گلباد

In order to carry out this research, the daily and three-hourly data of precipitation parameters and wind speed and direction were used for a period of 13 years (2009-2021) for 11 Ardabil synoptic stations. Percentile 95% free days were obtained for each station. For statistical analysis and consensus, the condition of choosing a representative day for each station was the simultaneous occurrence of rain and wind as a criterion, and for the sake of brevity, an event was analyzed at Meshkinshahr station. Using TRMM satellite NETCDF data, precipitation density was displayed in GIS software, and wind direction was shown using Golbad software, and synoptic maps were drawn using NCEP data. The statistical results for Meshkinshahr station showed the maximum wind frequency with 56% in the winter season. And the month of March occurred, which often entered the city from the south, but most of the rain was in spring with (41%) and May was the rainiest month. The results of synoptic analysis showed that the prevailing system over the studied area was low pressure over the Aral Lake and the rotating conditions of the air ascent followed. In the east of the Mediterranean Sea and the north of the Black Sea, high-pressure systems have formed, and with their outward movement, they have led the western currents towards the region. Also, the studied area is located in front of the descent axis in the west of Iran, and the positive rotation of the air has led to the strengthening of the divergence in the vorticosphere. The speed of the horizontal movement of the air has reached the speed of the wind and by containing the moisture of the Mediterranean Sea, it has injected 1.2 grams per kilogram of moisture into the atmosphere of the region.

One of the most important natural processes in arid regions is semi-arid wind erosion. Sand dunes are one of the most important facies of wind erosion. Sand dunes in the field of wind process are among the most dynamic geomorphic features of the earth's surface, which, on the one hand, are affected by the characteristics of speed, direction, wind frequency and, on the other hand, are affected by the characteristics of the earth's surface and sedimentary materials. Probability-based wind prediction for sand transport phenomena is a key element for human activities in arid regions. Wind erosion and movement of quick sands, which is considered as one of the important processes of land degradation and a serious challenge in Iran, occurs due to the interaction between climatic and terrestrial processes. The phenomenon of dust and the movement of quick sands is considered one of the important processes of land degradation and a serious challenge in Iran, and on the other hand, coastal areas are sensitive lands that have been affected by both sea and land ecology. They are also unique in terms of ecosystem diversity. Therefore, knowing the status of wind erosion and the activity of wind sediments, especially in landforms sensitive to this destructive environmental phenomenon, as well as identifying climatic factors affecting it can be an effective step in reducing desertification and improving air quality, especially in arid and semi-arid areas.

According to the purpose of the study, data on wind (frequency and direction), rainfall, temperature and number of dust days related to the synoptic station located in Jask city during a 20-year statistical period (2001-2021) were obtained from the Meteorological Organization. WR-Plot View 7 software was used to analyze the anemometer data. Also, using the mentioned capabilities of the software and considering the basic speed equal to the threshold speed of wind erosion, annual and seasonal storm rose were prepared. Land use maps and sand maps of the study area were prepared using aerial photographs, Google Earth satellite images and field visits.

Statistical analysis of climatic data in Jask region during the period (2001-2021) showed that significant annual changes in annual rainfall, temperature and wind occurred, so that the annual rainfall trend decreased significantly. The trend of annual temperature changes has not been significant, but the temporal changes of wind have taken a relatively downward trend and have shown a significant decrease in recent years. According to the annual windfall of Jask station, it was observed that 7.7% of the total annual observation hours, the air is calm and without direction, 3.92% of the winds blow in different directions and the speed is more than 0.5 m/s. The prevailing wind direction is from the west in all seasons and from the east in summer. The results of classifying the percentage of wind speed frequency showed that about 80% of winds have a speed of less than 6 m/s. The trend of changes in erosive winds during the statistical period under study has an upward trend until 2014 and in recent years has a decreasing trend so that in 2021 the lowest frequency of erosive winds was observed. The results of the portability calculation showed that the annual average of DP is 257 units. The final direction of movement of the sand is at an angle of 280 degrees to the north and the UDI index (RDP / DP) is 0.3, which indicates the variability of low wind directions. The Golmaseh diagram also showed that the wind sediments were moving to the northwest. The highest sand carrying capacity was seen in 2014 and the lowest in 2021. Considering the average of 257 vector units for Jask, the capacity of the amount of sand that can be moved annually is estimated to be about 18 cubic meters per unit width. In terms of land use, most of the area covers the rangeland. Also, sand zones cover about 5.7% of the area, which is mainly located in the south and southeast. The results of the interpretation of aerial photographs, satellite images, as well as field visits to the sand dunes of the southern regions of Iran, indicate the existence of sand dunes of the type of transverse hills, Barkhan and Seif, which are the result of two-way winds from one sector is blowing.

