Suomi NPP CrIS SDR Status · Jan. 25: First light image, 900 cm-1. BT 20-Jan-2012 12:54 to 23:57...
Transcript of Suomi NPP CrIS SDR Status · Jan. 25: First light image, 900 cm-1. BT 20-Jan-2012 12:54 to 23:57...
Suomi NPP CrIS SDR Status
Yong Han, CrIS SDR Team Lead
Suomi NPP EDR Product Provisional Readiness Review NOAA Center for Weather and Climate Prediction (NCWCP)
5830 University Research Park, College Park, Maryland January 17- 18, 2013
Outlines
• CrIS operational concept and SDR specification
• CrIS SDR Cal/Val milestones and events
• SDR Provisional Product highlights
• Product issues
• Summary
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CrIS Operational Concept
2,200 km Swath
NWP, EDR Applications
Decode Spacecraft
Data
±50° Cross track
Scans
3x3 Array of CrIS FOVs
(Each at 14-km
Diameter)
Ground Station
RDR = Raw Data Record SDR = Sensor Data Record EDR = Environmental Data Record
30 Earth Scenes
RDRs
EDRs
Co-Located ATMS SDRs
Global Temperature, Moisture, Pressure Profiles
CrIS on NPP
RDRs
Interferograms
Calibrated / Geolocated Spectra
SDRs
CrIS SDR Algorithm
NPP CrIS Sensor Data Record Calibration Uncertainty Specifications
Band Spectral range (cm-1)
N. of chan.
Resolution (cm-1)
FORs per
Scan
FOVs per FOR
NEdN @287K BB
mW/m2/sr/ cm-1
Radiometric Uncertainty @287K BB
(%)
Spectral (chan center) uncertainty
ppm
Geolocation uncertainty
km
LW 650-1095 713 0.625 30 9 0.14 0.45 10 1.5
MW 1210-1750 433 1.25 30 9 0.06 0.58 10 1.5
SW 2155-2550 159 2.5 30 9 0.007 0.77 10 1.5
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SDR Calibration Uncertainty
Radiometric uncertainty specification converted to that expressed in brightness temperature
CalVal Milestones and Events
• January 18th 2012: CrIS was powered up; team started instrument checkout and optimization.
• February 8th : Engineering packet v32 was uploaded (PGA setting and bit trim mask updates).
• February 22nd : Full spectral resolution RDRs (0.8 cm maxOPD for all bands) were collected.
• April 11th : Engineering packet v33 was upload (spectral calibration parameters, nonlinearity coefficients and ICT emissivity table updates).
• April 18th: A new FIR digital filter was uploaded to replace the corrupted one.
• May 15th : CrIS SDR product reached Beta maturity level .
• June 27th: Engineering packet v34 was uploaded (temperature drift limit updates)
• Product provisional review: October 23, 2012 • Validated product: 2013
Jan. 25: First light image, 900 cm-1 BT 20-Jan-2012 12:54 to 23:57 UTC from CCAST SDR processing system, UW/UMBC
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CrIS SDR Highlights
• Instrument noise (NEdN) • Spectral calibration and uncertainty • Radiometric calibration and uncertainty • Accuracy assessment with RTM and inter-sensor
comparisons • Geolocation calibration and uncertainty • SDR quality flag improvement
NEdN
7 Feb
1
Mar
2
May
2
Jun
4
Jul 4
Aug
6
NEdN
The noise levels are much better than the specification
The large NEdN at MW FOV 7 is a known issue before NPP launch
NEdN at selected wavenumber ranges
Stable NEdN over 8 months
Spectral Uncertainty
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Longwave band, 730-740 cm-1
Midwave band, 1350-1380 cm-1
Shortwave band, 2200-2250 cm-1
Inter-FOV spectral shifts relative to FOV5 derived from correlation analysis
Longwave band
Midwave band
ppm
pp
m
Spectral shifts assessed with RTM
LW & MW band frequency uncertainty < 3 ppm (specification 10 ppm) SW band frequency uncertainty relative to FOV5 < 3 ppm
Radiometric Uncertainty Assessment Inter-FOV difference
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LW, 672-682 cm-1, wrt FOV5
LW, 830-840 cm-1, wrt FOV5
MW, 1382-1408 cm-1, wrt FOV9
MW, 1585-1600 cm-1, wrt FOV9
SW, 2360-2390 cm-1, wrt FOV5
SW, 2500-2520 cm-1, wrt FOV5
BT D
iff (K
) BT
Diff
(K)
0.1
-0.1
0.1
-0.1
FOV-2-FOV differences are less than 0.04 K for LW and MW and less than 0.1 K for SW
Radiometric Uncertainty Assessment Daily Mean CrIS-AIRS Differences
10 Stable difference ~0.1 K
v33 upload
Mar
Mar Mar Mar
Mar Mar
Oct
Oct
Oct
Oct
Oct
Radiometric Uncertainty Assessment CrIS-IASI SNO (North Pole)
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Sample size = 411 CrIS
- IA
SI
CrIS IASI
The CrIS IASI difference is ~ 0.2 K
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Radiometric Uncertainty Assessment CrIS/VIIRS (M13 4um) comparisons
Difference is less than 0.2 K
Standard deviations of Biases vs Radiative Transfer Model (RTM) simulated radiances
Radiometric Uncertainty Assessment Radiance Bias Estimated with RTM
Overall bias < 0.2 K FOV-2-FOV differences < 0.1 K
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Standard deviation (over 9-FOVs) of Bias vs RTM simulated radiances
Bias
(K)
• Co-located VIIRS IR data are used to estimate the CrIS geolocation uncertainty A coding error was found that caused the geolocation error
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Geolocation Uncertainty Assessed with VIIRS
Geolocation uncertainty within 30o scan angles < 1 km (specification 1.5 km)
IDPS MX6.2 4.5 km geolocation error
error CrIS - VIIRS
IDPS MX6.3 CrIS image
Bias (m)
RMSE (m)
Track -21 80
Scan -8 64
VIIRS geolocation uncertainty
Image differences (CrIS – VIIRS) before and after a coding error fix
Overall Quality Flag Improvement
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Quality flag: Blue color – GOOD Green color - DEGRADED
Beta product
Current product
Engineering packet v34 uploaded
Perc
enta
ge (%
)
A false alarm (data labeled as Degraded) was fixed with code changes and parameter updates
Issues
• Software issues and IDPS SDR anomaly are still occurring
• Significant SW cold scene FOV differences
• Spectral ringing
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Summary
• CrIS SDR has reached the Provisional maturity level
• All critical DRs and document issues have been addressed
• A number of CalVal and software issues have been identified and will be addressed for the Validated product
• The team has a clear path moving forward for both NPP and J1 missions
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Calibration type Meet Specification
LW band MW band SW band
NEdN
Radiometric calibration
Spectral calibration *
Geolocation ** ** **
* Relative to FOV5 ** Within 30o scan angles