1. Xiangqian Wu and Mitch Goldberg NOAA/NESDIS Center for Satellite Applications and Research (STAR) P1.16 GLOBAL SPACE-BASED INTER-CALIBRATION SYSTEM (GSICS) Introduction The Global Space-based Inter-Calibration System (GSICS) is a WMO-sponsored collaboration among national and international agencies that manage operational environmental satellites (CMA, CNES, EUMETSAT, JMA, KMA, NESDIS, and WMO), with support from universities (UW/SSEC) and other organizations (NASA, NIST). GSICS has been primarily motivated by the increasingly demanding users, due to both the sophistication of the traditional applications such as numerical weather prediction (NWP) and the expansion to the new applications such as climate monitoring. GSICS is also motivated by the rapidly growing global observing system in terms of the number and diversity of the sensors. The goal of the GSICS is to enhance satellite instrument calibration and satellite data validation. These are critical components of the Global Earth Observation System of Systems (GEOSS). Review Calibration (CEOS Definition) The process of quantitatively defining the system responses to known, controlled signal inputs Space-based Inter-Calibration The quantitative analysis of responses by multiple space-borne instruments to common signal inputs Spatially co-located, Temporally concurrent, Geometrically aligned, Spectrally matched GSICS is led by its Executive Panel, with advisory support from GSICS Research Working Group (GRWG) and GSICS Data Working Group (GDWG). Most work is routinely performed at GSICS Processing and Research Centers (GPRC) at each member site, in collaboration with national space or standard agency and universities (Calibration Support Segment, CSS). These activities are coordinated through GSICS Coordination Center (GCC). Review Existing Area or nadir or both GSICS Pixel anywhere Save all and down select later Why Is mean bias all we care? Implementation Common Algorithm Start with a reasonable version that can be used as reference Improve over time and by consensus In each cycle, developer offers Algorithm (logics, threshold) Pseudo code (detailed spec) Actual code Data Results NESDIS is developing Version 1 with GRWG-I recommendations Member Executive Panel Research WGData WG CMA N. LuP. ZhangZ. Rong CNESD. RenautP. Henry EUMETSATJ. SchmetzM. KönigV. Gätner * JMAT. KurinoY. TaharaT. Matsumoto KMAM. OuS. Chung NOAAM. Goldberg * X. Wu * B. Barkstrom WMO J. Lafeuille (Secretary) Two types of orbit Low Earth Orbiting (LEO) and Geostationary (GEO) R. Iacovazzi J. Lafeuille Cao Tobin et al Schmetz et al GRWG-I, 22-23 JAN 2007, NESDIS Identified GEO-GEO inter-calibration as near term priority, even though it’s long been widely used Issues: Different instruments on different orbits Attribute radiance differences to calibration uncertainty Co-locations not uniquely determined by orbit intersection Opportunity: Hyperspectral instruments (AIRS & IASI) Strategy Focused on AIRS vs. GEO imager Reviewed existing algorithms Outlined the strategy for GSICS algorithm Four components of GSICS GEO-GEO, LEO-LEO, Sensors on common platform, GEO-LEO GRWG-II and GDWG-I, 12-14 JUN 2007, EUMETSAT Gunshor et al König et al Tahara Doelling et al Summary GSICS is a WMO-sponsored international collaboration. It is motivated by both user requirements and new challenges and opportunities of technology. Its goal is to enhance satellite instrument calibration and satellite data validation, which are critical components of the GEOSS. The GSICS has four major components. The LEO-LEO inter-calibration based on Simultaneous Nadir Overpass (SNO) is mature. The GEO-GEO and common platform inter-calibration promise many opportunities and challenges in future. The GEO-LEO inter-calibration is the near term priority of GSICS. After reviewing the existing algorithms and the GSICS requirements, the GSICS GEO-LEO algorithm strategy and implementation were outlined in GRWG-I and revised in GRWG-II. The Executive Panel has been providing timely guidance, and the GDWG made valuable contributions at its first meeting. The preliminary results from a prototype algorithm confirm that the strategy is feasible and the results will be valuable. Reviewed the progress since GRWG-I Web site & Newsletter Test data, algorithm, code, and results Revised Data distribution NESDIS distribute subsets of data for individual GEO EUMETSAT distribute similar IASI data Some thresholds values Data management Content, format, file name of archive Reviewed existing algorithms for GEO-LEO inter-calibration of solar bands R. Iacovazzi