Radiometric and Engineering Performance of the SeaWiFS Quality Monitor (SQM): A Portable Light Source for Field Radiometers (original) (raw)
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Volume 22, Prelaunch Acceptance Report for the SeaWiFS Radiometer
1994
The final acceptance, or rejection, of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) will be determined by the instrument's on-orbit operation. There is, however, an extensive set of laboratory measurements describing the operating characteristics of the radiometer. Many of the requirements in the Ocean Color Data Mission (OCDM) specifications can be checked only by laboratory measurements. Here, the calibration review panel (composed of the authors of this technical memorandum) examines the laboratory characterization and calibration of SeaWiFS in the light of the OCDM performance specifications. Overall, the performance of the SeaWiFS instrument meets or exceeds the requirements of the OCDM Contract in all but a few unimportant details. The detailed results of this examination are presented here by following the outline of the specifications, as found in the Contract. The results are presented in the form of requirement and compliance pairs. These results give conclusions on many, but not all, of the performance specifications. The acceptance by this panel of the performance of SeaWiFS must only be considered as an intermediate conclusion. The ultimate acceptance (or rejection) of the SeaWiFS data set will rely on the measurements made by the instrument on orbit. 331 695 420 897 488 987 4
Volume 31, Stray Light in the SeaWiFS Radiometer
1995
Some of the measurements from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) will not be useful as ocean measurements. For the ocean data set, there are procedures in place to mask the SeaWiFS measure-
Earth Observing Systems XIV, 2009
The SIMBIOS (Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies) Program was conceived as a result of a NASA management review of the agency's strategy for monitoring the biooptical properties of the global ocean through space-based ocean color remote sensing. SIMBIOS Radiometric Intercomparisons (SIMRICs) were carried out in 2001 and 2002. The purpose of the SIMRICs was to ensure a common radiometric scale among the calibration facilities that are engaged in calibrating in-situ radiometers used for ocean color related research and to document the calibration procedures and protocols. The SeaWiFS Transfer Radiometer (SXR-II) measured the calibration radiances at six wavelengths from 411nm to 777nm in the participating laboratories. The measured radiances were compared with the radiances expected by the laboratories. NIST calibrations of the SXR-II were obtained in December 2000, December 2001 and January 2003. Two independent light sources (SQMs, SeaWiFS Quality Monitors) were used to monitor changes in the SXR-II responsivity between the NIST calibrations and after, with monthly measurements until the end of 2003, and less frequent measurements thereafter. This paper discusses the calibration and trending history of the SXR-II from December 2000 to June 2008.
Optical close-range instruments can be applied to derive water quality parameters for monitoring purposes and for validation of optical satellite data. In situ radiometers are often difficult to deploy, especially from a small boat or a remote location. The water insight spectrometer (WISP-3) is a new hand-held radiometer for monitoring water quality, which automatically performs measurements with three radiometers (L sky , L u , E d ) and does not need to be connected with cables and electrical power during measurements. The instrument is described and its performance is assessed by an intercomparison to well-known radiometers, under real fieldwork conditions using a small boat and with sometimes windy and cloudy weather. Root mean squared percentage errors relative to those of the TriOS system were generally between 20% and 30% for remote sensing reflection, which was comparable to those of the other instruments included in this study. From this assessment, it can be stated that for the tested conditions, the WISP-3 can be used to obtain reflection spectra with accuracies in the same range as well-known instruments. When tuned with suitable regional algorithms, it can be used for quick scans for water quality monitoring of Chl, SPM, and aCDOM.