Journal of Spatial Analysis

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For a synoptic analysis of high polluted days in 13 and 14 November 2007, a combinatorial synoptic analysis was used. From methodology prospect, the present study has utilized the "circular environment" synoptic approach and with respect to the restrictions on very high-polluted days in Mashhad city, the subjective synoptic analysis used for data processing and analyzing the prevailing atmospheric conditions.

In the present research, four sets of the data, including the pollution data recorded at the stations monitoring air pollution, digital atmospheric data, data of upper air stations and the outputs of HYSPLIT model were utilized. The data on air pollution obtained from the Department of Environment Protection of Khorasan Razavi were related to Wahdat station located in the center of Mashhad city. The pollutants include CO, NO₂, SO₂, ozone, and particulate matter (PM₁₀(  prepared and processed on a daily scale for a 7-year statistical period (2005-2012). When studying the quality of air pollution over Mashhad city, it is necessary to indicate that Mashhad city had only one station monitoring air pollution (Wahdat station) until 2010 and unfortunately, out of 10 present stations for monitoring the air pollution, only Wahdat station was involved a suitable statistical period duration to be studied. Accordingly, the present study has been conducted only by using the pollution data recorded in Wahdat station and utilizing the data of other stations ignored due to the shortness of statistical period duration. The reanalyzed data of the National Centers for Atmospheric Prediction (NCEP) and the National Center for Atmospheric Research (NCAR) with a horizontal separation 2.5 × 2.5 were used in order to study the atmospheric conditions. The atmospheric conditions include the sea level pressure, geo-potential height, vertical velocity, and orbit wind (u) & meridian wind (v) components on different atmospheric levels from the past 48 hours and in a 6-hour interval. In addition, upper air data about Mashhad station (Mashhad airport) were used on a similar period. Upper air data have been obtained from the website of Wyoming university (http://weather.uwyo.edu/upperair/sounding.html) on under study days, including air temperature,  dew point, direction, wind intensity and the atmospheric stability and instability conditions (based on Skew-T Curves – logP). These data are only available on Zero Greenwich hour. The outputs of the HYSPLIT model were also used as complementary data for tracing particulate matter in days 10 -15 in November. In this study, the HYSPLIT model, version 4.9 was used. In the present research, the role of regional atmospheric circulation and pressure patterns were investigated on a synoptic scale in very high-polluted days in November 2007 in Mashhad metropolitan. For this purpose, the mechanism dominated on occurring a very high-polluted period in this city was analyzed using a combinatorial method based on synoptic and thermodynamic analyses as well as tracing particulate matter. The results of studies involve the following findings: the days 13 and 14 November 2007 (22 and 23 Aban, 1386) show the highest concentration rates among the polluted days in Mashhad city. The findings of the research show that the synoptic pattern dominated the very high polluted period (13 and 14 November 2007) is a migrant high-pressure pattern. Accordingly, it may be concluded that the incidence of serious pollutions in Mashhad is initially the result of interacting local conditions with air circulation on a regional scale and then the other local factors. In the other words, Mashhad city would experience very high-polluted days only when regional atmospheric circulation provides suitable conditions to increase the concentration of pollutants. What is obvious is that in the winter season the serious pollutions occurred in Mashhad city are mainly as the results of prevailing extra-tropical systems (migrant anticyclone). Studying subjective synoptic analysis, tracing the backtracking of particulate matter and the atmospheric thermodynamic conditions ( combinatorial synoptic analysis) have provided a deeper and more accurate understanding of the conditions prevailing in the occurrence of serious pollutions in the northeast of Iran. Studying the output of the HYSPLIT model indicates that the migrant stack system of western wave together with the subtropical stack would control the air circulation pattern on the northeast of Iran in 13 and 14 November 2007. Tracing the particulates shows an anticyclone system on the zone. Also, studying SKEW-T Curves related to the migrant high-pressure pattern revealed a different structure, so that the day 12 November 2007 faced with a radiation inversion along with an increased temperature, but on day 13 November 2007 an inversion from the sort of subsidence between the interval of level 850 to 700 hpa was appeared and also reached to higher than 700 hpa.

