Studies of Advanced Baseline Sounder (ABS) for Future GOES
Jun Li+
Timothy J. Schmit@
Allen Huang+
W. Paul Menzel@
@NOAA/NESDIS/ORA
+CIMSS, UW-Madison
ITSC-XII, Feb.27 - Mar.05, 2002, Lorne, Victoria, Australia
UW-Madison
More than 5 years of high spectral measurements from polar orbits: - AIRS (Atmospheric InfraRed Sounder)
- IASI (Infrared Atmospheric Sounding Interferometer)
- CrIS (Crosstrack Infrared Sounder)
Approximately 5 years of high spectral, spatial and temporal measurements from geostationary orbit:
- GIFTS (Geostationary Imaging Fourier Transform Spectrometer)
30 years of filter wheel technology in geostationary orbit:- VAS and GOES Sounder
40 years since the first interferometer flown in space to study the weather: IRIS (Infrared Radiation Interferometer Spectrometer)
ABS is scheduled to be on GOES-R in 2012
The time is right to update the GOES sounder! The technology is mature. The need is documented.
Limitations of Current GOES Sounders
– scan conflicts between oceans vs CONUS (regional vs hemispheric)
– low vertical resolution for moisture, temperature
– eclipse and related outages
User RequirementsCurrent (1999) NWS Thresholds
• Resolutions - Temporal: The ‘sounding disk’ in 1 hour
- Spectral: from 3.7-15.4 µm at 0.6 to 2.5 cm-1 resolution (similar to spectral performance of polar interferometers - CrIS)
- Spatial: 10 km horizontal resolution for independent observation
• Accuracies 1 degree K temperature; 10% relative humidity
• Applications - Nowcasting - Short-range weather forecasting - Longer-range numerical weather prediction
Table 3: Sounder Band Descriptions
Waveband (cm-1) Unapodizedspectral
resolution (cm-1)650 - 1200 0.6251210 - 1740 1.252150 - 2720 2.5
Sounder Comparison
Coverage Rate CONUS/hr Sounding Disk/hr
Horizontal Resolution
- Sampling Distance 10 km 10 km
Vertical resolution ~3 km 1 km
Accuracy
Temperature 2 deg. K 1 deg. K
Humidity 20% 10%
Current Requirement
Areas within 62 degrees local zenith angle from GOES-East and GOES-West sub-satellite points are indicated. Threshold coverage rate calls for the 62 arc region, excluding half of over-lap, to be scanned each hour. Current GOES -E and -W sounder hourly coverage is also shown.
SpatialCoverage
Geostationary Sounders
(# of channels)
VAS (experimental)
GOES Sounder(operational)
GIFTS(experimental)
(12)
(18)
(~1600)
(~1600)
Advanced BaselineSounder (operational)
time
Spectral coverage of the proposed ABS’, ABS, GIFTS and the current
GOES radiometer sounder
ABS:
Spectral widths Spectral resolutions
ABS 3-band:650 -1200 cm-1 0.625
1210-1740 cm -1 1.25
2150-2720 cm -1 2.5
ABS’ 2-band:650 -1200 cm-1 0.625 1650-2250 cm -1 0.625
Noise vectors used for the ABS simulations
ABS’
Is a new 2-band ABS’ comparable to a traditional 3-band ABS for Temperature?
UW/CIMSS
Is a new 2-band ABS’ comparable to a traditional 3-band ABS for Moisture?
UW/CIMSS
ABS’ LW 650 - 1200 cm**-1
ABS’ LW 650 - 1200 cm**-1
00 and 12 UTC only. Land-based CONUS locations.
12 UTC. Land-based CONUS location.
12 UTC Land-basedCONUS location
Detection of Temperature Inversions Possible with Interferometer
The detection of inversions is critical for severe weather forecasting. Combined with improved low-level moisture depiction, critical ingredients for night-time severe storm
development over the Plains can be monitored. Knowing if there is an inversion can also help improve the profiles estimates.
Spikes down - Cooling with height
Spikes up -Heating with height
Texas
Ontario
Bri
ghtn
ess
Tem
pera
ture
(K
)
(low-level inversion)
(No inversion)
GOESGOES
Wavenumber (cm-1)
Cloud-Top Information
Future GOES -- simulating the Advanced Baseline
Sounder (ABS) performance
Summary
The information from CrIS-like three spectral bands is close to that from GIFTS-like two spectral bands.
The Advanced Baseline Sounder overcomes existing instrument limitations.
Geostationary interferometer will resolve high temporal and vertical fluctuations of moisture that are not resolved by current in-situ or satellite measurements.
Only geostationary interferometer observes critical meteorological parameters (temperature, moisture, clouds, winds) with necessary temporal, spatial and vertical resolutions to support future • Nowcasting, • Short-range weather forecasting, and • Longer-range numerical weather prediction.
Technology is mature and meteorological need is documented. Time is right to update geostationary sounding instruments. Advanced Sounder will provide required high spectral resolution measurements.