produce the Kaluts. In this research we want to study the sedimentary characteristics’ of Kaluts and Iran pluvial lakes by sampling of one the high Kaluts in Lut desert and experimenting sedimentary and granolometery in these samples.
Firstly, through on extensive survey in the district and visual examination of Kaluts, a high Kalut of the district was selected for modeling. Then after recording the exact position of Kalut by GPS, the related Kalut was sampled. The taken samples crushed in geomorphology laboratory and sieved by shaker. Those samples that were under 63 micron were separated in 10 grams and were used in granolometery test in Pipette way and scaled graduated cylinder. This sampling was done in two days (8 samples for the first day and 2 samples for the second). After sampling in the specific time and in the specific depth of cylinder, the samples were dried and the remained sedimentary was weighted in the beakers. Thirdly, the GradiStat software was used to analyze the number gained from the pipette test and then the related and figures were drawn.
After testing 15 layers taken from the Kalut, granolometery elements of particles such as the context and the size of particles near to the average, qualitative and quantitative measures of Sorting, Skewness and Kurtosis of particles were identified with the help of GradiStat statistical software and of statistical relationship between Folk and Ward (1975). The gathering center of bimodal and Unimodal aggregation show very poorly sorted sediment. This position could be observed in most of underneath layers. This could be produced by shaping sedimentary in the specific context that could created different particles with different sizes. According to the obtained results from statistical & experimental analysis, the context of all layers in Folk triangles was determined as muddy & their particles in the rate of silt & clay. It was expected the Skewness of all layers was positive that results show that most of layers have positive title to fine and very fine particles.
Iran kaluts are unique example of the magnitude and extent of desert areas. This Kaluts although affected by wind erosion choice currently, but water and wind erosion processes are involved in their formation simultaneously. In this study, after sampling from a Kalut with height 33 meters and 15 layers, they transferred to the laboratory and examined samples granolometery tests.The finding reveal that the Kalut sedimentary in the rate of silt & clay have horizontal and lamination classification referring this fact that the tiny sedimentary hanging in the water and were deposited in a calm environment. Furthermore, on the muddy silts were observed some chaps. The silts were produced when the lakes were dried and the water was vaporized severely and then the sediments could be observed in the form of salty and chalky layers of Kaluts along with silt and clay particles that carried by the wind. This fact can be certified with the respect to this fact in the past the shallow lake in the low energy environment was severely vaporized and dried. As a result of this, the chalky and salty layers were made. Based on the experiments, the most of the related layers have the muddy context with very bad sorting and fine skewness that this reveals that the following activities in the district was low and the environment was low energy during sediment of the kaluts.

Flood is a natural hazard that takes place more frequently in recent years. In order to better flood mitigation and control, it's needed to recognize flood production factors and determine the high potential flood areas. Hydrological model is a simplified representation of natural system and the rainfall-runoff model is one of the most frequently used events for flood simulation. HEC-HMS is one of the computer models and for its ability in simulating short time events become very popular. The aim of this research is to investigate spatial prioritization of flooding in Beheshtabad sub-catchments using HEC-HMS software.
Material and Behashtabad Basin located in Chaharmahal-va-Bakhtiary Province, Iran, is 3866 km2 and its mean altitude is 2317 meter above sea level. It is divided into 6 sub basins according to 6 hydrometric stations. Land use categories of study basin extracted using ETM Images for 2009. Using 170 ground control points land use map of Beheshtabad basin was prepared with total accuracy of 99.34 and Kappa Index equals to 0.81. Rangelands covers most of the study area. Soil Hydrological groups and land use data used for mapping sub basin's curve number considering antecedent moisture of past five days as well. The mean curve number of study basin is 72.69. Daily precipitation data of 6 rain gauges in study area used for analyzing maximum 24 hr precipitation in different return periods. Rainfall hyetographs of flood events derived from recording rain gauges data. CN method used for estimating initial loss, SCS method used for runoff hydrograph simulation, and Muskingum method used for flood routing simulation. HEC-HMS model was calibrated using 2 Flood hydrographs and corresponding hyetographs for each sub-basin and validated for 1 flood event.
Rainfall loss in Beheshtabad sub basins varies from 0.13 to 0.19, curve number varies from 69.73 in Kooh-Sookhteh sub-basin to 73.71 in Kharaji sub basin, and lag time varies from 0.99 hr in end Beheshtabad to 5.72 hr in Kharaji sub-basin. Using optimized rainfall loss index derived from calibration stage, HEC-HMS validated for one flood event for each sub basin. Model validation shows very little difference (below 1%) between estimated and recorded data in all sub-basins. Among sub basins, Darkesh-Varkesh has the most and end Beheshtababd has the lowest peak discharge in all return periods. Priorization of sub basins according to their areas show that bigger sub basins havent essentially highest amount of the rate of Qsub/Qtotal. In this comparison Darkesh-Varkesh sub basin with a rate of Areasub/Areatotal of 0.13 has the highest rate of Qsub/Qtotal. Flood routing in streams showed that the rate of participation of sub-catchments in output flood is not proportional to sub-catchment peak discharge. Therefore, in order to eliminate the effect of area in participating sub-catchments, the rate of influencing each unit of sub-catchment area in output flood was calculated as well. The results of prioritization with respect to peak discharge, based on having participation of each sub-catchment in output location of watershed, indicates that Darkesh-Varkesh and Beheshtabad sub-catchments with 29.16 and 2.5 percent, have maximum and minimum of participation in output flood peak discharge of watershed, respectively Results of prioritization based on reducing discharge per unit area show that Beheshabad sub-catchment with having lowest area in comparison to other sub-catchments has highest participation and Tange-Dehno has lowest role and contribution.
