Identifying synoptic weather patterns that lead to temperature anomalies forms the basis of planning for environmental sustainability. Temperature anomalies, such as extreme heatwaves or cold spells, can alter the structure of the general atmospheric circulation and exert various impacts on ecological systems and ecosystems. The purpose of this study is to identify heatwaves and cold spells in Kermanshah Province during a 33-year period (1987–2019) and to analyze the synoptic role of the Arabian low- and high-pressure systems in generating them.

For this purpose, statistical characteristics of the standardized Z index, the persistence and duration of waves lasting two days or more in the region, and the spatial extent of waves covering three or more stations across the province were examined. Based on these criteria, a total of 6 super-heatwaves, 3 very intense heatwaves, 14 heatwaves, 13 super-cold spells, 12 very intense cold spells, 8 cold spells, and significant synoptic patterns were identified.

Geopotential height, temperature, and wind direction and speed maps at the 1000, 850, 700, and 500 hPa levels were prepared and plotted using a script in the GrADS software environment. Through visual inspection, the dominant synoptic patterns were identified. For detailed synoptic analysis, the dominant heatwave pattern of September 3, 2006, and the cold spell of January 5–6, 1992, were selected as representative examples of warm and cold wave patterns.

To analyze the synoptic patterns leading to heatwaves and cold spells, atmospheric data were obtained from the Meteorological Organization. The findings of the study indicate that the Arabian low-pressure system is one of the influential systems in the occurrence and persistence of heatwaves, whose ridges affect western and southwestern Iran. In contrast, the Arabian and African high-pressure systems are the main contributors to the occurrence and persistence of cold spells, with their ridges influencing northern and northwestern Iran. Their extension into Iran results in the dominance of cold air across the region.

In the not-so-distant past and even in some new sources, the subtropical high pressure, especially the subtropical high pressure of Arabia, was mentioned as a system affecting Iran's climate. Climate change detection and studies in this field have shown that the emission of greenhouse gases associated with human activities has contributed to the increase in surface air temperature, especially in the second half of the 20th century(Masson Delmotte et al,2021). According to the studies, Iran is one of the countries where climate change is very tolerant. Conducting research related to climate change is very necessary to prepare as much as possible to deal with the damaging costs caused by this change. Revealing the trend of temperature anomalies due to climate change and also the changing behavior of temperature in Kermanshah province is considered. Kermanshah province is considered one of the country's agricultural hubs, and a large part of the country's fruits and grains are produced in this province every year. For this reason, any change in air temperature and anomalies that occur in the province's climate will greatly affect the quantity and quality of the province's agricultural products. Therefore, the purpose of this research is to determine the trend of changes in temperature climatic parameters based on the limit values during the last thirty-three years of Kermanshah province in order to reveal the possible occurrence of climate change and to be aware of the occurrence of extreme climatic events and also to attract the attention of the provincial authorities to identify adaptation methods and solutions. It is to deal with it.

Two databases of surface environment data and upper atmosphere data have been used to investigate and study synopsis and changes in the dynamic structure of summer and winter patterns in Kermanshah province. Synoptic maps can be prepared both for the surface of the earth and for different levels of the atmosphere. Also, the daily maximum and minimum temperature statistics of 13 Hamdeed stations of the province were used during the statistical period from 1987 to 2019, which includes 4 stations of Kermanshah, Kangavar, Sar Pol Zahab and Islamabad West. To do this, the statistical characteristics and temporal-spatial (spatial) distribution of the waves were determined using the standard Z index and the duration of two days or more and three stations or more. In this order, 6 super heat waves, 3 very hot waves, 14 hot waves, as well as 13 super cold waves, 12 very cold waves and 8 cold waves are known. Then, hot and cold waves were detected using the visual method, using factor analysis in SPSS software, and to determine the patterns of these waves, using the website of the US National Center for Atmospheric and Oceanography (NCEP/NCAR) maps of geopotential height, temperature, direction and the wind speed of the hectopascal levels were drawn in the GRADS software environment. The synoptic patterns of heat and cold waves in Kermanshah province were processed with the representative day method. In this way, a day with a higher temperature was selected as a sample, and a map of temperature and geopotential height and wind direction and speed was drawn and interpreted.