فصلنامه پژوهش های جغرافیای طبیعی
پیاپی 102 (زمستان 1396)

Particulate matters are particles that have placed as dispersed particles, in solid or liquid, in gaseous intermediators. Recently, aerosols as one of the air pollutants, from natural or anthropogenic sources, have received the attention of many researchers due to the roles they play in global climate change and the environmental and health problems. They can scatter or absorb solar radiation and thermal radiation emitted from the earth surface. The aerosols as condensation nuclei of cloud droplets can also affect cloud formation and precipitation. Numerical studies have performed particulate matter (PM10) and their source identification.
Source identification of trace elements in PM2.5 in Mira Loma, in southern California, was performed using factor analysis, the backward air mass trajectory analysis, enrichment factor calculation and the Al/Zn ratio. Al is a major constituent in the earth crust but it is not in vehicle emissions. This study suggests that the Al/Zn ratio can be used to understand the dominance of soil-related sources. The low Al/Zn ratio shows that dominant sources are vehicle emissions.The purpose of this research is source identification of the main and trace elements of PM10 aerosols and also, investigation of effective areas in production of the aerosols (PM10) using satellite images in Kermanshah. In this research, the exploratory factor analysis has been used to identify natural and anthropogenic sources of the elements in PM10 aerosols.
In this research, sampling of aerosols has been performed by aerosol sampler. Then, the concentrations of the eleven elements (K,Al, Na, Ca, Cu, Ni, Pb, Mn, Fe, Mg, V) have been detected by ICP-OES.
In this study, the exploratory factor analysis has been used to identify potential sources of major and trace elements in aerosols. In this method, variables are placed in the factors so that the percentage of variance decreases from first factor to next factors. Hence, the variables in the first factor are most effective.
In this study, the days that particulate matter concentration was higher than permissible level, we have determined daily information of particulate matter concentration at Air Quality Monitoring Station in Kermanshah. Then, effective areas in production of aerosols (PM10) have been investigated using satellite images during February to July 2010.
In the factor analysis, the variables (elements) with the factor-loading less than 0.5 are not listed in the table. The total number of factors has been selected so that the cumulative percentage of the variance explained by all the selected factors was more than 77%. Only the factors are selected that had an eigenvalue greater than one. The last column shows the values of the communalities which explains the amount of common variance for each of the variables (elements) with the four factors.

Global warming and climate change are one of the most important bioenvironmental challenges in recent decades. Winter ecological processes are important drivers of vegetation and ecosystem functioning in temperate ecosystems. There, winter conditions are subject to the effects of rapid climate change. The potential loss of a longer-lasting snow covers with implications to other plant related climate parameters and overwintering strategies make the temperate zone particularly vulnerable to winter climate change. One of the indices suggested in analysis of climate changes and global warming is the frequency of frost days. Frost is an atmospheric phenomenon affecting agricultural activities in many parts of the Earth. The highest increase in average temperature is occurred in minimum temperature. Modeling and scientific research indicate that global warming and rise in night temperature have reduced the number of frost days in many parts of the globe.
The data of this study consisted of two groups of observational data and simulated data. The observational data are the daily minimum temperature values from 44 synoptic stations in various regions of Iran. The stations have the full data of thirty years (1981-2010) received from Iran Meteorological Organization.
The simulated data of the future period are generated using the downscaling output of general circulation models of atmosphere. One of the most famous models is stochastic weather generator, LARS-WG. The model is used to produce values of precipitation, radiation, and maximum and minimum daily temperature at one station under the present and future climate conditions. Among 15 LARS Models, two global climate models were selected; HadCM3 and GFCM21 Models. The data simulated by the two models for the periods 2045-2065 and 2080-2099 were performed and produced under the three emission scenarios AB, A2 and B1.
The average frequency of frost days in the selected stations in the period 1981-2010 is 62 days per year. The dispersion of the number of frost days in the area is highly different. The range of frost days (0-134) per year in the studied stations is different. The highest frequency of the frost days is associated with Hamadan, Ardabil, Shahrekurd, Zanjan, Uremia and Khoy with a frequency higher than 100 days per year. The most frequent frost days were related to Hamadan with an average of 134 days per year. Four coastal stations of southern Bushehr, Bandar Abbas, Bandar Lengeh and Chah Bahar lack frost and Ahvaz and Abadan and Iranshahr stations with an annual average of less than one day. They have the lowest incidence of frost.
Results have indicated that in the period (2046-2065) under the GFCM21 model and the A1B, A2 and B1 scenarios, the average annual frost days in Iran was 37, 46 and 41 days, respectively. Based on the HADCM3 model and the scenarios, the average annual frost days are 41, 42 and 46 days. In both models, in three scenarios greatest reduction occurred in Hamedan station. In the stations of Khorram Abad, Kermanshah and Shahrekord, Shahrood, Yazd and Fassa a large decrease was seen. In the observation period (1981-2010), five southern coastal stations were free of frost while in this period the stations that have a frequency less than 10 day, will be frost-free.
In the period (2099-2081) based on the GFCM21 model and scenarios A1B, A2, and B1, the annual average number of frost days in Iran is estimated to be 31, 29 and 43 days. Based on the HADCM3 model, the annual average number of frost days is 33, 28 and 38 days.
