广西大青山土壤水热特征及其对气象要素的响应

Soil moisture and temperature characteristics and the responses to meteorological factors in Daqingshan, Guangxi

利用广西友谊关森林生态系统国家定位观测研究站自动气象站的观测数据,分析了广西大青山地区土壤水热的变化特征及其与气象要素的统计关系,结果表明:(1)土壤温度的年内变化特征与气温一致,呈"单峰型",最低值出现在1月,最高值在7月,但存在滞后期,滞后时间随土层深度增加而增加。(2)土壤水分年内变化复杂,受各月气温、降水的影响而呈现出一定的波动性,1—4月份土壤含水率较高,4月下旬土壤含水率迅速降低,至7月底处于全年较低值,变化幅度随土层深度加深而减小。(3)影响土壤温度的主要气象要素为大气温度,土壤水分主要受降水和饱和水汽压影响。月尺度上这些气象要素对土壤水热的影响更加显著。(4)土壤温度和土壤水分为显著的负相关关系。研究结论为土壤水热对气候变化的响应提供参考资料,也为本区域森林经营管理提供科学依据。

By using Automatic meteorological station of Guangxi Youyiguan Forest Ecosystem National Research Station,we analyzed the relationships between soil temperature,soil moisture dynamics and other meteorological factors in Daqingshan.The results were shown as follows:(1)the changing characteristics of the soil temperature are largely consistent with the air temperature,and the seasonal dynamics of them showed one peak,the lowest value appeared in January,the highest value in July,while a lag phase between them was observed which increased with soil depth.(2)Soil moisture dynamics is much more complex compared with the temperature dynamics,and strongly affected by the precipitation and tempreture.The soil moisture content was high from January to April,and it decreased rapidly in late April,reaching a year-long low value at the end of July.Soil moisture dynamics decreases with soil depth.(3)On different time scales,Soil temperature is highly related with the air temperature,while the soil moisture is also highly related with precipitation and Saturated vapor pressure differences(VPD).Better statistical relationships between soil temperature,soil moisture dynamics and meteorological factors was observed at month-scale rather than a daily time scale.(4)Soil temperature and moisture shows an obvious negative correlation relationship.The research conclusion could provide reference material for the response of soil water and heat to climate change and provide the scientific basis for forest management in this region.