贵州喀斯特区域土壤湿度持续下降时期气象要素对土壤湿度影响研究

Response of Declining Soil Moisture on Meteorological Factors over Karst Area of Guizhou Province

基于贵州喀斯特区域10个自动土壤湿度观测站2011~2015年逐日土壤湿度、降水量、气温、地表温度、相对湿度、风速和日照时数资料,应用统计方法,分析了不同农业气候区土壤湿度持续下降、气温持续上升或下降阶段,气象要素对土壤湿度的影响,结果表明:(1)气象要素对土壤湿度的影响具有一定的滞后性,其滞后时间为10~25日。(2)累计降水、气温、地表温度和相对湿度与土壤湿度相关性均较好,相关系数为0.61~0.96;风速与土壤湿度相关性较差,相关系数为0.38~0.57;辐射与土壤湿度的相关系数仅在气温上升时期>0.64。(3)累计降水量越大、气温越低,累计降水滞后时间越长;气温和地表温度越高、累计降水量越少,气温和地表温度滞后时间越长。(4)滞后时间内累计降水小于11.5~70.9 mm(气温持续上升)或20.9~65.0 mm(气温持续下降),降水是影响土壤湿度的主要因子,其它气象要素的变化不能改变土壤湿度的降低趋势。(5)不同农业气候区气象要素与土壤湿度回归模型误差<7.50%,相对较小,能反映出气象要素对土壤湿度的影响规律。

The effect of meteorological factors on soil moisture was analyzed in different agroclimatic zones based on the daily date of soil moisture, precipitation, temperature, surface temperature, relative humidity, wind speed and sunshine duration of 10 soil moisture automatic observation stations in Karst area of Guizhou Province from 2011 to 2015. The effect of different meteorological factors on the daily soil moisture showed a certain lagging influence and its lagging time was 10-25 days. Precipitation, temperature, surface temperature and relative humidity had better relationship with soil moisture, with a correlation coefficients of 0.61-0.96. Wind speed was generally weakly related with soil moisture, with a correlation coefficient of 0.38-0.57. The correlation coefficient between radiation and soil moisture was more than 0.64 only during the period of rising temperature. The lower temperature and the higher accumulated precipitation extended the lagging days of precipitation. Precipitation played a major role in the daily changes of soil moisture, and the changes of other meteorological elements cannot change the downward trend of daily soil moisture when the accumulated precipitation was less than 11.5-70.9 mm（during the period of rising temperature） or 20.9-65.0 mm（during the period of declining temperature） in different agroclimatic zones. The errors of the regression model between soil moisture and meteorological factors were less than 7.50% in different agricultural climatic zones, which accurately reflects the response of meteorological factors on soil moisture over Karst area.