80% of winds have a speed of less than 6m/s, 20% of winds have a speed of more than 6 m/s. The monthly distribution of wind speeds below the threshold indicates that the highest number of erosive winds was observed in summer and the lowest frequency was observed in autumn. The wind direction is dominant throughout the year and all seasons except summer from the west. The amount of sand carrying capacity based on the threshold speed of 6.5 m/s is about 257 vector units moving from the southeast (coastal lands) to the northwest (coastal lands), which indicates that the direction of transfer of most sands from relatively arid and saline coastal areas (coastal grasses) are towards the plains and mountainous lands along the southern coasts of Iran. The ratio of vector to annual algebraic output (UDI) of this station is 0.3, which indicates composite multi-directional winds with sharp angles of variability of wind directions at low levels. Existence of sand dunes of longitudinal hills, seifs and silks is the result of two-way winds blowing from one segment. In the southern coasts of Iran, most of the main winds from the southwest and sub-southeast winds from the coast to the sea are effective in the formation of sand dunes. The strongest winds of the study area blow in summer and the weakest in autumn. The trend of changes in sand transport potential also showed the trend of wind energy in Jask station, which for most years has the ability to carry wind sediments in the middle class (DP> 200> 400), but a significant decrease was seen in 2018 to 2021; the highest sand carrying capacity was seen in 2014 and lowest in 2021. Also in the study station, the RDP/DP ratio has a range of changes between 0.022 to 0.8 in almost all seasons and throughout the year. The area of sandy regions has increased from 72.260 to 82.925 km2 between 2013 and 2021, which shows an increase of 10.66 m2.

The study of air accidents recorded 2007-2016 for all variety of present aircraft shows that 29.2% of all aviation accidents occurred due to unfavorable climate. between the climatic elements, wind conditions have the greatest impact on the safety of airplanes, especially during takeoff and landing. So that unfavorable wind conditions for flying, the main cause or at least a contributing factor in 47% of all aviation accidents related to climate. Also the contribution of various wind conditions in aviation accidents caused by this element are respectively: crosswind: 55%, tailwind: 22%, gusty wind(Sudden change in wind speed): 8%, wind shear(Sudden change in wind direction and speed): 8%, variable wind(Sudden change in wind direction): 5% and dust devil or whirl wind: 2%. generally, it can be said that various climatic elements have impact on aviation safety, and between these elements the greatest impact is the wind conditions and in particular the crosswind effects on aviation safety. As a result of changes in winds, it can be considered a hazard to the aircraft and it can increase the status of the aircraft in-flight loss of balance. As we know, runways are made in the prevailing wind direction of the area; as a result, a change in the prevailing wind direction of an airport can increase the amount of crosswind relative to the runway, thereby negatively affecting during takeoff and landing. Therefore, the impact of change on wind conditions and in particular on the direction or speed of prevailing winds are important and in this study the impact of their changes at the usability factor of the current runway of Tabriz airport, is discussed.

Study of the wind field of the meteorological Stations to detect the dust and salt prone storm and soil erosion was the concern of the meteorologists, natural researchers and agro meteorologists. To show the wind power in sand storm creation and sand displacement; the researchers used the wind rose, storm rose and sand rose which is a simple and efficient method to detect the wind's role on dust storm. Many Iranian researchers; used the Friberger,s  method  in which Ahmadi and et el(2001and 2002) are the frontiers who used the dust rose from 1994 to 2013 over many Iranian provinces. In this study the power of wind in dust and salt displacement is discussed in Orumiya Lake basin. The aim of this research is detection of the potential annual sand and salt transfer by wind around Ormia Lake due to its drying. To do that, the continuous three hourly wind data of the Oromia, Mahabad, Salmas and Piranshahr meteorological stations in west Azarbaijan and Bonab, Maragheh, and Tabriz stations from their stablishment till the end of 2014 in east Azarbaijan are statistically analyzed and then the diagrams of the wind rose, storm rose and sand rose are depicted by suitable soft wares. 

