DEVELOPMENT OF MOUNTAIN AND VALLEY WIND CIRCULATIONS IN THE KALI GANDAKI VALLEY IN THE HIMALAYAS DURING THE WINTER

Abstract

The intemational soaring expedition to the Nepalese Himalayas during January and February 1985 wis conducted to study the feasibility of soaring in this region. An instrumented motorglider was used to measure pressure, temperature and dewpoint. The flights took place close to or within the Kali Gandaki Valley northwest of Pokhara. This valley with a length of more than 120 km and an average sloping angle of approximately 1,7 degrees completely cuts the Himalayan range and thus connects the vast Tibetan plateau with the Indian plains almost 4000 m below. A special scientific objective was followed with the observation of the thermally driven mountain and valley wind circulation in this unique exposure. Unexpectedly, however, no properly developed circulations of this kind were encountered with the exception of one flight on 7 February 1985. A study of synoptic weather phenomena on a larger scale tries to eiplains this phenomenon. The investigation took place some time ago. As there are plans for a second Himalalayan soaring expedition, and in view of the continuing efforts of studying mountain/valley wind circulations in different scales, this paper may, nevertheless, still contribute useful information.