Difference in radiosonde temperature trend for the period 1979-1998 of MSU data and the period 1959-1998 twice as long

The difference in temperature trend for the 20-year period 1979-1998 and 40-year period 1959-1998 is estimated from a 63-station global radiosonde network. The variability of radiosonde-station temperature trends, as measured by their standard deviation, is about twice as great for 1979-1998 as 1959-1998. The cooling trend in the 100-50 mb layer of the low stratosphere is similar in polar, temperate and tropical zones, and about twice as great during 1979-1998 as 1959-1998. The cooling trend in the 300-100 mb layer of extratropics is also greater during 1979-1998 than 1959-1998, but the slight tropical warming is almost the same for the 2 periods. The warming trend in the tropospheric 850-300 mb layer is similar during 1959-1998 and 1979-1998, except in the south temperate zone where there is indicated to be cooling during 1979-1998. At the surface of the north polar zone the warming trend during 1979-1998 is nearly 3 times the warming during 1959-1998. In the global average the surface and 850-300 mb warmings are the same during 1959-1998, but the surface warms relative to the 850-300 mb layer during 1979-1998.