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| Titel |
Comparison of acetone measurements by the MIPAS-E satellite instrument to CARIBIC aircraft data |
| VerfasserIn |
David Moore, John Remedios, Andreas Zahn |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250056195
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| Zusammenfassung |
| Emissions of anthropogenic pollution result in the injection of a wide range of carbon
compounds into the atmosphere. Carbon monoxide (CO), methane (CH4) and volatile organic
compounds (VOCs) are released in significant amounts, affecting both the oxidation capacity
of the troposphere and ozone production. It has recently been established that the observation
of the global distribution of VOCs in the upper troposphere (UT) can be made by
measurements provided by Earth limb-viewing instruments such as the Michelson
Interferometer for Passive Atmospheric Sounding onboard ENVISAT (MIPAS-E). The use of
satellite based remote sensing of the atmosphere, with characterised errors, has provided a
greater understanding of the spatial distribution of these compounds in the UT and is
beginning to address questions of the lifetimes of these compounds in this region from a
global perspective.
The MIPAS-E samples vertically at 1.5 km intervals between 6 km and 21 km (with a
vertical resolution around 3 km), making MIPAS-E a useful instrument with which to study
organic compounds in the UT. The key for testing the quality of any satellite data-set
produced is by comparison to in-situ measurements. Specific aircraft campaigns that include
measurements of acetone are infrequent and often do not extend to altitudes above 8 km. The
Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument
Container (CARIBIC) is an innovative scientific project which makes extensive
measurements of important chemical and physical processes in the atmosphere. The
automated scientific instrumentation is flown on commercial aircraft greatly improving
spatial, vertical and temporal coverage, compared to specific campaigns which focus
on a particular region. Hence CARIBIC measurements are an excellent tool for
understanding detailed variability in particular regions and is complementary to
MIPAS-E.
In this work, we show the ability of the MIPAS-E and CARIBIC to provide a
unique dataset of global measurements of acetone in the UT and compare data
retrieved from the optimised spectral resolution period of MIPAS-E in 2008 to
CARIBIC aircraft measurements. We look at the great number of measurements made
by CARIBIC between Germany and India, data which cross important regions
such as the summer Indian monsoon and regions affected by biomass burning and
agricultural processes which are thought to be important sources of acetone. Measuring
long-range transport of acetone with MIPAS-E can also be studied and verified over
the Atlantic Ocean using data from CARIBIC flights from mainland Europe to
America. By using a coincidence of 6 hours and 1000 km horizontal distance between
MIPAS-E and CARIBIC data we find that the MIPAS-E acetone compares well to the
aircraft in most cases. The best comparisons are found where the CARIBIC data are
least variable along-track and so where the acetone volume mixing ratios within
the MIPAS-E field-of-view are most homogeneous. We show that the MIPAS-E is
providing unprecedented global VOC data with good spatial resolution, providing very
important new datasets with which to study the UT. This work on VOCs has the
potential to feed into retrieval studies for higher spatial sampling satellites, such as
PREMIER. |
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