气候变化领域集成服务门户(CCPortal): The study of near-ground free convection conditions at Nam Co station on the Tibetan Plateau

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DOI	10.1007/s00704-010-0393-5
	The study of near-ground free convection conditions at Nam Co station on the Tibetan Plateau
	Zhou, Degang; Eigenmann, Rafael; Babel, Wolfgang; Foken, Thomas; Ma, Yaoming
通讯作者	Zhou, DG (通讯作者)
发表日期	2011
ISSN	0177-798X
EISSN	1434-4483
起始页码	217
结束页码	228
卷号	105 期号:1-2
英文摘要	This study investigates the near-ground free convection conditions (FCCs) based on eddy covariance (EC) measurements at Nam Co station near the Nam Co Lake on the Tibetan Plateau (TP). The spatial and temporal structure of EC measurements at this station is evaluated by using the comprehensive software package TK2 together with a footprint model. The obtained high-quality turbulent flux data are used to study the occurrence of FCCs, which can be detected with the EC system by calculating the stability parameter. Two types of generation of FCCs can be identified. (1) During the wind direction change of a diurnal thermally forced land-lake circulation system in the morning, strongly reduced wind speeds and simultaneously high buoyancy fluxes lead to a period of dominance of buoyancy over shear, and hence, to the occurrence of FCCs. (2) On days with the appearance of clouds, the land-lake circulation is weakened or reversed, dependent on the temperature gradients between the land and the Nam Co Lake. During the period of adaptation of the land-lake breeze to the alternating situation of heating differences, wind speeds decrease and buoyancy again dominates over shear near the ground. These are the situations where FCCs are also detected during the entire day at Nam Co station. The investigation of FCCs regarding the whole measurement period shows that FCCs can be mainly attributed to case (1) during the non-monsoon period, while FCCs are generated by both mechanisms (1 and 2) during the monsoon season. An impact of the FCCs on the near-ground profiles of air temperature and humidity is demonstrated. The FCCs are assumed to play an important role for the land surface-atmosphere exchange processes and the atmospheric boundary layer (ABL) conditions on the TP by providing an effective transport mechanism of near-ground air mass characteristics into upper parts of the ABL.
关键词	EDDY COVARIANCE MEASUREMENTS SURFACE-ENERGY BUDGET CARBOEUROPE FLUX DATA QUALITY ASSESSMENT HEAT-FLUX FOOTPRINT VARIABILITY FOREST CARBON PRECIPITATION
语种	英语
WOS研究方向	Meteorology & Atmospheric Sciences
WOS类目	Meteorology & Atmospheric Sciences
WOS记录号	WOS:000293021500019
来源期刊	THEORETICAL AND APPLIED CLIMATOLOGY
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/257894
推荐引用方式 GB/T 7714	Zhou, Degang,Eigenmann, Rafael,Babel, Wolfgang,et al. The study of near-ground free convection conditions at Nam Co station on the Tibetan Plateau[J]. 中国科学院青藏高原研究所,2011,105(1-2).
APA	Zhou, Degang,Eigenmann, Rafael,Babel, Wolfgang,Foken, Thomas,&Ma, Yaoming.(2011).The study of near-ground free convection conditions at Nam Co station on the Tibetan Plateau.THEORETICAL AND APPLIED CLIMATOLOGY,105(1-2).
MLA	Zhou, Degang,et al."The study of near-ground free convection conditions at Nam Co station on the Tibetan Plateau".THEORETICAL AND APPLIED CLIMATOLOGY 105.1-2(2011).