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Soil moisture is an important hydrological parameter and a basic element for research in water cycle and climate change. Using hourly recorded soil moisture data of 374 stations from the new generation of automatic soil moisture encryption observation network constructed by China Meteo-rological Administration, we analyzed the spatial and temporal variations of soil moisture in North China from 2013 to 2019 and the relationship with precipitation and temperature. The results showed that soil moisture in 10-100 cm layer decreased fluctuatly as a whole, with the decreasing at the 100 cm being serious. The spatial distribution of soil moisture at different depths was characterized by high in the southeast and low in the northwest. About 63% of the surface layer was short of moisture. Soil moisture at different depths changed significantly with the seasons. In summer, soil moisture of each layer reached the highest and soil entropy of each layer was suitable, while it reached a low point in spring. Soil moisture was closely correlated with precipitation and temperature, but the correlation got weaker gradually with the increase of soil depth. Soil moisture was more sensitive to precipitation than to temperature.土壤水分是重要的水文参数,也是水循环、气候变化等研究的基本要素。本研究利用中国气象局新一代自动土壤水分观测网逐小时土壤水分观测数据,分析2013—2019年间华北地区土壤水分的时空分布和变化趋势及其与降水和温度的关系。结果表明: 研究期间,华北地区10~100 cm土层土壤水分整体呈波动下降趋势,尤以100 cm根区土壤水分减少最明显。华北地区不同深度土壤水分空间分布均呈东南高、西北低的特征。10 cm土层63%面积缺墒。不同深度土壤水分随季节变化明显,夏季各层土壤水分达到最高,墒情适宜,春季土壤水分处于低值。土壤水分与降水和温度均具有较好的响应关系,随着土壤深度的增加相关性逐渐减弱,且土壤水分对降水的响应比对气温的响应更显著。.

The detail variations of precipitation, potential evapotranspiration (PET) impacts the terrestrial ecosystem.The grassland water deficit or surplus status (GWDS) from 1961 to 2010 were systemically studied for the Qinghai-Tibetan Plateau (QTP) using daily data of all meteorological stations. The results indicated that the temporal variations of precipitation were not corresponding to those of PET in a year. The maximum monthly precipitation occurred in July, while the maximum monthly PET appeared in June, the spring precipitation was ranked the second, but its PET was ranked the first in a year. The total water deficit (PET-precipitation) from March to June was more, 51.4 % of the total annual value. Therefore, the drought more frequently occurred in Spring and June in the QTP. The grassland can be protected in a year, especially in Spring and June.