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The Moon, due to its extremely stable surface, has been a great interest to the satellite instrument calibration community for instrument in-orbit calibration, sensor-to-sensor inter-calibration, and historical data re-analyses. Yet using the lunar surface as a solar diffuser is always challenged with its non-uniform and non-Lambertian reflectance. To minimize the reflectance variation caused by the phase angle and libration variations, NOAA, in collaboration with Japan Meteorological Agency (JMA), are developing a lunar radiance calibration model over a set of selected region of interest (ROI) which are identified with both lunar hyperspectral and broad-band measurements, and lunar laser altimeter data as well. Yet accurate image-to-image registration to extract accurate ROI radiance is critical for the model development, especially for the images of relatively low spatial resolution bands. Two automatic image registration methods have been developed at NOAA over the past few years – a theoretic method to predict the ROI positions and an empirical algorithm based on the matched local features. Although the theoretic algorithm can well predict the central Moon position, the accuracy of ROI locations is often affected by fluctuations of instrument performance. The current empirical algorithm can successfully achieve the registration accuracy at sub-pixel level for the lunar images within certain phase angle difference, but the registration error increases when the images have large phase angle differences, due to the misclassification of potentially matched features over the global images. In this study, we are proposing to combine the theoretical and empirical methods to increase the number of matched features by restricting the searching area. The resulted lunar ROI radiance will be used to analyze the GOES-16 ABI and Himawari-8 AHI instrument degradations and compared with the solar calibrated data.

The Moon, due to its inherent reflectance stability and negligible atmosphere effect, has been used as a solar diffuser for the satellite instrument radiometric calibration in the solar reflective wavelength. Currently the lunar disk-equivalent irradiance is most commonly used to trend the instrument on-orbit degradation. Yet the accurate observation and simulation of the lunar irradiance are greatly challenged with the changes in lunar phase and libration. This is especially the case for the geostationary weather instruments in which the lunar image are obtained at any phase angles when the Moon appear within the instrument field of regard. Alternatively one can use lunar radiance at selected uniform sites as calibration reference, provided that the viewing and illuminating geometric effects at these sites can be well characterized. Two key techniques have been identified toward the site characterizations for the lunar radiance model development: relatively uniform site selections and auto-coregistration of satellite images for radiance extraction. NOAA recently has identified a set of spectrally and geospatially relatively uniform sites based on the high spectral and spatial resolution measurements of Japan Aerospace Exploration Agency (JAXA) lunar orbital SELENE instruments. Japan Meteorological Agency (JMA) Himawari-8 Advanced Himawari Imager (AHI), which has a very similar optical design as GOES-R Advanced Baseline Imager (ABI), has already acquired substantial lunar images since its launch in October 2014. These lunar images provide an opportunity to develop an accurate lunar radiance model for the radiometric calibration validation of new generation of GEO instruments. In this study, we evaluate the selected lunar targets with the Himawari-8 AHI data. Our early results from one AHI lunar-tracing event images show apparent bidirectional reflectance function (BRDF) effect at the selected sites. Effort and progress to characterize the BRDF effects at the selected sites will be reported in the coming meeting.

[ABSTRACT]SW radiation budget is estimated using geostationary satellites (GMS-5, GOES-8, GOES-10, METOSAT-5, METEOSAT-7). Each satellite data are calibrated, and optics properties of the cloud are retrieved. An accurate calibrated data propose the better accuracy for analysis of cloud and radiation budget. In this study, cloud and SW radiation budget analysis are done by CAPCOM algorithm and EXAM SYSTEM. On the other hand, aerosol optical thickness is retrieved by L-REAP algorithm. We discuss the possibility of aerosol-cloud-radiation interaction in north Pacific ocean and north Atlantic ocean.

[ABSTRACT]In this study, we develop a vicarious calibration technique and estimation algorithm of radiation budget for the global analysis. The vicarious calibration technique using three components ( clear sky sea surface, clear sky land surface, uniform cloud top) is applied to the geostationary satellites. This vicarious calibration technique is based on radiative transfer calculations and it has each optical properties (aerosol, cloud, surface BRDF/albedo) in three compon_~ntsT. he quality of three geostationary satellites (GMS-5, GOES-10, GOES-8) visible channel fixed accurately for global analysis. An accurate calibrated data set propose the better accuracy for analysis of cloud and radiation budget. Thus, cloud and radiation budget analysis algorithm are applied to new calibrated data set for global analysis. This is first result of trial for global analysis.

