جستجوی مقالات مرتبط با کلیدواژه « جنوب ایران » در نشریات گروه « جغرافیا »

Marine crimes on the southern borders of the country impose damage and costs on our community every year. Prevention management can be considered as one of the basic strategies for dealing with these crimes. Therefore, the purpose of this study was to investigate the status quo and the dimensions of marine crime prevention management on the borders of southern Iran. In terms of its objectives, this study is of an applied research type and in terms of the nature of the data it is considered as a quantitative-qualitative study, and in terms of its type it is a descriptive-analytic research. The statistical population of the research, including commanders and successors of provinces and maritime bases, flotation battleship groups, border offenders serving in Hormozgan, Sistan and Baluchestan provinces, Bushehr and Khuzestan. To determine the sample size, the Klein method was used and it showed that the appropriate sample for this statistical population was 364 people. The sampling method was proportional. A researcher-made questionnaire was employed. The validity of the questionnaire was evaluated by experts and elites and the reliability of the research questionnaire was calculated by Cronbach's alpha (0.95). The findings of the research show that the total mean of the current status of the marine crime prevention management is 2.35, and the mean of environment dimension is 2.42, the behavior dimension is 2.40, and then the structure dimension is 2.22. In the examination of the desired gap and the status quo, the difference between the two means is 1.3%, which is significant at 99% level. In other words, the mean of the desired situation is higher than the status quo. According to the research findings, in order to manage the prevention of marine crimes, due to more gaps the dimension of the structure should be emphasized.

Iran is located in southern mid-latitudes and undergone to environment hazard of dust storms (DSs). In recent decades, following the climate change and the extensive environment destructions, the frequency of DSs has increased and the visibility during dusty days has decreased over Western and Southern Iran (SI). As the aim of present study, we followed the classifying of DSs in SI based on their frequencies related to Indus Low (IL) characteristics including its pressure and location. The daily data-set of this research included 11 dust codes that gathered from 17 weather stations in the SI at 12 UTC from 2000 to 2009. 120 daily graphs that were plotted based on the frequency of dusty cities, determined 354 DSs. All DSs were classified in three categories including pervasive, semi-pervasive, and small ones and they determined 25 DSs as indicator ones based on their frequency of dusty cities and their dates. SLP data-sets during all dates at 12 UTC related to every category composed by C programming and it presented final composed models on sea level pressure. Composed model showed IL is strong and unified during Pervasive DSs (PDS) over Indus Plain as IL location. It revealed dusts were sucked and moved from two principal “routes” including “Southern Sahara-Hijaz-Southern Iran” and “Syria-Iraq-Southern Iran” and one subsidiary route “Central Asia-Southern Iran” during PDSs toward Indus Plain. All routes of IL were subsidiary, surface and scattered during Semi-pervasive DSs and we didn’t find any route during small DSs. West-ward air flows and decrease in relative humidity at low troposphere over South-eastern Iran as two findings from previous researchers and deepening and being focused of IL as a new finding are three indicators that can used for DS monitoring and warning and then environment management.

In this research, the impact of sea surface temperature on precipitation variation in southern part of Iran is examined using monthly data from meteorological and water resource institute during 1974-2005. The majority of precipitation occurs during the rainy season from October to May. Regional spatial precipitation on variability was identified by Empirical Orthogonal Function (EOF), applied to deterended monthly precipitation anomaly data. The first and second components, which determine 54 to 82.7% of the variance of the total precipitation from October to May were selected for the study. To study the rainfall variations, SST anomaly, moisture flux, geo-potential height and sea level pressure were analyzed for wet and dry years of first and second mode of EOF. The pattern of sea surface temperature anomaly for wet and dry years shows that the sea surface temperature of Indian Ocean has an important role on precipitation variation over the south part of Iran. In the first mode of EOF which represent 50% of total variance the positive (negative) sea surface temperature anomaly is in the East (west) part of Indian Ocean during wet (dry) years and it is associated with the equatorial easterly (westerly) moisture flux anomaly. In the second mode of EOF the SST anomaly over the Arabian Sea is positive in the wet years but it is a non-dominant feature for the dry years. The Arabian anticyclone has an important role to transfer moisture in lower level of atmosphere from southern water bodies to the cyclone near Iran and displacement of the Arabian anticyclone to westward (eastward) transports more moisture from southern water bodies to the western, south western (southern and south eastern) parts of Iran.

