Space and time variations of temperature trends in the Arctic stratosphere

Data of long-term upper-air soundings are used to update temperature trend values in the lower stratosphere of the Arctic. On the basis of 58 upper-air sites located between 65°N and 83°N, spatial fields of the trend values in the 50-100 hPa layer are considered. The temporal variability of the trend is analysed by comparing the trend values obtained for different (partly overlapping) 20-year periods of observation. Considerable spatial and temporal variability of the trend is confirmed testifying that dynamics should be an important contributor to it. The 40-year fields of the trend reveal that the negative trend values which dominate in the polar region seem to be greater over North Atlantic and northern Siberia than over the Canadian Arctic.