In this study the wind speed and direction data of the Met. stations around the Orumiya Lake are received  from Iranian Meteorological Organization(from starting activity up to 2014). Regarding the adequate historical length and quality of data, the Tabriz, Orumiye, Bonab, Maragheh, Piranshahr and Mahabad in Orumiye Lake basin are selected as the representative stations of the area. The monthly, seasonal and annual wind roses of these stations are depicted and then analyzed using the WRPLOT software. Since the frequencies of calm winds was high, they are deleted and then using the threshold wind speed of 6m/s, the storm roses are depicted and then analyzed. Applying the Friberger method, the sand rose software was designed and after depicting the monthly, seasonal and annual sand rose, the wind sand displacement ability in these stations are analyzed.   

Study the sand rose figures in meteorological stations around the Orumiya Lake shows that the sand displacement in Tabriz is strong from March to August, moderate in February, September, October and November and weak in March and April. In Orumiya it is moderate in March and April and feeble in other months. In Maragheh dust displacement power in July and August is very strong ,in March, June and September it is strong; in September it is feeble an in other months is moderate. In Bonab the sand displacement power is moderate from February to August and in other months it is feeble. In Mahabad the sand displacement power is very strong in January till April and in October till December it is strong, in June and September it is moderate and in other months it is feeble. In Piranshahr it is very strong from January till April, strong in September till December, moderate in June and feeble in other months. IN Salms the sand displacement power is very strong in March and April, strong in May till July, feeble in November and December and it is moderate in other months.    

The results of the study detected the potential of sand and salt displacement in the east and west Azarbaijan provinces.  Regarding the position of the different stations around the salt and dust basin of the Ormiya Lake and the net annual transfer of dust and sand, it can be concluded that Mahabad, Maragheh, Bonab, and Tabriz cities are more under danger of sand and salt transfer and their out coming air and soil pollutions. In other stations either due to topographical blocking or lack of sand and salt sources, the probability of air and soil pollution lowers.

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

Dust storms and high winds is a natural process that occurs in everywhere of arid and semi-arid land in the world. The phenomenon of dust is one of the most important consequences of the desertification that cause different damages. The aim of this study was to analyze the occurrence of dust in the city of Bandar Abbas. First, the frequency of monthly and annual dust from 1985-2005, in the city of Bandar Abbas was paid and then By using Mann-Kendall trend of phenomenon of dust as monthly and annual in Bandar synoptic stations were examined, and drawing Annual Wind Rose diagram of prevailing winds in the region. The overall results of the analysis with the Mann - Kendall in this period indicated that occurrence of days with dust is a constant process. And monthly trend analysis showed that trend from January to September period is constant and latest month is not constant trend. Study of Charts as partial indicates that the dust has increased since 1996 and then decline and again in 2000 this trend has increased. And because of its, reduced combat operations the phenomenon of dust and increases harvest locations in the province. The results of the correlation between annual precipitation and dust indicated that the rainfall has decreased in the years of dust has increased. As well as results of winds study showed that the higher speed winds in the dry months have increased. Rose diagram showed the direction of the prevailing wind in the region is north and the most frequent wind speed at station is 55/4 meters per second.

