Climate Change and Climate Disaster

Abstract In this research, the changes in Iran's drought were studied using the rainfall data of 100 synoptic stations and the Standard Precipitation Index (SPI) for the period from 1990 to 2020. Then, the atmospheric pattern affecting the occurrence of droughts was synoptic analyzed. The results showed that the number of years with drought and its severity in the country increased during the study period. The intensity and spatial extent of drought in the winter season has increased more than in the autumn season. In the 1990s, the extent of drought was greater than drought. With the beginning of the second decade (2000-2010), the intensity and spatial extent of drought and the number of droughts have increased. This trend has continued until 2016, so that the country's most severe droughts have occurred in the last decade. The increase in the extent of drought in the winter season (January and March) is more evident during the last decade. These conditions were caused by climate changes and variations in the behavior of circulation patterns. Also, the most severe droughts in the country occur in the cold period of the year,when the subtropical high pressure (STHP) extends to 30 degrees north latitude. In this case, the conditions of stability prevail due to the absence of conditions for the ascent and passage of rain waves. In general, droughts in the country have increased during the studied period, and the spatial extent of droughts is influenced by the location of the STHP.

Abstract One of the climatic characteristics of temperature is the occurrence of extreme temperature, which can significantly affect biological and non-biological phenomena. This research investigated the descriptive (statistical) attributes of hot days with extreme temperatures on the Persian Gulf coastline. In this regard, the general features of temperature (average and coefficient of variation) of 12 synoptic stations of the Persian Gulf coastline (Khuzestan, Bushehr, and Bandar Abbas provinces) from 1961 to the end of 2018 were explored. In examining the general characteristics (average and coefficient of variation) of daily temperature for all 12 stations, the findings indicate that the coefficient of temperature variation decreases with the increase in average temperature. Upon closer examination of the temperature change coefficients at the discussed stations, it is evident that January exhibits the highest coefficient of temperature change while July, the hottest month, demonstrates the lowest change coefficient. Furthermore, in this study, extreme temperature for each day is defined as exceeding the average of the 75th percentile of observations at each station on the same day. Additionally, a day with extreme temperature is identified when such conditions occur in at least 50% of the stations. The area under study experiences 554 hot days, with 291 occurring in the hot season and 263 in the cold season.

Abstract In this research, the frequency, amount and severity of precipitation of the incoming systems to south and southwest of Iran are investigated. For this purpose, the daily precipitation data of 43 stations in Hormozgan, Bushehr, Khuzestan, Ilam, Fars, Kohkiloyeh and Boyer Ahmad provinces, Four Mahal and Bakhtiari and Lorestan were received from the Meteorological Organization of the country.For this purpose, the daily rainfall data of 43 synoptic stations of the provinces, Hormozgan, Bushehr, Khuzestan, Ilam, Fars, Kohkiluyeh and Boyer Ahmad, Chahar Mahal and Bakhtiari and Lorestan were obtained from the Meteorological Organization of the country.After the preparation of the data received and the choice of the statistical base, the initial data set and table, based on the desired index (1 mm rainfall occurrence and more, 50 percent of the station, to the condition that at least 1 in 5 mm rainfall station occurred).The Frequency of systems (annual, monthly, and sustained), annual average rainfall, and annual average rainfall of annual systems were extracted and identified;The annual frequency of systems and the average annual rainfall during the period,The monthly frequency of systems in January, March, December, April and February,The frequency of the system is 1 to 4 days and the average annual precipitation annual systems, is decreasing. But the high frequency of the November and 5-day system is incremental.In general, the frequency of systems and the amount of precipitation in the studied area is decreasing. However, the rainfall intensity of the systems is not specific, but overall it has a decreasing trend.

Abstract The phenomenon of dust is one of the important climate hazards in arid and semi-arid regions of the world, which causes human and financial losses. In recent decades, due to the mismanagement of water resources in Iran, dust has increased in some areas and has affected many cities and villages. One of the regions that is most affected by this harmful phenomenon is Khuzestan province. This study examines the occurrence frequency and zoning of dust. For this purpose, hourly data of dust in 15 synoptic stations of the province for the period of 2000-2016 were received from the Meteorological Organization. The frequency of dust days for each station was extracted in different seasons, and the number of dust days in the province was zoned using the method of polynomial functions of the spline model. The results showed that the frequency of trans-local and local dust in Khuzestan province is 83 and 17 percent, respectively. Also, in the mentioned time frame, Safiabad station in the north of the province experienced the most trans-local dust and Bostan station in the west of the province experienced the most local dust, and the eastern and northeastern regions of the province had the least dusty days. The years 2017-2018 experienced the most trans-local dust and the years 2011-2021 experienced the most local dust. Also, the dry period and the spring season have the highest occurrence of local and trans-local dust.

