Zhou, D; Eigenmann, R; Babel, W; Foken, T; Ma, Y: Study of near-ground free convection conditions at Nam Co station on the Tibetan Plateau, Theoretical and Applied Climatology, 105, 217-228 (2011), doi:10.1007/s00704-010-0393-5
Abstract:

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 nearground 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.

There are additional file downloads belonging to this publication

Password
Upcoming ...


BayCEER Colloquium:
Th. 2020-01-16
Ecosystem functional types and biome concepts
Ecological-Botanical Garden:
Su. 2020-01-05
Auf ins Neue! Winterspaziergang im ÖBG
Su. 2020-01-05
Konzert: Musikalischer Jahresbeginn mit den Rockin`Dinos
Su. 2020-01-19
Kastilien, Navarra und das Baskenland: Orchideen im Land Don Quijotes
Geographisches Kolloquium:
Tu. 2019-12-17
The meat of the Anthropocene: Food, capital and the globalisation of industrialised animal killing
BayCEER Blog
24.05.2019
Stoichiometric controls of C and N cycling
07.05.2019
Flying halfway across the globe to dig in the dirt – a research stay in Bloomington, USA
07.05.2019
EGU – interesting research and free coffee
16.04.2019
Picky carnivorous plants?
RSS Blog as RSS Feed
Weather research site
Luftdruck (356m): 950.1 hPa
Lufttemperatur: 1.2 °C
Niederschlag: 0.1 mm/24h
Sonnenschein: <1 h/d
Wind (Höhe 17m): 9.8 km/h
Wind (Max.): 22.3 km/h
Windrichtung: SO

...more
This site makes use of cookies More information