In this study, we have used weather data from 44 synoptic stations of Iran, during the period 1981-2010. We have also applied the two models of the general circulation of atmosphere, HADCM3 and GFCM21, for the periods 2046-2065 and 2080-2099 under three emission scenarios of A1B, A2 and B1. Using these data and the outputs of the models, we have analyzed the effects of global warming on changes in the frequency of frost days in Iran. Both the models performed with the three scenarios have indicated a reduction in the frequency of frost days in both periods. The slope changes of the frequency of frost days in the period (1981-2099) under these scenarios have revealed the reduction of -5.5, -5.1 and -3.6 days per decade. Overall results showed that in all the stations, the number of frost days have declined in the coming decades. The rate of decline in the mid-northern and mountainous areas has the highest frequency of occurrence of frost more than that of the mid-South and beaches.

The issue of urban climate has been greatly addressed in the recent years. The migration of human beings to cities, along with the density of the residential units, the noise of urban vehicles and dangers of air pollution and many other things have had bad effects for the human beings like asthma, bronchitis, cardiovascular diseases, and skin cancer. The issue of air pollution is one of the main factors in urban climatology. The knowledge of climatology emphasizes on the effects of atmospheric pollution on the climate and vice versa. The investigation about the effects of air pollution on climate features has greatly been conducted in the east Iran. In the warm seasons of the year, especially in summer, Subtropical High pressure (STHP) covers large areas of lower, middle and upper levels of atmosphere. This extends vertically on top of the high pressure at 200 hp to 700 hp and results in a clear sky with no clouds and rain. Subtropical High Pressure (STHP) all over the country varies from one day to other day. In some areas it is very close to the earth surface, in the south east parts of Iran in some days it is about 2000 or 3000 meters above the earth surface and allows warm, low moist air. This situation sometimes spreads to northern Iran and causes monsoon rain with increase in temperature and decrease in air ascent. This means that when the height and activity of the STHP is high, there is suitable condition for clear sky and direct solar radiation. On top of the inversion water vapor content of the air is so low that it cant be measured. Subtropical system in high altitude is one of the reasons for the formation of deserts in Iran. Subtropical high is getting stronger with increasing height from the ground, while the polar high becomes weaker with increasing altitude.
As a matter of fact, mechanism for summer subtropical high pressure on Iran is a part of the Azores high pressure on the region. Thus, the above factors have caused the greatest events in the summer in Tabriz so that the city has experienced dangerous contaminants. With the beginning of autumn, the maximum and the minimum values of the dangerous contaminants was shifted compared with other seasons. However, in autumn there are dangerous infected cells in northern city of Tabriz in November and October, while in December the infected cells are in the center of Tabriz. The purpose of this study was to evaluate the frequency of Tabriz dangerous contaminants. For this purpose, the data of pm10 pollution index in the 8 years period (2005 to 2012) were evaluated by the Environmental Protection Agency in Tabriz (EPAT) for five stations of Baghshomal, RAhahan, Abrasn, Hakim Nezami, and Rastekhocheh. The index of this research is the day that the pm10 value of 420 is larger. The frequency and continuity of these dangerous days for each station were analyzed and investigated. In this study, we have used MATLAB for statistical analysis and SURFER for the mapping.
The results of the analysis have indicated that there were many dangerous air pollution events in summer in all stations with more dangerous contaminants in August as the highest frequency of the occurrence of dangerous infections.This indicates that formation of subtropical high pressure dominated on Tabriz play a key role in air pollution. However, in winter the occurrence of dangerous pollution has been reduced in most of the stations. Among the stations of this study, the stations of Baghshomal and Abrasan had the most dangerous pollution. The number of the days of infection in both stations has reached to more than 400 days during the study period. Furthermore, the results of the continuation of the dangerous contaminants of pm10 index indicate that more continuity of the pollution was in Baghshomal station and the lowest in Rahahan and Hakimnezami stations.
The spatial distribution of pollutant cells is varied in different months in Tabriz. However, based on PM10 density the dangerous pollution in most of the months has been formed in the city center. In January, February, June, September, October (multi-core) and December there were the core and the density of pollution in the city center. In March and August, the maximum contamination of Tabriz has been observed in the East. Intensity of infestation was observed only in April, July and November in west Tabriz while the maximum condensation has been observed in the northern and the southern parts of the Tabriz. Tabriz had no nuclei condensation of dangerous pollution in July.

Global mean sea level change due to climate change is resulted from changes in the interaction of its associated components in long periods of time. The difference between regional and global predictions of sea level change depends on manifestation of this phenomenon in terms of climatic and hydrological conditions of the regions. Since the rising in sea level in the near future is a serious threat to coastal communities, it is essential to estimate the increase in water level during the coming period. Sea level changes on a large spatial and temporal scale are created by some factors, including thermal expansion, ice melting and etc., resulted from the climate change. Sea level change is affected by two main causes: (1) volume change due to density of sea water, and (2) mass change due to water exchange with atmosphere and land through precipitation, evaporation, river runoff and ice melting. Regional sea level change may differ substantially from a global average. This shows complex spatial patterns resulted from ocean dynamic processes, movements of the sea floor, and changes in gravity due to water mass redistribution (land ice and other terres­trial water storage) in the climate system. In the period 2081–2100 compared with the that of 1986–2005, global mean sea level rise is likely (medium confi­dence) to be in the 5 to 95% of projections from process-based models. This gives ranges of 0.26 to 0.55 meter, 0.32 to 0.63 meter, 0.33 to 0.63 meter, and 0.45 to 0.82 meter for RCP2.6, RCP4.5, RCP6.0 and RCP8.5, respectively. In this study, an accurate assessment of the sea level changes due to climate change in coastal zones of Persian Gulf and Oman Sea has been estimated in the future, for the first time.
