The Praxeology of Climate System Changes; Emphasizing the Impact of Subtropical High Pressure Displacement on the Occurrence of Drought Hazards

Document Type : Applied Article


1 PhD in Meteorology, Department of Natural Geography, Kharazmi University, Tehran

2 Professor of Climatology, Department of Natural Geography, Kharazmi University, Tehran

3 Associate Professor of Meteorology, Meteorological Research Institute


Changes in climate systems are one of the most challenging environmental phenomena and depend on the human application systems in various fields such as agriculture, industry and so on. This is a pervasive environmental phenomenon in climate change that affects environ-mental characteristics such as evaporation, precipitation characteristics, drought, rising sea levels, displacement of high pressures, and so on. Meanwhile, drought is a frequent climate phenomenon in climate systems that its effects are not limited to arid and semi-arid regions. Given the relationship between climate change and drought, such as understanding the behavior and complexity of climatic systems, or the performance of human activities, causing turbulence and complexity. If this relation does not determine, environmental resources may be out of balance and in most cases, it may be endangered. Therefore, identifying and evaluating these changes in general will be an important step in predicting change trends, and ultimately environmental sustainability. Therefore, it can be said that identifying the behavior of these systems on issues such as displacement of sub-tropical high-pressure boundary, or the occurrence of droughts necessitates the interaction of quantitative and qualitative studies. In this paper, in response to this question, that is, identifying the boundaries of climate change from equilibrium to risk, we have tried to systematically identify and evaluate this process. As a case study, the behavior of the impact of displacement of sub-tropical high-pressure system on the occurrence and exacerbation of drought and its impact on management practices is discussed.
In order to evaluate the behavior of climate systems changes with emphasis on drought hazards caused by displacement sub-tropical high pressure to the northern latitudes, first step is to investigate the status of temporal and spatial variations of the subtropical stack, detecting its position, identifying its northern limit and its effects on droughts in the study area, which is  0 to 45 degrees latitude, and 0 to 71 degrees longitude. Then, the geopotential elevation data of 500 hPa were extracted from the database of National Center for Environmental Prediction, and National Center for Atmospheric Research, over a period of 70 years with a horizontal resolution of 2.5 degrees during the years 1948 - 2018. The reason for choosing this level is due to the most atmospheric disturbances in this level. Afterward, the pressure output data were plotted and analyzed using the Gards software to match the data and the accuracy of the data display. In the next step, to form a database to draw maps and graphs from the extracted data, first, geopotential pressure data was converted to standard format for analysis using panoply software. According to the trend of temporal and spatial variations of subtropical stack, the intensity of higher central curve of the subtropical high-pressure system, has higher the high-pressure power. In the last step, in order to conceptually analyze the theoretical approaches of climate systems, the method of information compilation was collected using library resources and databases. Thus, analyzing systematic approaches to the research, finally confirms relationship between the rate of movement process and high-pressure behavioral behavior. Regarding the drought changes, a qualitative analysis of the information has been obtained. Afterward, the levels of balance, crisis threshold, and environmental hazards of drought or wet were discussed. 
In this article, regarding the identification of the behavior of tropical high-pressure systems from equilibrium to hazard, it was attempted to identify and evaluate this process in the form of systematic thinking. As a case study, the behavior of displacement behavior of high-pressure system on the occurrence and exacerbation of drought is discussed. Given Iran's position on the dry belt and the subtropical high-pressure dominance in region during the warm season, the time of high pressure during the past 70 years, between 1948 and 2018, was investigated. In this study, the most externally influential high pressure language on Iran was routed in terms of intensity and direction (northwest). It indicates the influential tabs on Iran have spread to the north and northwest, as well as movement of tabs to higher latitude, higher altitude, greater penetration depth, and range over the study period. It also indicating warming, worsening drought and overall climate change. The results of this study in the quantitative approach indicate that the outer most affecting belt in Iran during the hot months studied reveals several levels of equilibrium, namely static, instantaneous, dynamic, and sustained equilibrium, which have had threshold effects for some years. It is a threat to the start of environmental hazard levels (severe and very severe droughts). In general, environmental hazards, and especially environmental disasters, are two phenomena that arise from the behavior of phenomena and the types of management levels that have great importance at the time of thresholds, in the case of unorganized or disturbed management and unpredictability of water system behavior. In the final step, in the form of a qualitative approach, the topic of drought management, based on climate system behavior (from equilibrium to disaster), was presented in the framework of active pre-crisis management and post-crisis management in both infrastructures. They have strategies in place to mitigate drought damage to manage and predict the environment. Therefore, it can be said that the interaction between quantitative perspective (statistical analysis from data) and qualitative perspective (equilibrium management levels, thresholds, hazards and disasters) can be effective as a practical approach in environmental management, predicting systems behavior, and reducing environmental hazards.


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