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The NPOESS Preparatory ProjectNPP

OSU MODIS WorkshopSeptember 4 , 2003

Dr. Wayne EsaiasNASA GSFC

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What is NPP?

• NPP is the NPOESS Preparatory Project• 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

• NPP will launch in the fall of 2006

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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)

Local Equatorial Crossing Time

0530

13300930

METOP

NPOESS

METOP

NPOESS

NPOESS

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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

• The Ozone Mapping and Profiling Suite (OMPS) continues the measurement series of SBUV & TOMS and adds a new limb profiler

• The Clouds and Earth Radiant Energy Sensor (CERES) may be added to the payload to continue the radiation budget data record initiated by ERBE and continued by CERES on Terra and Aqua

– Decision in late 2003

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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 of 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°)

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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

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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

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Detector Aggregation Reduces Pixel Growth

742 m 1104 m 1600 m

630 m

1260 m1600 m

262 m

786 m

Nadir 1700 km 3000 km• aggregate 3 samples• SNR increases by sqrt(3)

• no aggregation• aggregate 2 samples• SNR increases by sqrt(2)

Radiometric (“Moderate-Resolution”) Bands

371 m 552 m 800 m

315 m

630 m800 m

131 m

393 m

Nadir 1700 km 3000 km

• aggregate 3 samples• SNR increases by sqrt(3)

• no aggregation• aggregate 2 samples• SNR increases by sqrt(2)

Imaging (“High-Resolution”) Bands

Moderate and Imaging bands nest 2x2

To ~

To ~

VIIRSReducesPixel Size

AlongScan:

MuchBetter

HSR, SNRTowardNadir

AVHRR& MODIS“1 km”Bands:~2x6kmAt Edge

Vs.

VIIRS1.6x1.6 km

At Edge

HorizontalSamplingInterval

HorizontalSamplingInterval

to 1060km

to 1060km

To

To

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Reduced Pixel Growth Along Scan

Scan HSI as a Function of Scan Angle for Unit Raw GSD at Nadir

0123456789

10111213141516171819

0 8 16 24 32 40 48 56

Scan Angle (degrees)

Raw GSD (No Agg)

Agg 2 in Scan

Agg 3 in Scan

VIIRS HSI

HSI Returns to Nadirsize at the two transition

points (31.71o and 47.87o)

Rat

io o

f O

ff-n

adir

pix

el t

o n

adir

pix

el

~1500 km

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Dual Gain Bands Meet Ocean & Land Needs

Low Gain: = 1.1628E-04 = 1.6177E-02

High Gain: = 1.1628E-04 = 3.4392E-03

M1

0

500

1000

1500

2000

2500

0 100 200 300 400 500 600 700

L (W/m^2/sr/m)

SN

R

Spec. ValuesUnaggregated Pixels -

412 nm Band

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0

0.2

0.4

0.6

0.8

1

0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96

8 9 10 11MODIS: 12 13/14 15 16

MODIS Ocean Bands in the Vis/NIR

12

0

0.2

0.4

0.6

0.8

1

0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96

R-1 R-2 R-3VIIRS: R-4 R-5 R-6 R-7

VIIRS Ocean Bands in the Vis/NIR

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0

0.2

0.4

0.6

0.8

1

0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96

8 9 10 11MODIS: 12 13/14 15 16

Ocean Bands: MODIS - VIIRS TransitionR-1 R-2 R-3VIIRS: R-4 R-5 R-6 R-7

14

0

0.2

0.4

0.6

0.8

1

3.2 3.4 3.6 3.8 4 4.2

MODIS: 20 2321-22

MODIS Ocean Bands in the SWIR

15

0

0.2

0.4

0.6

0.8

1

3.2 3.4 3.6 3.8 4 4.2

MODIS: 20 2321-22

MODIS & VIIRS Ocean Bands in the SWIRVIIRS: R-12 R-13

16

0

0.2

0.4

0.6

0.8

1

6 7 8 9 10 11 12 13 14

MODIS Ocean Bands in the LWIR

29MODIS: 31 32

17

0

0.2

0.4

0.6

0.8

1

6 7 8 9 10 11 12 13 14

29MODIS: 31 32VIIRS: R-15 R-16R-14

MODIS & VIIRS Ocean Bands in the LWIR

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0

0.2

0.4

0.6

0.8

1

6 7 8 9 10 11 12 13 14

VIIRS: R-15 R-16R-14

VIIRS Ocean Bands in the LWIR

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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 thru space-view port

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VIIRS Status

• Critical Design Review was held in March 2002• Algorithms delivered from Raytheon to Northrop Grumman Space

Technologies (NGST) in Fall of 2002– Further algorithm testing by NGST until late 2004

• Sequential release of algorithms to Raytheon Aurora for conversion to operational code