This study estimates the amount of increase in sea level change using 24 AOGCM models suggested in fifth IPCC report, under the new scenarios of greenhouse gas emissions. In this study, sea level change in Persian Gulf and Oman Sea has been calculated by SIMCLIM model under climate scenarios by 2100 A.D. For this study, the SIMCLIM model has been applied based on different general circulation models, under RCP scenarios for 1995 to 2100. The regional sea level change has been estimated for this case study. In the SIMCLIM model the amount of water level change was estimated for a period based on rising temperatures leading to thermal expansion and polar ice melting. In this model, the spatial resolution is about 2.5° × 2.5° kilometer in global scales, and for regional sea level is about 0.1°.
To compare the increase in water level in the regional scale to the global mean sea level, the difference in water level is based on AOGCM models. The difference in predictions during 2081-2100 is compared with 2046-2065. This shows that regional sea level change during the same time periods is different from each other. In fact, this is changing with different rates and sea level changes more quickly and will be increased overtime. Predicted values under the RCP 8.5 scenario shows higher difference compared with the mean sea level change, among other RCP scenarios. According to regional predictions of sea level in this case study, the amount of change in the water level is about 11 cm under the RCP 8.5 scenario and about 6 cm under the RCP 2.6 scenario by 2100. To investigate regional sea level changes under different scenarios, the amount of sea level change based on ensembles of AOGCM was considered as the best estimate. The predicted values show that the increase in the water level in the second and third 25 years after 2020 is growing at a faster rate compared with the first 25 years after 2020. The rate of increase in the water level during the 2075 to 2100 is growing at a faster rate than other periods of the time.
Conclusio: The results of this research have indicated that sea level in this region under RCP2.6, RCP4.5, RCP6.0 and RCP8.5 scenarios will be 84.18, 86.62, 89.06 and 181 cm, respectively, by 2100. The values of general sea level change have been predicted about 0.61, 0.71, 0.73 and 0.98 cm per year under RCP scenarios, respectively. Comparison of these values shows the necessity of more accurate coast vulnerability estimation to flooding in the future.

Climatic comfort and adaptation with weather conditions is very important for human wellbeing. In fact, climatic comfort is a situation in which about 80% of people do feel neither cold nor warm. Temperature comfort is related to temperature balance of human body. The temperature balance is due to biological, spiritual and environmental facts which could control a complicated process of heat transfer between human body and the environment. Climate conditions are one of most important factors which could cause human comforts as well as human health. Climate conditions can also affect life quality, mental power and thinking ability. Accordingly, the potential of human activity is increased due to proper environment, and it is decreased due to hot or cold conditions. Inter-annual variation of weather can influence climatic comfort. In winter, especially in cold regions, natural gas is an important energy source to achieve climatic comforts. The climatic comfort which is due to climatic elements such as temperature, radiation, relative humidity, and wind speed is investigated by international and Iranian experts.
In an effort to investigate the effects of climate on the amount of natural gas consumption, we gathered the daily data of climate elements which might affect the temperature comfort, e.g. temperature in degree Celsius, relative humidity in percent, wind speed in meters per second, and sunshine hours, for Zanjan station over a 35 years period (from 21 March 1980 to 21 march, 2016). These data have been gathered from Islamic Republic Meteorological Organization (IRMO). The data of daily consumption of natural gas (in cubic meters) have also been gathered from Gas Department of Zanjan. We have also used MATLAB software in order to organize and test accuracy and homogeneity of the data and also to describe their characters. We have also used Novell, Terjong, and Olegy and SET, PET and PMV indices in graphic forms.
Bioclimatic condition of Zanjan is evaluated by Novell index, Terjong, and Olegy plots and the Ryman model indices, e.g. Standard Effective Temperature, Physiological Equivalent Temperature, and Predicted Mean Vote. We have compared all the above-mentioned methods and also their relationship with natural gas consumption. Accordingly, type of Zanjan climate is diagnosed and the comfort and uncomforted situation in daily and hourly scales was calculated. The results of these evaluations are represented in graphic display. Climatic situation of Zanjan city, especially in terms of elevation and latitude, shows a cold climate. As a result, in order to find the climatic comfort zone, it is essential to use natural gas. We have examined all bioclimatic situations by using all climatic indices and climatic graphs. All indices have indicated that the natural gas consumption is related to weather variation. It also revealed that Standard Effective Temperature is the best index to show this relation relative to other indices.
