Global Space-based Inter-Calibration System (GSICS)

Progress Report

Mitch Goldberg, NOAA/NESDIS GSICS Executive Panel chair

What is GSICS?• Global Space-based Inter-Calibration System (GSICS)

• Goal - Enhance calibration and validation of satellite observations and to intercalibrate critical components global observing system

• Part of WMO Space Programme– GSICS Implementation Plan and Program formally endorsed

at CGMS 34 (11/06)

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GSICS Mission• To provide sustained calibration and validation of satellite

observations

• To intercalibrate critical components of the global observing system to climate quality benchmark observations and/or reference sites

• To provide correction coefficients and algorithms to the user community for current and historical data

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Before intercalibraion

After intercalibration

Trend of global oceanic total precipitable water decreases from 0.54 mm/decade to 0.34 mm/decade after intercalibrations! Calibration uncertainties translate to uncertainties in climate change detection

Inter-Calibration is Critical for Climate Change Detection

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Current focus of GSICS

• Interagency collaboration on algorithms (GRWG) and data exchange and formats (GDWG)

• Product acceptance and documentation requirements, metadata standards, data formats, website standards

• Routine intercalibration (monitor and correct) of all operational GEO Infrared imagers using IASI and AIRS – MODIS and Deep Convective Clouds for visible

channels

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Current focus of GSICS• Intercalibration of LEO instruments

– HIRS, SSMI, AMSU, MHS, AVHRR, AIRS, IASI, FY3,– GOME-2, OMI, SBUV

• Traceability– Campaigns – Key collocation datasets– Requirements for pre-launch calibration

• Root causes and corrections

First GSICS Guideline document

Best Practice Guidelines for Pre-Launch Characterization and Calibration of Instruments for Passive Optical Remote Sensing

Report to GSICS Executive Panel

R.U. Datla, J.P. Rice, K. Lykke and B.C. Johnson (NIST)

J.J. Butler and X. Xiong (NASA)

September 2009

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Ch6Ch4 Ch3

Ch2

IASI

AIRS

First international coordinated GSICS project is the intercalibration of geostationary infrared channels with IASI and AIRS

Web Accessible

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GSICS Correction Algorithm for Geostationary Infrared Imagers GSICS will provide correction coefficients for all GEOs

from 2003 (beginning of AIRS record) to present

The first major deliverable to the user community is the GSICS correction algorithm for geostationary satellites.

The user applies the correction to the original data using GSICS provided software and coefficients.

The correction adjusts the GOES data to be consistent with IASI and AIRS.

The figures to the left show the difference between observed and calculated brightness temperatures (from NCEP analysis) before and after correction

The bias is reduced from 3 K to nearly zero.

Before 3K Bias

After: ~ 0K Bias

10Geneva, 29 April 2010

GSICS Executive Panel Meeting

currentJan/07 Jan/08 Jan/09

Status of GEO-LEO Inter-Calibration

GOES-11

Jun/07 Aug/08

MTSAT-1R

FY-2D

Jan/10

GOES-12GOES-13

Meteosat-7

FY-2C

AIRS IASI

Meteosat-9

Near-real time monitoring and correction for six operational GEO with baseline algorithm

2nd GSICS Users Workshop, Cordoba, Spain, 21 Sep 2010 11

MSG SEVIRI CSR with and without GSICS bias correctionAnomaly Correlation for 500 mb height over tropics (left) and NH (right)

Impacts of GSICS Correction for SEVIRI on GFS Forecast

Before GSICS correction After GSICS correction

IMPACT on Cloud Coverage ClassificationMSG March 2009

13Geneva, 29 April 2010 GSICS Executive Panel Meeting

Recent ApplicationsCharacterization of Midnight Blackbody Calibration Anomaly

(a) (b)

(c) (d)

Figure 4: Typical example scatter diagrams of orbit mean night time GEO-LEO brightness temperature differences during August 2009 for (a) Channel 2, (b) Channel 3, (c) Channel4, and (d) Channel 5. It can be noted from these plots that Channels 4 and 5 experiences significant midnight residuals while other channels do not exhibit a similar effect. The black colored squares indicate GEO differences with AIRS while the red colors indicate the same corresponding to IASI.

Accomplishments