Deuterium Content in the Himalayan Precipitation at Khumbu District, Observed in 1974/1975

Abstract

A total of 129 water samples of daily precipitations were collected at Lhajung (4420 m) from April 1974 to March 1975. Samples were collected for 124 days within 127 wet days. The deuterium content of each sample was measured by mass spectrometry. Specially high deuterium content was found in the pre-monsoon precipitations, while lowest content in the middle of the monsoon. Annual changes of deuterium content, air temperature, and precipitation amount are clearly divided into four stages. Analyzing the long term trend of daily deuterium content, deuterium rich precipitations in pre-monsoon are attributed to the direct transport of water vapour from the Indian Ocean to the Himalayas without much rainfall on the way. The history of isotopic depletion caused by rainfall at the Indian coast is analyzed, showing the travelling time from the coast near Calcutta to the Mt. Sagarmatha region to be about four days in the wet season.

Monsoon and dust signals recorded in Dasuopu glacier, Tibetan Plateau

“…From late winter to mid-spring, both 18 O and mean monthly temperature at Nyalam station increase, suggesting that 18 O values reflect air temperature during this period, although the rise in 18 O occurs prior to the rise in temperature. Comparing seasonal variations of 18 O in the Dasuopu core with those of D in precipitation at Lhajung station, located on the southern slope of the Himalaya (Wushiki, 1977), the same seasonal variation can be seen, the only difference being that the lowest D value at Lhajung appears a little earlier than the lowest 18 O value at Dasuopu.…”

Monsoon Variability in the Himalayas under the Condition of Global Waming

“…In the monsoon region the peaks of d 18 O and ions in the rainfall appear in the dry stage of spring (Wushiki 1977;Zhang 2001;Muradkami 1987;Luo and Yanai 1983). Thus the high annual accumulation allows preservation of distinct seasonal cycles in d 18 O, and ions which make it possible to reconstruct an annual record for the upper part of the cores.…”

“…18 O and ions appear in the dry stage of spring (Wushiki 1977;Zhang 2001), so accumulation recovered in the core represents precipitation from spring to spring. Most of the annual precipitation on Dasuopu falls during the summer monsoon season (June through August), suggesting accumulation from spring to spring is almost equal to precipitation in the monsoon season.…”

Thirty‐year history of glacier melting in the Nepal Himalayas

“… Yao et al [1996] and Thompson et al [2000] concluded that the stable isotopes could be used as a temperature index on a multidecadal scale, whereas Kang et al [2000] and Qin et al [2000] suggested that the stable isotopes indicated monsoon fluctuation in the Himalayas. It is well known that seasonal changes in stable isotopes in precipitation and temperature show an inverse relationship in the southern part of the Tibetan Plateau, including the Himalayas [ Wushiki , 1977; Tian et al , 2001; Zhang et al , 2001]. Strong monsoon activity in the southern Tibetan Plateau results in high precipitation rates and more depleted heavy isotopes, which is described as a precipitation “amount effect.” This effect causes a poor δ 18 O‐ T relationship on both seasonal and annual scales [ Tian et al , 2003].…”