precipitation

Open Access Article

1 - Analysis and comparing several climate droughts indicators and determine the best index in southeast of Iran
zahra hejazizadeh farshad pazhoh haniyeh shakiba

the drought is the most destructive weather events which cause significant causes both in natural resources sector and human’s life. The aim of this research is to compare the performance of drought’s indexes and determining the best index in the region of southeast of More

the drought is the most destructive weather events which cause significant causes both in natural resources sector and human’s life. The aim of this research is to compare the performance of drought’s indexes and determining the best index in the region of southeast of Iran. To this purpose with using 30 year of daily precipitation data (1985-2014) from meteorological organization and with using 8 most widely used indexes such as standard precipitation, rainfall anomalies, percent of normal, annual precipitation, Niche, the standard score, deciles and Chinese Z in 19 meteorological stations of Kerman, Hormozgan and Sistan va baloochestan the accuracy of each indicators examined in determining the drought intensity. Also the zoning has done in arc GIS9.3 for the driest year in the statistical time period and comparing the most severe drought category in 2 selected index. The accuracy of each index analyzed in 2 annual and monthly scales. In annual scale is used the efficient measures of minimum precipitation’s symmetry years with most severe droughts in region’s stations. The results showed that in the monthly scale in order to analyze the southeast drought of the country the dynamic index of standard precipitation (SPI) in a time period of 6 and 12 month had the best function. But in annual scale the rainfalls anomalies indexes (RAI) and Docile (DI) in all the stations had showed the minimum precipitation amounts with severe droughts which determined as the best index. Also the Niche index had the weakest function in determining the drought intensity in southeast of Iran’s stations. Manuscript profile

Open Access Article

2 - The Statistical analysis of Global Warming effect in Seasonal Rainfalls changes in Iran
zahra hedjazizadeh mohamadreza poodineh meysam toulabi nejad

Increasing greenhouse gases could increase the frequency of changes in precipitation in different regions of the world. So, identify the effects of global warming on precipitation in a country like Iran which is located in the dry area of the earth is of great importanc More

Increasing greenhouse gases could increase the frequency of changes in precipitation in different regions of the world. So, identify the effects of global warming on precipitation in a country like Iran which is located in the dry area of the earth is of great importance in planning related to water resources are. According to the study, statistical analysis method used. for analysis, total precipitation data of 34 stations from 1984 to 2012 was received from the National Weather Service. Also data of methane Gase (ppb) as one of the most important factors of global warming, the site of NOAA received. Outset this elements by method The Pearson correlation coefficient determined, afterwards long-term changes in precipitation than was calculated. The results of this study showed that, Bharhdr rainfall in the north and northwest parts of the country grew 13 mm; and Precipitation stations southern half of the country have faced long-term reduction of 46 percent. Due to the increasing amount of greenhouse gases, analysis of the data suggests a reduction of 30 mm of precipitation in summer than long-term stations in southern Iran, but in contrast rainfall in western and northern stations, an increasing of 14 mm. The results showed that the autumn precipitation is most relevant to global warming, in this season, about 24 mm of rainfall western stations to long-term decline, but the Southwest and Southeast stations surged 17 mm have experienced. Finally, the results of the Winters precipitation showed which, the West and Northwest stations were reduced 18/6 mm. Manuscript profile

Open Access Article

3 - Synoptic analysis of extreme and widespread precipitations in Caspian western coasts by emphasis on patterns of sea level pressure

In this research, for synoptic analysis of extreme and widespread precipitations in Caspian western coasts, we interpolated and traced the daily isohyet maps from 1340.1.1 to 1383.11.10 (15992 days) on the 14*14 km pixels by Kriging method and by use of daily precipitat More

In this research, for synoptic analysis of extreme and widespread precipitations in Caspian western coasts, we interpolated and traced the daily isohyet maps from 1340.1.1 to 1383.11.10 (15992 days) on the 14*14 km pixels by Kriging method and by use of daily precipitation data base of this region. These data provided the data of 48 studied local points for 15992 days to calculate maximum precipitation and area percent under precipitation for every precipitation day. On this basis, we identified the most extreme and the most widespread of region precipitations on the basis of 99th centile base index for studying and analyzing. By applying environment- circulation approach and agglomerative hierarchical cluster analysis by “Ward” method on the maps of sea level pressure, we could identify three circulation patterns which were effective and important for creating the extreme and widespread precipitations of Caspian western coasts. In continuation, for analyzing the precipitations in every pattern, the representative day defined on the basis of correlation coefficient with 95% threshold and in these days, sea level pressure maps, atmosphere thickness in 500-1000 hpa levels, functions of frontogenesis and humidity convergence flux traced and analyzed for 500, 600, 700, 850, 925 and 1000 hpa levels. The results of this research indicate the presence of high pressure system in the occurring time of patterns of sea level pressure on the Black sea. The average of received water volume of region is 906.9 million m3 in every three patterns which is a considerable number. The study of atmosphere thickness patterns indicate the relatively deep trough on the Caspian Sea. The analysis of frontogenesis function maps in the Caspian western coasts confirm the existence of front core on the Caspian Sea and around it too. The analysis of humidity convergence flux indicate that Caspian sea is the most important source of providing the humidity of western coasts precipitations of this sea, and Black sea is in the next importance ranking. Manuscript profile

