Synoptic analysis of days of extreme minimum temperatures due to the variation of pressure systems at the levels of 1000 and 850 millibars in the Baghdad station.

Abstract

       Extremism is the amount of change in climate elements that is less than the lower limit of the general rate and more than the upper limit of moderation, meaning that the values of the phenomenon fluctuate around the general rates or close to them, as the study detected daily thermally extreme days during the year 2020 over the months of the year and for the minimum temperature (Cold extreme days) at the Baghdad climate station. Just as the pressure systems varied in their strength or shallowness in each case, the researcher found a variation in the number of days (cases) of thermal extremes during one month, with one day being unique in recording the highest or lowest extreme values according to the depressions prevailing in its atmosphere. Or atmospheric highs, as the lowest extreme values in the cold days during the month of February became apparent on the twelfth day of the month at a rate of (-3.4) °C as a result of the European high’s concentration at the surface level of 1000 millibars above the city of Baghdad and its deepening in the pressure level of 850 millibars, which caused a decrease (extreme). It is clear in the minimum temperature rates for that day, followed by the cold thermal extreme on the twenty-sixth day of December by (-0.5) °C The reason for this is attributed to the dominance of the Siberian-Eurasian high above the surface and the deepening of its influence at the upper level of 850 millibars if the polar characteristics that it carries contribute. Effective in reducing and extreme minimum temperature for that day.

     We relied on the daily temperature averages at the Baghdad station issued by the General Authority for Meteorology and Seismic Monitoring, Climate Section, as well as using the interpretation of the daily weather map received from the National Oceanic and Atmospheric Administration (NOAA) for each day of extremes to trace the climatic reason behind the occurrence. Thermal extremes of minimum temperature.