Identification of dominant climate factor for pan evaporation trend in the Tibetan Plateau

摘要: Despite the observed increase in global temperature, pan evaporation many regions has been decreasing over past 50 years, which is known as “pan paradox”. The paradox” also exists Tibetan Plateau, where decreased by 3.06 mm a−2 (millimeter per annum). It necessary to explain mechanisms behind decline because Plateau strongly influences climatic and environmental changes China, Asia even Northern Hemisphere. In this paper, a derivation based approach used quantitatively assess contribution rate of climate factors trend across Plateau. results showed that, provided other remain constant, increasing temperature should have led 2.73 annually, while change wind speed, vapor pressure solar radiation decrease 2.81 a−2, 1.96 1.11 respectively from 1970 2005. combined effects four variables resulted 3.15 evaporation, close with relative error 2.94%. A speed was dominant factor for followed an radiation, all offset effect