 |
| Titel |
Validation of MIPAS HNO3 operational data |
| VerfasserIn |
D. Y. Wang, M. Höpfner, C. E. Blom, W. E. Ward, H. Fischer, T. Blumenstock, F. Hase, C. Keim, G. Y. Liu, S. Mikuteit, H. Oelhaf, G. Wetzel, U. Cortesi, F. Mencaraglia, G. Bianchini, G. Redaelli, M. Pirre, V. Catoire, N. Huret, C. Vigouroux, M. Mazière, E. Mahieu, P. Demoulin, S. Wood, D. Smale, N. Jones, H. Nakajima, T. Sugita, J. Urban, D. Murtagh, C. D. Boone, P. F. Bernath, K. A. Walker, J. Kuttippurath, A. Kleinböhl, G. Toon, C. Piccolo |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 7, no. 18 ; Nr. 7, no. 18 (2007-09-21), S.4905-4934 |
| Datensatznummer |
250005202
|
| Publikation (Nr.) |
 copernicus.org/acp-7-4905-2007.pdf |
|
|
|
|
|
| Zusammenfassung |
| Nitric acid (HNO3) is one of the key products that are operationally
retrieved by the European Space Agency (ESA) from the emission spectra
measured by the Michelson Interferometer for Passive Atmospheric Sounding
(MIPAS) onboard ENVISAT. The product version 4.61/4.62 for the observation
period between July 2002 and March 2004 is validated by comparisons with a
number of independent observations from ground-based stations,
aircraft/balloon campaigns, and satellites. Individual HNO3 profiles of
the ESA MIPAS level-2 product show good agreement with those of MIPAS-B and
MIPAS-STR (the balloon and aircraft version of MIPAS, respectively), and the
balloon-borne infrared spectrometers MkIV and SPIRALE, mostly matching the
reference data within the combined instrument error bars. In most cases
differences between the correlative measurement pairs are less than
1 ppbv (5–10%) throughout the entire altitude range up to about
38 km (~6 hPa), and below 0.5 ppbv (15–20% or more) above 30 km
(~17 hPa). However, differences up to 4 ppbv compared to MkIV have
been found at high latitudes in December 2002 in the presence of polar
stratospheric clouds. The degree of consistency is further largely affected
by the temporal and spatial coincidence, and differences of 2 ppbv may be
observed between 22 and 26 km (~50 and 30 hPa) at high latitudes near
the vortex boundary, due to large horizontal inhomogeneity of HNO3.
Similar features are also observed in the mean differences of the MIPAS ESA
HNO3 VMRs with respect to the ground-based FTIR measurements at five
stations, aircraft-based SAFIRE-A and ASUR, and the balloon campaign IBEX.
The mean relative differences between the MIPAS and FTIR HNO3 partial
columns are within ±2%, comparable to the MIPAS systematic error of
~2%. For the vertical profiles, the biases between the MIPAS and FTIR data are
generally below 10% in the altitudes of 10 to 30 km. The MIPAS and SAFIRE
HNO3 data generally match within their total error bars for the mid
and high latitude flights, despite the larger atmospheric inhomogeneities
that characterize the measurement scenario at higher latitudes. The MIPAS and
ASUR comparison reveals generally good agreements better than 10–13% at
20–34 km. The MIPAS and IBEX measurements agree reasonably well (mean
relative differences within ±15%) between 17 and 32 km. Statistical
comparisons of the MIPAS profiles correlated with those of Odin/SMR, ILAS-II,
and ACE-FTS generally show good consistency. The mean differences averaged
over individual latitude bands or all bands are within the combined
instrument errors, and generally within 1, 0.5, and 0.3 ppbv between 10 and
40 km (~260 and 4.5 hPa) for Odin/SMR, ILAS-II, and ACE-FTS,
respectively. The standard deviations of the differences are between 1 to
2 ppbv. The standard deviations for the satellite comparisons and for almost
all other comparisons are generally larger than the estimated measurement
uncertainty. This is associated with the temporal and spatial coincidence
error and the horizontal smoothing error which are not taken into account in
our error budget. Both errors become large when the spatial variability of
the target molecule is high. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|