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Record 1 of 12571
Methane as a Diagnostic Tracer of Changes in the Brewer-Dobson Circulation of the Stratosphere
External Online Source: doi:10.5194/acp-15-3739-2015
Author and Affiliation:
Remsberg, E. E.(NASA Langley Research Center, Hampton, VA, United States)
Abstract: This study makes use of time series of methane (CH4/ data from the Halogen Occultation Experiment (HALOE) to detect whether there were any statistically significant changes of the Brewer-Dobson circulation (BDC) within the stratosphere during 1992-2005. The HALOE CH4 profiles are in terms of mixing ratio versus pressure altitude and are binned into latitude zones within the Southern Hemisphere and the Northern Hemisphere. Their separate time series are then analyzed using multiple linear regression (MLR) techniques. The CH4 trend terms for the Northern Hemisphere are significant and positive at 10 N from 50 to 7 hPa and larger than the tropospheric CH4 trends of about 3%decade(exp -1) from 20 to 7 hPa. At 60 N the trends are clearly negative from 20 to 7 hPa. Their combined trends indicate an acceleration of the BDC in the middle stratosphere of the Northern Hemisphere during those years, most likely due to changes from the effects of wave activity. No similar significant BDC acceleration is found for the Southern Hemisphere. Trends from HALOE H2O are analyzed for consistency. Their mutual trends with CH4 are anti-correlated qualitatively in the middle and upper stratosphere, where CH4 is chemically oxidized to H2O. Conversely, their mutual trends in the lower stratosphere are dominated by their trends upon entry to the tropical stratosphere. Time series residuals for CH4 in the lower mesosphere also exhibit structures that are anti-correlated in some instances with those of the tracer-like species HCl. Their occasional aperiodic structures indicate the effects of transport following episodic, wintertime wave activity. It is concluded that observed multi-year, zonally averaged distributions of CH4 can be used to diagnose major instances of wave-induced transport in the middle atmosphere and to detect changes in the stratospheric BDC.
Publication Date: Apr 07, 2015
Document ID:
20150014330
(Acquired Jul 29, 2015)
Subject Category: METEOROLOGY AND CLIMATOLOGY; GEOSCIENCES (GENERAL)
Report/Patent Number: NF1676L-19581
Document Type: Journal Article
Publication Information: Atmospheric Chemistry and Physics; Volume 15; No. 7; 3739-3754
Contract/Grant/Task Num: WBS 479717.02.01.01.38
Financial Sponsor: NASA Langley Research Center; Hampton, VA, United States
Description: 16p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: STRATOSPHERE; METHANE; TRENDS; TIME SERIES ANALYSIS; HALOGEN OCCULTATION EXPERIMENT; WATER; TROPICAL REGIONS; NORTHERN HEMISPHERE; ATMOSPHERIC COMPOSITION
Availability Source: Other Sources
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