According to Novell index for Zanjan city, July is the warmest month in the year. As there is no need for natural gas to reach the comfort condition, the average of natural gas consumption is the lowest in comparison with other months of the year. According to Olegy diagram, Zanjan experiences its warmest and coldest months in Tir (June) and Day (January), respectively. The consumption of natural gas revealed that the highest and lowest consumption of natural gas occur in January and July, respectively.According to the heat sensitivity based on PET, PMV, and SET indices, we have calculated natural gas consumption. It is cleared that the natural gas consumption is in accordance to these indices. The more detailed study and an accurate cooperation between time series of each of the indices and that of natural gas consumption have indicated that Standard Effective Temperature (SET) is the most accurate comfort index in comparison with other indicators. According to our achievements, the building design process accustomed to the climate not only could produce an environmental adoption, but it could reduce energy consumption. As we have found in current study, the climate plays an effective role in energy consumption in Zanjan city. This could lead to an accustomed building design.The index Standard Effective Temperature was used to predict natural gas consumption for Zanjan city. It was found that the less the values of the index the more the consumption of natural gas. Accordingly, for each unit reduction in the index, the natural gas consumption in the city will increase by 63100

Clouds and water vapor are important modulators of climate and are involved in feedbacks that strongly affect global circulation and energy balance. Typically, 50% of the earth surface is covered by clouds, at any given time. A cloud is defined as a visible mass of condensed water droplets or ice crystals suspended in the atmosphere above the earth surface. The cloud phenomenon plays an important role in the water cycle, radiation, temperature, precipitation, predictors of climate, and etc. As there are not adequate information on the spatial distribution of clouds in Iran, except for synoptic stations data, it is necessary to conduct researches on the physical properties of cloud by remote sensing data. Therefore, these kinds of data can provide us with a more accurate and comprehensive understanding of cloud phenomenon. This study examines the spatial distribution of cloud Fraction (cover) over Iran in 2007 using remotely sensed data. The results of this fundamental research could be applied in practical knowledge such as weather forecasting, climate modeling, seeding clouds, site selection of solar panels, and etc.
The aim of this research is to survey the spatial distribution of Cloud Fraction (CF) over Iran in annual and seasonal timescales. To do this, daily data of cloud product of MODIS Terra (MOD06_L2.A) over Iran was used in 2007. The data was obtained from the ftp linkftp://ladsftp.nascom.nasa.gov/allData/6/MOD06_L2/. In this research, we have used spatial resolution of CF in 5 km×5 km scripting in MATLAB. In the first step, overlapping images have been removed and, then, the data within the Iranian border have been extracted from daily data. The data have been transferred into regular network of Iran for doing statistical computations.
The investigation on the annual mean percent of CF indicates that the value is 25.3% for the morning and 29.7%for afternoon. Thus, the amount of CF in the afternoon is increased compared to the morning times. In winter, the amount of CF for the morning is 48.2% but for the afternoon it is reduced to 44.1% and this reduction condition is not seen in other seasons. In spring, fall and winter seasons the amount of CF is increased in the afternoon compared to the morning. The spatial distribution of annual percent of CF indicates that the maximum is seen over the southern shores of the Caspian Sea and the minimum is observed in south east part of the country. The spatial distribution of seasonal percent of CF shows that the maximum amount of CF is over the highlands of Zagrous and Alborz mountains and the minimum is in south and south-east regions of the country. In this season, the maximum percent of CF is not seen over Caspian shores like other seasons. In spring, the maximum percent of CF can be seen over the southern shores of the Caspian Sea and parts of north-west but the minimum percent of CF can be observed over central areas of south and south-east regions of the country. In fall season, the maximum percent of CF is seen over the southern shores of the Caspian Sea and parts of north-east and the minimum is observed in south and south-east regions. In summer, the maximum percent of CF is in the southern shores of the Caspian Sea and the minimum can be seen over east and west parts of the country. In summer, the extent of minimum percent of CF is changed to other seasons and is far away from south-east regions.
In this investigation, the CF parameter of MODIS Terra was applied in the daily temporal resolutions for the year 2007 to explore the spatial distribution of cloud cover over Iran. As the data did not have a regular geographical coordinated grid, a regular coordinate was initially constructed and CF data were trasnferred to this regular grid. This process was conducted to analyze the climatology of cloud cover. The results from MODIS Terra data for the pass of morning and afternoon times revealed that the maximum annual percent of CF is seen over the southern shores of the Caspian Sea and the minimum is occurred over south-east part of the country which is consistent with the results of Rasooli et al. (2013) and Masoodian and Kaviani (2008). For the seasonal time scales, the maximum percent of CF is occurred over the southern shores of the Caspian Sea for spring, fall and summer seasons but in winter it is seen over the elevations of Alborz and north-west parts of the country. The minimum percent of CF is seen in south-east and east parts of the country for spring, fall and winter seasons. In summer, it is observed over east and west regions where shows that the formation process of cloud is different in winter and summer compared to the other seasons. The validation of CF values in the annual time scale indicates that MODIS overestimes CF by 3% compared to the synoptic stations. This is acceptable when the results are compared with the findings of Bisoolli and Pahl (2001) in Germany with the erros of 6% and Kotarba (2009) in July and January months with the error of 4.38% and 7.28% for the year 2004. In general, the estimation of cloud cover is identical for the two data sets.

