پهنه‌بندی مخاطرات جوی در غرب ایران

Weather causes many natural hazards. Throughout history, these hazards have continuously affected human life and caused damage to the environment. In this regard, atmospheric hazards, which are considered as subsets of natural hazards, operate with the origin of the atmosphere. Atmospheric hazards are recognized only when extreme events put heavy pressure on human societies. In fact, extreme events are considered a hazard when they impose a minimal level of damage on human societies and their assets (Smith, 1997). Atmospheric hazards occur almost everywhere on the planet and there are few places in the world that are immune from their effects or are less affected by them. Each of the atmospheric elements alone can cause important atmospheric hazards such as heat wave and heatstroke, strong winds, storms, heavy rain, hail, frost and frostbite. However, the most human and financial losses are caused by combined weather phenomena and secondary hazards caused by them (Mazandaran Meteorological Department, 2013).

According to international statistics, about 43 natural hazards have been identified so far. Among the natural hazards, the most frequent hazards are tornadoes, most of which occur in the United States of America. At the end of the 20th century, the occurrence rate of this atmospheric hazard has been higher than any other natural hazard (more than 250 occurrences per year). Floods and tropical cyclones are after hurricanes in terms of frequency. Tsunami is also in fourth place. Meanwhile, about 86% of the natural hazards of the 20th century are climate hazards (Mohammadi, 2007). Out of this number, 34 hazards occur in our country, and nearly 90 to 95% of them are weather-related. On the other hand, the situation of our country is worrying both in terms of earthquakes and changes in precipitation, temperature and phenomena caused by them, so that it is known as the tenth most unstable country in the world.In this research, in order to identify synoptic patterns leading to the phenomenon of temperature inversion in Kermanshah city, first the inversions that happened between 2000 and 2010 at 00 GMT were identified. The reason why the data at 00:00 GMT was used was because the inversion layer that occurs in the morning is more specific due to the large temperature difference, but around noon (12:00 GMT) due to the sunlight and the warming of the earth. The inversion layers gradually disappear (Jahanbakhsh, 2012). The data obtained using the information transmitted from the radiosonde at 00 GMT include the height of the base and top of the inversion layer, the starting temperature and the final temperature of the inversion layer, the difference between the base and the top of the layer, the starting pressure and the final pressure of the inversion layer, and the thickness They are inversion layer. Atmospheric hazards are one of the hazards that have affected different regions in the country. In this regard, and to investigate the atmospheric hazards in the west of Iran, including Hamedan, Kurdistan and Kermanshah provinces, from the observation data of 16 meteorological stations, including precipitation (rain and snow), minimum temperature, maximum temperature, wind direction and speed, visibility and the weather conditions from the beginning of the establishment of meteorological stations until 2012 were used for 8 hazards named 1-blizzard 2-dust 3-heavy rain 4-fog 5-frost 6-hail 7-heavy snow 8-thunderstorm extraction and Finally, the spatial distribution should be zoned. For this purpose and to better understand the effects of each of the mentioned hazards, a regression model was used to model latitude and longitude and altitude and their relationship with each of the hazards. The results showed that the highest correlation coefficient between the model is related to blizzard, thunderstorm and frost parameters, on the other hand, the lowest correlation coefficient is related to fog, hail and heavy rain. Investigations showed that Hamedan province suffers from the aforementioned weather events more than blizzards, frost and fog, Kurdistan province from hail and heavy snow, and Kermanshah province from thunderstorms, heavy rain and dust. The results of the regions with the same potential for occurrence of atmospheric hazards also showed that the northern half of Hamadan province, the northeastern Kurdistan province, and the western and southwestern regions of Kermanshah province are more affected by atmospheric hazards than other regions.