– SST delivered March 31, 2003– Ocean color to be delivered April 30, 2003– Some additional algorithm work possible after delivery for operationalization

• Problem with VIIRS optical design discovered in October 2002– Detectors see inside of rotating telescope which varies in temperature– 3 design options examined by Red Team in December– Design fix identified– Optics will be reduced from f/6.0 to f/6.2 resulting in small performance

degradation– CDR on new design May 8, 2003– No slip in delivery schedule

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NRA Status

• Approximately 70 proposals were received in response to the NPP NRA

• 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

• Selection of team planned for summer 2003• A second science team selection will be made closer to the launch

of NPP– NASA HQ working on plans for discipline-based themes to produce

Climate Data Records

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Some Web Sites

• A description of the NPP mission may be found at:– http://jointmission.gsfc.nasa.gov/

• The VIIRS instrument is described at:– http://www.ipo.noaa.gov/viirs.html

• The VIIRS ATBDs are at:– http://npoesslib.ipo.noaa.gov/atbd_viirs.htm

• The complete list of NPOESS requirements may be obtained at:– http://npoesslib.ipo.noaa.gov/Req_Docs.htm

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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, CO2 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

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Visible Infrared Imaging Spectroradiometer (VIIRS)

Cryoradiator

4-Mirror AnastigmatAll Reflective

Aft Optics Imager

3-Mirror AnastigmatAll reflective

Rotating telescope

FPIE

Solar Diffuser

Blackbody

Half-angle Mirror

Separately Mounted Electronics Module

Cold FPADewar Assembly

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Warm Focal Plane

Dewar

Cold FocalPlanes (Inside)

Aft Optics

Half Angle Mirror

Rotating Telescope

Yields Lower Scattered Light than MODIS

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Band name DNBM1 M2 M3 M4 I1 M5 M6 M7 I2 M8 M9 M10 I3 M11M12 I4 M13M14 M15 I5 M16Band position 700 412445488555645672751865865 1.2 1.4 1.6 1.6 2.3 3.7 3.7 4.1 8.6 10.8 11.512.0Band width 400 20 18 20 20 50 20 15 39 39 0.020.0150.060.060.050.180.380.160.30 1.00 1.900.95

ImagerySea Surface Temp.Soil MoistureCloud Base HeightCloud Cover/LayersCloud Partical SizeCloud Thickness Cloud Top HeightCloud Top PressureCloud Top Temp. Land Surface Temp.FireVegetation IndexSnow Cover (Binary)Snow Cover (Fraction)Vegetation/TypeAlbedoFresh Water IceIce Surface Temp.Littoral TransportNet Heat FluxOcean Color/Chloro.Sea Ice age/motionMass (turbidity)Ocean Currents Aer Opt Thick (Ocean)Aer Opt Thick (Land)Aer Part Size (Ocean)Aer Part Size (Land)Suspended Matter Total Prec. WaterCloud Mask

nm/mVIIRS’ 0ptimized Bandset Provides Rich Data for All EDRs

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Band NameWavelength Ltyp SNR Effective

Algorithm SNR

Trk Scn Trk Scn Trk Scn Trk Scn Trk Scn Trk ScnM1 0.412 742 262 1094 617 44.9 352.0 1 3 1 1 742 786 609.7 13001300M2 0.445 742 262 1094 617 40.0 337.8 1 3 1 1 742 786 585.2 13001300M3 0.488 742 262 1094 617 32.0 310.6 1 3 1 1 742 786 538.0 13001300M4 0.555 742 262 1094 617 21.0 257.1 1 3 1 1 742 786 445.3 13001300M5 0.672 742 262 1094 617 10.0 242.1 1 3 3 3 2226 2358 1258.0 13001300M6 0.751 742 262 1094 617 9.6 199.1 1 3 3 3 2226 2358 1034.6 13001300M7 0.865 742 262 1094 617 6.4 #N/A 1 3 3 3 2226 2358 #N/A 13001300

EOS

Effective GSD

Native Sensor

Product HCS

Aggregation Factor

Aggregation Factor

Algorithm GSD

NADIRFine coastal

Onboard On ground

NADIR

Ocean Color/Chlorophyll EDR - RDR Data Summary

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Band (m)

# in TDI Gain

Ltyp or

Ttyp Q or K

Lmax or

Tmax Q or K

SNR @ Ltype (c-/c-)

NEdT @ Ttyp (K)

SNR@ Ltyp (c-/c-)

NEdT @ Ttyp (K)

SNR2 Lty (c-/c-)

NEdT @ Ttyp

(K)

SNR Required

(c-/c-)

NEdT Require

d (K)

