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土壤水分是土壤-植被-大气连续体的一个重要组分,是决定陆地生态系统水分状况的关键因子,也是作物的水分供应库.为了估算站点尺度不同深度的土壤水分,基于下垫面能量平衡方程和水分亏缺指数,提出了基于地面遥感信息(归一化植被指数和下垫面温度)和气温估算土壤相对湿度方法.利用2014年中国气象局固城生态与农业气象试验站夏玉米水分控制试验资料验证的结果表明:该方法可以有效估算不同深度的土壤相对湿度,陆地生态系统的潜在干旱程度即实际蒸散与潜在蒸散之比与不同深度土壤湿度呈显著的线性关系.其中,0~10 cm土层的土壤水分估算精度最高,决定系数达0.90;0~20 cm到0~50 cm土层土壤水分估算的平均相对误差均在15%以内,相对均方根误差均在20%以内.研究结果可为作物的干旱监测与灌溉管理提供参考.
Soil moisture is an important component of the soil-vegetation-atmosphere continuum and is the key factor determining the water status of terrestrial ecosystems and also the water supply reservoir of crops.In order to estimate the soil moisture at different depths of the site scale, Equation and water deficit index, a method of estimating soil relative humidity based on remote sensing information (normalized vegetation index and underlying surface temperature) and air temperature was proposed.By using the data of summer maize moisture at Station Gucheng Ecological and Agricultural Meteorological Station of China Meteorological Administration in 2014, The results of control test data show that this method can effectively estimate soil relative humidity at different depths, and the potential drought degree of terrestrial ecosystems is a significant linear relationship between soil evapotranspiration and potential evapotranspiration and soil moisture at different depths, of which 0 ~ The soil moisture estimation accuracy of 10 cm soil layer was the highest, with a determination coefficient of 0.90. The average relative errors of soil moisture estimation in 0-20 cm to 0-50 cm soil layers were all within 15%, and the relative root mean square error was less than 20% The results can provide reference for crop drought monitoring and irrigation management.