Characteristics of the Seasonal Variation in OLR Field over the Tibetan Plateau

By using 13-year pentad mean Outgoing Longwave Radiation (OLR) data (1979~1991) observed by NOAA satellites, the characteristics of the seasonal variation in OLR field over the Tibetan Plateau are investigated. The results show that the OLR field has outstanding seasonal variation. The major feature is that the OLR field is “ moderate variation condition” in winter and summer, and “abrupt variation condition” during the transition seasons of spring and autumn. There is persistent and strong positive interpentad change of OLR over the southwest of Tibetan Plateau in spring. It means that the enhanced heating field over the Plateau in spring has probably important effect on the seasonal transition of the regional climate. Additionally, the interannual variability of the seasonal transition of the OLR field over the Tibetan Plateau is also clear. It is closely related to the anomalies of the monsoon precipitation, that the summer over the Plateau comes early or late