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| Titel |
Upper-troposphere and lower-stratosphere water vapor retrievals from the 1400 and 1900 nm water vapor bands |
| VerfasserIn |
B. C. Kindel, P. Pilewskie, K. S. Schmidt, T. Thornberry, A. Rollins, T. Bui |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 3 ; Nr. 8, no. 3 (2015-03-09), S.1147-1156 |
| Datensatznummer |
250116206
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| Publikation (Nr.) |
 copernicus.org/amt-8-1147-2015.pdf |
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| Zusammenfassung |
| Measuring water vapor in the upper troposphere and lower stratosphere is
difficult due to the low mixing ratios found there, typically only a few
parts per million. Here we examine near-infrared spectra acquired with the
Solar Spectral Flux Radiometer (SSFR) during the first science phase of the
NASA Airborne Tropical TRopopause EXperiment (ATTREX). From the 1400 and
1900 nm absorption bands we infer water vapor amounts in the tropical
tropopause layer and adjacent regions between altitudes of 14 and 18 km. We
compare these measurements to solar transmittance spectra produced with the
MODerate resolution atmospheric TRANsmission (MODTRAN) radiative transfer
model, using in situ water vapor, temperature, and pressure profiles acquired
concurrently with the SSFR spectra. Measured and modeled transmittance values
agree within 0.002, with some larger differences in the 1900 nm band (up to
0.004). Integrated water vapor amounts along the absorption path lengths of 3
to 6 km varied from 1.26 × 10−4 to
4.59 × 10−4 g cm−2. A 0.002 difference in absorptance at
1367 nm results in a 3.35 × 10−5 g cm−2 change of
integrated water vapor amounts; 0.004 absorptance change at 1870 nm results
in 5.50 × 10−5 g cm−2 of water vapor. These are 27%
(1367 nm) and 44% (1870 nm) differences at the lowest measured value
of water vapor (1.26 × 10−4 g cm−2) and 7%
(1367 nm) and 12% (1870 nm) differences at the highest measured value
of water vapor (4.59 × 10−4 g cm−2). A potential method
for extending this type of measurement from aircraft flight altitude to the
top of the atmosphere is discussed. |
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