The possible cause of the change of the minimum and maximum surface air temperatures in the second half of the 20th century

摘要

Long-time variations of the minimal (night), maximal (daytime) surface air temperatures and the daily amplitude of the air temperature are researched in middle and high latitudes of the northern hemisphere in the second half of the 20th century. Rise of extreme air temperatures and the decrease of daily variation are determined starting from 1970-s of the last century. The largest changes both of extreme values and the daily variation value are registered in continental regions at middle latitudes of the northern hemisphere and, in particular, in Siberia and at high latitudes during the winter season. It is determined that the increase of average daily temperature of the air takes place generally because of the increase of minimal temperature of the air. Comparison of extreme temperatures changes of the air and the daily variation amplitude with geomagnetic activity variations at high latitudes has been carried out. It is shown that the major part of observed changes is caused by the solar activity influence, which is not considered by the contemporary climate models.