Interannual Variability of Atmospheric Heat Source over the Tibetan Plateau and Its Driving Factors

The atmospheric heat sources over the Tibetan Plateau (TP) play a significant role in the outbreak, evolution, advancement of the Asian summer monsoon, and the global climate system. Therefore, the variation mechanism of the TP atmospheric heat source has attracted increasing attention in recent years. This study reviewed the variation mechanism of the atmospheric heat sources over the TP in different seasons. Besides, the authors classified the interannual variability of monthly total atmospheric heat source over TP using the JRA55 (Japanese 55-year Reanalysis) dataset from 1980 to 2018. Further, the authors explored the anomalous large-scale circulation systems and SST (Sea Surface Temperature) driving factors affecting different total atmospheric heat sources over the TP. In addition to the traditional “winter type” and “summer type” interannual variability modes of the TP atmospheric heat source, “early spring type” and “transition type” are also proposed in this study. Generally, the interannual variability of the total atmospheric heat source over TP is caused by the latent heat of condensation induced by precipitation anomaly. The “winter type” and “early spring type” anomalies are primarily concentrated in the western TP and are influenced by the teleconnection wave train at middle and high latitudes. The “winter type” is also affected by the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). The “summer type” atmospheric heat source anomaly over TP is characterized by a dipole mode with an east–west inverse distribution, with the largest center of the anomaly appearing in the southeastern TP, which is primarily affected by the North Atlantic Oscillation (NAO). The “transition type” atmospheric heat source anomaly over TP is characterized by a dipole mode with a north–south inverse distribution, jointly influenced by the sea surface temperature anomaly in the tropical Pacific Ocean and the Indian Ocean. The driving factors of the interannual variability of the total atmospheric heat source over the TP are shown to vary remarkably depending on the background atmospheric circulation.