A Semi-Decadal Multi-Sensor Gridded Data Record of Outgoing Longwave Radiation (OLR) from Aqua

Launched on May 4, 2002, Aqua carries two well calibrated independent infrared (IR) instruments, Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectro- radiometer (MODIS), which together could provide a precise decadal measurement across the IR electro- magnetic spectrum from 3.7 um to 15um to form a fundamental climate data record. According to the National Academy of Science - Nation Research Council report,the notion of a fundamental climate data record (FCDR) is defined as "a time series of measurements of sufficient length and continuity to determine climate variability and change from sensor data (e.g., calibrated radiances, brightness temperatures (BT), radar backscatter) that have been improved and quality controlled over time." AIRS and MODIS have been continuously returning upwelling IR spectral radiance measurements while maintaining a nominal grid precision of ~0.2 - 0.4 K BT [2] with quality controlled calibration improvements for more than five years. Based on the Aqua senior Project Review of available flight fuel, power and orbital maneuvers, the assessed life span of the satellite Aqua is estimated to be 2013. AIRS and MODIS instrument teams also expect their passive radiometers to continue providing self-calibrating measurements with the same precision through the year 2013. With these assumptions, we show in this paper that with these two independent sensors on the same platform with on orbit relative validations, this data record would be of sufficient length and continuity to meet the FCDR definition to observe and determine the decadal variability of seasonal to interannual climate processes. In addition, NPOESS preparatory project will launch satellite systems carrying instruments similar to AIRS and MODIS which will enable production of an FCDR record for additional decades.