Resolving the impact of stratosphere-to-troposphere transport on the sulfur cycle and surface ozone over the Tibetan Plateau using a cosmogenic 35 S tracer
| Autor: | Guoshuai Zhang, Shichang Kang, Qianggong Zhang, Mark H. Thiemens, Jason Hill-Falkenthal, Chuen Yu Chan, Mang Lin, Antra Priyadarshi, Zhisheng Zhang, Lin Su |
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| Rok vydání: | 2016 |
| Předmět: |
Atmospheric Science
geography Plateau geography.geographical_feature_category 010504 meteorology & atmospheric sciences Sulfur cycle Mineral dust 010502 geochemistry & geophysics Snow 01 natural sciences Troposphere Geophysics Space and Planetary Science Climatology TRACER Earth and Planetary Sciences (miscellaneous) Water cycle Stratosphere Geology 0105 earth and related environmental sciences |
| Zdroj: | Journal of Geophysical Research: Atmospheres. 121:439-456 |
| ISSN: | 2169-897X |
| DOI: | 10.1002/2015jd023801 |
| Popis: | The Himalayas were recently identified as a global hot spot for deep stratosphere-to-troposphere transport (STT) in spring. Although the STT in this region may play a vital role in tropospheric chemistry, the hydrological cycle and aquatic ecosystems in Asia, there is no direct measurement of a chemical stratospheric tracer to verify and evaluate its possible impacts. Here we use cosmogenic S-35 as a tracer for air masses originating in the stratosphere and transported downward. We measure concentrations of S-35 in fresh surface snow and river runoff samples collected from Mount Everest in April 2013 to be more than 10 times higher than previously reported by any surface measurement, in support of the Himalayas as a gateway of springtime STT. In light of this result, measurements of (SO2)-S-35 and (SO42-)-S-35 at Nam Co in spring 2011 are reanalyzed to investigate the magnitudes of stratospheric air masses from the Himalayas to the tropospheric sulfur cycle and surface O-3 level over the Tibetan Plateau. A simple one-box model reveals that the oxidative lifetime of SO2 is reduced in aged STT plumes. Triple oxygen isotopic measurements of sulfate samples suggest that enhanced O-3 levels may shift the oxidation pathway of SO2 in the troposphere, which may be constrained by further intensive sampling and measurements. Comparison with surface O-3 measurements and traditional meteorological tracing methods shows that S-35 is a potentially unique and sensitive tracer to quantify the contribution of stratospheric air to surface O-3 levels in fresh or aged STT plumes. |
| Databáze: | OpenAIRE |
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