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This article discusses how the GOES-R ABI can provide operational continuity for current GOES Sounder products. It covers key aspects such as spatial resolution, refresh rate, and performance comparisons using ABI inputs.
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GOES-R ABI and the current GOES Sounder Timothy J. Schmit, Jaime Daniels NOAA/NESDIS/STAR Jun Li, Mat Gunshor CIMSS Madison, WI and Many others December 19, 2006
Can the GOES-R ABI Supply Current GOES Sounder Continuity Operational Products?Yes. The needed ‘continuity’ products from today's sounder can be provided by the ABI. • 3 Key Aspects to Consider • Spatial Resolution • Refresh Rate • Performance
Background Outline • Spatial resolution comparisons • Refresh rate comparisons • Performance comparisons using ABI inputs • Spectral bands • Simulations • Information content • Simulations • Simulations with current GOES Sounder • Historical examples/experience • Conclusions
Spatial Resolution Comparisons • IR spatial/horizontal resolution of current sounder • 10 km • IR spatial/horizontal resolution of ABI • 2 km • ABI also have finer visible and near IR bands to help the product performance
Improved spatial resolution with simulated ABI over the current Sounder TPW 2km “ABI resolution” - - TPW 10km “Sounder resolution”
Background Outline • Spatial resolution comparisons • Refresh rate comparisons • Performance comparisons using ABI inputs • Spectral bands • Simulations • Information content • Simulations • Simulations with current GOES Sounder • Historical examples/experience • Conclusions
CIMSS Much improved coverage with ABI over the current Sounder Current GOES Sounder coverage in one hour ABI in 5 minutes Cloud Top Pressure
GOES-12 Imager CTP Recently operational GOES-12 imager cloud top pressure image
Background Outline • Spatial resolution comparisons • Refresh rate comparisons • Performance comparisons using ABI inputs • Spectral bands • Simulations • Information content • Simulations • Simulations with current GOES Sounder • Historical examples/experience • Conclusions
The 18 IR and 1 visible spectral bands of the current GOES Sounder {20 UT 06 Oct 2006}
“0.47m” “0.64m” “0.86m” “1.38m” “1.61m” “2.26m” “3.9m” “6.19m” “6.95m” “7.34m” “8.5m” “9.61m” “10.35m” “11.2m” “12.3m” “13.3m” Advanced Baseline Imager (ABI) has 10 IR bands
ABI (blue) and current GOES sounder (green) spectral coverage compared showing a high spectral resolution brightness temperature spectrum (black). ABI has few bands for upper level temperature.
GOES-R ABI Weighting Functions ABI has 1 CO2 band, so upper-level temperature will be degraded compared to the current sounder
GOES-13 Sounder WFs The GOES-N sounder has 5 CO2 bands, more SW bands than ABI
Background Outline • Spatial resolution comparisons • Refresh rate comparisons • Performance comparisons using ABI inputs • Spectral bands • Simulations • Information content • Simulations • Simulations with current GOES Sounder • Historical examples/experience • Conclusions
MODIS data can be used to simulate ABI contributions to sounding
Skin Temperature GOES Sounder 30 km resolution (Now improved to approximately 10 km) MODIS 5 km resolution
Profile information content analysis J. Li et al CIMSS In general, note that the moisture content is similar between the ABI and the current GOES Sounder. The Sounder does show more temperature information than the ABI. More than 300 profiles over CONUS with lifted index <0 (unstable atmosphere) are used in analysis. This information content does not include any spatial or temporal differences. November 6th, 2006
The relative vertical number of independent pieces of information is shown. Note that the moisture content is similar between the ABI and the current GOES Sounder. The Sounder does show more temperature information than the ABI. Caveat: Even if two systems have the same number of pieces of information, they may represent different vertical levels. This information content analysis does not account for any spatial or temporal differences.