Runoff velocity is high in urban basins with smooth man-made channel and impermeable areas. As residential zones and various commercial and industrial activities are concentrated in urban areas, the potential of the flood losses are increasing in the cities. The first step in flood management is prepare flood risk zoning maps to show the probability of flooding in agricultural, residential, commercial and industrial land parcels. Multi-criteria evaluation methods are widely used in environmental science. One of these methods is Analytic Hierarchy Process (AHP) often used by many of researches to provide the flood risk mapping. In these studies, we have used several parameters to flood zoning such as distance from channels, depth of ground water, slope, population density, drainage density, runoff coefficient, land use, building and unbinding area, and etc. Several floods were happened in Torbat Heydariyeh in last year. The catastrophes caused damage and losses to local communities. Thus, it is necessity to study the flooding in this city. The aim of this research is to provide the flood risk mapping for the central part of Torbat Heydarieh by AHP method based on field observation.
Torbat Heydarieh County with semi arid climate lies in northeast part of Iran, in58˚ 41' and 60˚ 07' E and 34˚ 59' to 35˚ 51' N. Mean Annual precipitation and temperature of Torbath Heydariyeh are 274 mm and 13.7˚C, respectively. The central part of the city has flooding problem, so the area with 352.3 ha was selected as study area. In this research, the Analytical Hierarchy Process was used as one of the most comprehensive methods of multi criteria decision making. This process is considered as various options in decision making and it is able to do sensitive analytical method on criteria and sub criteria. The values of credit decisions are related to quantity and quality of questionnaire. In this research, we have identified the 7 parameters including elevation, slope, drainage density, land use, distance to channel, capacity of drainage channel and the area covered by each channel. The questionnaires have been completed by 14 experts. The matrix of binary comparison criteria was calculated by geometric average. To estimate consistency and the weight of criteria and sub-criteria, the final matrixes of binary comparison were entered into Expert choice software. The weight of criteria and sub-criteria have been calculated and added to each map in GIS. The zoning map of flood risk was drawn with four classes: low risk, moderate risk, high risk and very high risk. To compare the results of AHP and actual situation of flooding, the depth of flood were measured in the index points in three shower events of 4/3/2014, 11/5/2014 and 1/10/2015. Then, to identify the accuracy of AHP flood risk zoning, the percentage of the adaptation between measured point and flood map risk was calculated in each shower.
The results of pairwise comparison between study criteria showed the classes including the slope lower than 2%, lower than 40 meters distance from main channel, lower than 1350 meter elevation, commercial and ministerial land use, drainage density upper than 325 m/ha, channel capacity lower than 0.5 m3/s and the area covered by each channel; the weights of the factors are 0.599, 0.531, 0.379, 0.378, 0.382, 0.615 and 0.571 respectively. The map of flood risk zoning showed 126.79 ha, 118.30 ha, 78.62 ha and 28.42 ha of the study area in low, moderate, high and very high risk classes, respectively. Most of the measured flooded points were placed in moderate and high risk classes. The results of sensitive analysis showed distance from main channel as sensitive factor.
The results of this research indicated combination of GIS and AHP as effective tools to determine the areas with potentiality of flood in urban basins. The evaluation of potentiality of urban flood risk by AHP represented 67.75% of measured points of flood in high and moderate risk classes when rain intensity was increased. Thus, the results of urban flood risk zoning with AHP was acceptable. In central part of Torbat Heydarieh, the most important factor related to flooding was distance from main channel. In potential map of flood risk, the regions with very high and high risk were mostly near the main channels

An important characteristic of river is channel form and meandering rivers for active forms. Dams as barriers to water and sediment flow can create discontinuities in fluvial geomorphological conditions. The objectives of this paper are to assess the effects of reservoir on the meandering river morphology. The Gorgan River catchment is located in the southern part of Golestan province with a total area of 11,380 km2. This river is originated from the Alborz Mountains into Caspian Sea. A reach of the river, 44 km long, that is examined in this research is situated in middle Gorgan River, between Gonbad Kaboos city and Digjeh. The construction of reservoir and changes in land use is effective on the main activities that potentially impact water regime, sediment transport and fluvial dynamics in the Gorgan River.
The data of the flow discharge and suspended sediment load of Gorgan River are available in 1973- 2015 at the Ghazaghli gauge station (73 km downstream from the Golestan reservoir Dam). The hydrological analysis was divided into two periods: before dam construction (1973-2001) and after dam construction (2001-2015). Sediment rating curves were created by daily mean suspended sediment discharge and daily mean water discharges by a power function. The fluvial changes have been measured using aerial photographs of 1967 at a scale of 1:20,000, Landsat satellite images (Landsat TM) 2001 and Google Earth images, 2015. The river was digitized from photographs and satellite images, after they were geographically referenced with the help of ArcGIS 10.2. Meander morphology was described based on some of form parameters such as wavelength, amplitude and radius of curvature, and bank width of the channel. Lateral migration and channel activity was analyzed as geomorphic activity. The normality hypothesis was studied for each parameter and conducted with the Kolmogorov–Smirnov test. If the normality test was not rejected, an ANOVA test was applied. If the normality hypothesis was rejected, the Kruskal–Wallis test was used. In all cases, the significance level assumed was α=0.05, as a threshold for rejecting the null hypothesis. The spatial distribution for these parameters was analyzed in order to change downstream the channel. Thus, the correlation coefficient of Spearman was calculated.
