李博,张淼,唐世浩. 2018. 基于组网观测的那曲土壤湿度不同时间尺度的变化特征[J]. 气象学报, (0):-, doi:10.11676/qxxb2018.057
基于组网观测的那曲土壤湿度不同时间尺度的变化特征
Variations of Soil Moisture over Nagqu at Different Time Scales Based on Network Observatory
投稿时间:2018-03-06  修订日期:2018-06-28
DOI:10.11676/qxxb2018.057
中文关键词:  土壤湿度,土壤温度,季节变化,冻融,日变化
英文关键词:Soil moisture, Soil temperature, Seasonal variation, Freeze-thawing, Diurnal variation
基金项目:公益性行业(气象)科研专项项目(项目编号:GYHY201406001),国家重点研发计划项目(项目编号:2016YFA0600101),国家自然科学基金项目(项目编号:41605028)
作者单位E-mail
李博 国家卫星气象中心 boli@cma.gov.cn 
张淼 国家卫星气象中心 zhangmiao@cma.gov.cn 
唐世浩 国家卫星气象中心 tangsh@cma.gov.cn 
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中文摘要:
      利用第三次青藏高原大气科学试验的土壤湿度观测数据,分析了那曲多空间尺度组网观测的28个站2、5、10、20和30 cm 5个不同深度土壤湿度的季节变化和日变化特征,并对比讨论了土壤湿度站点间的差异。分析表明,各层土壤湿度均存在显著的季节变化。在冬春季节, 20cm以上土壤湿度随深度变浅而减小。夏秋季节土壤湿度随深度增加而减小,并分别在7月上中旬和9月出现两个峰值。10月以后进入土壤湿度衰减期。土壤温度和土壤湿度存在协同变化关系。在一定的温度范围内,土壤发生冻结-融冻过程,引起土壤湿度变化。在太阳辐射加热下,土壤表层水分蒸发,进而影响土壤温度。不同观测站间土壤湿度差异较大,夏秋季离散性大于冬春季。不同季节土壤湿度的日变化存在差异。春季10 cm以上土壤湿度日变化明显,在8-10时达到最低,19-20时达到最高值。夏季土壤湿度日变化较为平缓。秋季2 cm深度土壤湿度日变化明显。线性拟合结果表明,1、4、10月土壤湿度和土壤温度间是正相关关系。但是在夏季,土壤湿度与土壤温度为负相关。站点间土壤湿度变化的离散性表明,多测站才能全面体现高原某区域的陆面状态。本文结果为青藏高原地区土壤湿度卫星参数验证和数值模式参数化提供了多角度的观测依据。
英文摘要:
      Based on the soil observatory under the support of the Third Tibetan Plateau project, the seasonal and diurnal variations of soil moisture measured at 2, 5, 10, 20 and 30 cm depths at twenty-eight stations in Nagqu were analyzed. The results showed that in winter and spring, the soil moisture decreased from the 20 cm depth to the shallower depths, while in summer and autumn, the soil moisture decreased with the increase of depth. Two peaks of soil moisture occurred in early-to-mid-July and early September until early October following a decay period. Soil temperature and humidity interacted. Freezing-thawing process occurred within a certain range of soil temperature, causing changes in soil moisture. Soil temperature would be affected by soil surface evaporation. The dispersions among different observational stations of summer and autumn were lagers than that in spring and winter. The diurnal variation in spring above 10 cm was obvious, and the minimum and maximus of soil moisture appeared at 8:00 to 10:00 and 19:00 to 20:00, respectively. The diurnal variation of the soil moisture was gradual in summer and obvious on surface in autumn. The linear results showed that soil moisture and temperature were positively correlated in January, April and October, while negatively correlated in July. Soil moisture discretions among the sites indicated that only few observatories cannot reflect the comprehensive status of land surface in the Tibetan Plateau. The current study provides a basis for satellite parameters validation and numerical model parameterizations of soil moisture in Tibetan Plateau.
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