bollasina_etal_2002.html
Bulletin of Glaciological
Research 19 (2002) 1-11
©Japanese Society of Snow and Ice
Meteorological observations at high altitude in the Khumbu Valley, Nepal Himalayas, 1994-1999
Massimo
BOLLASINA1, Laura
BERTOLANI1 and
Gianni TARTARI2
1 Climate
Research Division, Epson Meteo Center, Milan, Italy
2 Water Research Institute, National Research Council, Milan,
Italy
Abstract
The main meteorological features of the area surrounding Mt. Everest (Khumbu Valley, Nepal Himalayas) were investigated by means of the dataset collected at the Pyramid Meteorological Station (5050 m a.s.l.) from 1994 to 1999. Particular attention was given to the characteristics of the summer monsoon season, whose mean onset and decay dates (12 June and 5 October, respectively) were identified. The predominant type of summer monsoon precipitation was drizzle, with sporadic more intense events from the late afternoon through the night. Active/break periods of the summer monsoon were identified and their large-scale characteristics were highlighted by means of daily global gridded data. Two different daily profiles were found within the Pyramid precipitation and wind direction records, depending on the level of activity of the summer monsoon circulation. Spectral analysis revealed the existence of a 5-day and a 10-day periodicity in the daily precipitation records associated to similar oscillations of the Tibetan High.