Open Access Article

4 - Migration crisis caused by short-term droughts in Sistan and Baluchestan Province

Drought is a complex phenomenon that is the definition of it is difficult. Definitions, it is presented in different areas and each of them has different definitions depending on the amount of average rainfall. Since the beginning of the formation of human civilization More

Drought is a complex phenomenon that is the definition of it is difficult. Definitions, it is presented in different areas and each of them has different definitions depending on the amount of average rainfall. Since the beginning of the formation of human civilization so far, the drought has always been considered one of the natural disasters and catastrophic impact human activities have on. This paper describes a method of analysis to assess the drought and its relationship with the inhabitants of Sistan and Baluchestan Province migration. To understand the different effects on rainfall, water resources, leading to the return of the SPI to be used to evaluate the drought in Sistan-Baluchistan province. Data monthly precipitation (mm), the years 2005 to 1985 for four stations in Sistan and Baluchestan (Zahedan, Zabol Iranshahr, Chharbhar, Konarak) were studied. Results indicate that water shortages in drought affected areas are the result of increased immigration flora. The occurrence of severe in the region, has left the economic and social adverse effects due to the economy's heavy reliance on agriculture people in Sistan and Baluchestan this crisis has led to the phenomenon of origin and demographic balance, the economic, social and ... unbalanced and lead to regional and underdevelopment of the region. Manuscript profile

Open Access Article

5 - The Survey of moisture advection pattern of Iran's Comprehensive precipitations

Transferring the water vapor in the atmosphere directly depend on the conditions of atmospheric circulation, amount and path of humidity changes related to the atmospheric circulation variation. one of the main factors of atmospheric circulation affecting on transferrin More

Transferring the water vapor in the atmosphere directly depend on the conditions of atmospheric circulation, amount and path of humidity changes related to the atmospheric circulation variation. one of the main factors of atmospheric circulation affecting on transferring the moisture is high pressure centers that if placed on the water surface and humidity resources causes the moisture advection in a widely area. However, the role of low pressure systems and cyclones in advection and moisture flux, although not as much as high-pressure systems, but also played a significant role in transmitting and condition of moisture advection. the aim of this study is survey the moisture advection of Iran's precipitations. in this regard, pressure data, specific humidity, u wind and v wind parameters in 500, 700, 850 and 1000 hpa from NCEP/NCAR database were extracted and analyzed. the results showed that the moisture advection of iran's precipitations is related to the moisture advection pattern of low pressure of dual-core of Sudan and east Mediterranean - Europe high pressure, moisture advection pattern of multicore low pressure of central Iran, east Mediterranean and south east of Saudi Arabian, moisture advection pattern of high-pressure of north west of Europe- low pressure of Persian gulf, moisture advection pattern of high pressure of Siberia and Kazakhstan- low pressure of south east of Iran and low pressure of Mediterranean. Overly, the results showed that Arabian Sea in low level and Mediterranean Sea in high level had an important role in moisture advection of Iran's precipitations. Manuscript profile

Open Access Article

6 - The effect of precipitation and lithology on hydrochemical characteristics of the Karstic Springs in North Khorasan Province
Fatemeh Bagheri Gholamhossein karami rahim bagheri Javad Meshkini

Karstic aquifers are vital water resources which are used for irrigation and drinking purposes in arid and semi-arid regions. Understanding of the hydrogeological behavior of these springs and the qualitative tracing of these water resources are the first step in their More

Karstic aquifers are vital water resources which are used for irrigation and drinking purposes in arid and semi-arid regions. Understanding of the hydrogeological behavior of these springs and the qualitative tracing of these water resources are the first step in their better management. There are wide outcrops of Tirgan karstic formation in the study area, in the north of Khorasan province. In this area, there are a few karstic springs the discharge rate ranges from 50 to 500 lit/s. The recharge area characteristics of these springs vary significantly with their elevation, catchment size, thickness of epikarst and degree of karstification. In this study, temporal and spatial hydrogeochemcal variations of the five karstic springs including Arnaveh, Rezghaneh, Estarkhi, Ghordanlo and Sarani and 3 rain stations are investigated during one year period. The effects of both precipitation and lithology on the chemistry of these karstic springs are also considered. The dominant rain water types are Ca-SO4-Cl and Ca-HCO3 which change into Ca-Mg- HCO3 type during ground water flow in karstic system. This karstic aquifer is recharged during winter snowfall. The EC values of the rainfall vary from 70 µmohs/cm in Namanloo station to 100 and 150 µmohs/cm in Estarkhi and Ghale Barbar stations, respectively. The summer precipitations have more EC value than winter precipitations. This is due to long trajectory of air masses through arid regions with dust particles. The time series variations of discharge value are negligible in some karstic springs except for Sarani and Estarkhi springs. Hydrochemical composition of Sarani, Ghordanlo and Estarkhi springs are mostly affected by precipitation; while, Arnaveh and Rezghaneh springs with the same precipitation composition in this area have higher EC values. This is due to soil cover in catchment area, dissolution of clay minerals and diffusion. Manuscript profile

