ABSTRACT: The measurement timeseries produced by the infrared component of the CLimate Absolute Radiance and REfractivity Observatory (CLARREO) recommended by the recent National Research Council (NRC) Decadal Survey can provide observational constraints on longwave radiative climate feedbacks. Constraining the climate feedbacks is a key component in a strategy of testing and improving decadal-scale climate forecasts, which is a major objective of the CLARREO program. The uncertainty associated with these constraints is directly related to the measurement uncertainty resulting from the details of the sensor performance. These uncertainties are quantified on-orbit through appeal to the paradigm of SI traceability, tying the on-orbit accuracy to international measurement standards and creating a foundation for on-orbit tests of systematic measurement uncertainties. The impact of these systematic uncertainties on the CLARREO program objectives may be quantitatively estimated through the use of a climate Observational System Simulation Experiment (OSSE) combined with analysis of the sensor calibration equation. We present such a combined OSSE-sensor analysis based on a candidate design for the CLARREO infrared sensor. The sensor analysis utilizes laboratory data quantifying subsystem performance to realistically simulate the impact of uncertainties arising from blackbody quality, optical performance, and system nonlinearity on the total accuracy achieved by the observing system. Combined with realistic Earth spectra produce by the OSSE portion of the analysis, the uncertainty in feedback strengths for select longwave feedback processes is calculated. These feedback uncertainties are then examined in the context of the overall objective of testing and improving climate models.

MKV Carrier Vehicle Sensor Calibration: Joseph Tansock, Scott Hansen – USU/Space Dynamics Laboratory; Jason Williams, Bryan Sisko, Kajal Pancholi – Missile Defense Agency; Aaron Plotnik – MIT Lincoln Laboratory; Jon Albritton – Missile Defense Agency; Michael Margulis, Micah Kalscheur, Dan Welsh – Lockheed Martin Space Systems Company; Deon Dixon – USU/Space Dynamics Laboratory; Steven Brown – Missile Defense Agency; Katharine Ip – Lockheed Martin Space Systems Company; Karl Burk, Mark Greenman, James Peterson, Alan Bird, David Marchant, Dean Ferguson, Brent Haslem – USU/Space Dynamics Laboratory; William Shaw – BAE Systems

ABSTRACT: The Multiple Kill Vehicle (MKV) system, which is being developed by the US Missile Defense Agency (MDA), is a midcourse payload that includes a carrier vehicle and a number of small kill vehicles. During the mission, the carrier vehicle dispenses the kill vehicles to address a complex threat environment and directs each kill vehicle toward the intercept point for its assigned threat object. As part of the long range carrier vehicle sensor development strategy, MDA and project leaders have developed a pathfinder sensor and are in the process of developing two subsequent demonstration sensors to provide proof of concept and to demonstrate technology. To increase the probability of successful development of the sensor system, detailed calibration measurements have been included as part of the sensor development. A detailed sensor calibration can provide a thorough understanding of sensor operation and performance, verifying that the sensor can meet the mission requirements. This approach to instrument knowledge will help ensure the program success and reduce cost and schedule risks. The Space Dynamics Laboratory at Utah State University (SDL) completed a calibration test campaign for the pathfinder sensor in April 2008. Similar calibration efforts are planned later this year for the two demonstration sensors. This paper provides an overview of calibration benefits, requirements, approach, facility, measurements, and preliminary results of the pathfinder calibration.

CLARREO Mission Visible and Near–Infrared Radiometry Studies: Greg Kopp, Peter Pilewskie, Ginger Drake, David Harber, Karl Heuerman – LASP / University of Colorado; Joe Rice, Howard Yoon – NIST

ABSTRACT: We describe two new studies to determine requirements and improve accuracies for the CLARREO mission's benchmark measurements of Earth climate in the visible and near-infrared spectral regions. A science-directed study will clarify the requirements of the CLARREO Earth-viewing measurements in these spectral regions, which sample the solar-reflected radiance from the ground and atmosphere. This study will 1) help define the CLARREO benchmark measurement requirements in the visible and near-infrared, and 2) examine potential benefits from cross-calibrating other on-orbit Earth-viewing instruments to improve their accuracies or extend the CLARREO observations spatially or temporally. The results of this study help determine instrument measurement requirements for absolute accuracy, long-term stability, spectral resolution, global coverage, and spatial resolution. Additionally the cross-calibration considerations may help select optimal orbital parameters for the mission.

An instrument incubator program will study methods to improve radiometric accuracy for hyperspectral imaging in the visible and near-infrared by on-orbit cross-calibrations using spectral solar irradiance. Unlike traditional solar diffuser calibrations, the methods to be demonstrated utilize direct observations of the Sun. Maintaining low uncertainties in radiance attenuation enables transfer of the accurately-known solar irradiance to Earth-viewing spatial/spectral instrumentation. A visible and near-infrared prototype hyperspectral imager will demonstrate and quantify the accuracies to which this calibration transfer can be achieved, enabling end-to-end on-orbit radiometric calibrations and long-term stability corrections.

We describe these NASA-funded studies intended to refine CLARREO measurement requirements based on the mission's science requirements and improve the on-orbit radiometric accuracy of spectral measurements for the mission in the visible and near-infrared.

NPP VIIRS, CrIS, ATMS, OMPS SDR Cal/Val Planning: Paul Lee, James Done, Denise Hagan, Lushalan Liao – Northrop Grumman Space Technology

ABSTRACT: The National Polar-Orbiting Operational Environmental Satellite System (NPOESS) is being developed under contract by Northrop Grumman Space Technology (NGST) for the tri-agency Integrated Project Office for NASA, NOAA and the U.S. Air Force The NPOESS Preparatory Project (NPP) NPP satellite sensor suite consists of Visible/Infrared Imager/Radiometer Suite (VIIRS), Crosstrack Infrared Sounder (CrIS), Advanced Technology Microwave Sounder (ATMS), Ozone Mapping and Profiler Suite (OMPS), and Clouds and the Earth’s Radiant Energy System (CERES). The developmental sensors VIIRS, CrIS, ATMS, and OMPS are responsible for producing 26 NPP Environmental Data Records (EDRs). The performances of these EDRs are driven by the Sensor Data Records (SDRs) that include sensor radiance calibrations and geolocation verifications. This paper will provide a status of the current NPP SDR Calibration and Validation Plan including schedules, calibration and validation approaches, truth data targets, and spacecraft calibration and validation maneuvers.

Cross-comparisons with other spaceborne sensors on the missions deployed in the NASA “A-train”, along with others missions, are used to achieve a quick assessment of the data product performances.