Comparison of surface and tropospheric temperature trends estimated from a 63‐Station Radiosonde Network, 1958–1998

Abstract

Comparisons of surface and tropospheric (850–300 mb) temperature trends for climate zones, hemispheres and globe are presented for the period 1958–1998, based on seasonal and annual‐mean temperatures from a 63‐station radiosonde network. Globally, the surface warmed by 0.14±0.13K/decade during the 41‐year period, the 850–300 mb layer by 0.10±0.09K/decade. This small difference in global trend results from the surface warming by 0.12K/decade relative to the 850–300 mb layer in the northern hemisphere, but the 850–300 mb layer warming by 0.04K/decade relative to the surface in the southern hemisphere. In north polar and temperate zones the warming of the surface relative to the 850–300 mb layer is greatest in winter‐spring and there is little difference in trend in summer. There is a tendency for a similar seasonal variation in trend difference in south extratropics, warming of the surface relative to the 850–300 mb layer occurring only in winter in the south polar zone, and cooling of the surface relative to the 850–300 mb layer greatest in summer in the south temperate zone. Globally, the warming of the surface relative to the 850–300 mb layer is 0.11K/decade during 1979–1998, compared to 0.04K/decade during 1958–1998, but with the 95% confidence intervals approximately twice as great for the 20‐year period as for the 41‐year period.