Abstract
Exelis has developed some new calibration methodologies for Satellite Earth observation data. Maintaining calibration of climate data records (CDRs) is challenging due to many reasons. For example, optics can be subject to degradation of up to 30% in the UV, often due to contamination. Many existing instruments do not have stable on-board calibration sources in the UV-visible region and establishing traceability to NIST standards for solar wavelengths is difficult. On-board blackbodies have also been seen to drift in their thermal output to extents not reflected by their incorporated temperature sensors. Exelis techniques can use Deep Convective Cloud albedo and available lunar scans to correct CDRs dating back decades. It is important to consider natural variability when attempting to detect trends in climate benchmarks. This makes it necessary to have at least 20 years of Earth observation data to detect changes due to cloud climate feedback, even for a perfectly calibrated instrument. Hence the launch of improved, state of the art instruments in the near future still would not enable the detection of cloud forcing for nearly 30 years. Thus improvement of both past and future data using Exelis techniques could make cloud radiative forcing trends observable within ten, rather than thirty years and at low cost & risk.
Low Cost, Low Risk Use of Improved Calibration Techniques to Detect Cloud Climate Feedback Within One Decade of the Present
Exelis has developed some new calibration methodologies for Satellite Earth observation data. Maintaining calibration of climate data records (CDRs) is challenging due to many reasons. For example, optics can be subject to degradation of up to 30% in the UV, often due to contamination. Many existing instruments do not have stable on-board calibration sources in the UV-visible region and establishing traceability to NIST standards for solar wavelengths is difficult. On-board blackbodies have also been seen to drift in their thermal output to extents not reflected by their incorporated temperature sensors. Exelis techniques can use Deep Convective Cloud albedo and available lunar scans to correct CDRs dating back decades. It is important to consider natural variability when attempting to detect trends in climate benchmarks. This makes it necessary to have at least 20 years of Earth observation data to detect changes due to cloud climate feedback, even for a perfectly calibrated instrument. Hence the launch of improved, state of the art instruments in the near future still would not enable the detection of cloud forcing for nearly 30 years. Thus improvement of both past and future data using Exelis techniques could make cloud radiative forcing trends observable within ten, rather than thirty years and at low cost & risk.