Clear Sky temperature and moisture retrieval simulation: HES, GOES-N and ABI • Near Global Radiosonde Observations (RAOBs) • 600 independent sounding retrievals • Retrieval algorithm is based on regression (first guess) followed by physical (final) • HES spectral coverage assumed • 675 – 1200 with spectral resolution of 0.625 cm**-1 • 1689 – 2150 with spectral resolution of 1.25 cm**-1 • 2150 – 2400 with spectral resolution of 2.50 cm**-1 • Noise from PORD • Current GOES Sounder spec noise is assumed • ABI 9 IR spectral bands are used • 0.1 K @300 K for all IR bands, except that • 0.3 K @300 K for 13.3 um band From Jun Li, CIMSS
HES 10 km ABI 5x5 GOES-N ABI + GOES-N Retrieval Simulations CIMSS/UW-Madison
Retrieval Simulations GOES-N ABI 5x5 ABI + GOES-N HES 10 km CIMSS/UW-Madison
RMSE HES: 2.12 GOES Sounder: 3.72 ABI (5x5): 4.23 RMSE HES: 0.19 (cm) GOES Sounder: 0.49 (cm) ABI (5x5): 0.54 (cm) Lifted Index and TPW Retrieval Simulation • HES option assumed: • 675 – 1200 with spectral resolution of 0.625 cm**-1 • 1689 – 2150 with spectral resolution of 1.25 cm**-1 • 2150 – 2400 with spectral resolution of 2.50 cm**-1 • Noise from PORD UW/CIMSS
Regional simulation (08Sept2006) • Using time/space collocated RAOB/Forecast over CONUS • HES option 1a assumption, GOES-12 (for GOES-N class), ABI were used in simulation. PORD noise were used for HES and ABI, HES option 1a: • 675-1200 with 0.625 cm-1 spectral resolution • 1689-2150 with 1.250 cm-1 spectral resolution • 2150-2400 with 2.50 cm-1 spectral resolution • ~300 independent profiles are retrieved with Lifted Index <0 (unstable atmosphere) • Water Vapor Relative Humidity (RH) and TPW are used for performance analysis
RMS 0.48 cm 0.52 cm 0.44 cm 0.28 cm Simulated TPW retrievals over CONUS with lifted index <0 (~300 independent cases)
RMS 0.48 cm 0.32 cm 0.32 cm 0.18 cm Simulated TPW retrievals over CONUS with lifted index <0 (~300 independent cases)
Regional simulation (06Dec2006) • Using time/space collocated RAOB/Forecast over CONUS • HES option 1a assumption, GOES-12 (for GOES-N class), ABI were used in simulation. PORD noise were used for HES. • HES option 1a: • 675-1200 with 0.625 cm-1 spectral resolution • 1689-2150 with 1.250 cm-1 spectral resolution • 2150-2400 with 2.50 cm-1 spectral resolution • ~900 independent profiles are retrieved • Lifted index and TPW (including layer TPW) are used for performance analysis
RMSE Forecast: 2.27 ABI (5X5): 3.92 GOES Sounder: 3.73 HES: 2.21
RMSE Forecast: 2.27 ABI (5X5) + fcst: 2.19 GOES Sounder + fcst: 2.22 HES + fcst: 1.79
RMSE Forecast: 0.40 ABI (5X5): 0.56 GOES Sounder: 0.62 HES: 0.23
RMSE Forecast: 0.40 ABI (5X5) + fcst: 0.32 GOES Sounder + fcst: 0.37 HES + fcst: 0.16
RMSE Forecast: 0.12 ABI (5X5): 0.19 GOES Sounder: 0.18 HES: 0.13
RMSE Forecast: 0.12 ABI (5X5) + fcst: 0.12 GOES Sounder + fcst: 0.12 HES + fcst: 0.11
RMSE Forecast: 0.23 ABI (5X5): 0.35 GOES Sounder: 0.39 HES: 0.19
RMSE Forecast: 0.23 ABI (5X5) + fcst: 0.21 GOES Sounder + fcst: 0.24 HES + fcst: 0.14
RMSE Forecast: 0.17 ABI (5X5): 0.15 GOES Sounder: 0.20 HES: 0.07
RMSE Forecast: 0.17 ABI (5X5) + fcst: 0.12 GOES Sounder + fcst: 0.13 HES + fcst: 0.05
Current Sounder “ABI” bands of current Sounder First Guess Lifted index simulations using GOES sounder
Channels used in the retrieval process to ‘simulate’ the ABI spectral bands from similar bands on the current GOES sounder ABI-6 6.5, 7.0, 11.0, 12.0, 12.7, 13.4 m ABI-8 6.5, 7.0, 11.0, 12.0, 12.7, 13.4 plus, 13.9 and 14.1 m
Caveats on GOES ABI simulations: RESOLUTON The current GOES sounder is approximately 10 km resolution, while the ABI will be disseminated at 2 km resolution. SPECTRAL RESPONSE No attempt was made to use the exact proposed spectral response functions. Only channels on the current sounder are being turned off or on. 6 Channel ABI uses 3.9, 6.5, 7.0, 11.0, 12.0 13.3 um channels. Several bands on the ABI were not simulated, for example the 10.35 um band. The 8 channel ABI adds 13.9 and 14.1 um channels. NOISE Estimates for the ABI are expected to be comparable to those on the current sounder. ALGORITHM The current physical retrieval algorithm was in not optimized in any way for the reduced number of channels. CO2 CHANNELS The greatest benefit of adding at least a 13.9 m (and may be even a 14.1 m) would be in a better determination of clouds heights. Currently the most frequently used sounder CO2 pair is the 14.2 and 13.9 m. The pair of 13.3 and 11.0 m isn’t use very often currently.
Background Outline • Spatial resolution comparisons • Refresh rate comparisons • Performance comparisons using ABI inputs • Spectral bands • Simulations • Information content • Simulations • Simulations with current GOES Sounder • Historical examples/experience • Conclusions