基于温度差监测西北地区的土壤相对湿度

在2012年黑河生态水文遥感试验（HiWATER）观测资料的基础上，结合卫星的地表温度产品计算观测点的垂直温度差及温度的日较差，并分析了不同时间尺度上温度差与浅层土壤相对湿度（包括土层深度2 cm，4 cm和10 cm的土壤相对湿度）的相关性。为检验温度差在区域含水量监测中的效果，利用经度、纬度和海拔高度对气温进行插值。同时为消除温度的区域性差异，将各温度差进行归一化处理，最后将归一化后的垂直温度差区域分布与土壤相对湿度进行了对比。结果表明:在各温度差中，地表温度和气温计算的垂直温度差与浅层土壤相对湿度的相关性最好；在时间尺度上，温度差与浅层土壤相对湿度的相关系数随时间尺度的增加而增大；在各土层深度中，温度差与4 cm的浅层土壤相对湿度相关性更好；在气温插值中，在纬度和海拔高度基础上插值出的气温与实测值之间更为接近；区域尺度上，归一化后的垂直温度差有效地解决了地理位置和下垫面对垂直温度差的影响，可以很好地监测月尺度上土壤湿度的变化的情况。

The Soil Water Content Monitoring Based on the Temperature Difference in the Northwest China

Based on the HiWATER data in 2012, the vertical temperature difference (the difference between land surface temperature and air temperature) and the diurnal range of temperature on sites were calculated using the land surface temperature product of remote sensing, and then the correlations between the soil moisture (the 2 cm, 4 cm and 10 cm soil moisture) and temperature parameters on varied time scales were analyzed. In order to verify the monitoring ability of the temperature parameters, the air temperature of the study area was estimated using the longitude, latitude and altitude, and the temperature parameters were normalized to avoid the difference of geographical. Compared the normalized temperature parameters with the soil moisture, the result showed that among the temperature parameters, the correlation between the vertical temperature difference and soil moisture was the best. The correlation coefficient between the temperature parameters and soil moisture increased with the increase of time scale. In each soil depth, the temperature difference was better correlated with the soil moisture of 4 cm depth. In the air temperature interpolation, the air temperatures estimated by latitude and altitude was closer to the measured values. On the regional scale, normalized vertical temperature difference could effectively solve the influence of geographical and the underlying surface, and could well monitor the change of soil moisture on month scale.