# Presentation: 168682

## NOAA-18 AVHRR SST and Aerosol Products

- Alexander Ignatov, John Sapper,
- William Pichel, Xiaofeng Li, Yury Kihai

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status

##  AVHRR products over ocean

- _Solar Reflectance Bands (Aerosol)_* **(No onboard calibration)*
-  1: 0.63 m   	*τ**1**: Single-channel LUT*
-  2: 0.83 m   	*τ**2**: Single-channel LUT*
-  3A:1.61 m 	*τ**3**: Single-channel LUT* *(N18: disabled 8-16 Jun 05)*
- _Earth Emission Bands (SST)_* **(Onboard calibration)*
-  3B: 3.7 m 	*(Daytime: not used due to solar reflectance)*
-  4: 11 m
-  5: 12 m

*** ***_Night SST derived using triple-window MCSST_

*** ***_Day SST derived using split-window NLSST_

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status

##  Status of N18 Algorithms

- _Aerosol Algorithm:_
- Sensor-filter specific LUTs calculated using RTM
- Retrieval algorithm delivered to OSDPD Dec 2004

*** ***Status of N18 Algorithms

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status

##  Data

*** ***Data

- NOAA-16/L  	(Sep 2000;   3 PM)
- NOAA-17/M	(Jun  2002; 10 AM)
- NOAA-18/N  	(May 2005;  2 PM)

- Operational NESDIS SST and Aerosol over global ocean 8-16 Jun 2005 from 3 AVHRR/3
- NOAA-18, NOAA-17, and NOAA-16

- SST/AEROBS 8-day rotating files CEMSCS (N18: started on 7 June 2005 with N16 coeff)
- τ1, τ2, τ3, NLSST, MCSST, Climate TS
- 8km (2×2 GAC pixels) × daily
- AEROBS: Day only/40 glint/anti-solar side
- SSTOBS:  Day/Night + glint/solar side

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status

## Sea Surface Temperature

*NB:*
*N18 SST in these analyses use N16 coefficients*
*New coefficients were implemented on 2 August 2005*
*The SST/AEROBS 8-day rotating files will be fully refreshed by 11 Aug 2005*
*Comprehensive evaluation of SST will be completed after that date*
*SST coefficients might be adjusted based on evaluation before 31 Aug 2005*

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status

##  NLSST June 2005

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status

##  NLSST Anomalies June 2005

- (Bauer-Robinson 1985 climatology subtracted)

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status

## Conclusion to SST

-  ORA calculated SST coefficients from buoy match ups
-  OSDPD implemented 2 August 2005
-  Analyzed daytime NLSST (11/12 μm) derived w/N16 coefficients
-  No excessive noise found in N18 daytime NLSST
-  N16/17 SSTs remain globally consistent within ~0.1K

- _Work underway_
- - Do global analyses w/correct N18 coefficients (after 11 Aug 2005)
- - Include night-time SST in consistency analyses (3.7 μm)
- - Document at the AMS’06 Conf on Satellite Meteorology & Oceanography

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status

## Aerosol

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status

##  Aerosol June 2005: 1

*** ***Aerosol June 2005: 1

- τ-errors: due to AVHRR calibration

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status

##  Aerosol Jun 2005: 2

*** ***Aerosol Jun 2005: 2

- τ-errors: due to AVHRR calibration

***Sensitivity charts show error in AOD2 as a function of AOD2, for 4 levels of cal error from 5% to 20%.            ***

*** ******AVHRR band 2:    N18 biased high by    ~-1% with respect to N17 and by ~-4% with respect to N16.***

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status

##  Aerosol Dec 2003: 

*** ***Aerosol Dec 2003: 

- α-errors: due to AVHRR calibration

*** ******Angstrom exponent  (related to a ratio of two AODs in bands 1 and2)  is a ***_***very***_*** sensitive indicator of AVHRR cal (shows unresolved combination of bands).***

*** ******Black curve shows the expected distribution of Angstrom exponent. High bias in N18 band 1 and low bias in band 2  work in the same direction and amplified in Angstrom exponent. ***

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status

## Conclusion to Aerosol

-  N18 AVHRR channel 1 is biased high by +6..9%
-  N18 AVHRR channel 2 is biased low by -1..-4%
-  Vis Cal should be fixed for the quality aerosol product
-  Channel 3A was not available for analyses from 8-16 June 2005
-  No “unusual” anomalies in solar reflectance bands observed

- _Work underway_
- - Re-examine aerosol product after Vis Cal adjustments
- - Do global analyses of SST/Aerosol correlations (after 11 Aug 2005)
- - Document at the AMS’06 Conf on Satellite Meteorology & Oceanography

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status

## Conclusion to SST/Aerosol:

- Recommend declaring N18 operational by end August

- N18 Cal/Val Workshop 9 Aug 2005: SST and Aerosol Status