Cal/Val QC/QA of SST, Aerosols and Clear Sky Radiances over Oceans
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Cal/Val QC/QA of SST, Aerosols and Clear Sky Radiances over Oceans NDE Preliminary Design Review, 22 March 2007, 9-11:30am, WWB Rm. 707. Global consistency of MetOp-A & NOAA18-15 AVHRR Clear Sky Brightness Temperatures using MODTRAN-4.2 forward RTM. Prasanjit Dash STAR/CIRA

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Prasanjit Dash STAR/CIRA Alexander Ignatov STAR

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Prasanjit dash star cira alexander ignatov star

Cal/Val QC/QA of SST, Aerosols and Clear Sky Radiances over OceansNDE Preliminary Design Review, 22 March 2007, 9-11:30am, WWB Rm. 707

Global consistency of MetOp-A & NOAA18-15 AVHRR Clear Sky Brightness Temperatures using MODTRAN-4.2 forward RTM

Prasanjit DashSTAR/CIRA

Alexander IgnatovSTAR

Acknowledgment

John Sapper, OSDPD– Providing MUT AVHRR Data

Yury Kihai, STAR/QSS– Archiving GDAS Data from NCEP

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 f-RTM: OBJECTIVE

Check consistency of TOA BTs in AVHRR Earth Emission Bands onboard MetOp-A & NOAA-KLMN

by

intercomparing RTM ‘forward simulations’ and ‘measurements’

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTMAPPROACH

REALIZATION :

Step 1 :

SPATIAL MERGING OF

AVHRR vs. NCEP

  • Atmo: T, RH, GP (Z), P

  • Surf: Ts

Forward Simulation, 1cm-1

(MODTRAN 4.2)

5 UTCs for a Date

Step 2 :

Surf:Modeled Spectral Emissivity

(1cm-1 intervals & 17 angles)

Step 3 :

Temporal Interpolation of

forward RTC betw. 2 UTCs

RESULTS

Intercomparison (statistical analysis)

forward model BT

vs.

gridded AVHRRs’ BT

INPUT DATA :

  • AVHRR Brightness Temperatures from heritage

  • SST processor (Main Unit Task- MUT), NIGHT-TIME

  • NCEP GDAS profiles (atmosphere)

  • Emissivity (Fresnel’s law), Tsurface from NCEP (surface)

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM

Step3: TEMPORAL INTERPOLATION

Temporal Variation of Column Water Vapor (Feb 2007)

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM

RESULTS: BT (RTM – MetOp-A AVHRR) MAPS

Channel 3B (RTM - AVHRR)

Channel 4 (RTM - AVHRR)

Channel 5 (RTM - AVHRR)

BT (RTM – AVHRR) CAN BE PLOTTED AS :

  • HISTOGRAM

OR AS A FUNCTION OF :

  • LATITUDE

  • VIEW ZENITH ANGLE

  • COLUMN WATER CONTENT

  • AIR-SEA TEMPERATURE DIFFERENCE

  • WIND SPEED

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM

RESULTS: BT (AVHRR – proxy) as a function of View Zenith Angle

MetOp-A, NOAA18 through NOAA15

AVHRR - RTM

AVHRR – NCEP RTG SST

AVHRR RSR (ncdc.noaa.gov)

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM

RESULTS: BT (AVHRR - proxy) as a function of VZA vs. SNO

AVHRR Channel 3B - RTG

DETECTION OF SENSOR PROBLEM USING:SNO MATCH-UPS

Channel 3B (NOAA 18 vs. MetOp-A)

DETECTION OF SENSOR PROBLEM USING:FORWARD_RTM APPROACH

Channel 3B (AVHRR - RTM)

Source:

Intersatellite Instrument CharacteristicsPOES NOAA18 AVHRR and Metop-A AVHRR

http://www.orbit.nesdis.noaa.gov/smcd/spb/calibration/icvs/n18-metopa-avhrr.html

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM

RESULT HIGHLIGHTS

Using RTM Forward RTC as an expected state for TOA BT is an effective tool for monitoring (QC)

  • Ch-4 shows excellent consistency for 5 platforms and Ch-5 too …

  • Ch-3B of AVHRR onboard MetOp-A and NOAA-16 show anomalous pattern

    • cause being explored – RSR ? Or Cal ? Or anything else ?

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

BACK-UP SLIDES

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM

RESULTS: BT (RTM – AVHRR) as a function of #SSTOBS in GRID

Channel 3B

Channel 4

Channel 5

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM

RESULTS: BIAS and STANDARD DEVIATION, e.g., NOAA-18

NOAA-18, STATISTICS FROM GRIDS WITH STATISTICALLY SIGNIFICANT #OBS e.g., >= 8

Channel 3B: BIAS: 0.86 STDV: 0.55

Channel 4: BIAS 0.18 STDV: 0.67

Channel 5: BIAS:1.07 STDV: 0.67

Cross-platform consistency of AVHRR Clear Sky BT


Emissivity spectral variation for metop a avhrr 3b 4 5 channels

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM

Step 2 :EMISSIVITY MODELING

Emissivity angular variation

Validation against Masuda et al. (1988)

Emissivity spectral variation for MetOp-A AVHRR 3B, 4, 5 channels

Ch-4

Ch-5

Ch-3B

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM

RESULTS: BT (RTM – AVHRR) as a function of View Zenith Angle

MetOp-A, NOAA18 through NOAA15

Channel 3B (RTM - AVHRR)

Channel 4 (RTM - AVHRR)

Channel 5 (RTM - AVHRR)

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM

AVHRR Relative Response Functions Channel 3B

AVHRR Channel 3B Relative Response Functions (MetOp-A & NOAA 18-15) annotated over Mid-Latitude Summer Transmissivity Values calculated with MODTRAN at 1cm-1

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM

AVHRR Relative Response Functions Channel 4

AVHRR Channel 4 Relative Response Functions (MetOp-A & NOAA 18-15) annotated over Mid-Latitude Summer Transmissivity Values calculated with MODTRAN at 1cm-1

Cross-platform consistency of AVHRR Clear Sky BT


Prasanjit dash star cira alexander ignatov star

Global QC/QA of AVHRRs’ TOA BT using MODTRAN-4.2 forward-RTM

AVHRR Relative Response Functions Channel 5

AVHRR Channel 5 Relative Response Functions (MetOp-A & NOAA 18-15) annotated over Mid-Latitude Summer Transmissivity Values calculated with MODTRAN at 1cm-1

Cross-platform consistency of AVHRR Clear Sky BT


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