India and the United States of America (U.S.A.) held a joint conference from June 21-25, 2004 in
Bangalore, India to strengthen and expand cooperation in the area of space science, applications, and
commerce. Following the recommendations in the joint vision statement released at the end of the
conference, the National Oceanic and Atmospheric Administration (NOAA) and the Indian Space and
Reconnaissance Organization (ISRO) initiated several joint science projects in the area of satellite product
development and applications. This is an extraordinary step since it concentrates on improvements in the
data and scientific exchange between India and the United States, consistent with a Memorandum of
Understanding (MOU) signed by the two nations in 1997. With the relationship between both countries
strengthening with President Bush's visit in early 2006 and new program announcements between the two
countries, there is a renewed commitment at ISRO and other Indian agencies and at NOAA in the U.S. to
fulfill the agreements reached on the joint science projects. The collaboration is underway with several
science projects that started in 2005 providing initial results.
NOAA and ISRO agreed that the projects must promote scientific understanding of the satellite
data and lead to a satellite-based decision support systems for disaster and public health warnings. The
projects target the following areas:
--supporting a drought monitoring system for India
--improving precipitation estimates over India from Kalpana-1
--increasing aerosol optical depth measurements and products over India
--developing early indicators of malaria and other vector borne diseases via satellite monitoring of
environmental conditions and linking them to predictive models
--monitoring sea surface temperature (SST) from INSAT-3D to support improved forecasting of
regional storms, monsoon onset and cyclones.
The research collaborations and results from these projects will be presented and discussed in the
context of India-US cooperation and the Global Earth Observation System of Systems (GEOSS) concept.
Under cloud-free conditions during the daytime, global synergistic retrievals of sea surface temperature (SST) and aerosol optical depths (AOD, or ) are made from the AVHRR instruments flown onboard polar-orbiting sun-synchronous NOAA-16 (equator crossing time, EXT~1400) and -17 (EXT~1000) satellites. Validation against buoys and sun-photometers is customarily considered the ultimate check of the quality and accuracy of SST and AOD retrievals. However, ground-truth data are not available globally and their quality is non-uniform. Moreover, the remotely-sensed parameters may not be fully comparable with their counterparts measured from the surface (e.g. skin vs. bulk SST), and the current procedures to merge data in space and time are not fully objective and may themselves introduce additional errors. In this paper, we propose to supplement the traditional validation with another global diagnostic system. The proposed Quality Control/Assurance (QC/QA) system is based on a comprehensive set of statistical self- and cross-consistency checks. Here, it is illustrated with 8 days of global NOAA-16 and -17 data in December 2003. The AODs and SST anomalies have been first aggregated into 1-day, 1-degree boxes, and their global statistics examined. Analyses are best done in anomalies from the expected state (climatology), which is currently available for the SST but not for the AOD. Histograms of NOAA-16 and -17 SST anomalies are highly correlated (R~0.77), both showing an approximately Gaussian shape, with a mean of ~+0.3K and RMS~1K. AODs also show much similarity but reveal significant cross-platform biases. The magnitudes and even the signs of these biases are band-specific, suggesting that they are due to calibration differences between the two AVHRRs flown on the two platforms. Recall that the AVHRR solar reflectance bands used for aerosol retrievals lack on-board calibration, and therefore may be subject to large calibration errors.