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| Titel |
Thermal and near-infrared sounding for weather, air quality and greenhouse gas monitoring in the Arctic from highly elliptical orbits |
| VerfasserIn |
K. A. Walker, C. Sioris, J. C. McConnell, H. Buijs, L. Moreau, The PHEMOS Science Team |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250070797
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| Zusammenfassung |
| The Canadian Space Agency’s PCW (Polar Communications and Weather) mission is a dual
satellite mission with each satellite in a highly eccentric orbit with apogee ~42,000 km and a
period in the 12-24 hour range to deliver continuous (24x7) communications and
meteorological data over the Arctic. The baseline meteorological instrument is a 21-channel
spectral imager similar to MODIS or ABI. The PHEMOS (Polar Highly Elliptical Molniya
Orbital Science) mission is a science complement to the PCW mission to address weather,
climate and air quality issues. The instrument package consists of a Fourier transform
spectrometer (FTS) to cover the near-infrared and mid-infrared spectral range and an
ultraviolet-visible (UVS) spectrometer.
In a phase A study funded by the Canadian Space Agency, we are configuring an FTS
instrument for thermal infrared sounding as well as for greenhouse gas monitoring via
near-infrared solar reflection. Using imaging detectors allows many measurements in parallel
with increased observation time up to 100 s per view. The field-of-regard (FOR) is subdivided
into a number of views such that a full measurement of the FOR is completed in about 1
hour. A pointing mirror is used in a step and stare mode. The thermal infrared is
covered with two optimized bands; band 1 covers 700 to 1400 cm-1 and band 2
covers 1800 to 2500 cm-1 for which the scientific focus are temperature and water
vapour profiles and air quality species (including CO, O3, HNO3, NH3). The spectral
resolution is 0.3 cm-1. The near-infrared spectral bands target absorption signatures of
CO2, CH4, and O2. The two relevant spectral ranges are 5990-6450 cm-1 and
13060-13168 cm-1 (O2-A band), measured with spectral resolutions of 0.3 and 0.6
cm-1, respectively. The O2-A band is used to determine surface pressure, albedo,
and aerosol optical depth and vertical distribution, the latter of which is critical
for CO2 retrieval. The FTS instrument design will be presented as well as design
challenges and expected performance. Retrieval studies examining the feasibility
of measuring CO2, CH4, and aerosol properties as a function of signal-to-noise
ratio, radiometric accuracy, surface albedo, and other factors will be presented as
well. |
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