Title: The use of satellite data has the potential to significantly improve weather forecasts.
1The use of satellite data has the potential to
significantly improve weather forecasts.
- NWP models needs knowledge of the state of the
atmosphere and surface. - Satellites provide an excellent avenue to acquire
global data using the same suite of instruments. - Future significant improvements in weather
prediction need significant improvements in the
accuracy of satellite products.
2Improved product accuracy will be achieved with
new advanced infrared sounders
- Current low spectral resolution sounders, with
relatively few spectral bands, are being phased
out by advanced high spectral resolution infrared
sounders with thousands of narrow spectral bands
(channels). - The Atmospheric Infrared Sounder (2002) will be
the first high spectral resolution infrared
sounder to be used routinely in numerical weather
forecasting. - AIRS will be followed by CrIS and IASI (both
2006)
3Spectral coverage of AIRS, IASI and CrIS
Number of channels
2378
AIRS
IASI
8461
IASI
8461
19 HIRS Channels
1300
CrIS
CrIS
1300
500 1000
1500 2000
2500 3000
4Each channel has a weighting function
With one channel the retrieval is the observed
brightness temperature which can be thought of as
deep-layer mean temperature. The layer is
defined by the weighting function. Need many
overlapping weighting functions to derive an
accurate pointwise temperature profile.
5Benefits of high spectral resolution
- Improved spectral resolution results in
- Sharper weighting functions
- Clean channels (e.g. temperature channels
not contaminated by water vapor lines) - Many channels with sharp weighting functions
combined with low noise improves vertical
resolution - Retrieval accuracy is greatly improved
- (atmospheric temperature , moisture , ozone,
skin temperature and surface emissivity)
6More channels low instrumental noise
better retrievals
AIRS temperature Weighting functions
7Temperature and moisture retrieval accuracy from
AIRS is much improved when compared to
current operational sounder ATOVS
8AIRS Real-Time Products from NESDIS
- Clear and cloud-cleared radiance datasets for
direct assimilation of radiances. - Full resolution retrievals for assimilation of
retrievals. - Users - NCEP, ECMWF, Goddard DAO,
Meteorological Service of Canada , Met. Office,
and Meteo France - Products based on real-time simulations are now
available
9Example of simulated AIRS window channels LW,
SW
10 - For additional information on AIRS and
availability of AIRS products in near real-time
contact Mitch Goldberg - Mitch.Goldberg_at_NOAA.GOV