In the present study, rainfall-runoff modeling is carried out using HEC-HMS hydrologic model. Results of simulation in 18 events and comparison of simulated and observed hydrographs showed that the model can applied for simulation of rainfall-runoff in study area. Other researches like Kumar and Bhattacharjya (2011) and Hegdus et al (2013) have same results as our findings. Ranking sub basins according peak discharge without flood routing show that Darkesh-Varkesh has the most and end Beheshtabad has the lowest peak discharge. According contribution in total discharge also results are the same. Soleimani et al (2008) and Zehtabian et al (2010) also found the same results. Finally, according to decrease in total Q per unit area, ranking show that end Beheshtabad sub basin despite of having the smallest area, has the highest contribution in total Q per unit area Nasri et al (2011) also concluded that areas are located near the outlet of study basin have the most contribution in flood production. This research show that the Darkesh-Varkesh sub basin need the most attention in selecting management practices especially in optimizing flood control and flood mitigation solutions.

Shamal winds recognized as a climate regime with a common occurrence in the Persian Gulf that makes the event of adverse weather conditions in this region periodically. Among the phenomenas that occurring under effect of Shamal wind, can be noted to dust storms, Low-level winds and inappropriate sea conditions. Shamal winds are categorized into two types, winter Shamal and summer Shamal. Sea-land breezes also are classified as a frequent mesoscale and heat driven flow associated with coastal areas. Temperature gradient between sea and land is the main reason for the formation of a sea breeze circulation that blows from sea to land in low level coastal atmospheric boundary layer. The suitable conditions for Sea-land breezes establishment when the synoptic winds are weak (low synoptic forcing) and temperature level is high in the coastal city of Bushehr. The purpose of this research is to investigate seasonal Shamal wind event and its associated synoptic conditions by observations analyzing and numerical expriments on Persian Gulf. The impact of these conditions on wind pattern in the northwestern Persian Gulf coastal area and in optional case in the coastal area of Bushehr are studied and it is intruded interaction between meteorological mesoscale (sea-land breeze) and large-scale (synoptic pattern Shamal wind) forcing effects in this area. North of middle east are areas that dominated by the seasonal Shamal wind regime, that begin from the central deserts of Iraq and the mountains of northern Iraq, Turkey and Syriat to Persian Gulf. In this study, the coastal city of Bushehr that located in the northwest of Persian Gulf and southwest Iran have been selected to investigate about interaction of Shamal wind pattern on local breeze on the coastal areas . Based on the location of the Bushehr and sea-land breeze definition, sea breeze will occurr in the sector of 180-270 degree.
In this study, in order to analyze the time series of coastal wind, it is used hourly wind speed and direction data from meteorological tower and meteorological station of Bushehr power plant and also wind data from Bushehr airport weather station. In the next step, the NCEP FNL data used to generat the initial and boundary conditions for regional simulations by WRF model. This data has 1° × 1° resolution and are available for every 6 hours. This data produce by Global Data Assimilation System (GDAS) that continuously receive monitoring global data for analyze from Global Telemetry System (GTS) and other resources.
The results of the observational time series analyzes from the meteorological tower of Bushehr power plant are shown for winter (January) and summer (May) selective periods. These results show the mean detail information of typical wind regimes such as summer and winter Shamal and sea-breeze regimes during January and May 2010. In this work is represented formation quality, duration, mean speed, mean direction of sea-breeze wind in the beginning and ending of sea-breeze regimes during these months. It also is represented frequency of daily occurrence of typical wind regimes with themselves mean speed in Bushehr coastal area. It was observed that the northern of Saudi Arabia is influenced by a high pressure system and Persian Gulf and west of Iran by a low pressure trough and a heat low pressure system is seen over east of Iran (region of Afghanistan, Pakistan and etc.) during summer Shamal. Turkey, Iraq and west of Zagross mountain rang regions are affected with interaction of these thermal and dynamical systems that lead to the creation of Shamal wind in north west of Persian gulf. This area is affected by winter Shamal wind regime with significant cold advection after passage of synoptical cold front of a dynamical mid-latitude cyclone.
In general, Shamal wind affects Turcy, Iraq, Iran, Arabian Peninsula and adjacent areas. The maximum activity during 2010 observe in the winter in late of January and in the summer in June by maximum number of Shamal days. This result is obtained by analyzing data from the meteorological tower at height of 100 meters in Bushehr weather station that the summer Shamal causing disruption of coastal wind pattern in 14 days of May, 14 days in June and about 10 days in July of 2010 and in other months, usually less than three to five days. Winter Shamal occurs at intervals of 3 to 9 days from December to March. During the period that the sea-breeze is removed by synoptical Shamal winds forcing, the average daily wind speed more than period of sea-breeze activity.