Tehran, in the south of Alborz Mountains, is faced with three types of weather risk, weather risk caused by geography, climatic risks caused by air resistance and weather risk due to global warming. The aim of this study is to examine the three types of risk in Tehran. The method of this study was to evaluate the changes of synoptic factors that affect global warming and urban development. In order to detect the height changes of 500 hPa two 5-year periods including 1948 to 1952 and 2010 to 2014, were studied.The results showed that changes in heights of 500 geopotential, there was an increased risk in the city of Tehran. The effect of climate change in recent decades, increased the stability of air in Tehran. Human factors in the formation of heat islands, increase LCL height and density of the air balance is transferred to a higher altitude. Changing urban wind field, atmospheric turbulence intensified, exacerbated thermodynamic gradient, fat and refugee cyclones, heat island effect of the city.Thermal stability in the warm period will appear. The thermal stability of all levels of lower, middle and upper troposphere was intensified. Thermal stability couraged the development of subtropical high pressure in the area. With the arrival of the atmospheric pressure during calm and humid days the stability and pollution were increased. Negative vorticity from early June developed the intensive high pressure over the region. Compare the conditions of the two study periods showed that: the height of the high pressure was 100 meters higher than the second period. The number of days of intensified subtropical high increased during the second period. The high pressure has moved to the northern areas during the second period. This change in the subtropical high pressure increased the dry periods motivating the loss of vegetation. Heat island effect was increased as well. More than 90% of the temperature inversions occurred at an altitude of less than 500 meters in both warm and cold periods of year. Wind direction at both stations has shown that the establishment of any pollutant source in the West of Tehran will increase the pollution.

BACKGROUND AND OBJECTIVES: Hydrometeorological disaster management and agriculture sectors require accurate spatial and temporal rainfall data. However, in situ rainfall gauges were very limited and distributed unevenly. In this context, satellite-based rainfall estimates were used as a reference and complement to in situ measurements on Kalimantan Island, Indonesia. The island possessed complex climate phenomena such as the inter-tropical convergence zone. This study aimed to i) validate rainfall data estimates from climate hazards group infrared precipitation with stations, ii) identify movement in Inter-Tropical Convergence Zone variability, and iii) analyze the variability of rainfall in the inter-tropical convergence zone region.METHODS: A synthesis of descriptive and categorical statistics was used, with European Centre for Medium-Range Weather Forecasts Reanalysis 5th generation data serving as the basis for identifying the inter-tropical convergence zone, while power spectrum density analysis was used to assess rainfall variability. The normal characteristics of monthly rainfall in each season type are compared between observed rainfall data, climate hazards group infrared precipitation with stations with correction, and climate hazards group infrared precipitation with stations without correction.FINDINGS: The results showed that the best climate hazards Group InfraRed Precipitation with Stations performance was found in the southeast of Kalimantan, characterized by flat to undulating areas from the coast to the valley behind the hills, mainly forest and cultivated land cover types, and a high density of rainfall observations. The climate hazards group infrared precipitation with stations performance testing approach from point to pixel versus using the Seasonal Zone region is similar; however, point to pixel is clearly preferable. The movement pattern of the intertropical convergence zone influences the accuracy of rainfall estimation using climate hazards group infrared precipitation with stations. The climate hazards group''s infrared precipitation dataset with stations that have been validated against the movement of the intertropical convergence zone in Kalimantan. Seasonal zones with equatorial, monsoonal, equatorial-1, equatorial-2, Monsoonal-1, and Monsoonal-2 types generally does not affect the performance differences of the climate hazards group infrared precipitation with stations. The variation between climate hazards group infrared precipitation with stations rainfall estimates and observations does not differ systematically.CONCLUSION: climate hazards group infrared precipitation with stations performance was strongly influenced by Inter-Tropical Convergence Zone movements, and the dataset was reliable in estimating rainfall for areas in Kalimantan with a reduced number of observation stations. The inter-tropical convergence zone movement pattern is impacted by local, regional, and global climate variability caused by land-sea-atmosphere interactions on the Indonesian maritime continent, resulting in significant variations in the center and width of the inter-tropical convergence zone band. the major cycle of corrected and observed climate hazards group infrared precipitation with stations rainfall in the seasonal zone is annual and seasonal, with monsoonal and equatorial rainfall types.

The occurrence of climatic hazards is one of the main characteristics of the climate of Iran, which it always has economic, social, and financial losses. Undoubtedly, the first step in reducing the climate impact of the country is to identify the causes of these hazards. Sea level pressure is one of the most important climatic elements that can affect important climatic factors such as temperature, rainfall and wind that cause climate hazards. Increase or decrease severity and the expansion of the eastern and northern levels of sea level pressure centers is one of major determinants of dry and humid periods in Iran. The study of published works and resources shows that a comprehensive study is required on changes in Iranian sea surface pressure in different seasons. Therefore, the purpose of this study is to reveal the trend of sea level pressure changes in different seasons. For this purpose, sea level data with NC format at 12 GMT Obtained from the NCEP/ NCAR database from 1948 to 2016. Afterward, to obtain the seasonal categorization and mapping, the next steps were converted to TXT, Matlab, EXCEL, and GIS formats. Then, long-term changes in sea surface pressure were revealed. Study of time series trend diagram as well as values of mean, average, minimum, and average of maximum sea level pressure with the Mann Kendall test in different seasons showed that the level of significance level in all cases is smaller than 0.05, and the average annual pressure level of the Iranian sea has a significant upward trend, which is increasing by 0.047 hpa per year. The average 10-year map of Iran's surface pressure was similar in different seasons, and the average pressure dropped from the north of Iran to the south. Anomalous maps of the mean of ten years of sea-surface pressure showed that anomalous amounts have reached their highest positive levels in recent decades. Considering the importance of the issue and the vulnerability of the country to environmental hazards, it is clear that climate risk management will have a higher chance of success and credibility with increasing sea- level pressure.

This study is aimed to investigate the effect of climatic hazards on the number of foreign tourists in Isfahan. To do that, we used statistics of total precipitation, absolute minimum of temperature, absolute maximum of temperature, maximum precipitation in 24 hour, number of dusty days, number of icy days and air quality index in Isfahan City and statistics of Number of foreign tourists on monthly basis from 1382 to 1393. So we used linear regression and Pearson Correlation. The results have shown that during the studied period the number of tourists has been affected more than other hazards respectively by air pollution, extreme heats, icy days, extreme cold, dust, drought and finally extreme precipitation...

The activities of people and societies have increased significantly over the past century and have had a great impact on the natural environment and the living environment of societies and on people collectively or individually. On the other hand, the effect of natural events on the activities of people and societies is increasing. Based on this, the nature of hazards science is to measure the risk effect of these activities and events. The method of producing this article is empirical and historical analysis.It contains the well-known collection of testimonies and complaints of the natural and social environment. Of course, the amount that the authors did not remain unaware of. The question of this article is, what kind of hazards have these activities and events caused, and based on those hazards what types of hazards science has? The answer to this question will cause hazards scientists to be fundamentally and organized and increasingly and more actively engaged in solving and managing social, individual and natural environmental hazards. On the other hand, the contribution of hazards science to the understanding of hazards will be developed. Also, other interested people from other fields of science, who have the opportunity to enter hazards science, should be guided to the field of risk science typology.