The effects of climate warming on large-scale atmospheric systems of the Northern Hemisphere

In the present study, we examine the impact of climate warming on the variability of the main climatic drivers in the northern hemisphere, using 40 years (1979-2018) of ERA-Interim reanalysis data. We applied Sen’s slope estimator and the Mann-Kendall significance test to identify regions with significant variability of 500-1000 hPa thickness. The findings reveal that climate warming is particularly pronounced at latitudes ranging from 80º to 90º and also in subtropical regions. The increase in thickness is most notable in mid-latitudes during the summer season, owing to climate warming. The steeper trend slope observed in autumn indicates a faster warming rate compared to other seasons. Moreover, despite climate warming, significant trends in large-scale atmospheric circulation systems demonstrate the strengthening of the Siberian high-pressure in winter and autumn. Additionally, a segment of the core of the Azores high-pressure system has also experienced strengthening during winter. Conversely, the monsoon and Aleutian low-pressure systems have weakened in spring and winter, respectively. The subtropical high-pressure system exhibits a positive and significant trend in winter, spring, and summer, aligning with the positive significant trends observed in atmospheric thickness, thereby confirming the effects of climate warming.