Abstract In order to use solar energy optimally, the first step is to identify the amount of solar radiation. It is useful to use satellite data to identify the amount of solar radiation in any situation. Therefore, the aim of the current study is to investigate the time-space amount of net short wavelength solar radiation in Iran. Then, in order to check the time of the data on a monthly and seasonal scale, their graphs were drawn, and linear and polynomial regression were used to determine trends. In order to carry out this research, monthly radiation energy data in nc format was prepared from the FLDAS satellite model for the years 1982 to 2021. The result of the long-term linear trend shows that Iran has a stable trend to some extent, but its non-linear trend shows several alternating upward and downward periods. Also, for the spatial analysis of the radiation spread in Iran, zoning was done in the Arc Gis environment. The results showed that the maximum amount of radiant energy in June is 296 watts per square meter and the lowest amount is 101 watts per square meter in December. The highest coefficient of change occurred in January (6.69%) and the lowest in September (1.47%). Therefore, Iran has the same

Abstract One of the unique features of the northern plains of the Zanjan River Basin is the existence of waterways that flow in parallel in deep valleys; the presence of smooth and low slopes around the valleys indicates that the existing landforms are not well adapted to today's geomorphological processes and conditions. Deep and water-like valleys are located on low-slope plains. The geomorphological analysis of such plains and valleys is based on field investigations (the state of watercourses, wide and glacial valleys, wandering moraines and mixed glacial sediments), the interpretation of geomorphological evidence from topographic and geological maps, along with the reconstruction of past climatic conditions. The evidences reflected in the topographic maps and field studies indicate the lack of necessary conditions for the formation of a wide alluvial fan; While the digging of deep valleys has occurred in the heart of the old contiguous alluvial deposits that have covered the entire plain. Rivers such as Sohrin, Sarmsaqlo and Qarahcherian, with a significant catchment area in mountainous areas, flow in valleys with a depth of more than 100 meters outside the mountains, and sometimes they connect to Zanjan River by maintaining the difference in initial height compared to the surrounding areas. The results indicate the dominance of tectonic, alluvial processes (formation of vast alluvial deposits), changes in the base of Zanjan Rood, glacial and fluvial processes in the transformation of the northern plains of Zanjan Rood.

Abstract wheat is the most important crop of the country and has an important role in providing nutrition to the people,if it is possible to identify suitable areas for wheat cultivation with the climatic requirements of this product that the climate has created in the environment. More performance per unit area can be achieved. In this study, using 20-year climatic data (1377-1396),based on which the average of climatic variables 10 months of the year(October -July)in It is considered and using the parameters used in this research(average monthly minimum and maximum temperature,average monthly temperature,average total 10 months temperature, average minimum and maximum humidity,average monthly humidity, average total 10 months humidity,average monthly rainfall The average total rainfall of 10 months,number of hours of sunshine(GDD), suitable wheat cultivation sites in Lorestan province have been investigated. After analysis and data for each station by cluster analysis of suitable cultivation areas in Lorestan province were identified and classified and for each variable a map was drawn.Then by drawing a tree diagram for the data and by cutting the clustering tree,through the Euclidean distance,in relation to the favorable climatic needs for wheat cultivation,four classifications were drawn for Lorestan province.The results showed that suitable areas for wheat cultivation in terms of all climatic elements are in the second,third and fourth classes (Boroujerd,Azna,Aligudarz,Droud,Kuhdasht and parts of Khorramabad, Aleshtar, Noorabad) and weak wheat cultivation classes from in terms of rainfall and humidity,they are located on the first floor of the first floor (Poldakhtar) and the southern parts of Khorramabad.

Abstract The city of Arak is one of the industrial centers of the country that has been facing population growth in recent decades. Increasing population as well as increasing energy consumption on the one hand and global warming on the other hand have caused changes in climatic elements such as relative humidity. In this paper, the relative humidity behavior of Arak city during the period 1961 to 2017 was investigated using Mann-Kendall statistical test and linear and nonlinear regression. The findings of this study showed that the trend of relative humidity of Arak station is different at different hours during the year and seasons. The most significant changes in the relative humidity of Arak are related to 6.5 and 9.5 hours, which has a downward trend. Using SDSM statistical downscaling model, relative humidity statistics of Arak until 2070 were predicted. The findings of this part of the study showed that the SDSM model can simulate and predict relative humidity. According to two scenarios A2 and B2, the relative humidity of Arak will decrease in the future