[ABSTRACT]The re-construction of the GMS-5 visible channel calibration table is examined. It is based on the comparison of satellite observation with reference. To obtain the reference, satellite radiance is simulated over various reference targets of clear sea area, clear land area and cloud top as dark, medium and bright references, respectively. Parameters necessary to compute the radiance are prepared independently from GMS-5 observations. The recalibrated visible table improves the GMS-5 data. That is confirmed from the improvement of aerosol and cloud products retrieved from the GMS-5 data.

[ABSTRACT]In this study, we analyze Refined -Visible and Infrared Spin-Scan Radiometer (R-VISSR) data set. An accurate calibrated data propose the better accuracy for analysis of cloud and radiation budget. Therefore, in Asian Atmospheric Particle Environmental Change Studies (APEX) -E2 period, diffuse component and aerosol optical thickness showed the pattern that looked like well. Thus, analysis of 12 months of 2001 was executed that the results indicate a feature trend of the direct and the diffuse component of downward solar radiation from East Asia to North Pacific Ocean. Moreover, contrast is clear between East Asia and South side of Australia in direct and diffuse components.

[ABSTRACT]MTSAT-1R infrared intercalibration with the hyper sounder AIRS and IASI is operated at MSC. Comparison methodology is on the basis of algorithm determined in GSICS, one of the components of WMO. To match-up data of two sensors, observation time difference, satellite zenith angle difference and environment uniformity are checked. To adjust spectral response difference, a super channel is generated from hyper sounder to have the same SRF as a MTSAT-1R infrared channel. In case that there are spectral gaps or failed channels in hyper sounder, their radiances are estimated with good accuracy by using observations and beforehand simulated radiances of hyper sounder. The intercalibration is examined once a day, and results are posted on the MSC webpage (http ://mscweb.kishou.go.jp/ monitoring/calibration.htm).

The Multi-functional Transport Satellite (MTSAT)-1R is a geostationary imager located at 140°E over the tropical western pacific operated by the Japanese Meteorological Agency and was launched on February 26, 2005. It has been operational from June 2005 to June 2010 and now serves as the backup instrument when the MTSAT-2 ground segment is maintained annually during November and December. The Clouds and the Earth's Radiant Energy System (CERES) project utilizes geostationary (GEO) derived broadband fluxes to infer the regional diurnal cycle between CERES observed broadband observations. The GEO visible channels are first calibrated against Aqua-MODIS using ray-matched coincident 0.5° gridded radiance pairs, which are regressed monthly to determine the GEO calibration coefficients. Unlike other GEOs the MTSAT-1R visible channel exhibited a nonlinear sensor response. In order to ensure that the ray-matching algorithm is not introducing any systematic biases, the navigation, the MTSAT-1R and MODIS spectral band differences, and MTSAT-1R space offset are carefully examined and were determined not to be the cause. Also Terra-MODIS or TRMM-VIRS and MTSAT-1R ray-matched radiance pairs also showed similar nonlinear behavior. However, VIRS onboard the TRMM precessing satellite, revealed that the nonlinear behavior was dependent on solar zenith angle or dynamic range. No further progress could be achieved until coincident MTSAT-2 and MTSAT-1R images taken in December 2010 became available. Comparing the coincident imagery the image blurring effect was noticeable. Dark regions neighboring bright clouds within 500-km were brightened. This effect was not noticed in the IR imagery, even though both visible and IR optical paths are shared. The slight blurring effect is attributed to the mirror surface by either flawed polishing or by a dust contaminant. The dispersed light of the signal was assumed to be small and randomly distributed around the optical axis allowing the image to be deconvolved using an inverted point spread function. The PSF removed ~80% of the blurring effect and the MTSAT-1R sensor observed a linear response when ray-matched with Aqua-MODIS radiance pairs. This chain of events, emphasizes the need for coincident imagery when replacing operational GEO imagers, as part of the commissioning process. If MTSAT-2, which was launched in February 2006, provided coincident imagery with MTSAT-1R within a few months after launch, retrieval quality imagery could have been available 5-years earlier.