Hot, humid weather causes to the sultry feel. Sultry condition is usually accompanied with loss of physical ability and human respiratory and it has an adverse effect on peoples who have circulatory or other heart problems and this feeling is more than others. Sultry feel is a feeling like any other sensitive reflections of mental state. And this state apparently can’t be measured by special instruments. With this description, there are a lot of efforts has been done to identify this phenomenon by meteorologists and climatologists. And a series of psychological climate tests show that we can examine the creation and incidence of this sense based on empirical studies as a scientific and objective attitude. Therefore, this study aims to classify the sultry days in the southern half of Iran based on sultry continuous hours. And the obtained results are presented as a form of zoning maps.
The studied zone in this research is selected stations in the southern half of the country located in the province of Sistan & Baluchestan, Kerman, Hormozgan, Fars, Bushehr and Khuzestan. This area is located between two latitude 25 and 35 north and length of 47 to 63 east degrees. To achieve this goal, hourly partial pressure of water vapor of 13 selected stations were obtained for a period of 15 years (1995-2009) from Meteorological agency. After obtaining data and creating the database, to separate sultry conditions from non-sultry conditions, threshold of partial pressure of water vapor of Scharlou which was equivalent to 8.18 Hpa were used.
Based on these data, the hours and days that the partial pressure of water vapor was equal or greater than 8.18 hpa will have sultry conditions and otherwise, they have non-sultry conditions. Then, based on this threshold, sultry days were divided into eight categories. The basis of this classification is that if in a particular day among eight branches of observation, one station, only in one observation record a pressure equal to or greater than 8.18 hpa was observed, it will be placed in first class and if only two observed records a value equal or greater than defined value, it will be placed in second catagory and finally, if all eight observations amounts equal to or greater than 8.18 had been recorded, it will be placed in eight class. After placing the sultry days in one of eight branches of classes, long-term averages of monthly, quarterly, quarterly and annual were calculated and mapped.
Based on defined thresholds, sultry days were separated from non-sultry days, then sultry days were extracted and it was placed in first to eighth classes. The results of this classification showed that on monthly scale, January has the fewest sultry days in twelve months of the year. In this month, only two stations of Chabahar and Bandar Abbas had the sultry days of eighth classes. It means that 24 hours, they were in sultry conditions. Other stations that have a sultry day in this month, often their sultry days are from first to fourth classes and it means that they had maximum 3 to 12 hours of sultry conditions during the day. Most sultry days can be seen in two June and July months. So, in these two months, all studied stations have at least one sultry day,Specially in three stations of Chabahar, Bandar Abbas and Bushehr. And all 61 days, they have sultry conditions. In terms of classification of sultry days, all 61 days of Chabarhar station are part of sultry days of eighth class. In two stations of Bandar Abbas and Bushehr, except few days that are from sixth and seventh classes, other days are from eightth class, other stations experienced one of the eightth classes of sultry days with different ratios. , and at the seasonal scale, winter has the lowest days of sultry and summer has the most days of sultry days. In term of classification of sultry days in seasonal scale, there are conditions as monthly scale. The interesting point in summer season is that sultry days on two stations of Zabul (35 days) and Iranshahr (51 days) are considered due to their Geographical locations. In Zabul station, the reason of these sultry days can be due to the neighborhood of this station with Hamoon Lake. But it should be mentioned about Iranshahr stationthat the reason of its sultry condition is entrance of monsoon low pressure and moisture transfer by the system on the south-east of Iran an especially Iranshahr. On an annual basis, it was also observed that always in south east of Iran (Especially Chabahar station), the number of sultry days is much more than south west of Iran, also occurring sultry days with eighth, seventh and sixth classes in this zone is so different from south-west of Iran. The reason of these differences in number of sultry days and sultry classes related to the latitude of south east of Iran which is lower that south west and in other words, we can say that climate of south East of Iran is more similar to tropical climate than subtropical climate.

