نشریه پژوهشهای تغییرات آب و هوایی
پیاپی 3 (پاییز 1399)

Thermal stress poses significant direct and indirect risks to human health. Under climate change, both mean temperature and the frequency and intensity of extreme thermal stress events are projected to increase. Located within an arid to semi-arid region, Iran is anticipated to experience particularly intense temperature and humidity changes under climate change, potentially heightening the public health challenges associated with thermal stress. To facilitate improved adaptation to these thermal threats, accurate high spatial resolution thermal heat stress risk maps are important. This study combines various climate indices to produce such a thermal stress risk map for the reference period 1980-2010, with RCP4.5 projections for the period 2020-2049. Although the results of the various indices are statistically significantly correlated, each index returned a remarkably different spatial distribution and risk classification. Therefore, a fuzzy approach was followed through a geographical information system (GIS) to combine the results of the five bioclimatic indices and prepare a final thermal stress risk map. Based on the RCP4.5 scenario, the results indicate a notable 24.5% reduction in the areas susceptible to thermal stress at the high-risk and very high-risk levels, compared to the reference period. The lowest projected risk is for the central parts of Iran, while the southern and northern coasts of Iran were the zones of the highest risk, for which adaptation responses are most necessary.

Extreme climatic events are rare phenomena that are rare in severity and frequency, and since the ecosystems and physical structures of human societies are regulated by normal climatic conditions, they can rarely prepare for the occurrence of these phenomena. Changes in the occurrence of extreme events can often have significant effects on ecosystems and society compared to changes in moderate climatic conditions. The purpose of this study is to investigate the trend of temperature furnaces in the northern strip of the country. The trend of temperature extremes in the two observation periods of 2015-1982 and the future period of 2055-2020 has been extracted. The data used in this study are the minimum and maximum recorded temperatures of the studied stations on a daily basis and for the next period, the micro-scaled output of the CanESM2 general circulation model based on 4.5RCP and 8.5RCP scenarios has been used. The results showed that the minimum and maximum daily of the studied stations will increase in the next period, which is accompanied by a steeper slope according to the 8.5RCP scenario. Relatively, Gorgan station has the highest temperature increase among the studied stations. Statistical analysis shows that in all stations and in each period of the observed and modeled period, temperature oven indices are associated with trends and changes so that cold extremes (ID icy days, TN10p cold nights FD forest days , TX10p cold days) with decreasing slopes and warm extremes (SU25 summer days, TR20 tropical nights, TN90p warm nights and TX90p warm days) face an increasing slope in both observation and future periods. The slope of some night temperature indices such as tropical nights and warm nights seems to be more intense than other indices.

Consequences of climate change affect many aspects of human societies. Unfortunately, the impacts of climate change has less studied and analyzed In terms of security. One of the important effects of climate reimpacts is the impact on water resources of different regions. Access to proper water resources is one of the biggest challenges in the present century, as it is limited to water resources, and the consumption and demand of it is always increasing. Hence, the situation of water resources will play a significant role in the formation of relations flow and development movement in Iran's geographic space. Due to the growing importance of water competition, identification of the positive and negative capacities of the country's hydropolivalent can be used to provide the macro and micro strategies. The present study is applied in terms of purpose. With descriptive approach following the systematic analysis of the spatial status of water resources (aqueous flows from neighboring countries and precipitation). It tries to analyze the challenges of dehydration and security consequences of water resources, especially in boundary and border areas. Dehydration and water crisis in Iran are the result of physical and economic factors resulting from poor management of water resources. Other factors such as annual rainfall, persistent drought, limited water access, population increase, climate change, water distribution, different spatial dispersion, water efficiency in different sectors of agriculture and lack of sustainable water planning can not be ignored. The above factors lead to a gradual reduction in agricultural activities, increasing tension and involvement over water resources, increasing unemployment and expanding poverty cycle, migrating to major cities and margins, emptying the land of the population, increasing trafficking, dissatisfaction.

Climate change is one of the major challenges facing mankind today. Various climatic parameters such as temperature, precipitation and wind in one place are factors that influence the climate of that area and Their knowledge determines the climate of that region. Occurrence of phenomena such as sudden increase or decrease of temperature, rainfall and velocity and direction of wind over one or more years can be attributed to climate change in that region. One of the most important climate issues in recent years has been the opinion of researchers and even heads of governments and organizations due to their effects on political, social, economic and other activities. In our country this issue has been less attention, but in recent years has been the result of research and conferences To Study Climate Change in Kurdistan Province Average, Minimum, Maximum Temperature and Average Precipitation and Mean, Minimum, Maximum Wind Speed and Direction, Sanandaj Station during the Years 1960-2017 Obtained from the Meteorological Organization and set in time series and analyzed using Mann-Kendall nonparametric test. In this research, using the above model, the type and timing of changes in these elements have been identified. The results of the data analysis show that the onset of most changes was sudden and of both trend and fluctuation. Average and minimum temperature parameters have negative trend and maximum temperature parameter has positive trend and show negative trend precipitation and the mean and minimum wind speed parameters have a negative trend and the maximum wind speed parameter has a positive trend and the mean wind direction parameter has a negative trend.

