# Presentation: 660826

## OCEAN PARAMETERS FROM NPP/NPOESS

- Wayne E. Esaias
- NASA GSFC Code 614.2
- October 27, 2005
- wayne.esaias@nasa.gov

## 		Ocean EDRs 

- Ocean Color			VIIRS           NPP/NPOESS
- Sea Surface Temperature IR	VIIRS           NPP/NPOESS
- Sea Surface Temperature 	CMIS            NPOESS
-     (Microwave)

## IMPORTANCE of OCEAN   COLOR

- Ocean color is a new Requirement for the operational system.
- Visible ocean bio-optical reflectance of surface layer (<30 m).
- Provides estimate of marine ecosystem state (bio-optical absorption, scattering, chlorophyll) and variability.
- Primary observable for marine ecosystem studies and the
- ocean carbon system.  Direct applications for Harmful Algal Bloom events, Hazards, and fisheries activities/science.
- Describes variations in solar energy penetration (heat).
- Provides estimate of near-surface visibility (divers, detection)
- and depth.
- Flow visualization complements temperature patterns.

## MODIS HERITAGE CHLOROPHYLL 8-Day AVERAGE

## Ocean Color Products

- Heritage:
-  MODIS, SeaWiFS (Research Products)
- 5 normalized water leaving radiance 412, 443, 490, 555, 670
- Chlorophyll a
- absorbance, scattering at 5 wavelengths
- Algorithms:
- Atmospheric Correction - Based on heritage algorithms,
- 		VIIRS Cloud Mask
- 		OMPS Ozone
- In-water Algorithms - Based on MODIS semi-analytic model

- _Ocean Color Products_

## VIIRS OCEAN COLOR ATTRIBUTES

- SNR and Spatial Resolution improve over heritage.
- Seven Vis/NIR bands (520 nm and fluorescence capability are omitted).
- Radiometric stability is crucial. Stability tests are planned.
- 	Rqmts: 2% calibration, 0.3% stability, 1 NEdL between detectors
-  Polarization sensitivity is specified to be less than 2%
- 	 (MODIS 6%, SeaWiFS <.5%)
- 	Ability to characterize polarization may be a limiting factor.
- 	Polarization ray trace modeling is being pursued at NGST, and
- 	GSFC (Waluschka et al./Voss).
- Solar Diffuser will permit orbit by orbit calibration when Earthshine is excluded (modification underway).
- Uncertainty requirements are stratified (low, med, high Chl) and challenging.

## Slide 7

## Will NPP VIIRS Provide Heritage Quality Sensor Data for Ocean Color?

- Ocean Color is technically challenging, and radiometric requirements have been an instrument driver.
-  At the present stage of EDU testing, VIIRS sensor observations are expected to be of heritage quality after on- orbit tuning and calibration.
- Initialization, on-orbit cal/val, processing, archive and distribution of value-added products are still being worked.

## Sea Surface Temperature

-  A Key variable for climate change studies.
- Air-Sea temperature differences help control ocean-atmosphere coupling and transfer of heat, momentum, and gases.  _Essential_ for weather forecasting, climate and ecosystem process studies...
- Patterns in SST reveal ocean currents...
- Satellite radiometers provide the best method for producing globally consistent data.

## MODIS HERITAGE DAYTIME SST - 8 Day AVERAGE

##     SKIN and BULK SST

-     _SKIN and BULK SST_
- Skin SST
- Sensed by IR, wave sensors
- Controls sea-air exchange
- Up to 0.5 Cooler than Bulk
- Slight windspeed dependency
- Bulk SST
- More analogous to buoy SST
- Reflective of the heat content of
- the upper mixed layer
- Preferred by some climate models

- Eifler & Donlon 2001

- Minnett et al.

- Meters

## VIIRS SST Requirements

- _VIIRS SST Requirements_
- Range 271-313 K
- HCS  0.75 km Nadir, 1.13 Worst Case   (Improved over 4 km GAC)
- Uncertainty (Skin) 0.35 K for favorable conditions
- 	            (< 285K, <40° scan, no adjacent clouds, no cirrus, AOT < 0.2)
- 	                  0.5 K for clear but not favorable
- Uncertainty (Bulk) 0.5 K
- Precision (Skin & Bulk, Clear)  0.27 K
- Long term stability	0.1 K

## DECREASED AEROSOL EFFECTS

-  _WITH 4 MICRON SPLIT WINDOW_

- K

## Minnett et al.

- MODIS NIGHT TIME PERFORMANCE

## VIIRS SST ALGORITHM

- 	Glint avoidance, Aerosol correction
- TS  = a0 + a1 T11+ a2T12+a3(sec(z)-1) + a4 T3.7+ a5T4.0 + a6T3.7cos(zs)        	+ a7T4.0cos(zs) + a8(T11-T12)2
- 		_AVHRR NLSST /MODIS (Day):_
- TS  = a0 + a1 T11+ a2TSFC(T11-T12)  + a3 (T11-T12) (sec(-1)
- 	MWIR (SST4) algorithm used only at night for MODIS:
- SST4  = c0 + c1 T11+ c2T3.9 + c3 (T3.9-T4) (sec(-1)
- The VIIRS algorithm is considerably more complex than heritage and interactions are ongoing.

- _VIIRS SST ALGORITHM_

## Microwave All Weather SST - CMIS

- HERITAGE:  SSM/I, SSMIS
- 	TMI on TRMM
- 	AMSR E on AQUA
- CMIS REQUIREMENTS
- 	Range 271-313 K
- 	HCS  50 km
- 	Uncertainty (Skin & Bulk) 0.5 K
- 	Precision (Skin & Bulk)  0.5 K
- 	Long term stability	0.1 K
- Performance will degrade in some weather, observing conditions
- First available on NPOES

- _Microwave All Weather SST - CMIS_

## http://www.ssmi.com/sst/sst_data_daily.html

## Oceans Summary

- NPP/NPOESS Ocean Products represent a significant upgrade/transition of heritage R&D capability to the on-going operational system, which will be of great benefit to the nation.
- Many instrumental and IT challenges have been overcome, and some continue to be worked, to ensure that this endeavor is successful.