During the pre-dam period (1967–2001), mean discharge below the dam was 14 m3 s-1. These values were 10.5 m3 s-1 after the dam was constructed (2001-2015). Power regression between suspended sediment discharge and water discharge data shows that suspended sediment load is reduced to 50 % after dam construction. The values of wavelength and amplitude show minor differences in the three records and do not show significant differences. The radius of curvature, the length in 1967 (124.7 m) was reduced in 2001 (100.6 m) and 2015 (103 m). The dispersion values show significant differences, with a maximum in 1967 and reductions in 2001 and 2015. Bank width shows significant variations in the three records. In 1967 and 2001, it reached the values of 31 and 33 m, respectively. This is decreased to 15.7 m in 2015(-50% from 1967). Thus, bank width loses half of its value in the pre-dam. In pre-dam period (1977-2001) channel lateral migration was reached 39.3 m and in post-dam (2001-2015) the displacement was recorded to 22.2m. The channel activity during the time period 1967–2015 reached 0.65 m/y. The ratio between radius of curvature and the bank width (Rc/W) is changed from 4.14 in 1967 to 3.04 in 2001 and 7.48 in 2015. These results have indicated that migration capacity is decreased. The stability state shows the spatial distribution of the values. There is no significant relationship between landuse and lateral migration.
After construction of the three dams, upstream flow discharge is reduced (26%) and mean width of river is reduced (50%) from 2001 to 2015. Suspended sediment discharge has decreased (50%) after the construction of dams. Wavelength and amplitude do not show significant differences throughout the time period. The ratio Rc / Wb doubles from 1967 to 2015. The results show that geomorphological activity is decreased and a static equilibrium was obtained

Evapotranspiration (ET), which includes water evaporation from soil surface and vegetation transpiration, represents a fundamental process of the hydrological cycle. For water resource management, especially in arid and semi-arid regions, this is a key element. A lot of empirical methods have been developed in order to estimate ET from meteorological data since 50 years ago. The major problem of this method is that it can be used for evaluation of uniform regions near the station. This could not be extracted for other regions. Nowadays, remote sensing based methods often used for calculation of different parameters of ET, are suitable to extract different parameters of ET at proper temporal and spatial scales.
One of the most famous algorithms for estimation of actual evapotranspiration is Surface Energy Balance Algorithm (SEBAL). This algorithm calculates all fluxes of the energy balance at the earth's surface including net radiation (Rn), soil heat flux (G), and sensible heat flux (H) from satellite images. Finally, actual ET is computed based on the energy balance at the earth surface. The aim of the current study is to evaluate the spatial and temporal variation of actual evapotranspiration of wheat in Agricultural Research Station of Haji Abad using SEBAL algorithm. The area has geographic coordinates 55° 54 'N, 28° 18' E, with an elevation of 900 m above mean sea level. For this purpose, 4 cloud free Landsat 7 / ETM images are used. Landsat 7 Enhanced Thematic Mapper Plus (ETM) in cloud free satellite images were downloaded from the USGS Earth Explorer site [(http://edcsns17.cr.usgs.gov/NewEarthExplorer/)]

The importance of Quaternary period in morpho-climatic interpretations is due to severe and consecutive climate changes, erosional processes and their environmental and socio-economic consequences. In the study of Quaternary nature and statues, chronology of erosional processes and river sediments provides an appropriate framework to determine the environmental, tectonic, climate and anthropogenic changes. Rivers, as one of the features in terrestrial landscape, are sensitive to changes that regulate their forms against a wide range of internal and external forces over time. River sediments are significant and long, although disconnected, archives of earth landscapes evolution as well as many Quaternary sedimentary sequences that reflect the reactions of drainage systems to changes in sea level and past environments.
Material and Saqqez River basin with an area of 865 square KMs is located in northwest margin of Sanandaj-Sirjan zone. From a morphological point, middle parts of the study basin are largely constituted of Cretaceous clastic and volcanic rocks. They have a mild topography accompanied by low-lying hills and flat erosion levels. In this study, the physical and chemical analyses have been used to investigate the characteristics of Paleo-sediments of Saqqez river basin. First, a profile was selected as a study profile; recognition of the sedimentary characteristics of this profile was possible in field research based on genus, color and position of layers. Buried paleosol, carbonate layer, fluvial sediment (conglomerate), unconsolidated sediment, flood-plain deposit, exhumed paleosol, and recent sediments are the most important layers in the profile. Samples were taken from each of sedimentary deposits and 20 samples were collected finally. Thin sections were prepared from the samples for the analyses of mineralogy, point counting, physically tracing of sediments and recognizing the type of the carbonate cement. In laboratory, the thin sections were investigated using polarizing microscope in two modes of Plain Polarized Light (PPL) and Cross Polarized light (XPL) for the purpose of determining the samples’ shape and type of sediments. Point counting of the samples was done through visual method and microscopic interpretation. Carbonated samples were chemically staining using Alizarin Red-S solution to distinguish between the types of carbonates. Isotopic compositions of oxygen were measured in isotopic laboratory of Geoscience School of Ottawa University (Canada). Generally, 10 samples were used to oxygen isotope analysis. Isotopic compositions of the samples have been reported according to common scale of δ as part per thousand. The measurements analyses precision has been reported according to vpdb standard as ±0.1 per thousand.