SNR margin

in Design

M1 0.4 1 Dual200.0465.0 1780.5 n/a 145.8 n/a 1028.0 n/a 841.0 n/a 22%2.0 0.4 1 Dual 55.5 469.0 2456.0 n/a 2005.4 n/a 1418.0 n/a 866.0 n/a 60.0%M3 0.5 1 Dual 51.8 541.0 3050.1 n/a 2490.4 n/a 1761.0 n/a 963.0 n/a 82.9%4.0 0.6 1 Dual 29.0 590.0 3275.3 n/a 2674.3 n/a 1891.0 n/a 1018.0 n/a 85.8%M5 0.7 1 Dual 22.0 468.0 3346.3 n/a 2732.3 n/a 1932.0 n/a 1379.0 n/a 40.1%M7 0.9 1 Dual 25.0 278.0 3713.1 n/a 3032.1 n/a 2144.0 n/a 1059.0 n/a 102.5%M13 4.1 1 Dual 380 500 844.7 0.039 844.7 0.048 597.3 0.068 386.5 0.105 54.5%

Source File: F.VRPMO14.xls Q=watt m-2 sr-1m-1 1 x 3 aggregation1 x 2 aggregation 1 x 1 aggregation

Low gain for dual-gin bands

Performance Summary for Low-gain State of Dual-gain Bands

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Band (m) # in TDI Gain

SNR @ Ltype (c-/c-)

NEdT @ Ttyp (K)

SNR@ Ltyp (c-/c-)

NEdT @ Ttyp (K)

SNR2 Lty (c-/c-)

NEdT @

Ttyp (K)

SNR Required (c-/c-)

NEdT Required (K)

SNR margin in Design

M1 0.412 1 Dual 44.9 135.0 763.9 n/a 623.7 n/a 441.0 n/a 352.0 n/a 25.3%M2 0.445 1 Dual 40.0 127.0 976.6 n/a 797.4 n/a 563.9 n/a 337.8 n/a 66.9%M3 0.488 1 Dual 32.0 107.0 1,067.1 n/a 871.3 n/a 616.1 n/a 310.6 n/a 98.3%M4 0.555 1 Dual 21.0 78.0 931.8 n/a 760.8 n/a 538.0 n/a 257.1 n/a 109.3%I1 0.645 1 Single 22.0 468.0 335.2 n/a 273.7 n/a 193.5 n/a 10.0 n/a 48.1%M5 0.672 1 Dual 10.0 59.0 645.3 n/a 526.9 n/a 372.6 n/a 242.1 n/a 53.9%M6 0.751 1 Single 9.6 41.0 557.0 n/a 454.8 n/a 321.6 n/a 199.1 n/a 61.5%I2 0.865 1 Single 25.0 278.0 435.3 n/a 355.4 n/a 251.3 n/a 151.2 n/a 66.2%

M7 0.865 1 Dual 6.4 29.0 864.1 n/a 705.5 n/a 498.9 n/a 215.3 n/a 131.7%M8 1.24 1 Single 5.4 95.0 228.4 n/a 186.5 n/a 131.9 n/a 101.0 n/a 30.6%M9 1.378 1 Single 6.0 41.0 256.5 n/a 209.4 n/a 148.1 n/a 82.7 n/a 79.0%I3 1.61 1 Single 7.3 56.7 148.7 n/a 121.4 n/a 85.9 n/a 6.0 n/a 1331.1%

M10 1.61 1 Single 7.3 72.5 866.5 n/a 707.5 n/a 500.3 n/a 352.2 n/a 46.2%M11 2.25 1 Single 0.12 5.6 26.2 n/a 21.4 n/a 15.1 n/a 10.0 n/a 51.2%I4 3.74 1 Single 270 310 46.4 0.408 37.9 0.500 26.8 0.707 7.6 2.500 253.4%

M12 3.70 1 Single 270 310 146.1 0.128 119.3 0.157 84.3 0.222 47.3 0.396 78.2%M13 4.05 1 Dual 300 343 893.6 0.028 729.6 0.035 515.9 0.049 237.7 0.107 117.0%M14 8.55 1 Single 270 310 1,627.7 0.027 1,329.0 0.033 939.7 0.046 475.8 0.091 97.5%M15 10.7625 1 Single 300 408 2,233.4 0.030 1,823.6 0.036 1,289.5 0.052 950.6 0.070 35.7%I5 11.45 1 Single 210 310 91.7 0.382 74.9 0.468 52.9 0.661 23.3 1.500 126.8%

M16 12.0125 2 Single 300 340 2,428.1 0.030 1,985.5 0.037 1,401.8 0.053 1,024.4 0.072 36.9%DNB 0.70 Variable 6.70E-0.5 500 30.0 n/a - - 6.6 n/a 6.0 n/a 10%-400%

1 x 3 aggregation1 x 2 aggregation 1 x 1 aggregation

Source File: F.VRPMO14.xls Q=watt m-2 sr-1m-1

Low gain for dual-gin bands

Ltyp or Ttyp Q or

K

Lmax or

Tmax Q or K

Performance Summary for Single Gain or High Gain