塔克拉玛干沙漠腹地人工绿地生长季的小气候特征

Microclimatic Characteristics over Artificial Shelter Forest Land in Growing Season in Hinterland of Taklimakan Desert

利用小气候观测资料,分析了塔里木沙漠腹地人工灌溉林地小气候特征及其影响因素,并与林地外原始流沙地进行了对比。结果表明,人工灌溉林地具有调节地表温度和贴地层气温,缩小温差,提高大气湿度等重要生态作用。人工灌溉林地地表温度与流沙地差异极显著,白天林地的地表温度低于流沙地而夜间相反,林地土壤温度的日较差比流沙地低18.26℃;在09:00—15:00期间,林地的气温高于流沙地,平均温度高1.44℃,其它时段,林地的气温低于流沙地,平均温度低3.22℃;两者之间温差夜间大于白昼,林地的气温日较差较流沙地高4.41℃。全天林地绝对湿度和相对湿度均大于流沙地。不同树种的林地温湿度存在差别,但是差异不显著。不同覆盖度林地地表温度、空气温湿度都表现出不同的特征。研究结果对于进一步探讨极端干旱条件下人工灌溉林地近地层物质和能量交换具有重要意义。

Using observed microclimatic data, we analyzed the microclimatic characteristics over irrigated shelter forest land and the external influence factors in Tarim Desert in autumn and make the comparison with shifting sand land. Results showed that the irrigated shelter forest land had particular climate functions, such as modifying surface temperature differences, reducing soil temperature, and improving humidity. Sur- face temperature between shelter forest land and shifting sand land had significant difference. Surface soil temperature in shelter forest land was lower than that in shifting sand land in the daytime, whereas it was contrary in the nighttime. The daily difference of surface soil temperature in shifting sand land was 18.26℃ higher than that in shelter forest land. From 09：00 to 15：00, the average air temperature in shelter forest land was 1.44℃ higher than that in shifting sand land, whereas in other time, it was 3.22℃ lower averagely. The difference between shelter forest land and shifting sand land in the daylight was greater than that in the night. The daily difference of air temperature in shelter forest land was 4.41℃ higher than that in shifting sand. Air absolute humidity and relative humidity in shelter forest land was higher than those in shifting sand. Microclimate among different shrubs species exhibited the different characteristics but no significant difference. Soil surface temperature, air temperature, and humidity between different forest covers showed the different characteristics. The observed results are of significance to further exploring material and energy exchange near surface layer under irrigation condition in the extremely arid conditions.