Physical investigations about the components of sediments and identifying the source rock of clastic sediments revealed that sediments nature are including fluvial sediments affected by pedogenic (sandy carbonate mudstones, sandy mudstones, sandy gravely sediments, conglomerates and micro conglomerates), coarse-grained fluvial deposits (unconsolidated sediment), and flood-plain deposits (silty sand and gravely muddy sand). Volcanic, metamorphic (Schist) and sedimentary (Shale) rock fragments are formed as the main components of sandy carbonate mudstone. Clastic grains of the volcanic and metamorphic rock fragments, such as slit, are the major components of sandy mudstone. Given the sandy gravely sediments, the main components are coarse rock particles including a variety of volcanic and metamorphic rock fragments (such as different types of schist and slit). The sandy parts are made up of Quartz and Feldspar. The conglomerates are mainly composed of rock fragments and monocrystalline Quartzes. The results of point counting phase show that with the igneous fragments in the samples the frequency of volcanic grains are much higher; also in the metamorphic fragments the frequency of Schist is too higher in comparison with other metamorphic fragments. Chemically staining of carbonate samples using Alizarin Red-S revealed that calcite composition for carbonated matrix in the samples of the study profile is the Sparite carbonate. The crystals of Sparite calcite have usually fine zoning that is resulted from small changes in the amount of iron and manganese.
A glance at dispersion of the lithological units across Saqqez River basin indicates that rock unit of Schist is located either near main channels of rivers or downstream the basin where river terraces (conglomerates) is formed. Accordingly, the hydrological and topographical conditions of the basin are organized in a way that the transport of schist rock fragments to downstream might have occurred via the main channels, thus, increase the frequency of Schist; as it is proved in the present study by the point counting of conglomerate rock fragments. Using the zoning pattern in the calcite in a sequence and a regional scale it would be possible to create the cement stratification which, in turn, contributes to reconstruction of the basin hydrology in a major scale. Sparite calcite indicates a more negative amount of O18 than the string calcite which reflects its deposition in a higher temperature. Therefore, Sparite cement of the study profiles from Saqqez River could be indicative of the hot and humid weather at the time of their formation. Also, the results of oxygen isotope analysis prove this claim. The amounts of carbonates δO18carb has varied from -8.9 to -8.18 which shows the minor changes of these values. Given the low values of δO18carb in the analyzed samples, vaporization has relatively taken lower amounts of O16; thus, most probably the study profile carbonates have experienced a wet condition in Saqqez River.

The amount of solar energy absorbed by earth surface features and converted into heat energy is measured as temperature. General temperature values are a function of elevation and latitude. Other secondary factors such as location of water bodies and land cover properties as local agents can form temperature structure of each location. One of the exceptional temperature situations representing minimum temperature values is cold waves. Given the general circulation pattern of the northern hemisphere, Iran is located in a place influenced by a variety of air masses. One of the important climatic phenomena prevailing in most of the country is cooling and freezing condition. Northwest Iran as a cold region is always experiencing losses by the extreme cooling events. Therefore, investigation about the patterns creating the extensive cooling waves can help us understand the behavior of the climatic phenomenon.
In order to examine the synoptic patterns of the cooling waves in northwest Iran as the purpose of this study, we have obtained the minimum temperature of 42 synoptic stations from Iran Meteorological Organization. We have selected the stations with longest period of data available. After sorting and quality control of the data and test of sufficiency of the sample stations, the minimum temperature has been interpolated by kriging method using scripting. In the procedure, a matrix 42*365 has been formed for the variables of each year. After the interpolation has been done, a matrix 5082*11323 has been formed for the 30 year statistical period and used as database in next stages of the research.
In this study, we have selected the days with cooling waves that have: (1) standard score less than -1.2, (2) spatial coherence, (3) 50% of spatial coverage, (4) the cooling waves in two successive days. Using these conditions, the days with the cooling waves have been selected for the Northwest Iran. After classification of sea level pressure data, suitable site has been selected to determine the representative days. Using scripting in MATLAB, we have calculated the correlations between the maps of different days for each class (2-6 groups), in 0.5 coefficient. We have used mean daily temperature data from 44 synoptic stations in northwest Iran from 1980 to 2010. The daily temperature data have been interpolated by kriging method using scripting in MATLAB, in the cells of 15x15 km and a total of 5082 cells. Using the defined threshold, up to 1196 cold days have been selected. They have been divided into four patterns combined by clustering program to draw the maps in Surfer. For more precise analysis of the cold waves in northwest Iran, other dynamic quantities including thermal blowing, atmospheric divergence and convergence, and prevailing meridian winds.