Abstract Hail and identify areas susceptible to precise information on the time of the determination of damages on living organisms, can be extremely important. In this study by taking the role the surface and atmosphere of the North West, this phenomenon with both statistical methods and synoptic, evaluated in order to predict and control it is safer. For such an analysis, using the software Excel, Spss and Gis Hail frequency codes (27, 90-87, 93, 94, 96 and 99) of the 100 Codes about Group 7(willing weather) 25 synoptic stations, the Statistical analysis was performed and the results map was prepared. Based on the data center Ncep/ Ncar synoptic maps of sea level, 850, 700 and 500 hPa cold wind, wet wind, omega, volubility and job front and with selected software Grads were plotted . The results showed that in addition of local factors such as topography of the area, hailing systems such as west winds have been effected in the highest frequency of south west, south and center of the study area. The most frequency of hail is in March to may with peak raining in April as a result of same factors such as the activities of west winds by very cold weather,the humidity of the Mediterranean and Black sea on the region, the temperature difference between the surface of the earth and high levels associated with cold fronts and rising surface air masses.

Abstract Cold temperature extremes are a natural aspect of the climate that occur annually, leading to challenges in agricultural, industrial, and economic sectors, as well as contributing to road accidents. Severe temperature drops can have undesirable effects on various aspects of life and activities for both humans and plant life conditions. The purpose of this study is to examine the synoptic patterns influencing extreme cold waves in northwestern Iran. To achieve this, daily minimum temperature data from 36 synoptic stations in the northwestern region of the country were utilized for the period between 1986 and 2017 Using the standardized cold days index with a threshold value of 1.2 to identify cold wave days, monthly counts of cold wave days were extracted for each station. Applying factor analysis to the geopotential height at the level of cold wave days, four influential patterns for the formation of extreme cold waves in northwestern Iran were identified. The results of analyzing these patterns indicate that the synoptic systems governing the cold wave events ito the advection of cold air masses from northern latitudes into this area. At the 500 hPa level, the presence of a ridge, the occurrence of a blocking pattern, or the establishment of a persistent western arm of a deep trough over northwestern Iran contributes to mid-level atmospheric convergence.strengthens dynamic subsidence and stability in the lower atmospheric levels, enhancing the advection of cold upper-level air into the region. Consequently, these factors lead to the formation of extreme cold waves in northwestern Iran.

Abstract Climate change in the twenty-first century is the most important challenge facing human societies. Considering the effect of temperature in each region's climate and the importance of its prediction in environmental planning, the use of general atmospheric circulation models has been widely used to assess and predict temperature variations. In this research, the prediction and evaluation of temperature changes in the west and southwest of Iran during the statistical period of 1961-1990 for the period of 2011-2100 has been discussed. For this purpose, temperature network data of 30 synoptic stations related to western and southwestern provinces of Iran have been used on a daily, monthly and annual scale. Then, by using exponential microscale model, the average temperature changes were predicted and evaluated by RCP 2.6 and RCP 4.5 and RCP 8.5 scenarios, then its maps are drawn by Surfer software. The results indicate an average temperature increase in all seasons. According to the annual period scenarios, the highest mean increase with a high coefficient of variation in the northern regions, including the stations of Sanandaj, Bijar, Saqez and Hamadan, has been observed. Some of the southern half of the range, such as Izeh and Koohrang, with the least variability, will experience the slightest increase in average temperatures.

Abstract Temperature changes, in the context of the phenomenon of climate change, are one of the important issues of the current societies. It is important to study the trend of temperature changes on a global, regional, and local scale. The general atmospheric models of the atmosphere, including the instrument of simulation and the assessment of future climate-temperature conditions, are considered under various scenarios. One of the main topics in the application of these models is their spatial separation. This problem can be explored with the aid of a downscaling method and can be solved to a large extent. One of the tools of statistical downscaling (SDSM) is using multivariate linear regression technique. In this study, using SDSM, at stations (Yazd and Shiraz) and according to the RCP 8.5 scenario for the upcoming periods 2018-2048, 2078-2078 and 2079-2099, using the output of the change model the canESM2 climate can be monitored for temperature variations. The average daily temperature observation for the 1976-2005 period has been modeled as input. Output results of the downscaling model showed that in the upcoming periods and based on the scenario under review, the average temperature increase would increase. This increase will increase by almost 1 degree Celsius in the first two stages, with a 30-year-old step, and in the last-20-year-old period. In the third period (2108- 2079) the largest increase, compared to the baseline is expected. The highest seasonal increase, For the summer season is and then autumn. Meanwhile, the first place is for Shiraz and Yazd stations in July. The months of June and August are jointly in the next place.