The Variation of Soil Temperature at Various Depths in the Badain Jaran Desert Hinterland
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【Author in Chinese】 安然；
【Author's Information】 兰州大学， 地球系统科学， 2018， 硕士
【Abstract in Chinese】 研究沙漠腹地土壤温度的变化规律,不仅是对特殊的沙漠地区在土壤温度研究领域的进一步深化和拓展,也对水分蒸散发、水循环、植被类型、数量及其分布等具有深远的影响。本文选取了巴丹吉林沙漠腹地苏木巴润吉林地温观测站所观测的数据,数据观测时间从2012年5月到2017年12月共五年零五个月左右,分别对巴丹吉林沙漠腹地不同深度的土壤温度观测数据的季节性日变化特征、月变化特征以及年际尺度变化进行分析。其次利用不同埋深的地温数据进行空间差值分析,并和其它不同地区的变化特征及其规律进行对比。其次利用逐步回归模型对10 cm的浅层土壤温度和对应的气象因子进行回归分析,研究相关因子和浅层土壤温度数据的相关性程度。得出的研究结论如下:(1)巴丹吉林沙漠腹地苏木巴润吉林的月平均温度变化呈正弦曲线规律变化;10 cm处在二月初,最先达到最低值,到八月中旬达到最高温度,而180 cm深度在三月下旬和四月初降到最低温度值,在九月下旬和十月初达到最高值。随着深度增加,表现出明显的滞后性;从10 cm到180 cm深度,滞后时间长达一个半月左右。(2)巴丹吉林沙漠腹地苏木巴润吉林60 cm及其以下深度没有季节性日变化特征也不存在季节性冻土。随着深度的增加,日较差不断变小。存在土壤垂直温度梯度的方向转换,白天由浅层向深层传递,夜间相反。(3)从全年来看,浅层土壤温度主要受气温影响,受降水作用影响较小,相对湿度影响影响微弱可以忽略;各个季节又有所不同,春冬两季几乎不受降水影响,也说明沙漠地区降水主要集中在夏秋季节。
【Abstract】 The study of soil temperature changes in the desert hinterland was not only deepening and expansion of the special desert areas in soil temperature research,but also has an important impact on water evapotranspiration,water cycle,vegetation types,vegetation quantity and distribution.In this paper,we have selected the soil temperature data were from May 2012 to December 2017 for a total of five years and five months and observed by the Sumubari Jilin geothermal observation station in the hinterland of Badain Jaran Desert.Firstly,we analyzed seasonal,monthly,and inter-annual changes in soil temperature at different soil depths under the hinterland of the Badain Jaran Desert,respectively.Secondly,the geothermal data of different soil depths were used for spatial interpolation analysis,and compered with the soil temperature variation characteristics and laws of other regions.Thirdly,a stepwise regression model was used to conduct a regression analysis between the shallow soil temperature of 10 cm and the corresponding meteorological factors and the correlation degree.The research conclusions as follows:(1)At the Sumbabunir Jilin in the hinterland of the Badain Jaran Desert,the monthly mean temperature changes at eight soil depths all show a sinusoidal pattern.The soil temperature at 10 cm was firstly reached lowest value in February.However,it was in late March and early April for 180 cm.At 10 cm,the maximum soil temperature occurred at Mid-August,but the soil temperature can reach the highest value in late September and early October for 180 cm.From the soil depth of 10 cm to 180 cm,with the depth changes of 20 cm,40 cm,60 cm,80 cm,100 cm,140 cm,and 180 cm,the significant hysteresis was exhibited and the lag time was about one and half months.(2)There is no seasonal diurnal variation at the depth below 60 cm in the Badain Jaran Desert Hinterland.There is also no seasonal frozen soil.The variation range of soil temperature decreased with the increase of soil depth.There is a change in the direction of the vertical temperature gradient of the soil,which is transmitted from the shallow to the deep during the day and vice versa.(3)The results shown that the influence factors of soil temperature at 10 cm depth were different in the four seasons.And the temperature was the main influencing factor in four seasons,followed by the influence of precipitation,and the relative humidity was less affected,but the influence of precipitation and relative humidity in spring and winter was less and can be ignored.In the change of soil temperature throughout the year,air temperature was the main influence factor at 10 cm,followed by precipitation,.The relative humidity also had a certain influence,but the impact factor was small.