Heat and Water Balance Estimates over the Tibetan Plateau in 1997-1998
Heat and Water Balance Estimates over the Tibetan Plateau in 1997-1998
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DOI：
10.2151/jmsj.83.577
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发表时间：
2005-08
影响因子：
3.1
通讯作者：
Jianqing Xu;S. Haginoya;K. Masuda;R. Suzuki
中科院分区：
文献类型：
--
作者：
Jianqing Xu;S. Haginoya;K. Masuda;R. Suzuki
利用一个多层土壤模式，估算了1997-1998年青藏高原热量平衡和水分平衡的季节变化。以常规气象资料为输入数据，对1997年和1998年的14个站和17个站进行了计算。与1997年相比，1998年西藏西北部降水量偏少，东南部降水量偏多。地表潜热通量的变化与土壤含水量的变化有关，而土壤含水量的变化又受降水量的变化所控制。因此，1998年藏东南地区潜热通量大于1997年，而藏西北地区则相反。湿润指数计算结果表明，1997 ~ 1998年，西藏西北部气候偏干，东南部气候偏湿。1998年西藏东北部由于春季降水偏少，土壤含水量偏小，感热通量偏大。1997年和1998年西藏东南部春季降水量基本相同，但1998年降水量增加，并集中在季风后期，导致土壤含水量增加，蒸发量增加。这些增加并不像降水量的变化那样剧烈，大部分降水量的增加导致径流量的急剧增加，并流入河流。季风季节过后，1997年和1998年降水量的差异变得很小，而土壤含水量在这两年的末尾几乎相同。土壤含水量随降水量的变化而变化。
Seasonal variations of heat and water balances have been estimated by using a multi-layer soil model for the Tibetan Plateau in 1997-1998. Input data was from routine meteorological data, and calculation was carried out for 14 stations in 1997 and 17 stations in 1998.Compared with 1997, annual precipitation was smaller in northwestern and larger in southeastern Tibet in 1998. The variations of latent heat flux from the ground surface, connected with the changes of soil water content that are controlled by change of precipitation. Thus, the latent heat flux of 1998 was larger than that of 1997 in southeast Tibet, but in northwest Tibet, the situation was reversed. The calculation result for Wetness Index (WI), showed that from 1997 to 1998, the climate in northwest Tibet become more dry, and southeast Tibet wetter. The climatic difference became more severe between those two regions.In northeast Tibet, soil water contents were smaller and sensible heat flux was larger in 1998, than in 1997, because the precipitation was relatively small in the springtime of 1998. In southeast Tibet, the amount of the precipitation were almost the same in the springtime of 1997 and 1998, but the rainfall amount became larger, and concentrated in the latter monsoon season in 1998, this led to the increase in soil water contents, and the amount of evaporation. Those increases were not as sharp as the changes of precipitation, and most of the precipitation contributed to sharply increase the run off, and flowed into the rivers. After monsoon seasons, the differences between the amount of precipitation in 1997 and 1998 became very small, and the soil water contents were almost the same in the end of those two years. Soil water contents changed with the precipitation.