近50年中国北方土壤湿度时空变化特征及未来预估

Temporal and Spatial Variation Characteristics of Soil Moisture in North China in Recent 50 Years and Its Future Prediction

摘要: 基于1960~2010年GLDAS的土壤湿度数据和GPCP月降水数据，分析了近50年中国北方四层(0~10 cm, 10~40 cm, 40~100 cm, 100~200 cm)土壤湿度的时空变化特征，并讨论了土壤湿度变化与降水之间的关系，进一步，运用CSIRO-mk3.6.0模式在RCP4.5和RCP8.5排放情景下的数据，对2020~2100年中国北方土壤湿度的变化进行预估。结果表明：1) 近50年中国西北地区土壤湿度正在逐渐增大，但是这种增加的趋势随着土壤深度的加深而逐渐减小。华北大部分地区、内蒙古中东部、中国东北的大部分地区土壤湿度则逐渐下降；2) 0~10 cm土壤湿度与降水存在显著的正相关，随着土壤深度的加深，土壤湿度与降水之间的关系逐渐减弱，甚至到40 cm以下，土壤湿度与降水的关系由正相关转变为负相关。3) 在RCP4.5和RCP8.5两种排放情景下2020~2100年中国西北地区如新疆、甘肃西部土壤湿度处于上升趋势，而华北、内蒙古东部、东北地区土壤湿度将处于下降趋势。随着排放浓度的增加，新疆等地土壤湿度增加的强度增大，而内蒙、东北等地土壤湿度则由减少逐渐转变为弱增加。总的来说，从区域平均来看，相对于1986~2005年，中国北方土壤湿度将呈现出减少的趋势。

Abstract: Based on the soil moisture data from GLDAS and precipitation data from GPCP during 1960~2010, the temporal and spatial variation characteristics of soil moisture in four layers (0~10 cm, 10~40 cm, 40~100 cm, 100~200 cm) of Northern China in recent 50 years were analyzed, and the relationship between soil moisture and precipitation was discussed. Further, based on the data of CSIRO-mk3.6.0 model under RCP4.5 and RCP8.5 emission scenarios, the change of soil moisture during 2020~2100 is projected. The results show that: 1) The soil moisture in Northwest China was increasing gradually in recent 50 years, while it declined gradually in most parts of North China, Middle East of Inner Mongolia and Northeast China; 2) The soil moisture in the depth of 0~10 cm had a significantly positive correlation with precipitation, as the soil deepens, the correlation between soil moisture and precipitation gradually became weak, even below 40 cm, the correlation became negative correlation from positive correlation; 3) Under the two emission scenarios RCP4.5 and RCP8.5, soil moisture has an increasing trend during 2020~2100 in Xinjiang and the western part of Gansu, while it will decline in North China, Eastern Inner Mongolia and Northeastern China. As the emission concentration rises, soil moisture becomes more in Xinjiang and the western part of Gansu, but the soil moisture in Inner Mongolia and Northeast China will change from decreasing to weak increasing. In general, relative to the period of 1986~2005, soil moisture in Northern China will display a decreasing trend on regional average.