In:
Journal of Geophysical Research: Atmospheres, American Geophysical Union (AGU), Vol. 105, No. D17 ( 2000-09-16), p. 22211-22223
Kurzfassung:
The interpretation of recent odd hydrogen measurements in the stratosphere from balloons and in the mesosphere from space indicates a serious lack of understanding in atmospheric HO x chemistry. In order to resolve these persisting problems, coincident measurements of HO x molecules and/or measurements that cover both altitude regions are desirable. In this work, the airborne 2.5THz heterodyne spectrometer Terahertz OH Measurement Airborne Sounder (THOMAS) is introduced. Since the first THOMAS measurements in 1994/1995, the spectrometer was significantly improved by modification or replacement of individual components. The THOMAS instrumental setup and properties are presented together with a retrieval algorithm for atmospheric parameters based on a Phillips‐Tikhonov regularization scheme. Furthermore, the results of a complete error assessment are given. In August 1997, during the second CRISTA/MAHRSI campaign (Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere / Middle Atmosphere High Resolution Spectrograph Investigation), OH observations were performed by THOMAS covering altitudes between about 30 and 90 km over a full diurnal cycle. Hydroxyl column densities derived from THOMAS measurements are presented and compared to photochemical model results. The model calculations using the standard HO x chemistry systematically show higher values by about 15% for the 40–90 km and 50–90 km OH columns. Moreover, a recently proposed change of an HO x chemistry reaction rate is included into the comparison which, for the same altitude intervals, yields OH column densities that are about 10% lower than the THOMAS measurements. A detailed comparison of the THOMAS and MAHRSI measurements is presented in a seperate publication [ Englert et al. , 2000].
Materialart:
Online-Ressource
ISSN:
0148-0227
DOI:
10.1029/2000JD900305
Sprache:
Englisch
Verlag:
American Geophysical Union (AGU)
Publikationsdatum:
2000
ZDB Id:
2033040-6
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3094104-0
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2130824-X
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2016813-5
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SSG:
16,13
