Local wind system in the Rongbuk Valley on the northern slope of Mt. Everest

摘要

To better understand the local wind systems in the Himalayas, wind and related atmospheric parameters were observed in the Rongbuk Valley on the northern slope of Mt. Everest, during the HEST2006 campaign, from May 29 to June 29, 2006. Data analysis and a simple numerical simulation show that the dominating down-valley flow in this valley is mainly formed by the thermally driven winds, +ACI-valley wind'', +ACI-mountain wind'' and +ACI-glacier wind''. The vertical air motion is composed of a descending flow from the morning to midnight and an ascending flow for the rest of the day, with important modification from the vertical component of the above down-valley flow and a compensation flow of the +ACI-slope wind''. The analysis also shows that the local wind system is well confined in the Rongbuk Valley due to topographic shielding effects.