Observations of foehn onset in the Southern Alps, New Zealand |
| |
Authors: | H A McGowan A P Sturman M Kossmann P Zawar-Reza |
| |
Institution: | (1) Department of Geographical Sciences and Planning, The University of Queensland, St. Lucia, Brisbane, Australia, AU;(2) Department of Geography, University of Canterbury, Christchurch, New Zealand, NZ |
| |
Abstract: | Summary Local scale windfield and air mass characteristics during the onset of two foehn wind events in an alpine hydro-catchment
are presented. Grounding of the topographically modified foehn was found to be dependent on daytime surface heating and topographic
channelling of flow. The foehn front was observed to advance down-valley until the valley widened significantly. The foehn
wind appeared to decouple from the surface downstream of the accelerated flow associated with the valley constriction, and
to be lifted above local thermally generated circulations including a lake breeze. Towards evening, the foehn front retreated
up valley in response to reduced surface heating and the intrusion into the study area of a deep and cool air mass associated
with a regional scale mountain-plain circulation. Differences in the local windfield observed during both case study events
reflect the importance of different thermal and dynamic forcings on airflow in complex terrain. These are the result of variation
in surface energy exchanges, channelling and blocking of airflow. Observations presented here have both theoretical and applied
implications with regard to forecasting foehn onset, wind hazard management, recreational activities and air quality management
in alpine settings.
Received January 23, 2001 Revised October 17, 2001 |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|