Paper Info
Title
A Semi-Decadal Multi-Sensor Gridded Data Record of Outgoing Longwave Radiation (OLR) from Aqua
Abstract
Launched on May 4, 2002, Aqua carries two well calibrated independent infrared (IR) instruments, Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS), which together could provide a precise decadal measurement across the IR electro- magnetic spectrum from 3.7um to 15um to form a fundamental climate data record. According to the National Academy of Science - Nation Research Council report (1), 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 (2) 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 inter- annual climate processes. In addition, NPOESS preparatory project will lauch satellite systems carrying instruments similar to AIRS and MODIS which will enable production of an FCDR record for additional decades. An FCDR requires stable and consistent measurements throughout the entire period of observation. We have implemented the Service Oriented Atmospheric Radiance (SOAR) system (3), featuring gridded datasets and analysis capabilities for inter-comparisons of gridded AIRS and MODIS spectral radiances. SOAR can establish the stability and consistency of these measurements over their entire 5 year flight history. In particular, a dataset is available on a lat-lon grid of averaged AIRS radiances over 5 years at a grid resolution of 0.5 X 1.0 degrees from 2005 through 2007. The SOAR system will also produce 5 years of gridded MODIS radiance data at the same resolution from 2002 through 2007. In addition to the averaged radiances for AIRS and MODIS available online, SOAR also provides maximum and minimum radiances for ascending and descending orbits. Figure 1 shows a plot produced by SOAR of AIRS and MODIS gridded radiances across all their measured IR spectral channels for a given day October 1 2007, five years after launch. The plot of the radiances of these two instruments show that the relative measurements of the IR OLR for each of the MODIS spectral channels are consistent with AIRS with the same relative accuracies. We ascribe this consistency to the fact that both instruments have been fully ground calibrated at NIST with the black body instruments, in orbit traceable to the NIST black body calibration.
Year
DOI
Venue
2008
10.1109/IGARSS.2008.4779351
IGARSS
Keywords
Field
DocType
acoustic imaging,image resolution,life span,meteorology,climatology,infrared spectra,brightness temperature,time series,infrared,radiance,electro magnetic,radiometers,optical imaging,radiometry,seasonality,spectrum,temperature measurement
Meteorology,Atmospheric Infrared Sounder,Moderate-resolution imaging spectroradiometer,Satellite,Brightness temperature,Computer science,Remote sensing,Radiometry,NPOESS,Radiance,Radiometer
Conference
Citations 
PageRank 
References 
0
0.34
0
Authors
3
Name
Order
Citations
PageRank
Milton Halem18629.78
David Chapman200.34
Phuong Nguyen3516.56