A recent work about assessment on tropospheric temperature changes over China has been published in Journal of Geophysical Research-Atmosphere. The authors of this paper are Dr. Lixia Zhang and Prof. Tianjun Zhou of LASG/IAP.
The vertical profile of atmospheric temperature reflects a balance between the radiative, convective, and dynamical heating (cooling) of the surface-atmosphere system. Temperature trends at the upper tropospheric atmosphere may be different from that at the surface. However, estimating long-term tropospheric temperature trends often involves large uncertainties. The availability of temperature data sets provided opportunities to do an extensive comparison of tropospheric temperature changes derived from different data sets and to detect some reliable variability.
Based on four radiosonde data sets and three reanalysis data sets, the long-term tropospheric temperature changes over China for the period 1958-2001, and the uncertainties are analyzed. The results show that the year-by-year changes of temperature over China are largely in agreement among the radiosonde and the reanalysis data sets. Except for HadAT2 and NCEP-20CR, the troposphere temperature trend over China during 1958-2001 can be well captured by the other datasets. The uncertainties of upper troposphere temperature changes are larger compared with those of the lower troposphere. The uncertainty was relatively small during 1970–1990 and large during 1958–1970 and from 1990 to the present. The warming trend of HadAT2 at 300hPa is produced mainly by the stations over south China and is due to the choice of neighbor stations during construction. The temperature trend at 300 hPa in NCEP-National Center for Atmospheric Research is cooler than the other data sets due to its abrupt cooling around the early 1990s. This work provides a full observational picture of the long-term changes of tropospheric temperature across the past half century and a good metric for model evaluation.
Figure: The vertical profile of the monthly mean temperature trend averaged over China (oC/decade) derived from each dataset for (a) 1958-2001, (b) 1958-1979, and (c) 1979-2001. The shaded area is the spread, i.e., standard deviation of all datasets.
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