关键词: 干旱半干旱区, 下垫面, 土壤温度, 热传导方法, 热传导?对流方法, 最小方差拟合法

Abstract: Using soil temperature data observed at Dunhuang, Badanjilin Desert center, Badanjilin Desert edge and Pingliang from July to Aug. 2009, the soil thermal diffusivity and soil water flux density are calculated with thermal conduction algorithm and thermal conduction-convection algorithm. Based on these results and taking the soil layer at the depth of 5 cm as the upper boundary, the soil temperatures at the depth of 10 cm in the 4 areas are modeled using the two algorithms. The results show that both of the two methods could correctly model the soil temperature, and the soil temperature modeled at daytime is more exact. The soil thermal diffusivities of Dunhuang, Badanjilin Desert center, Badanjilin Desert edge and Pingliang are 1.62 × 10^-7, 6.92 × 10^-7, 8.01 × 10^-7and 16.10 × 10^-7m²/s, and the soil water flux densities of Badanjilin Desert center, Badanjilin Desert edge and Pingliang are 4.72, 9.22 and 7.06 m2/s. The standard error of soil temperature modeled by thermal conduction algorithm is less at Dunhuang Gobi, where the soil moisture is low. The standard errors of soil temperature modeled by thermal conduction-convection algorithm are less at Badanjilin Desert center, Badanjilin Desert edge and Pingliang, where the soil moistures are high.

Key words: arid and semi-arid region, underlying surface, soil temperature, thermal conduction algorithm, thermal conduction-convection algorithm, minimum variance fitting method