# Presentation: 779896

## Update on the VIIRS Sensor

- Presented to the MODIS Science Team
- July 22, 2002

- Dr. Robert E Murphy
- NPP Project Scientist
- Code 920
- NASA GSFC

## What is NPP?

**NPP is a “bridging mission” that provides for the continuation of measurement series initiated with EOS Terra & Aqua for NASA’s global change research**
**Climate change**
**Global carbon cycle**
**Global water cycle**
**NPP provides risk reduction for the National Polar-Orbiting Operational Environmental Satellite System (NPOESS) which will continue these measurements into the indefinite future**
**NPP is a joint program of NASA and the Integrated Program Office (IPO), the tri-agency activity that is responsible for NPOESS**

## What is the NPOES Mission?

**Mission**
**Provide a national, operational, polar-orbiting environmental capability**
**Achieve National Performance Review savings by converging DoD and NOAA polar satellite programs**
**Incorporate new technologies from NASA and others**
**Incorporate, where appropriate,  International Cooperation (EUMETSAT)**

## Satellite Transition Schedule(9 March 2001)Slopes indicate 10-90% need (NPOESS GAP 5b)

**CY**

**99**

**00**

**11**

**12**

**13**

**14**

**15**

**16**

**17**

**18**

**03**

**08**

**09**

**10**

**01**

**02**

**07**

**04**

**05**

**06**

- Earliest Availability

**S/C**
**Deliveries**

**0530**

**1330**

**DMSP**

**0730 - 1030**

**NPOESS**

**C3**

**POES**

**NPOESS**

**C2 or C1**

**N’**

- Earliest Need to back-up launch

**F20**

**NPOESS**

**DMSP**

**POES**

**METOP**

**NPOESS**

**C1 or C2**

**F16**

**N**

**M**

**F17**

**F19**

**F15**

**F18**

**L (16)**

- Satellite Transition Schedule**(9 March 2001)***Slopes indicate 10-90% need (NPOESS GAP 5b)*

- Projected End of Life based on 50% Need

**Local Equatorial Crossing Time**

## NPP Sensors

**The Visible Infrared Imaging Spectroradiometer Suite (VIIRS) extends measurement series initiated by MODIS on EOS Terra & Aqua**
**Design is evolutionary from MODIS**
**The Cross-track Infrared Sounder (CrIS) continues measurement series initiated by AIRS on EOS Aqua**
**Utilizes a Michelson interferometer in contrast to AIRS, which is a spectrometer**
**The Advanced Technology Microwave Sounder (ATMS) continues the measurement series initiated by the AMSU on NOAA-15**
**MMIC Technology used to reduce mass, power & volume**
**An Instrument of Opportunity is under consideration**
**Aerosol Polarimeter Sensor**
**CERES**
**OMPS**
**SAGE III**
**Code S payload**
**Decision August 2002**

## NPP & NPOESS Orbits

**NPP has 824 km Sun synchronous orbit**
**10:30 AM descending node**
**98.74° inclination**
**Mimics Terra ground track repeat**
**16 day ground-track repeat**
**Swath width 0f 3,000 Km (±56.06°)**
**NPOESS has 833 km Sun synchronous orbits**
**All 3 satellites will carry a VIIRS**
**09:30 descending node**
**13:30 ascending node**
**17:30 ascending node**
**Swath width of 3,000 km (±56.06°)**

## Operational & Research Data Products

**The operational system (NPOESS) will produce Environmental Data Records (EDR’s) of geophysical products in less than 90 minutes from acquisition**
**Timeliness requirement limits accuracy & consistency that can be obtained**
**Yesterday’s weather is of limited use**
**NASA’s program requires maximum accuracy and consistency over many years**
**Timeliness is not an issue**
**NASA will produce similar geophysical products in the form of Climate Data Records (CDR’s)**

## Visible Infrared Imaging Radiometer Suite (VIIRS)

_**Purpose:**_**  Global observations of land, ocean, & atmosphere parameters at high temporal resolution (~ daily)**
_**Predecessor Instruments:**_**  AVHRR, OLS, MODIS, SeaWiFS**
_**Management**_**: Integrated Program Office**_** **_
_**Status:**_**Phase C/D (Raytheon)**
_**Approach:**_**  Multi-spectral scanning radiometer (22 bands between 0.4 ********m and 12 ********m)   12-bit quantization**
_**Swath width:**_**  3000 km**

