# Presentation: 302232

## NOAA-18 Instrument Calibration and Validation Briefing  

- NOAA/NESDIS/Office of Research and Applications
- As of the Week of July 11, 2005
- For archived activities and latest news, please visit
- http://www.orbit.nesdis.noaa.gov/smcd/spb/n18calval

## Weekly Highlights (July 11-15)

- HIRS Cal/Val
- HIRS noise remains fluctuating and most LW channels do not meet the noise specification
- Bias characterization for several HIRS LW channels
- NESDIS ATOVS Plan
- Demonstrate IOC using combined NOAA-18 HIRS, AMSU-A and MHS in operational sounding products generation
- Demonstrate impacts of reduced FOV size for HIRS onboard NOAA-18 from 17km to 10km
- The Metoffice Assessments on Direct Broadcast NOAA-18 Data
- Quantify the errors through comparing direct broadcast data with NOAA global level-1b

## NOAA-18 Instrument Payload

- AVHRR/3 Advanced Very High Resolution Radiometer
- HIRS/4 High Resolution Infrared Sounder
- AMSU-A Advanced Microwave Sounding Unit-A
- MHS Microwave Humidity Sounder
- SBUV/2 Solar Backscattered Ultraviolet Radiometer

**We focus on these instruments:**

## Calibration and Validation Legend 

- PRT:  Platinum Resistance Thermometers
- NEDN/T: Noise Equivalent Delta Radiance/Temperature
- ATOVS: Advanced TIROS Operational Vertical Sounder (TOVS)
- TOAST: Total Ozone Analysis using SBUV/2 and TOVS
- MSPPS: Microwave Surface and Precipitation Product System
- NDVI: Normalized Difference Vegetation Index
- SST: Sea Surface Temperature
- UV: Ultraviolet
- TPW: Total Precipitable Water
- CLW: Cloud Liquid Water

## ORA NOAA-18 Instrument Cal/Val Mission Goals

- Monitor and improve NOAA-18 instrument post-launch calibration
- Assess and quantify instrument noises though analyzing calibration target counts and channel measurements
- Monitor possible instrument  anomaly and provide recommended solution
- Quantify satellite geolocation errors
- Characterize other biases in radiance and products such as cross-track asymmetry through forward modeling and inter-satellite calibration
- Validate NESDIS NOAA-18 products (ATOVS and MSPPS, TOAST, UV index, NDVI, SST) for operational implementation
- Provide early demonstration and assessments of NOAA-18 data for improving numerical weather prediction through JCSDA

## Our Team  

- Mitch Goldberg: ORA/SMCD Division Chief, - Management and Technical Oversight
- Fuzhong Weng: ORA/SMCD/Sensor Physics Branch Chief and NOAA-18 cal/val team leader, instrument asymmetry and microwave products and algorithms, radiance bias assessments for NWP model applications
- Changyong Cao: HIRS instrument calibration
- Fred Wu: AVHRR VIS/IR instrument calibration
- Tsan Mo: AMSU/MHS instrument calibration
- Jerry Sullivan: AVHRR thermal channel calibration/ NDVI validation
- Tony Reale: HIRS/AMSU/MHS sounding channel/products validation
- Mike Chalfant: HIRS/AMSU/MHS sounding channel/products validation /geolocation
- Ralph Ferraro: AMSU/MHS window channels/MSPPS products validation
- Larry Flynn: SBUV product validation
- Tom Kleespies: AMSU on-orbit verification
- Hank Drahos: Sounding product validation
- Dan Tarpley: AVHRR product NDVI monitoring
- John LeMashall:  Impacts assessments of NOAA-18 data for NWP applications

## HIRS Cal/Val Summary

- The filterwheel was put in high power mode for one orbit on July 12. So far, there is no impact from this test  on the HIRS LW noise level
- HIRS channel 1 through 4, and channel 12 are not (yet) suitable for product generation
- NOAA-18 HIRS channel 5 displays a cold bias on the order of 5 K
- NOAA-16 and 18 HIRS channel 8  are  comparable

## HIRS Channel 5 calibrated radiance temperatures (K) are compared for N15 (upper left), N16 (upper right) and NOAA-18; each panel is scaled identically allowing direct color comparison of differences.   The region of coverage is an approximately 5000 km2  region in the remote west tropical pacific.  Random noise characteristics for N18 are now comparable to N16; a cool bias (less red) on the order of 5K is observed for N18 measurements relative to N16.             