One of the common and destructive phenomena in dry and arid regions of the world and Iran is dust storm which may have harmful effects on human life and environment. Iran is also exposed to this phenomenon because of its geographical location in arid and semiarid areas. Fars province, especially its southern and central regions, due to being located in low latitudes and its geographical position, takes less advantage of humidity routes, and its proximity to the major sources of dust within the deserts of Arabia and Iraq always exposes it to this phenomenon. Therefore, understanding how such dust is produced can be of benefit in reducing its destructive effects in the region. This research examines the hourly data of wind direction and speed and the current weather condition of synoptic stations in southern and central Fars (Shiraz, Lar, Lamerd, Darab and Fasa). After extracting the codes related to dust phenomenon (codes 6-9 and 30-35) and a statistical analysis of the aerology data related to this phenomenon using an SPSS software, the annual and monthly Wind Roses and Dust Roses of the synoptic stations in southern and central Fars were drawn using WDconvert and WRplot software during the common statistical period of 1992-2008. The results of this investigation show that the dust occurs in the stations of southern and central Fars province on most days in spring and summer. Also, the highest monthly frequency of this phenomenon may be assigned to the central stations of this province (Shiraz and Fasa), In the southern stations (Lar, Lamerd and Darab), the highest monthly frequency is related to July. In addition, the average days with dust in Lar, Lamerd, Darab, Fasa and Shiraz stations are 88.1, 39, 54, 30.3 and 56.1 a year respectively. Among the selective stations, Lar station has the highest annual average in terms of dusty days. The results of the research also suggest that the most days with dust occur in spring and summer.The highest frequency of this phenomenon in central and southern stations is May and July respectively. Studying the monthly and annual Wind Roses and Dust Roses of station, it is clear that the wind direction of dusts is equal to the direction of the dominant wind, and the maximum occurrence of this phenomenon is in afternoon hours. Since the average annual wind speed of dusts in this region is almost 1m/s, dust phenomenon in Fars province doesn’t have a local source (code 07); rather, the major origin of 98% is outdoors (code 06).

The purpose of this research is an appropriate analysis of the anemometer data to study the wind regime in Kashan and to investigate the role of different land uses in the sand storms. Therefore، anemometer data obtained from synoptic station of Kashan were analyzed during a 40-year period (1966-2005) using different methods and were drown seasonal and annual wind roses and storm roses for different lands using WRPlot software (considering the various threshold wind velocity for each area). Finally، the annual wind rose showed that direction of prevailing wind in kashan is the northeast and then north and north-west winds will be in the next rank. Moreover it was shown that the frequency of calm winds is 8/84%. Storm roses of relating to the different lands showed that in the pasture lands، the winds of the northeast، north and west and in incult crop lands and active sand dunes، the winds of northeast، north and west have the most role in wind erosion. Also، the risk of soil erosion is not tangible in agriculture lands، sand dunes covered with Haloxylon and reg. The drawing of seasonal storm roses in each of studied lands showed that the erosive winds have the highest frequency in spring and in this season، the most erosive winds blow with the speed more than 25 m/s.

Necessity for energy is rising very fast by the increasing industrial development and presenting world energy cycle. In order to obtain new and substitute energy sources it is estimated that there exists more than five mps of wind speed at the altitude of 10 meters in more than one fourth of earth lands.This paper has studied appropriate places to install wind turbines in East Azerbaijan Province, by determination of wind energy density using air density variation with height and temperature. It has also determined proportionate places for wind energy utilization with presentation of wind velocity distribution in seven synoptic stations of the Province using wind rose diagrams. Results show that Sahand and Jolfa Stations have significant frequencies of wind speed distribution in the velocities over five m/s and can be taken into account as windy regions for making wind farms.

Air Pollution of cities has nowadays turned into an environmental, social problem.Population growth, asymmetric development in which scientific principles are notalways observed, physical tissue of cities, increase in tools,and polluting resourceshave jeopardized human life in some cities, there by threatening their health.As the largest city of Iran , Tehran is among the most polluted cities throughout theworld. In view of the effects caused by air pollution to the environment and humanhealth, precise identifying of pollutants and specifying of polluted scopes in order tolessen pollution are necessitated.In this research, data pertaining to carbon monoxide (Co) were extracted from 10main stations for measuring the air pollution settled by Tehran Clean Air Control Co.based on the PSI index and were specified by means of Excel software for a 10 –yearstatistic period of clean and dirty air, and 5 samples of the most serious polluted dayswere selected to be studied. Then, for scoping, some maps were provided by GIS.Investigation of the maps drawn revealed that direction and pace of wind played amajor role in movement of air pollution. Highly unhealthy scopes were observed incentral and southern areas, such as Fatemi, Bazar, Azadi, Mehrabad and Bahmanstations. In the samples studied, clean and permitted scopes existed more in northern,northwestern, and northeastern parts except for the sample of the day 04/12/2005,when no clean air existed anywhere in the city.