基于GIPL2模型的青藏高原活动层土壤热状况模拟研究

青藏高原活动层土壤热状况，对深入了解高原活动层的厚度变化特征、下垫面的热力作用以及对气候变化预测均有重要意义。利用GIPL2模型模拟青藏高原多年冻土区不同植被状况下活动层土壤热状况。模拟结果表明：模型在高寒草原（QT06）试验点模拟效果较好，高寒沼泽草甸（QT03）试验点的模拟效果较差，高寒草甸（QT01）、高寒荒漠草原（QT05）和高寒草原化草甸（QT04）试验点的模拟效果介于高寒草原试验点和高寒沼泽草甸试验点之间。QT01、QT03、QT04、QT05和QT06的土壤温度模拟值与观测值相比，均方根误差分别为0.67、1.29、0.73、0.7和0.56℃；相关系数分别为0.99、0.87、0.98、0.98和0.96；平均误差分别为0.37、0.61、0.31、0.45和0.16℃。QT06模拟结果较好，原因在于此点土壤质地变化不大，模型的分层与所取的参数更加接近此点的实际状况。QT03模拟结果较差，可能由于此地区土壤中存在砾石，在导热率参数化方案中没有考虑砾石含量，导致模拟结果偏差较大。总体而言，GIPL2模型对青藏高原活动层土壤热状况的模拟具有一定的优势，是一种模拟多年冻土区活动层土壤热状况较为理想的模型。

Thermal condition of the active layer on the Qinghai-Tibet Plateau simulated by using the Model of GIPL2

The knowledge of the thermal condition within the active layer is of great significance for understanding the variation characteristics of the active layer, the thermal effect of the upper underlying ground and for predicting climate change on the Qinghai-Tibet Plateau. In this paper, the GIPL2 model was used to simulate the soil thermal variations at different depths under different vegetation in permafrost regions over the Qinghai-Tibet Plateau. The simulated results indicate that the GIPL2 model has performed better at the alpine steppe observation site (QT06), but at the alpine swamp meadow observation site (QT03) it has performed bad; between both there are the alpine meadow observation site (QT01), the alpine desert steppe observation site (QT05) and the alpine steppe observation site (QT04). The root-mean-square errors at QT01, QT03, QT04, QT05 and QT06 are 0.67, 1.29, 0.73, 0.7 and 0.56℃, respectively; their correlation coefficients are 0.99, 0.87, 0.98, 0.98 and 0.96 and their mean bias errors are 0.37, 0.61, 0.31, 0.45 and 0.16℃, respectively. The GIPL2 model has better result at QT06, which probably results from the soil stratification used in the model is closer to real condition. The simulated results at QT03 is worse, which may be due to the existence of gravel in the soil and the thermal conductivity parameter in the model has not considered the gravel content. Overall, the GIPL2 model can simulate soil temperature of multiple soil layers in permafrost regions on the plateau. It means that the GIPL2 model could be used to simulate the thermal regime of the active layer of the permafrost on the Qinghai-Tibet Plateau.