**HIRS Channel 5 calibrated radiance temperatures (K) are compared for N15 (upper left), N16 (upper right) and NOAA-18; each panel is scaled identically allowing direct color comparison of differences.   The region of coverage is an approximately 5000 km****2****  region in the remote west tropical pacific.  Random noise characteristics for N18 are now comparable to N16; a cool bias (less red) on the order of 5K is observed for N18 measurements relative to N16.             **

**Notes:**
Calibrated radiance temperatures for HIRS channel 5 are illustrated for consecutive orbits of NOAA-15, NOAA-16 and NOAA-18; the NOAA-15 data are approximately 6 hours later (in the evening) than those for NOAA-16 and 18 which are at approximately 1:30 in the afternoon. The region of coverage is an approximately 5000 km2  region in the remote west tropical pacific.  The relatively warm values toward the center of the orbital swaths are due to the cross-track scanning characteristic of the sounder, and the regions of relatively cold measurements (blue) indicate clouds.  Unlike HIRS channels 1 through 4 (not shown), HIRS channel 5 onboard NOAA-18 although marginally noisy does appear suitable for products generation.  The relative cool bias in the calibrated measurement (less red) for NOAA-18 compared to  NOAA-16 and 15 (about 5K) needs investigation but can be compensated for in product generation (similar cool bias is also observed for HIRS channels 15 and 16 onboard NOAA-18).   Close inspection also suggests components of coherent noise particularly evident in the NOAA-15 data.   

## HIRS Channel 8 calibrated radiance temperatures (K) are compared for N15 (upper left), N16 (upper right) and NOAA-18; each panel is scaled identically allowing direct color comparison of differences.   The region of coverage is an approximately 5000 km2  region in the remote west tropical pacific.  Random noise characteristics for N18 are now comparable to N16 for this channel; HIRS channel 8 is a critical channel for cloud detection.             

**HIRS Channel 8 calibrated**** ****radiance temperatures (K) are compared for N15 (upper left), N16 (upper right) and NOAA-18; each panel is scaled identically allowing direct color comparison of differences.   The region of coverage is an approximately 5000 km2  region in the remote west tropical pacific.  Random noise characteristics for N18 are now comparable to N16 for this channel; HIRS channel 8 is a critical channel for cloud detection.**

**Notes:**
Calibrated radiance temperatures for HIRS channel 8 are illustrated for consecutive orbits of NOAA-15, NOAA-16 and NOAA-18; the NOAA-15 data are approximately 6 hours later (in the evening) than those for NOAA-16 and 18 which are at approximately 1:30 in the afternoon. The region of coverage is an approximately 5000 km2  region in the remote west tropical pacific.   Areas of relatively cold measurements (yellow to purple) indicate clouds.   HIRS channel 8, an important channel for cloud detection, is now performing suitable for cloud and sounding products generation.  

## HIRS Channel 12 calibrated radiance temperatures (K) are compared for N15 (upper left), N16 (upper right) and NOAA-18; each panel is scaled identically allowing direct color comparison of differences.   The region of coverage is an approximately 5000 km2  region in the remote west tropical pacific.  Random noise characteristics for N18 are now comparable to N16 but still unsuitable for products generation.

**HIRS Channel 12 calibrated radiance temperatures (K) are compared for N15 (upper left), N16 (upper right) and NOAA-18; each panel is scaled identically allowing direct color comparison of differences.   The region of coverage is an approximately 5000 km2  region in the remote west tropical pacific.  Random noise characteristics for N18 are now comparable to N16 but still unsuitable for products generation.**

**Notes:**
Calibrated radiance temperatures for HIRS channel 12, sensitive to upper tropospheric moisture, are illustrated for consecutive orbits of NOAA-15, NOAA-16 and NOAA-18; the NOAA-15 data are approximately 6 hours later (in the evening) than those for NOAA-16 and 18 which are at approximately 1:30 in the afternoon.  The region of coverage is an approximately 5000 km2  region in the remote west tropical pacific.  The regions of relatively cold measurements (blue) indicate clouds.  Unlike HIRS channels 5 through 11, the noise characteristics for HIRS channel 12, although improved from early June, are not yet suitable for sounding products generation.   Close inspection also suggests components of coherent noise particularly evident in the NOAA-15 data.   

## Plan for ATOVS-200x

- Demonstrate IOC using combined NOAA-18 HIRS, AMSU-A and MHS in operational sounding products generation:
- Develop contingencies for removing selected HIRS channels (i.e., channels 1, 2, 3, 4, and 12)
- Deploy revised ATOVS-200X scientific algorithms to realize maximum impact from available data
- Demonstrate impacts of reduced FOV size for HIRS onboard NOAA-18 from 17km to 10km:
- Cloud detection
- Sounding products
- Cloud products

## The Metoffice Assessments using Direct Broadcast  NOAA-18 Data 

- Local global consistency is at least as good as NOAA-16 and in some respects better due to AAPP processing aligning more closely with NOAA processing.
- The direct broadcast facility is working very well and direct broadcast AMSU-A and MHS data can be used with confidence in data assimilation systems or for product generation (given that other studies have confirmed quality of the global data).
- As with NOAA-16 the match for HIRS is not as good as for microwave channels but unlike NOAA-16 several HIRS channels are now agreeing very well and consideration could be given to using some HIRS channels from direct broadcast data. There is an problem for HIRS channel 1 which is not yet understood and is under investigation in the AAPP team.