China News Service, Beijing, February 29 (Reporter Sun Zifa) How much is the average annual evaporation of the Qinghai-Tibet Plateau, known as the "roof of the world", "the third pole of the earth" and "the water tower of Asia"?
The latest calculation by Chinese scientists based on data accumulated over the past 40 years gives an answer of 930 billion tons.
The Tibetan Plateau Institute of the Chinese Academy of Sciences announced on February 29 that researcher Ma Yaoming and others from the institute's geoatmospheric and climate effects team used ground station and eddy related observation data on the Tibetan Plateau, as well as shallow soil moisture content and soil texture data to By improving the MOD16-STM evapotranspiration model and combining the latest soil properties, meteorological data and remote sensing data, a set of monthly-scale evapotranspiration and its component data sets for 37 years (1982-2018) was generated, and passed 9 Independent validation of flux towers.
Mathematical statistics of annual averages of 18 evapotranspiration (ET) data sets on the Tibetan Plateau.
Institute of Tibetan Plateau Research, Chinese Academy of Sciences/Photo provided
This study found that in the past 40 years, the average annual evapotranspiration of the Qinghai-Tibet Plateau was approximately 346.5±13.2 mm per year, which means that the amount of water transferred into the atmosphere through evapotranspiration on the entire plateau every year was 9300±37 billion tons.
This important research paper on the Tibetan Plateau was recently published in the international professional academic journal Earth System Science Data.
Ma Yaoming, co-corresponding author of the paper, pointed out that the vegetation type on the Qinghai-Tibet Plateau is dominated by alpine meadows, and an arid or semi-arid climate is its main hydrological and meteorological feature.
Evapotranspiration plays a vital role in the region's water balance.
Previous studies have shown that shallow soil water reflects the characteristics of water and heat exchange between the Tibetan Plateau and the earth. The active layer fundamentally affects hydrological processes and affects the direct exchange of water and heat between the atmosphere and deep soil.
The evapotranspiration values of the Tibetan Plateau that researchers have previously used models to evaluate have large differences in the size and spatial distribution of the estimated values, because the parameters that drive the evapotranspiration model require a large amount of measured data, making it difficult to understand the spatiotemporal dynamics and regulation of evapotranspiration in the Tibetan Plateau. Insufficient understanding of mechanisms limits the ability to assess evapotranspiration.
Researcher Chen Xuelong, co-corresponding author of the paper and Institute of Tibetan Plateau Research, Chinese Academy of Sciences, said that the verification results showed that the data set generated in this study showed more reliable performance.
This data set is of great value to water resources management, drought monitoring, and ecological environment research and analysis on the Tibetan Plateau.
The average annual evapotranspiration growth trend of the entire Tibetan Plateau is about 0.96 mm per year. This upward trend is attributed to the warming and humidification of the Qinghai-Tibet Plateau climate.
Studies have shown that the main contributor to evapotranspiration on the Qinghai-Tibet Plateau is soil evaporation, accounting for more than 84%.
The Tibetan Plateau Institute of the Chinese Academy of Sciences said that relevant data from this study have been publicly released in the National Tibetan Plateau Scientific Data Center and Scientific Data Bank for global sharing.
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