Record Details
Dynamic range and sensitivity requirements of satellite ocean color sensors: learning from the past
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Dynamic range and sensitivity requirements of satellite ocean color sensors: learning from the past |
| Names |
Hu, Chuanmin
(creator) Feng, Lian (creator) Lee, Zhongping (creator) Davis, Curtiss O. (creator) Mannino, Antonio (creator) McClain, Charles R. (creator) Franz, Bryan A. (creator) |
| Date Issued | 2012-09-01 (iso8601) |
| Note | This paper was published in Applied Optics and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/ao/home.cfm. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. |
| Abstract | Sensor design and mission planning for satellite ocean color measurements requires careful consideration of the signal dynamic range and sensitivity (specifically here signal-to-noise ratio or SNR) so that small changes of ocean properties (e.g., surface chlorophyll-a concentrations or Chl) can be quantified while most measurements are not saturated. Past and current sensors used different signal levels, formats, and conventions to specify these critical parameters, making it difficult to make cross-sensor comparisons or to establish standards for future sensor design. The goal of this study is to quantify these parameters under uniform conditions for widely used past and current sensors in order to provide a reference for the design of future ocean color radiometers. Using measurements from the Moderate Resolution Imaging Spectroradiometer onboard the Aqua satellite (MODISA) under various solar zenith angles (SZAs), typical (L[subscript typical]) and maximum (L[subscript max]) at-sensor radiances from the visible to the shortwave IR were determined. The L[subscript typical] values at an SZA of 45° were used as constraints to calculate SNRs of 10 multiband sensors at the same L[subscript typical] radiance input and 2 hyperspectral sensors at a similar radiance input. The calculations were based on clear-water scenes with an objective method of selecting pixels with minimal cross-pixel variations to assure target homogeneity. Among the widely used ocean color sensors that have routine global coverage, MODISA ocean bands (1 km) showed 2–4 times higher SNRs than the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) (1 km) and comparable SNRs to the Medium Resolution Imaging Spectrometer (MERIS)-RR (reduced resolution, 1.2 km), leading to different levels of precision in the retrieved Chl data product. MERIS-FR (full resolution, 300 m) showed SNRs lower than MODISA and MERIS-RR with the gain in spatial resolution. SNRs of all MODISA ocean bands and SeaWiFS bands (except the SeaWiFS near-IR bands) exceeded those from prelaunch sensor specifications after adjusting the input radiance to L[subscript typical]. The tabulated L[subscript typical], L[subscript max], and SNRs of the various multiband and hyperspectral sensors under the same or similar radiance input provide references to compare sensor performance in product precision and to help design future missions such as the Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission and the Pre-Aerosol-Clouds-Ecosystems (PACE) mission currently being planned by the U.S. National Aeronautics and Space Administration (NASA). |
| Genre | Article |
| Identifier | Hu, C., Feng, L., Lee, Z., Davis, C. O., Mannino, A., McClain, C. R., & Franz, B. A. (2012, September 1). Dynamic range and sensitivity requirements of satellite ocean color sensors: learning from the past. Applied Optics, 51(25), 6045-6062. doi:10.1364/AO.51.006045 |