**Changes to specifics of band dynamic ranges, bandpasses & band centers negotiated**
**Consideration of adding 6.7 micrometer water vapor band to FM3 & later models**
**CDR Completed March 2002**

## Visible Infrared Imaging Spectroradiometer (VIIRS)

## VIIRS Spectral Bands

**22 Bands**
**Subset of MODIS bands plus day-night panchromatic band**
**Two spatial resolutions**
_**Imagery**_** resolution bands:    370 m at nadir**
_**Moderate**_** resolution bands:  740 m at nadir**
**Features**
**8 (Moderate) or 16 (Imagery) detectors per scan**
**Bands spatially nested**
**Some bands have dual gain**
**Maximize dynamic range without precision penalties**
**Constrained pixel growth with scan angle**

## VIIRS Optimized Bandset Supports All EDRs

## Slide 12

## Slide 13

## Slide 14

## Slide 15

## Slide 16

## Slide 17

## Slide 18

## Slide 19

## Slide 20

## Slide 21

## Detector Aggregation Reduces Pixel Growth

**Moderate and Imaging bands nest 2x2**

**To**** ~**

**To**** ~**

**VIIRS**
**Reduces**
**Pixel Size**
**Along**
**Scan:**
***Much***
***Better***
***HSR, SNR***
***Toward***
***Nadir***

**AVHRR**
**& MODIS**
**“****1 km”**
**Bands:**
**~2x6km**
**At Edge**
**Vs.**
**VIIRS**
_**1.6x1.6 km**_
**At Edge**

**Horizontal**
**Sampling**
**Interval**

**Horizontal**
**Sampling**
**Interval**

**to 1060km**** **

**to 1060km**** **

**To**

**To**

## Reduced Pixel Growth Along Scan

**Ratio of Off-nadir pixel to nadir pixel**

**~1500 km**

## Calibration

**Stray light much better than MODIS**
**Driven by needs of the day-night (DNB)**
**Rotating telescope, extensive baffling reduces scattered light**
**V-grove blackbody similar to MODIS**
**Baffled to avoid Earth illumination**
**Emissivity of 0.9998**
**Controlled to 290K by pulsed voltage **
**Heat to 315K**
**Solar Diffuser (SD) evolutionary from MODIS**
**1 time door**
**New design eliminates “ripples”**
**Solar Diffuser Stability Monitor (SDSM) evolutionary from MODIS**
**7 bands**
**Views 70% of SD area**
**Planning to use 2nd order polynomial for all bands**
**Characterization plan similar to MODIS**
**Lunar views possible**

## Some Issues

**Dynamic range for fire is inadequate**
**Similar issue faced on MODIS**
**“****Imagery” & SST are the two highest priority EDRs for the IPO**
**“****MODIS compromise” not acceptable**
**Multi-band algorithmic solution may be possible**
**645 nm band (I-1) dynamic range increased to avoid saturated pixels for imagery**
**Spectral requirements changed from center wavelength of 645nm (50 nm wide) to 640nm (80nm wide)**
**Modest compromise to VI work**
**751 nm band (M-6) center wavelength changed from 751nm to 746nm**
**NASA geolocation requirement (200 m 3 ********) not an IPO requirement**
**Margin is eroding to achieve this accuracy**
**Consideration being given to adding 6.7 micrometer band for FM3 & beyond**

## Fine Scale WV Depiction 

_**Fine Scale WV Depiction**_** **
**MODIS 1 km resolution reveals mountain waves**

## Imagery	Energy Budget/Spectral			Adapted	Y2466

SST	4-Channel Skin--ATSR, MODIS			Adapted (ATSR, Brown, Emery)	Y2386
	Air-mass classification
	Cirrus, aerosol mitigation

Soil Moisture	CMIS/VIIRS Data Fusion			Adapted (Carlson)	Y2387

Aerosol Optical 	Dark Pixel Method			Adapted (Kaufman, Tanre, Vermote)	Y2388
Thickness, Particle				Developed radius (Vermote)
Size, Effective Radius		

