1976 Volume 38 Issue Special Pages 66-73
The climate of the highland in Khumbu Himal is described in analysing the observational data taken at Lhajung (4420 m) in 1973 and 1974. There are marked rainy and dry seasons. 70-80% of annual precipitation (54 cm in 1973 and 35 cm in 1974) is concentrated in 4 months in the summer monsoon. The monsoon activity was somewhat weaker in 1974 than in 1973. Solar insolation is almost twice that of observed at sea level at the same latitude except in the monsoon season. The mean annual temperature at Lhajung is nearly 0°C. The weaker monsoon in 1974 than in 1973 appeared also in the temperature and humidity patterns. Diurnal and daily variations of temperature or humidity are very small in the monsoon season, while they are large, having a periodic change, in dry season. A very stationary valley wind governs the diurnal changes of meteorological parameters at Lhajung through out the year. However, the valley wind is confined to a thin layer of about less than 1500 m thick in the main valley of the Himalayas.