Drought is one of climate hazards that over time brings a lot of damage on human life and natural ecosystems. Commonly Droughts are divided to four main groups of meteorological, hydrologic, agricultural and socio-economic .All Types of droughts are different from each other significantly. In another sense, the occurrence of an event of drought would be the cause of another draught. Various methods have been used for the analysis and assessment of drought and its impacts on human activities and natural resources. Statistics, Synoptic, Remotely sensed methods, and several types of models such spatial, dynamic and statistics models can be seen in the most studies related to drought. The zoning of drought using spatial-statistics indices and generally the spatial zoning and regional distribution of dry periods is one of important features that makes a better understanding towards the phenomenon of drought and a closer consideration of the effects of it. In the past four decades remote sensing widely provide drought monitoring tools, and many drought monitoring model is presented, which is generally based on vegetation and thermal indices especially Normalized Difference Vegetation Index (NDVI), land surface temperature (LST), moisture and reflection at the visible and infrared areas. Golestan province is located in the North East of Iran in the neighborhood of the Caspian Sea and the northern slopes of the Alborz Mountains, Which following local conditions of the Caspian coast line and high peaks, with increasing altitude, vegetation diversity there are certain bands. From the peaks over 1500 meters to foothills is covered with dense forest broadleaf. Field craps are the dominant vegetation’s From Foothills to the plain. From North Gorganrood to border of Turkmenistan due to rare moisture Resources vegetation is thinner than the southern and central provinces. The research in terms of nature and methods in theoretical basis is parts of the descriptive researches and due to relationship and impact is an applied one. In the present study for following meteorological drought and ecological in Golestan province, two types of data were used. 72 pluviometry stations on monthly rainfall data (period 1971-2010) and remote sensing data in the three periods (July, 1975, 1987 and 2000), derived from Landsat satellite images. Standard Precipitation Index (SPI) is used to identify and to zoning meteorological drought and the Normalized Difference Vegetation Index (NDVI) is used for the detection of the plant tension that were affected by drought. In the following the results of two parameters and their relationships were compared to each other.  Examining maps of drought frequency and severity of droughts indicates that most of frequency droughts of stations occurred in the North and North-East Province. And gradually the intensity and frequency of droughts reduced to the South and South West. The most severe drought that can be seen in parts of the North East belongs to the Hutan station. However the lowest number has occurred in the central and western regions of Golestan province. According to table (3) correlation between both NDVI and SPI are positive in three years. In all the years of study SPI index-correlation with NDVI was fairly good together. Overall the parts of Northern Province and East Sea have most drough in the selected three years. While most of the wet years are related to the southern part of the province (northern slopes of the Alborz mountain range).  According to conducted research either in the country or abroad, it seems that the use of SPI index as representative of meteorological drought and NDVI index as representative of indicators satellite drought are appropriate for monitoring this kind of droughts. According to the study, two SPI drought index and NDVI due to adaptation with each other are proposed for drought monitoring and meteorological satellite in Golestan province.

The intensity and amount of air pollution in urban areas affected by climate change and global warming has increased in recent years and its effect is evident in large industrial cities such as Isfahan. In order to retrieve and investigate this effect, meteorological information and statistics of Isfahan Synoptic Station were used to study climate change and AQI index data were used to examine the severity and extent of pollution. My revies have shown that in a 63-year period, the average annual temperature of Isfahan city increases by 1.43 degrees Celsius, which has caused the amount and severity of air pollution in Isfahan city to increase at the end of the period (1390-97). The results showed that based on the average monthly AQI index in 83 months from 96 months from 90 to 97 in yellow or healthy condition, in 12 months orange status and in one month red status prevails. The months of the warm season with almost constant conditions are mostly yellow or orange. But in the cold season due to atmospheric turbulence, the conditions are completely changed so that both under the conditions of absolute air stability and inversion, there is red and even dangerous and critical conditions, and under the conditions of atmospheric instability, completely clean air occurs. Of course, days with pollution have a larger number. Therefore, in order not to face a critical and dangerous situation in air quality in cold months, the average AQI index should be reduced from 84.3 to below 50, as clean air.