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A climatological view of HNO 3 partitioning in cirrus clouds
Author(s) -
Krämer M.,
Schiller C.,
Voigt C.,
Schlager H.,
Popp P. J.
Publication year - 2008
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.253
Subject(s) - cirrus , atmospheric sciences , environmental science , water content , geology , geotechnical engineering
Abstract A new in situ climatology of cirrus ice water content (IWC) is used, together with observed molar ratios of HNO 3 /H 2 O in cirrus ice particles, to estimate the range of HNO 3 content in cirrus ice in the temperature interval 185–240 K. We find that nearly over the complete temperature range HNO 3 percentages in ice between 0.01 and 100% are possible in cirrus clouds and that IWC is a major parameter determining the content of HNO 3 in ice at given temperatures. Considering average conditions, the HNO 3 content increases with decreasing temperature from 1% to about 10% in the range 240–200 K. For colder ice clouds, the average HNO 3 content again decreases down to 6%. At higher temperatures, less efficient HNO 3 uptake limits the HNO 3 content in cirrus ice, while at low temperatures small IWCs permit only little HNO 3 in ice, thus causing the convex‐shaped average HNO 3 content curve. The highest HNO 3 content is expected in tropical ice clouds with very large IWCs, especially at temperatures between 190 and 210 K. Thus, tropical cirrus clouds show the highest potential to vertically redistribute HNO 3 . Copyright © 2008 Royal Meteorological Society