Temperature lapse rate in complex mountain terrain on the southern slope of the central Himalayas
Temperature lapse rate in complex mountain terrain on the southern slope of the central Himalayas
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DOI：
10.1007/s00704-012-0816-6
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发表时间：
2013-08
影响因子：
3.4
通讯作者：
D. B. Kattel;T. Yao;Kun Yang;L. Tian;G. Yang;D. Joswiak
中科院分区：
文献类型：
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作者：
D. B. Kattel;T. Yao;Kun Yang;L. Tian;G. Yang;D. Joswiak
根据尼泊尔56个站20年的地面气温记录，首次给出了喜马拉雅山南坡气温直减率的月、季和年特征。这些监测站位于海拔72米至3，920米之间。证明了直减率可以用线性回归模型计算。温度直减率的年周期表现出双峰型：两个最大值分别在前和后季风季节的两个极小值，分别在冬季和夏季分开。这一模式与其他山区的研究结果不同，表明在各个季节有不同的控制因素。最高温度直减率出现在前季风期，并与强干对流有关（即，对应于晴朗的天气季节和相当大的感热通量）。后季风季节的直减率次之，其原因与前季风季节相似，但在多雨的夏季之后，热力强迫效应相对较小。最低的直减率出现在冬季，与低海拔地区的强辐射冷却和冷空气流有关。夏季直减率的最小值是由于高海拔地区的潜热加热和低海拔地区的太阳能加热减少。
This study presents the first results of monthly, seasonal and annual characteristics of temperature lapse rate on the southern slope of the central Himalayas, based on 20 years record of surface air temperature at 56 stations in Nepal. These stations are located at a range of elevations between 72 and 3,920 m above sea level. It is proven that the lapse rate can be calculated with a linear regression model. The annual cycle of temperature lapse rate exhibits a bi-modal pattern: two maxima in the pre- and post-monsoon seasons respectively separated by two minima in winter and summer, respectively. This pattern is different from the findings from the other mountain regions and suggests different controlling factors in the individual seasons. The highest temperature lapse rate occurs in the pre-monsoon and is associated with strong dry convection (i.e., corresponding to the clear weather season and considerable sensible heat flux). The post-monsoon has the second highest lapse rate, and its cause is similar to the pre-monsoon season but with a relatively small thermal forcing effect after the rainy summer. The lowest lapse rate occurs in winter and is associated with strong radiative cooling and cold air flows over low-elevation areas. The summer lapse rate minimum is due to latent heating over the higher elevations and reduced solar heating over the lower elevations.