New Findings on Tibetan Plateau Field Experiment (TIPEX)

To get better understanding on the physical mechanism of Tibetan air-land interaction on climate change and the formation and development of disastrous weather systems, the second TIbetan Plateau EXperiment (TIPEX) was launched during May-August in 1998. This experiment was centered on monitoring the planetary boundary layer of Tibetan Plateau with many advanced instruments. During TIPEX, large amount valuable high-quality data were obtained. Data processing and the establishment of database of TIPEX have been finished. Some new findings obtained from TIPEX are as follows: 1. There exists apparent humidity reversion phenomenon in plateau PBL, which suggest that there exist some kind of weak moisture transportation channel at mid-upper levels of Tibetan PBL.

2. Solar radiation is rather strong over the plateau. Global radiation is usually beyond solar constant (1360w/m2) (Fig.4). It is seldom found in other area.

3. There exists heat imbalance between net radiation and the sum of sensible heat flux, latent heat flux and soil heat flux on Tibetan Plateau.

4. Strong meso-scale convection is very active over the Plateau.

5. Unstable stratification would develop rapidly after the sunrise over the Plateau. 6. With Doppler radar, typical plateau meso-scale activity was also found in GAME/Tibet experiment.

7. CD and CH vary greatly along with the features of topography on Tibetan Plateau.