Assessment of the calibration performance of satellite visible channels using cloud targets: application to Meteosat-8/9 and MTSAT-1R

Abstract

and MTSAT-1R visible channel reflectances. In the simulation, cloud three-dimensional (3-D) radiative effect associated with subgrid variations is taken into account using the lognormal-independent column approximation (LN-ICA) to minimize the simulation bias caused by the plane-parallel homogeneous assumption. Third, an independent method uses the typical optical properties of deep convective clouds (DCCs) to simulate reflectances of selected DCC targets.Although all three methods are not in perfect agreement, the results suggest that calibration coefficients of Meteosat-8/9 0.640-µm channels are underestimated by 6-7%. On the other hand, the calibration accuracy of MTSAT-1R visible channel appears to be variable with the target reflectance itself because of an underestimate of calibration coefficient (up to 20%) and a non-zero space offset. The results further suggest that the solar channel calibration scheme combining the Correspondence to: B. J. Sohn (sohn@snu.ac.kr) three methods in this paper can be used as a tool to monitor the calibration performance of visible sensors that are particularly not equipped with an onboard calibration system.

Explaining darker deep convective clouds over the western Pacific than over tropical continental convective regions

“…In that paper, a criterion of TB 11 < 190 K was used for defining DCCs. The Sohn et al method was implemented for examining the calibration performance of the Meteosat-8/9 Spinning Enhanced Visible Infra-Red Imager (SEVIRI) 0.640 µm channel (Ham and Sohn, 2010), successfully demonstrating that Meteosat-8/9 0.640 µm channels are underestimated by 6-7 %.…”

“…DCCs over the tropics can supply moisture from the lower troposphere to the upper troposphere, enhancing the water-vapor greenhouse effect (Soden and Fu, 1995;Sohn and Schmetz, 2004;Chung et al, 2007;Sohn et al, 2008). Furthermore, DCCs can be used as calibration targets from which satellite-borne solar channels can be calibrated (Sohn et al, 2009;Ham and Sohn, 2010;Doelling et al, 2013;Kim et al, 2014). Thus, it is of interest to examine the optical and physical properties of DCCs to attain a better understanding of their impact on the radiation balance and for better parameterization of their optical properties for radiative transfer simulations.…”

COMS Visible Channel Calibration Using Moon Observation Data

“…After selecting DCC targets, typical optical properties were assumed as inputs to the RTM, based on an examination of DCC properties using MODIS cloud products. Reference values of sensor-reaching radiances were then produced from theoretical calculations, and these values were compared with Level 1B radiance products for calibration monitoring [7,31]. The bulk scattering properties for ice particles [32,33] were used as a scattering database in the RTM [7].…”

“…In addition to using the DCC method for comparison, three different earth targets were used (ocean, desert, and water cloud) to consider the wide reflectance range from the ocean's surface around longitude 70 • E-165 • E and latitude 30 • S-25 • N as well as from a water cloud around longitude 128±40 • E and latitude 40 • S-40 • N [7,31]. All three targets used RTM-calculated results as the calibration reference; inputs were MODIS products and NCEP (National Centers for Environmental Prediction)/NCAR(National Centers for Atmospheric Research) reanalysis data, such as TPW, UWIND, and VWIND.…”

An Investigation of a Novel Cross-Calibration Method of FY-3C/VIRR against NPP/VIIRS in the Dunhuang Test Site

“…On-board calibrators, reference to lamp sources and/or solar illumination or lunar illumination, and approaches using Earth scenes imaged in-flight are effective for operational calibration and monitoring of the performance of sensors. However, due to power, weight, and space restrictions, some satellites are not well characterized by on-board calibrators, especially in the solar reflective spectral region [4]; thus, the calibration approach using Earth scenes is significant.…”