Meteorological Aspects of the First Flight Over Everest

Although the first conquest of Everest by mountaineers in 1953 is the stuff of legend, little is heard about the first flight over Everest in 1933. Meteorological information was critical to the success of the mission but not much was known about wind conditions at such high altitudes in this remote region. Moreover, since photographic mapping was the major justification for the mission, it was important to forecast cloud cover to be expected along the route. Reports of the flight by several participants provide extensive meteorological information. The most striking observation is the report of thick haze extending up to 19000 ft. This is a ubiquitous feature of the atmosphere above the Indo-Gangetic Basin in the pre-monsoon season. Current satellite and surface measurements have revived interest in this issue. Most parts of the world were essentially in a pre-industrial state till the mid-twentieth century. Therefore it may be possible to infer the radiative forcing of tropospheric aerosol by going back to that time period instead of all the way back to 1750. This will finesse the problem created by the absence of the control pre-industrial condition for aerosol optical thickness since there may be reliable observations from several stations dating to the mid-twentieth century.