Open Access Article

7 - Relationship between topographic indices and widespread rainfall in Alborz mountainous region
maryam naghavi Buhlool Alijani mehry akbary ebrahim fatahi

Heavy rains are among the natural hazards that knowledge of their temporal and spatial distribution helps to reduce potential damage. For this purpose, the existence of a significant relationship between widespread precipitation and topographic indices of Alborz mountai More

Heavy rains are among the natural hazards that knowledge of their temporal and spatial distribution helps to reduce potential damage. For this purpose, the existence of a significant relationship between widespread precipitation and topographic indices of Alborz mountainous region has been investigated. In this study, Pearson correlation test was used and in this model, the dependent variable of total daily precipitation of the study area (precipitation occurred in more than 70% of synoptic stations in the area) and the independent variable of data related to topographic indicators of the study area (station height Synoptic, station slope and direction, longitude and latitude of the station, distance from the northern baseline, distance from the ridge, average height of the station in a radius of 2.5 km, average height of eight blocks fifty km in eight geographical directions to the center of the synoptic station, height difference Its average is eight blocks from the average height of the station in a radius of 2.5 km). First, the correlation between precipitation (129 days) and topographic indices based on common synoptic stations in three seasons of winter, spring and autumn was identified and then the correlation coefficients with 95% confidence interval at a significance level less than 0.05 were investigated. Each season, a sample day with the highest correlation coefficients in the majority of topographic indices was selected as the representative of that season. The study area, which is the vast Alborz mountain range, has been divided into areas with topographic and climatic similarities due to the complexity of topography and the diversity of its climatic conditions in each area. The highest number of significant statistics in terms of temporal and spatial scale between widespread precipitation with topographic indices is related to widespread precipitation in spring with 18 cases and the lowest is related to widespread precipitation in winter with 9 cases in autumn 14 cases of significant linear relationship have been identified. Among the topographic indices, the strongest index is related to the difference between the average height of blocks 50 km from the average height of the station in a radius of 2.5 km in different directions according to different seasons of the year and Evidence of the effect of direction on inclusive rainfall in the study area and that the area is in a certain direction to receive more rain , meaning that the mass of humid air entering from the northern parts of the country, including Siberian high pressure (Babaei Fini, 1393) due to low altitude and proximity to the ground is affected The surface roughness is located and the mass of moist air entering from the northwestern and western parts of the country, including the western migratory high pressures (Qashqaei, 1375), (Moradi, 1385)) due to higher altitude and more power is less affected by surface roughness. And the region's precipitation is affected by these high-level atmospheric systems. On the other hand, widespread precipitation in the northwestern and south-central Alborz region has the highest and the lowest south-western Alborz region has a significant linear relationship with the values of topographic indices. The results of this study have a significant linear relationship with most topographic indices (22 indices out of 24 Index) with widespread precipitation to be able to estimate and predict the most effective indices affecting precipitation in the region. The two topographic indices for the station and the distance from the ridge did not enter the correlation model on any day and in any area of the study area and did not establish any significant linear relationship, albeit weakly, with the total precipitation of the area Manuscript profile

Open Access Article

8 - Investigating the effect of climate change on temperature and precipitation using the LARS-WG model (case study: Bashar river basin)
Hamid reza Panahi Hossein Montaseri Aliakbar Hekmat zadeh Reza Khalili

The increase of greenhouse gases and the resulting increase in temperature have caused the balance of the earth's climate system and climate changes in most areas of the earth. Therefore, adapting and dealing with climate changes in the water resources sector along with More

The increase of greenhouse gases and the resulting increase in temperature have caused the balance of the earth's climate system and climate changes in most areas of the earth. Therefore, adapting and dealing with climate changes in the water resources sector along with reducing their reflection should be seriously addressed as part of a comprehensive regional response to the vulnerability caused by climate change. In this study, using LARS-WG exponential microscale software and the HadCM3 oceanic atmospheric general circulation model in the form of different scenarios defined in the fourth IPCC report (basic scenarios), including scenario A1, A2, B1, B2, which are more related to regional issues. And the world is concerned from an economic and environmental point of view, the amount of temperature changes and precipitation in the next 100 years of Bashar river basin was predicted. Then the fifth report scenario (RCP) was used and the results were compared with the basic scenarios. The results showed that in both scenarios in the coming period, we will face a large increase in average air temperature, but the decrease in precipitation will not be significant. In the climate change scenario section, RCPs until the end of the 21st century indicate an increase in temperature and a decrease in precipitation in the coming years. The amount of temperature changes in RCP2.6 was estimated between 3 and 13% and in RCP8.5 between 4 and 14%; This increase in temperature on a large scale increases evaporation and prolongs drought periods. Manuscript profile

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