A Tibetan Taylor Cap and a halo of stratospheric ozone over the Himalaya

Abstract

With an average elevation in excess of 4000 m asl, the Tibetan Plateau is one of the Earth's most prominent topographic features. The plateau plays an important role in the global climate system by acting as a heat source during the summer and a heat sink during the winter. There also exists evidence that its influence extends into the upper-troposphere and lower-stratosphere through the existence of a region of low total column ozone over the plateau. We report on observations of ozone concentration from the Bhutanese Himalaya that support the hypothesis that a Taylor Cap exists over the plateau. We argue that the presence of this cap results in the formation of a halo of ozone-rich air in the upper-troposphere around the perimeter of Tibet. The Himalaya are within this halo and the higher peaks may be exposed to ozone concentrations similar to those found in industrialized cities. Copyright 2005 by the American Geophysical Union.