Validation of atmospheric correction over the oceans

Abstract

Abstract. By validation of atmospheric correction, we mean quantification of the uncertainty expected to be associated with the retrieval of the water-leaving radiance from the measurement of the total radiance exiting the ocean-atmosphere system. This uncertainty includes that associated with the measurement or estimation of auxiliary data required for the retrieval process, for example, surface wind speed, surface atmospheric pressure, and total ozone concentration. For a definitive validation this quantification should be carried out over the full range of atmospheric types expected to be encountered. However, funding constraints require that the individual validation campaigns must be planned to address the individual components of the atmospheric correction algorithm believed to represent the greatest potential sources of error. In this paper we develop a strategy for validation of atmospheric correction over the oceans that is focused on EOS/MODIS. We also provide a description of the instrumentation and methods to be used in the implementation of the plan.

The Potential of Autonomous Ship-Borne Hyperspectral Radiometers for the Validation of Ocean Color Radiometry Data

“…To determine R rs , in situ radiometric measurements are performed with above-and in-water optical radiometers from fixed offshore platforms [5,6], moored buoys [7,8] or ships [9][10][11]. The aboveand in-water approaches to determine R rs rely on radiometric measurements analysed with different underlying assumptions: (i) in-water radiometry enables the determination of immediately below surface radiometric quantities based on the extrapolation of subsurface continuous or fixed-depth profiles of radiometric quantities [5,7,12]; (ii) above-water systems operate with non-nadir viewing geometry and can be corrected for the skylight reflected into the field-of-view by the air-sea interface [5,6,12,13].…”

VIIRS Reflective Solar Bands Calibration Progress and Its Impact on Ocean Color Products

“…This is also true for 412 nm (M1) and 488 nm (M3). The trend from the Marine Optical Buoy (MOBY) data, the direct in situ measurements of nL w (λ) using a system of buoys [47,48], are also shown in Figures 15 and 16 (in solid triangles). The comparison with the MOBY result further confirms that the SDR using hybrid F-factors significantly elevates the accuracy of the ocean color products.…”

Biological Oceanography by Remote Sensing

“…8 As noted in the previous subsection, if the improved radiometric sensitivity of the new sensors means that a better atmospheric correction be applied to the data, this in turn will need to be validated. 31 The details of the calibration and validation process are rather involved and so will not be discussed in detail here. There are on-board calibration systems that monitor the performance and stability of the sensor (see, for example, Evans and Gordon 8 for CZCS and Barnes et al 28 for MODIS).…”

“…25 To achieve this a comprehensive calibration and validation plan has been adopted. 32 Similar procedures are being adopted for the other ocean color missions 31 and should provide well-calibrated data for use in scientific studies.…”

“…More generally, what are required are accurate measurements of the optical properties of the water and of the atmosphere (particularly with regard to atmospheric aerosols), and of the phytoplankton and associated pigments found in the water. Instruments that can be deployed from both ships and buoys have been developed to make such measurements (see, for example, Clark et al 31 ). In addition, measurements of other contributions to the radiance seen by the satellite sensor, such as that due to whitecaps, need to be made.…”