几种蒸散产品在我国不同下垫面的适用性评估

Applicability Evaluation of Several Evapotranspiration Products on Different Underlying Surfaces in China

蒸散量(ET)是地球表面水循环研究的重要因素,在能量循环、碳循环中也起到重要作用,其数值大小与变化对区域农业发展及生态布局具有重大影响。本文将根据2004年到2010年FLUXNET、GLDAS、MERRA2三种蒸散模型分别对半湿润地区禹城、高寒草甸地区当雄、草原地区内蒙古和半干旱地区千烟州等空间上相隔较远的、不同类型的下垫面及气候条件的地区,进行空间插值并于测站观测值相比较,通过RMSE、r、BIAS三个指标分析了不同蒸散产品的蒸散量(ET)模拟值在中国不同区域的适用性。从而分析各蒸散产品的优劣势,然后在此基础上利用最好的模型计算出全国蒸散量(ET)的平均值及其变化趋势。主要研究成果如下:1) 基于空间插值法对禹城、当雄、内蒙古、千烟州四大区域内3种蒸散产品(FLUXNET、GLDAS、MERRA2)进行评估,发现各产品模拟值差异较大、FLUXNET产品是综合表现最好的产品。2) 不同蒸散产品对春、冬两季的模拟较好,对夏、秋两季的模拟较差。3) 中国地区的蒸散量分布呈现自南向北递减,南方蒸散量大于北方的趋势。中国地区的蒸散量在纬度相同地区其ET平均值总体上呈自东部沿海向西部内地递减。有些地区ET平均值与其周围地区存在数量级上的差异,产生这种现象有气候、地形等因素。

Evapotranspiration (ET) is an important factor in the study of the earth's surface water cycle. It also plays an important role in the energy cycle and carbon cycle. Its value and change have a significant impact on regional agricultural development and ecological layout. Based on FLUXNET, GLDAS and merra2 evapotranspiration models from 2004 to 2010, the spatial interpolation of different types of underlying surface and climatic conditions in Yucheng, Dangxiong of alpine meadow, Inner Mongolia of grassland and Qianyanzhou of semi-arid region are carried out by spatial interpolation, and the observed values are compared by RMSE, r and BIAS. The applicability of ET simulation values of different evapotranspiration products in different regions of China was analyzed. Based on the analysis of the advantages and disadvantages of each evapotranspiration product, the average value of national evapotranspiration (ET) and its change trend are calculated by using the best model. The main research results are as follows: 1) Three evapotranspiration products (FLUXNET, GLDAS and MERRA2) in Yucheng, Dangxiong, Inner Mongolia and Qianyanzhou were evaluated based on spatial interpolation method. It was found that the simulation values of FLUXNET, GLDAS and merra2 were quite different, and FLUXNET was the best product in comprehensive performance. 2) The simulation results of different evapotranspiration products were better in spring and winter than in summer and autumn. 3) The distribution of evapotranspiration in China is decreasing from south to north, and the evapotranspiration in South China is larger than that in North China. In general, the ET of evapotranspiration in China decreases from the eastern coast to the western inland in the same latitude. There is a difference of magnitude between the average ET value of some areas and its surrounding areas, which is caused by climate, topography and other factors.