Suspended Matter	Multiple Indices & 			Adapted	Y2390
	Dominant Type

Cloud Base Height	Cloud Property LUT			Adapted (Hutchison, Wilheit)	Y2391

Cloud Cover/Layers	Clustering based on cloud properties 		Adapted	Y2392

Cloud Effective 	UCLA Ice & Water			Adapted (Ou, Liou)	Y2393
Particle Size

Cloud Top Height, 	UCLA Ice & Water IR			Adapted (Ou, Liou)	Y2395
Temp., Pressure

**SST****	****4-Channel Skin--ATSR, MODIS****	****	****	****Adapted (ATSR, Brown, Emery)****	****Y2386**
**	****Air-mass classification**
**	****Cirrus, aerosol mitigation**
**Soil Moisture****	****CMIS/VIIRS Data Fusion****	****	****	****Adapted (Carlson)****	****Y2387**
**	****	****	**
**	****	**
**Aerosol Optical ****	****Dark Pixel Method****	****	****	****Adapted (Kaufman, Tanre, Vermote)****	****Y2388**
**Thickness, Particle****	****	****	****	****Developed radius (Vermote)**
**Size, Effective Radius****	****	**
**Suspended Matter****	****Multiple Indices & ****	****	****	****Adapted****	****Y2390**
**	****Dominant Type**
**Cloud Base Height****	****Cloud Property LUT****	****	****	****Adapted (Hutchison, Wilheit)****	****Y2391**
**Cloud Cover/Layers****	****Clustering based on cloud properties ****	****	****Adapted****	****Y2392**
**	****	**
**Cloud Effective ****	****UCLA Ice & Water****	****	****	****Adapted (Ou, Liou)****	****Y2393**
**Particle Size**
**Cloud Top Height, ****	****UCLA Ice & Water IR****	****	****	****Adapted (Ou, Liou)****	****Y2395**
**Temp., Pressure**

- Algorithm Development Status (1 of 3)and Delivery of the V5 ATBDs

- EDR	Final Baseline					Adopted/Adapted/Developed	ATBD#

## Albedo, Surface	Bright surfaces: Linear regression		Adapted (Liang)	Y2398	Dark surfaces: MODIS kernel-driven		Adapted (Strahler, Lucht, Schaaf)

Land Sfc. Temp	4-Channel Land Cover			Adapted	Y2399

Vegetation Index	NDVI, EVI			Adapted (Tarpley, Deering, Huete)	Y2400
	FPAR, LAI, NPP, PSN			Adapted (Running, Knyazikhin, Myneni)

Snow Cover/Depth	Spectral Mixture			Adapted (Hall, Dozier)	Y2401
	and MODIS	
	threshold

Surface Type	Decision Tree			Adapted (Townshend, DeFries)	Y2402

Fresh Water Ice	Energy Budget/Spect. Mix.			Adapted	Y2404

Ice Surface Temp.	Split Window			Adapted	Y2405

**	**
**Land Sfc. Temp****	****4-Channel Land Cover****	****	****	****Adapted****	****Y2399**
**Vegetation Index****	****NDVI, EVI****	****	****	****Adapted (Tarpley, Deering, Huete)****	****Y2400**
**	****FPAR, LAI, NPP, PSN****	****	****	****Adapted (Running, Knyazikhin, Myneni)**
**Snow Cover/Depth****	****Spectral Mixture****	****	****	****Adapted (Hall, Dozier)****	****Y2401**
**	****and MODIS****	**
**	****threshold**
**Surface Type****	****Decision Tree****	****	****	****Adapted (Townshend, DeFries)****	****Y2402**
**Fresh Water Ice****	****Energy Budget/Spect. Mix.****	****	****	****Adapted****	****Y2404**
**Ice Surface Temp.****	****Split Window****	****	****	****Adapted****	****Y2405**
**	**
** **

- Algorithm Development Status (2 of 3)

- EDR/SDR	Final Baseline					Adopted/Adapted/Developed	ATBD#

## Net Heat Flux	Regression/Neural/Bulk			Adapted (Ruprecht, Liu) 	Y2407

OC/Chlorophyll	Carder/MODIS Case 2			Adapted (Carder)	Y2408
	Regionally tuneable

Ocean Atmos. Corr.	Improved SeaWiFS			Adapted (Gordon, Wang, Liu)	 Y2411
	With full residual				    (IP)
	polarization handling

