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| Titel |
A long-range link experiment demonstrating infrared-laser occultation for measurement of atmospheric greenhouse gases |
| VerfasserIn |
Susanne Schweitzer, Jin-Guo Wang, James Brooke, Philip Martin, Vasili Kasiutsich, Veronika Proschek, Christoph Gerbig, Gottfried Kirchengast, Peter Bernath |
| 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 |
250054609
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| Zusammenfassung |
| The infrared-laser occultation technique (LIO) is a powerful, active occultation method for
the measurement of various atmospheric trace gases. This technique exploits narrowband
laser signals in the short-wave infrared spectral range (SWIR, 2 μm to 2.5 μm) to derive the
concentrations of a range of trace species via differential absorption spectroscopy. Recent
studies showed that the accuracy of trace gas profiles measured using LIO will
be very high. In particular, using the signals which are foreseen for the so-called
ACCURATE mission for climate benchmark profiling of greenhouse gases and
thermodynamic variables and wind from space, the volume mixing ratios of H2O, CO2
(12CO2, 13CO2, C18OO), CH4, N2O, O3, and CO can be determined accurate to
within 1 % to 4 % individual-profile rms error over the upper troposphere and lower
stratosphere (UTLS). Together with the high vertical resolution, unbiasedness and good
global coverage of the data—characteristics which are intrinsic to the occultation
method—the LIO technique is highly complementary to currently operated measurement
methods.
This presentation will deliver insight into an experiment which will demonstrate the LIO
technique for the first time. The experiment will be ground based and be performed at an
altitude of about 2.4 km between two observatories at the Canary Islands which are about
144 km apart. The instrumentation needed, i.e., transmitter and receiver for testing the
infrared-laser occultation, is currently constructed and tested at the Univ. of York,
UK, together with the Univ. of Manchester, UK, with scientific support from the
Univ. of Graz, AT. Optionally also cameras for additional analysis of the data are
considered (focus scintillation studies), scientifically supported by M. Gorbunov and A.
Gurvich from the Inst. of Atmospheric Physics, Russian Acad. of Sciences, RU. The
measurement campaign, together with related in-situ greenhouse gas measurements for
validation supported by the MPI for Biogeochemistry Jena, DE, is foreseen in July
2011. This experiment, focused in terms of parameters on the key species CO2
(12CO2, 13CO2, C18OO), CH4, and H2O, will deliver important insight into the LIO
technique and be an essential step towards operation of the LIO technique in space. |
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