Wind is considered as one the most important causes for erosion and land degradation in arid and semi arid regions. Thus، it is necessary to study temporal pattern of wind properties to prevent the huge damages. (Refahi، 1999:22). There are a variety of different methods، parameters، indicators and diagrams for analysis of windy status and wind dynamic conditions. These are wind rose، storm rose and sand rose diagrams، drift potential، dustiness indices and wind threshold velocity maps. The main objective of this research is the investigation about the effects of wind direction on the orientation of coastal sand dunes in the southern coast of Iran. The results of this research can play a significant role in designing wind breaks and sand dune stabilizing projects. This study is done on coastal sand dunes، in south of Iran، in Khuzestan، Bushehr، Hormozgan، Sistan and Baluchestan Provinces. Commonly، western and south western winds influence the sand dunes located in southern Iran (Zareian Jahromi، 2008). These winds with high sand drifting potential cause strong sand storms in this area، from end of winter to begining of fall. In addition، Monsoon hurricanes blow in eastern and south eastern coasts of Iran، during summer. The application of WR PLOT View 5. 2. 1. is employed for anemometer data analysis and drawing storm rose and wind rose. Data from five synoptic stations in the southern coast of Iran including Ahvaz، Kangan Jam، Bandar Lenge، Bandar Jask، and Chabahar with 25 years period (1982 - 2006) were selected. WD Convert 2. 0. is used for converting data format (IRIMO to SCARM format) for wind data analysis and preparing data for drawing Wind Rose. Sand Rose software designed by Ekhtesasi and Saremi Naeeni (2003) based on Fryberger & Lettau (1975) equation is used for drawing Sand rose. Sand Rose was able to show different factors of wind data characteristics. Result of wind rose showed that dominant wind direction in surveyed stations is from west. Analysis of dust storm rose based on wind erosion threshold، at minimum speed (6. 5 m/s)، showed that hurricane and erosive winds in the study area is blowing from the west and southwest direction. Sand Rose Graph 3. 0. software was used for sand rose drawing، sand drifting potential and sand dunes morphology analysis. The results showed that the direction of sand transition in study area is dominantly from south and west south to north and north east. Thus، high conformity can be observed between wind direction and sand dunes orientations (RDD index: Resultant Drift Direction)، with 90. 5 percent conformity by Boolean logic approaches. It is reported that Ahwaz station in the northeast sector of Iran has highest accuracy. The most of the sand transport report (Total Drift Potential: DPt equal to 336. 8) is belonging to Bandar e Jask station، that lead to the formation of sand dunes in Surgalm، Sedij and Bayahi Region. UDI index (Uni- Directional Index) value derived from sand rose is less than 0. 59 for all stations. Therefore، this represents a bi- directional wind in study region. Different landforms such as sand dunes، longitudinal dunes، zigzag silk and Sif are observed in study area by interpretation of aerial photos and satellite imagery on Google Earth. These formations are evidence for existing bi - directional winds that blows from the southwest (erosive winds) and southeast (formed winds). Analyzing the results by sand rose and also sand dunes in a vast area of southern Iranian coasts revealed that southern (southwest to southeast) winds with local origin، reinforced by crossing the sea and warm coast (anabatic conditions)، cause wind erosion and sand drifting from beach into plains and Pedi- plains. Southeast and southwest winds and different sand drift potentials is resulted in reduction of unidirectional index (UDI) in all over the southern coasts of study area. Qua، the UDI varies from 0. 2 to 0. 5 in most cases، indicates the potential formation of longitudinal dunes in the region. Bidirectional winds influence most of the southern Iranian coast dunes as longitudinal dunes such as sif، Linear Silk and zigzag Silk. The role sea shore wind play in abrasion، transition and formation of sand dunes in southern Iran is determined by matching results obtained from analysis of erosive wind the morphology of hill sand.

The ocean has an important role on climate variability. Most of the water that evaporates from oceans is precipitated back into them and continents. Because of its low annual mean precipitation, Iran is commonly regarded as an arid country. So it is important to understand the processes that govern on the moisture transport in atmosphere and how they are related to precipitation over Iran. Therefore the goal of the study is identifying the role of the adjacent Seas on the winter precipitation over the southern part of Iran.
Monthly precipitation data from 183 stations in the southern part of Iran were made available by the Iranian Meteorological Organization and Iranian water resource institute. The SST data used in the present study is obtained from the Hadley centre sea ice and sea surface temperature. It is monthly data with 1ºx1º horizontal resolution. The NCEP/NCAR reanalysis data is used for wind, specific humidity, geopotential height and sea level pressure. For all data, we adopted the period from December 1974 to February 2005. To capture the dominant mode of interannual variability, we have applied the EOF analysis to deterended monthly precipitation anomaly data from 183 stations. To characterize the dynamical features related to each precipitation regime composites of sea surface temperature, moisture flux and SLP were computed for wet and dry years. Wet (dry) years correspond to those years with the principle component of the first EOF mode for each month above 0.8 (below -0.8) standard deviation.
Regional spatial precipitation on variability was identified by Empirical Orthogonal Function (EOF). The first 2 components represent more than 66% of total variance. In the first mode of EOF which represent 50% of total variance the positive (negative) sea surface temperature anomaly is in the Arabian Sea during wet (dry) years. The southeasterly moisture flux anomaly over the Arabian Sea turns anti-cyclonically and transport more moisture to the southern part of Iran from Arabian Sea, Red Sea, and Persian Gulf during wet years. On the other hand, the moisture flux has northerly anomaly over Iran during the dry years, which results in reduced moisture supply from the south. In the second mode of EOF the sea surface temperature anomaly over the Arabian Sea is positive in the wet years but it is not dominant for dry years. The displacement of Arabian anticyclone to eastward (westward) in wet (dry) years transport more moisture from Arabian Sea, Red Sea to south and east (west) part of Iran.
The results of this study showed that the Sea surface temperature variation over adjacent Seas causes the precipitation variation over southern part of Iran. The main source for the winter precipitation in the south part of Iran is Arabian Sea at the lower level and Red Sea at the middle level. In almost all precipitation regimes the trough and Arabian anticyclone have an important role to transfer moisture from southern water bodies to the southern part of Iran.

