| Trends and Scales of Observed Soil Moisture Variations in China |
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| 作者姓名： | 聂肃平 罗勇 朱江 |
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| 作者单位： | Institute of Atmospheric Physics Chinese Academy of Sciences，National Climate Center China Meteorological Administration，Institute of Atmospheric Physics Chinese Academy of Sciences，Beijing 100029 Graduate University of Chinese Academy of Sciences Beijing 100049 Beijing 100081 Beijing 100029 |
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| 基金项目： | National Basic Research Program of China，国家自然科学基金，China Meteorological Administration Grant |
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| 摘 要： | A new soil moisture dataset from direct gravimetric measurements within the top 50-cm soil layers at 178 soil moisture stations in China covering the period 1981-1998 are used to study the long-term and seasonal trends of soil moisture variations, as well as estimate the temporal and spatial scales of soil moisture for different soil layers. Additional datasets of precipitation and temperature difference between land surface and air (TDSA) are analyzed to gain further insight into the changes of soil moisture. There are increasing trends for the top 10 cm, but decreasing trends for the top 50 cm of soil layers in most regions. Trends in precipitation appear to dominantly influence trends in soil moisture in both cases. Seasonal variation of soil moisture is mainly controlled by precipitation and evaporation, and in some regions can be affected by snow cover in winter. Timescales of soil moisture variation are roughly 1-3 months and increase with soil depth. Further influences of TDSA and precipitation on soil moisture in surface layers, rather than in deeper layers, cause this phenomenon. Seasonal variations of temporal scales for soil moisture are region-dependent and consistent in both layer depths. Spatial scales of soil moisture range from 200-600 km, with topography also having an affect on these. Spatial scales of soil moisture in plains are larger than in mountainous areas. In the former, the spatial scale of soil moisture follows the spatial patterns of precipitation and evaporation, whereas in the latter, the spatial scale is controlled by topography.
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| 关 键 词： | 中国 土壤湿度 变化趋势 时空规模 |
| 文章编号： | 10.1007/s00376-008-0043-3 |
| 收稿时间： | 2006-10-28 |
| 修稿时间： | 2007-04-23 |
Trends and scales of observed soil moisture variations in China |
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| Nie?Suping,Luo?Yong,Zhu?Jiang.Trends and Scales of Observed Soil Moisture Variations in China[J].Advances in Atmospheric Sciences,2008,25(1):43-58. |
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| Authors: | Nie Suping Luo Yong Zhu Jiang |
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| Institution: | Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029;National Climate Center, China Meteorological Administration, Beijing 100081;Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 |
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| Abstract: | A new soil moisture dataset from direct gravimetric measurements within the top 50-cm soil layers at 178 soil moisture stations in China covering the period 1981 1998 are used to study the long-term and seasonal trends of soil moisture variations, as well as estimate the temporal and spatial scales of soil moisture for different soil layers. Additional datasets of precipitation and temperature difference between land surface and air (TDSA) are analyzed to gain further insight into the changes of soil moisture. There are increasing trends for the top 10 cm, but decreasing trends for the top 50 cm of soil layers in most regions. Trends in precipitation appear to dominantly influence trends in soil moisture in both cases. Seasonal variation of soil moisture is mainly controlled by precipitation and evaporation, and in some regions can be affected by snow cover in winter. Timescales of soil moisture variation are roughly 1-3 months and increase with soil depth.Further influences of TDSA and precipitation on soil moisture in surface layers, rather than in deeper layers,cause this phenomenon. Seasonal variations of temporal scales for soil moisture are region-dependent and consistent in both layer depths. Spatial scales of soil moisture range from 200-600 km, with topography also having an affect on these. Spatial scales of soil moisture in plains are larger than in mountainous areas. In the former, the spatial scale of soil moisture follows the spatial patterns of precipitation and evaporation,whereas in the latter, the spatial scale is controlled by topography. |
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| Keywords: | soil moisture trend temporal scale spatial scale |
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