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Atmospheric Layers Measured from the NASA DC-8 During PEM-West B and Comparison with PEM-West AThe Pacific Exploratory Mission-West B (PEM-West B) explored atmospheric layer structure using measurements of O3, H2O, CO, and CH4 from the NASA DC-8 fast-response instruments. The mission took place in February-March 1994 over the western Pacific, mainly in the northern hemisphere. Results were compared with similar measurements made during the Pacific Exploratory Mission-West A (PEM-West A) in September-October 1991. PEM-West B sampled 94 vertical profiles, with an average atmospheric depth per profile of 6.4 km, and this sampling yielded 254 discrete layers. PEM-West A sampled 105 profiles, also with a 6.4 km average depth, yielding 538 layers. Both missions revealed that layers containing high ozone and low water vapor were the most abundant, and low ozone and high water vapor layers were the next most abundant. Lidar images and potential vorticity cross sections showed the former associated with subsidence from the stratosphere in middle latitudes, spreading into the tropics. The latter was associated with convection from the boundary layer. The partition among different types of layers only changed slightly in the two missions, although PEM-West B had half as many layers. Compared to PEM-West A, PEM-West B showed only one-third the number of layers associated with polluted continental air. However, PEM-West B revealed significantly more layers showing characteristics of descended clean marine air. In some cases these layers originated from the southern hemisphere. For ozone- and water-vapor-rich layers, the ozone deviation amplitude was higher in low latitudes and lower in high latitudes in PEM-West B. The mean thickness of layers increased from about 450 m in PEM-West A to 680 in in PEM-West B. Layers also existed in the Intertropical Convergence Zone. CO2 measurements had sufficient vertical resolution to show layer structure as well.
Document ID
19990019275
Acquisition Source
Langley Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Wu, Zhongxiang
(Massachusetts Inst. of Tech. Cambridge, MA United States)
Newell, Reginald E.
(Massachusetts Inst. of Tech. Cambridge, MA United States)
Zhu, Yong
(Massachusetts Inst. of Tech. Cambridge, MA United States)
Anderson, Bruce E.
(NASA Langley Research Center Hampton, VA United States)
Browell, Edward V.
(NASA Langley Research Center Hampton, VA United States)
Gregory, Gerald L.
(NASA Langley Research Center Hampton, VA United States)
Sachse, Glen W.
(NASA Langley Research Center Hampton, VA United States)
Collins, James E., Jr.
(Science and Technology Corp. Hampton, VA United States)
Date Acquired
September 6, 2013
Publication Date
December 20, 1997
Publication Information
Publication: Journal of Geophysical Research
Publisher: American Geophysical Union
Volume: 102
Issue: D23
ISSN: 0148-0227
Subject Category
Geophysics
Report/Patent Number
Paper 97JD01097
Funding Number(s)
CONTRACT_GRANT: NAG1-1252
Distribution Limits
Public
Copyright
Other
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