青藏高原东坡理塘地区近地层湍流通量与微气象特征研究

Analyses of turbulent fluxes and micrometeorological characteristics in the surfacelayer at Litang of the eastern Tibetan Plateau.

中文关键词:  青藏高原， 理塘， 近地层， 微气象特征， 湍流通量

英文关键词:Tibetan Plateau, Litang, Surface layer, Micrometeorological characteristics, Turbulent flux

中文摘要:

      简要介绍青藏高原东坡理塘大气综合观测站长期观测试验，并利用2006年1、7月资料分别代表该站冬季和夏季，初步分析和比较该地区冬、夏季近地层微气象特征和湍流通量输送情况，得到了以下结论：（1） 风、温、湿均表现出明显的日变化特征。冬季风速值平均大于夏季，风速极大值均出现在下午；冬季温度梯度早晚大，白天小，而夏季均较小；湿度梯度早晚大于白天。（2） 中性条件下风速廓线对数关系表现为一条直线而非中性条件下略偏离对数关系，晚上均有逆温现象出现，在一定高度能观测到较弱的逆湿现象。（3）冬季以感热为主，潜热值较小，夏季以潜热为主，但感热也较大，且冬季通量值要远小于夏季；冬季动量通量平均大于夏季，二氧化碳通量远小于夏季；浅层（地面以下2和5 cm）土壤热通量也具有明显的日变化特征，白天从土壤吸收热量，夜间则放出热量。（4） 地面热源强度具有显著的日变化特征：白天为强热源，夜间冷热源特征不明显。冬季和夏季全天平均表现为热源，但夏季强度远大于冬季，平均达到134 W/m2左右，冬季仅约35.3 W/m2。

英文摘要:

      A comprehensive field experiment of atmospheric boundary layer is briefly introduced. The experiment was held in Litang area of eastern Tibetan Plateau in November 2005. By using the observational data in January and July of 2006 which represent winter and summer season respectively, some micrometeorological characteristics and turbulent fluxes transport are preliminarily analyzed and compared. The main results are as follows: (1) Marked diurnal variations of wind speed, air temperature and relative humidity are found. Wind speed is higher in winter than in summer, and its maximum value occur in the afternoon in both winter. In winter, air temperature gradient is higher in the night time and early morning than in the daytime, while it is smaller in summer. Humidity gradient and summer is higher in the night time than in the daytime. (2) Wind speed profiles generally accord with the logarithm law. Temperature inversion phenomenon always occurs in the night time, and weak humidity inversion sometimes happens above a certain height. (3) In winter, sensible heat flux is large and latent heat flux is very small, while in summer latent heat flux is overwhelming, but the value of sensible heat flux is also large. Furthermore, turbulent fluxes and carbon dioxide flux in winter are much less than in summer, but momentum flux is on the contrary. Soil heat flux also presents an obvious diurnal variation at the depth of 2 and 5 cm. (4) Surface heat source shows a diurnal variation remarkably: strong heat source appears in the daytime and it is not very evident in the night time. On daily average, heat source dominates in both winter and summer, but it is stronger in summer (about 134 W/m 2) than in winter (about 35.3 W/m 2).