Elevation dependency of temperature trend over the Qinghai-Tibetan Plateau during 1901–2015

Abstract

The Qinghai-Tibetan Plateau (Q-TP hereafter) has experienced dramatic warming in recent decades, resulting in severe effects on the ecosystems and downstream. However, none of previous studies investigated elevation-dependency temperature trend with the high resolution over the long-term period. Based on monthly temperature dataset with 0.1° developed by generative adversarial network, elevation-dependency temperature trend over the Q-TP and 5 climate zones (humid, humid-semihumid, semihumid, semiarid, arid region) during 1901–1946, 1946–1965, 1965–1997 and 1997–2015 are investigated. Snow cover (SNC), high cloud cover (HCC), middle cloud cover (MCC), specific humidity (SHUM) and soil moisture content (SOILM) are introduced to analyze possible mechanism. There are 4 cases of elevation-dependency temperature trend, which are positive/negative elevation-dependency warming (EDW+/EDW–) and cooling (EDC+/EDC–). These patterns (EDW+, EDW–, EDC+ and EDC–) are identified as warming/cooling trends that become stronger/weaker with increasing elevation. EDW– signal is found during 1901–1946 due to the influence of SOILM. The most prominent EDW– signal occurs over the arid region. EDC+/− is presented during 1946–1965 under the dominance of SHUM and SOILM. The stronger EDC signal is shown over the arid and semiarid region than over the humid-semihumid region. The subtle EDW+ signal is shown over the semihumid, semiarid and arid regions during 1965–1997 when SOILM has a relatively large contribution to temperature trend. The robust EDW+ signal is exhibited from 1997 to 2015 when SNC plays a vital role in regulating the temperature change. There is a more significant EDW+ over the humid, humid-semihumid, and semihumid regions than that over the semiarid and arid regions during this period. Above all, SNC, SHUM and SOILM are found to be the primary contributors to elevation-dependency temperature trend. SOILM and SHUM are associated with hydrological effects and control temperature variations over the Q-TP during 1901–1997. SNC is related to snow/ice-albedo feedback and dominates temperature variations over the Q-TP during 1997–2015.