his is a study of change in annual precipitation amounts and ariability in southern part of Iran during 974-2005. Southern part of Iran has been regionalized based on six factors in 183 stations using rincipal Component Analysis (PCA) and Cluster Analysis (CA). The stations were grouped into four ndividual clusters. Topography and latitude play an important role in determining boundaries between dentified subdivisions and existence of spatial differences between them as well. Spatial variability and elationship between the precipitation series at 183 of stations were investigated by principal omponent analysis. A PCA of annual precipitation reveals five components that account for 68% of he total variance. The annual precipitation PCs are controlled by atmospheric circulation. Analysis of he results revealed that annual precipitation in south part of Iran is mainly related to Sudan and editerranean wave.

In this study، the relationship between annual sunspot number (ASN) and annual precipitation totals (APT) has been investigated over the northern coasts of the Persian Gulf and Oman Sea using two statistical cross-correlation function and contingency tables. Bushehr، Jask and Shiraz stations are alone stations in which long term annual precipitation records more than 100 years exist have in the south half of Iran. Precipitation records of these three stations were collected from three resources of Iran Meteorological Organization، Regional Water Organization of Fars Province and Smithsonian Miscellaneous Collections، respectively. The statistical gaps were filled with suitable regression models. Daily international sunspot numbers in 1871-2005 periods were prepared from the National Geophysical Data Center. Results indicate negative significant cross-correlation coefficients between 3-year lagged ASN and APT over two stations of Bushehr and Jask but nothing is found Whatsoever significant relationship for Shiraz station in none of lags. On the basis of this 3 year lags، for two stations of Jask and Bushehr have been constructed several contingency tables. The chi-square test was used to determine whether there was a dependency between observations. Also Kendal Tau-b coefficient can show the intensity of association between observations. Almost in all cases for Jask (Tau-b=-0. 2 averagely)، the Chi-square tests Were significant at the 5% level while there Were not a significant relationship for Shiraz and Bushehr but there Were minor cases in Bushehr (tau-b=-0. 03 averagely). Inasmuch as a sunspot minimum has occurred in 2007 and 2008، therefore we Would expect that Oman Sea coasts precipitation during 2009-2011 Was higher than normal.

Precipitation as the most important climatic element in Iran territory has faced with certain complexities. The aim of this study is using latent state model of Marcov chain for modeling the continuity of Iran two states conditions for the purpose of better recognition of wet and dry year condition to optimal management of water resources optimally in this part of the country. Therefore for conducting such modeling, the data related to the annual precipitation of three (3) synoptic meteorology stations of Bushehr, Jask and Shiraz, which have the longest data in south of Iran, were used. The indices derived from this model are: wet and dry separation indicator (WADSI), climate steady state indicator (SSI), steady state time index (SRT) and intensity indicator of continuing structure (SPS) and intensity indicator of continuing structure (SPS). The findings obtained from this model for annual precipitation in south of Iran are as the following:Based on wet and dry separation indicator (WADSI), separation of wet and dry years for the three (3) under study stations in the south part of Iran is simply possible. The indicator value of climate steady state (SSI) for the three(3) under study stations on south of Iran indicates the weak steady state in dry and wet conditions for Shiraz station and medium steady state for Jask and Bushehr stations. The time period of the steady state of each dry and wet condition for the three under study areas is between 1-4 limit.The final research model for annual precipitation of south of Iran based on the equal intensity of continuing structure of the stations (W, W, WADSI) was recognized that indicates a full probable structure for having a two states continuity.