Sea Ice Age/Edge	Maximum Cross-Correlation		Adapted (Emery)	Y2409

Land Atmos. Corr.	Radiative Transfer LUT (MODIS)		Adapted (Vermote)	Y2411
(Surface Reflectance)					   (IP)

Cloud Mask	Thresholding/Phase			Adapted (MODIS/CLAVR, Stowe)	Y2412

Precipitable Water	Five-band TIR			Adapted (Huang)	Y3251

Active Fires	Raytheon HSS/MODIS			Adapted (HSS, Giglio/Justice/Kaufman)	Y3252
					(ARR)

**	****	**
**OC/Chlorophyll****	****Carder/MODIS Case 2****	****	****	****Adapted (Carder)****	****Y2408**
**	****Regionally tuneable**
**	****	**
**Ocean Atmos. Corr.****	****Improved SeaWiFS****	****	****	****Adapted (Gordon, Wang, Liu)****	**** Y2411**
**	****With full residual****	****	****	****	****    (IP)**
**	****polarization handling**
**Sea Ice Age/Edge****	****Maximum Cross-Correlation****	****	****Adapted (Emery)****	****Y2409**
**Land Atmos. Corr.****	****Radiative Transfer LUT (MODIS)****	****	****Adapted (Vermote)****	****Y2411**
**(Surface Reflectance)****	****	****	****	****	****   (IP)**
**Cloud Mask****	****Thresholding/Phase****	****	****	****Adapted (MODIS/CLAVR, Stowe)****	****Y2412**
**	**
**Precipitable Water****	****Five-band TIR****	****	****	****Adapted (Huang)****	****Y3251**
**Active Fires****	****Raytheon HSS/MODIS****	****	****	****Adapted (HSS, Giglio/Justice/Kaufman)****	****Y3252**
**	****	****	****	****	****(ARR)**

- Algorithm Development Status (3 of 3)

- EDR	Final Baseline					Adopted/Adapted/Developed	ATBD#

## NRA Status

**An NRA for an initial science team for NPP is nearing release**
**The team will assist NASA in preparing to use the operational system for long term climate research**
**Which EDRs can be used as CDRs?**
**What steps need to be taken to assure climate quality data?**
**Use simulations based on real and synthetic data sets**
**Provide insight into sensor characterization**
**A second science team selection will be made closer to the launch of NPP**

## Summary

**MODIS quality measurements will be continued in the operational system (NPOESS)**
**VIIRS draws heavily on its MODIS heritage**
**Some research capabilities (e.g. fluorescence, CO****2**** slicing bands) are not continued**
**Overall similar radiometric quality**
**Improved geometric resolution**
**Continued commitment to characterization and calibration**
**NASA science team to be competed soon**

## Back-Up Charts

**Land Vis-NIR Bands**
**Ocean SWIR Bands**
**Atmosphere Vis-NIR Bands**
**Atmosphere SWIR Bands**
**Atmosphere MWIR Bands**

## Slide 33

## Slide 34

## Slide 35

## Back-Up Charts

**Land Vis-NIR Bands**
**Ocean SWIR Bands**
**Atmosphere Vis-NIR Bands**
**Atmosphere SWIR Bands**
**Atmosphere MWIR Bands**

## Slide 37

## Slide 38

## Back-Up Charts

**Land Vis-NIR Bands**
**Ocean SWIR Bands**
**Atmosphere Vis-NIR Bands**
**Atmosphere SWIR Bands**
**Atmosphere MWIR Bands**

## Slide 40

## Slide 41

## Slide 42

## Back-Up Charts

**Land Vis-NIR Bands**
**Ocean SWIR Bands**
**Atmosphere Vis-NIR Bands**
**Atmosphere SWIR Bands**
**Atmosphere MWIR Bands**

## Slide 44

## Slide 45

## Slide 46

## Back-Up Charts

**Land Vis-NIR Bands**
**Ocean SWIR Bands**
**Atmosphere Vis-NIR Bands**
**Atmosphere SWIR Bands**
**Atmosphere MWIR Bands**

## Slide 48

## Slide 49

## Slide 50

## Slide 51