1. NPOESS Conical Scanning Microwave Imager/ Sounder (CMIS) Overview
David Kunkee
June 23, 2002

2. Background NPOESS Conical Scanning Microwave Imager Sounder (CMIS)
Continues and Improves on the Missions of SSM/I, SSMIS
Next Generation Polar-orbiting Operational Radiometer
MISSION:
Provide a variety of data-products: 22 Environmental Data Records (EDRs)
An integral part of the NPOESS constellation
Design
CMIS design was optimized with respect to an Integrated Requirements Prioritization List (IRPL) and risk

3. CMIS Data Products and Design Priorities

4. CMIS Design Overview CMIS primary design drivers: Current CMIS Design
Cat I EDRs, Cat II EDRs and Cost
Current CMIS Design
77 Channels: 37 channels with 40 FFT channels
Two main reflectors:
Low Frequencies (LF): 2.2 m
High Frequencies (HF): 0.5 X 0.7 m
Two feedhorn clusters
LF cluster: 12 feedhorns, 6 – 89 GHz
HF cluster: 4 feedhorns, 166 and 183 GHz
>0.9 reliability after 7 years on orbit + 8 years storage
Substantial redundancy
257 kg mass; 280 kb/s data rate; 291 W orbital average power

5. Conical-Scanning Microwave Imager/Sounder

6. CMIS Channel Set *
*Polarizations: V=Vertical, H=Horizontal, P=+45 degrees,
M =–45 degrees, L=Left-hand Circular, R=Right-hand Circular

7. CMIS Scan Geometry

8. CMIS Footprint Arrangement

9. Antenna Beam Sampling Co-registration of footprints
Requires up to 9 scan rotations
High Frequency observations are offset in elevation to overlay Low Frequency antenna beam footprints
Antenna Beam Sampling
CMIS Provides Nyquist sampling for all channels along scan
Nyquist sampling achieved cross-scan beyond ~20 degrees of the center of scan
Head-to-toe (contiguous) sampling along track

10. CMIS Data Products and Algorithms
Atmospheric and Environmental Research (AER)
All EDRs (and intermediate data products) except Ocean EDRs
Remote Sensing Systems (RSS)
Ocean EDRs
Microwave Operational Algorithm Team (MOAT)
Government/University advisory board to CMIS
Shares latest science and techniques with AER/RSS
Sea Surface Wind Direction:
10, 18, 37 GHz (V,H) 18, 37 GHz (–45, +45) 10, 18 GHz (LH, RH)
Temperature Sounding:
60 GHz (9 channels from 50.3 to GHz, V-pol)
40 FFT channels centered on 7+ O2 line ( GHz)

11. CMIS EDR Algorithms AER uses a unified retrieval approach
All available radiometric & auxiliary/ancillary data supplied to a physical retrieval scheme
Optimizes solution based on the internal model
Retrieval produces vertical moisture profile and vertical temperature profile
Output generated at predetermined altitudes
Includes Surface Temperature & Emissivity
Output is supplied algorithms that produce remaining non-ocean EDRs

12. CMIS EDR Algorithms (Cont’d)
Ocean EDRs Remote Sensing Systems
Based on CMIS calibrated brightness temperatures
Ocean EDRs are supplied as input to the unified retrieval
Sea-Surface Wind Direction (SSWD) is a key development of CMIS

13. Heritage Radiometers Several sensors qualify as “heritage”
SSM/I (special-sensor, microwave imager)
Only Operational Conical-Scanning microwave imager on orbit
SSMIS (microwave imager/sounder)
Not yet launched – scheduled for October 2002
Includes temperature and moisture sounding channels
Other ‘pathfinders’
AMSR-E
Includes imaging channels 6 – 89 GHz 1.6 m reflector
WINDSat
Sea surface wind direction from polarimetric microwave measurements
Full polarimetric capability at 10, 18 and 37 GHz
Risk reduction for CMIS

14. SSM/I Scan Geometry
J.L Hollinger, J. L. Peirce and G. A. Poe, “SSM/I Instrument Evaluation”,
IEEE Trans. Geosci. Remote Sensing, 28(5), Sept 1990

15. SSM/I and CMIS Imaging Channels

16. Conical Scanning Radiometers (I) L-R: TMI CMIS SSM/I

17. Conical Scanning Radiometers (II)
Advanced Microwave
Scanning Radiometer (EOS)
(AMSR-E)
Special Sensor Microwave
Imager Sounder (SSMIS)

18. Summary CMIS offers: New operational data products
Sea Surface Wind Direction
Soil Moisture
Cloud Base Height
Quantifiable improvements in heritage data products
Spatial Resolution
Measurement Range