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The study and Comparison of desertification process on the basis of climate Criterion (Case Study: Abbas and Dehloran Plains, Ilam)
Soraya Yaghoobi, Kamran Karimi, Marzban Faramarzi
Abstract:
Nowdays desertification is a disaster in many countries , especially in developing countries. This problem includes natural factors and improper human activities. According to the expansion of desertification, providing the appropriate management methods will be reduced desertification intensity and its expansions. In this way, knowledge of processes of desertification and factors causing and  the intensifier it and also awareness of intensity and Weakness the processes and factors that are important and necessary   that should review and evaluate. Recognition criteria and indicators for provide a model to show the process of desertification and for determine one of the  best reason effective factors for prevent the spread of desertification factors is necessary. To knowledge and Trend of desertification and separation of  vulnerable  areas versus degradation factors .we should indentifi and evaluat  criteria and indicators affecte  at desertification. Therefore in this study of  the Iranian model IMDPA to assess trends and Comparison of desertification in recent years has used.
The studied area of  Dehloran plain is located in southeast of Ilam province (47^◦ 02′ 16″ to 47^◦ 25′ 07″ E and 32^◦ 48′ 33″ to 32^◦ 18′ 48″N) with an area of 54252  hectares, With precipitation  average 251.6 mm and Abbas plain is located in south of Ilam province(47^◦ 37′ 55″ to 47^◦  50′ 57″ E and  32^◦ 17′ 77″ to 32^◦ 29′ 25″N) with an area of 34104 hectares With precipitation  average 227.1mm. In this study, in dehloran plain of six stations in this Inside and outside the area also in Abbas plain of five  stations outside the area  used to measure the amount of rainfall in different seasons of year. In this study, to assessment  and Comparison of desertification in two study area of the Iranian model IMDPA used. In this study, of climate criteria, were used. which according to the IMDPA model for this criteria, indexes are considered for evaluation e.t.c: Climate criteria: (1) the amount of annual rainfall 2-drought indexe(SPI) 3. continuing drought In IMDPA model  All measurements  do in this work  units. To this end, first, working unit maps (geomorphologic facies) were created using slope, geology, and land use maps. a map was generated for each index according to assigned weights, such that the qualitative map of the desired criteria were obtained using the geometric mean of indicators.
The results earn  of  evaluation  of desertification  showed that  in the period  2005-2009  weight average of climate criteria is same with 1.50 all of the region are in the classe Middle sub class 1 and class low sub class3 . in the period  2010-2014  Also  weight average of climate criteria is same with 1.88 in classe Middle sub classes 2 and 3.  Also weight average of climate criteria in Abbas plain In the first period is same with 1.92  in the classe Middle sub classe2. Also In the second period with weight average is same 2.3 in classe Middle sub classes 2 and 3. The results showed that SPI index, as the most effective indexes, in plain Abbas In the first and second periods with the weighted average 3.04and 3.2 in the intense class under class 2 and 3. in front in Dehloran plain SPI index in the first and second periods with weighted average of 1.93 and 2.25 in the moderate classe and sub-classes 1, 2 and 3 and intense sub-classe 1.
In this study, to assess and Comparison of desertification Dehloran and Abbas Plains to provide regional model has done. . In this way  of  a criteria, also important and effective indexes belonging to this criteria of desertification used in dehloran and Abbas plains . The obtained results of the analysis criteria and Indexes indicated that in dehloran and Abbas plains in the first period ( 2005-2009) And second period (2010-2014)  between  indexes  the amount of annual rainfall, standard precipitation index (SPI) and drought duration Evaluated on the areas respectively standard precipitation index (SPI),  rainfall and drought duration index the most important factors in exacerbating desertification. Can be concluded that the intensity of desertification in Abbas plain compared to dehloran plain terms of climate is In more adverse conditions. In general, it can be concluded that desertification would intensify in future decades.
Keywords: Desertification, IMDPA, Climate, Abbas Plain, DehloranPlain
 

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