The results of the cooling wave patterns have indicated that four synoptic patterns are influencing the cooling waves. These patterns are including low pressure belt of west Russia and North Africa with East Turkey high, East Europe low pressure, enormous high pressure of east Europe with Sudan low, Siberian high with European high pressure. The most severe cold waves occurred when the enormous high pressure of east Europe moved the high latitude cold air through a cyclone movement into the study area. As a result, a low was formed over north Europe and moved towards the east and lower latitude areas. This movement developed the high pressure on North Africa and Mediterranean Sea. It also brought Siberian high pressure over the region with a cold weather condition. There was also a negative pressure anomaly at the location of the low. The pattern formed in trough part suitable for overshooting of cold air. In this pattern, a progressive change can be observed in contours from Europe towards Iran. This provided suitable condition for descend of the cold air from northern Europe and cold air flows from higher latitudes towards Iran. In a comparative analysis of the effective patterns in cooling waves in northwest Iran, it can be argued that the influence of the patterns revealed that two patterns of east Europe low and the west Russia and north Europe low with east Turkey high have the greatest influence on creation of the cold wave in the region. This is due to extensive descending of the high latitude cold air into median and low atmospheric levels. Since the study area is located in the east part of the overshooting of warm air from low latitudes into the median atmospheric levels, the third pattern reduced the severity of the cooling wave. The fourth pattern moved parts of Siberian high and European low towards northwest areas and created a high with prevailing cold weather. This has the lightest severity of the cold wave because the cold air was not penetrated into median atmospheric levels.
This research has investigated the synoptic patterns of three days lasting cooling waves in northwest Iran in the last decades. The research has revealed some synoptic patterns for the cooling in the region. The results of the patterns have indicated that most of the prevailing cooling events in the northwest Iran are resulted from formation of Siberian high pressure near the earth surface. Arrangement of the two high pressure systems of Siberian high and western migrating highs have played the most important role in conducting the high latitude cold air into the northwest region. In most of the patterns, the most important phenomenon and the principal agent of cooling event is establishment of a deep trough over the region. In other cases, establishment of sub-polar low in northern Europe and Russia made the polar cold air masses to penetrate into lower latitudes and the northwest Iran.

The flood is considered as a natural disaster with the highest financial losses according to the Report of the United Nations Development Program. The floods are harmful to the urban and suburban areas. River floods and flood plains have been a source of great interest in the past while the flood has been considered less in the urban environment. The socio-economic consequences of flood in the urban environment have affected inevitably more than 2.49% of the world inhabitants.
Construction of buildings on urban areas is increasing impermeable surfaces. Development of built surfaces in the urban areas can also decrease permeable levels of the basin that is useful for absorbing runoff. It has increased the total volume of runoff in the city. Until now, flood risk zoning with the aim of flood control in Urmia has not been considered greatly. This topic received not remarkable attention in the form of a research project. Therefore, flood risk zoning and controlling is essential to predict the extent of flood damage in different economic and social circumstances.
In this research, we have used linear weighted Combination and fuzzy multi-criteria analysis and Geographic Information System (GIS) for zoning of flood hazard in urban areas of ​​Urmia. The weighted linear combination method is the most commonly used technique in multivariable analysis. This technique is called either simple additive weighting or scoring method. This method is based on the mean weight concept. The analyst directly estimates the criteria based on the "relative importance" of each criterion. After multiplying the relative weights in the values of each criterion, a final value for each alternative is obtained. After determining the final value of each alternative, the alternative with the highest value will be selected for the goal. The weighted linear composition method is an averaging technique that simplifies the hard decisions of the Boolean method and avoids excessive estimation. The linear weighting method consists of four steps: 1) First, to determine a set of evaluation criteria (map layers) as well as a set of possible options; 2) to standardize each map variable; 3) Third, to determine directly the relative importance of weights of each criterion; 4) at the end, to create a standardized weighted map. In this research, various natural and human criteria have been used to achieve the goal. At first, we have prepared nine natural and human effective indicators including distance to river, runoff coefficient, building age, construction density, population density, slope, CN coefficient, open space availability and land use condition. After digitizing the maps, since each map has a different measurement scale, for the analysis and evaluation of several criteria, we need to make same measurement scale for all of our variables. Standardization of data converts all values ​​of the maps into the same domain, for example, between 0 to 1 or 0 to 255. Then, by defining the binary comparison matrix, using the Hierarchical Analytic Hierarchy Model, the significance of the weights was determined with 0.07 inconsistency ratio in the Expert Choice software. According to the final map of flood risk zonation, the central areas of the Urmia City are more susceptible to floods. This problem has been exacerbated by the proximity of urban areas to densely populated areas and buildings in flood prone area where increase the amount of runoff and accumulation of surface waters. The WLC technique using weighting method has provided powerful solutions for researchers in multi criteria problems like flood zoning. On the other hand, this model is one of the commonly used methods for evaluating environmental problems with the MCDM fuzzy method that have been widely used in the GIS environment.
After creating a flood risk zoning map, it was declared that the central areas of the Urmia City had the highest flood potential. The flood risk map shows that from all the total area of the Urmia City, about 22.31% is located in the very high danger zone, 29.08% in the high risk zone, 26.45% in the middle danger zone, 17.52% in the low risk zone, and 4.64% in the very low risk zone. Urmia Urban Development strategy should be planned with regarding the flood potential map of the city. The map showed that over 50% of the urban areas are categorized in very high and high risk zones. Given the flood potential map, it is suggested that it is required to create underground and diverse canals in flood-prone areas for discharges of surface runoffs to secure vulnerable areas, especially in the central parts of the Urmia City.
According to the results of this research, more than 50 percent of the Urmia city is very highly and highly at risk of flooding. Therefore, it is necessary to the flood prone areas for municipal activities and urban management. To secure vulnerable areas, underground canals and flood diversion route, especially in the downtown areas, can be constructed to discharge surface runoff to avoid the flood damage.