Calendar Event Details
AEROCENTER: Santiago Gassó
Affiliation: GSFC 613 and GESTAR/Morgan State University
Event Date: Tuesday, March 15, 2016
Location: G133
Time: 11:00 AM
The World at 380 nm: Analysis of Radiances and Derived Products from a High Spatial Resolution UV Global Imager (CAI) and Comparisons with OMI.
To be clear from the beginning, this presentation is not about aerosols. I will be talking about radiances and corrected surface reflectances in the UV range in mostly aerosol-less scenes. However, not so far in the future, a number of satellite detectors containing UV to NIR bands will be deployed and used for aerosol remote sensing, so you may want to swing anyways.
The Cloud and Aerosol Imager (CAI) is a global high spatial resolution (500m) detector and is used for cloud and aerosol screening of the greenhouse sensor onboard the same platform (the GOSAT satellite). Deployed in 2009 by JAXA, it has a descending orbit with an equator crossing near 14UTC and frequent overlaps with OMI. CAI has a narrow band channel centered at 382 nm and is the only currently operating detector with a high spatial resolution UV channel, far surpassing the pixel resolution of other UV detectors such as OMI and OMPS. A number of planned missions will incorporate uv and visible channels (PACE, TropoOMI, TEMPO) and they will have higher spatial resolution. They will be better at avoiding cloud contamination, a major drawback in current UV detectors. Thus, the study of CAI along with OMI observations offer a way to get ideas and a peek on how these detectors will perform in the future.
This presentation will highlight some of the studies that I have been carrying out with CAI and OMI. What started as a project to collocate in space and time CAI and OMI overpasses and study cloud contamination in OMI, it drifted into a study on how to evaluate CAI’s vicarious calibration constant by using OMI observations. This lead to a methodology to derive Lambertian Equivalent Reflectances over the 382nm of CAI and to a comparison with the same product derived by OMI. This resulted in an independent derivation of the CAI’s calibration constant. Also, by comparing the LERs from both detectors, it was possible to troubleshoot some of the anomalous Aerosol Indexes that OMI derives over certain regions of the world. Finally, I will show high resolution maps of 382nm LERs over several representative regions (a first for this audience) and highlight in particular that some surface features at this wavelength that only become apparent at high spatial resolution.
This study demonstrates the power of collocating in time and space observations from two different platforms and shows how a careful study can result in benefits in the characterization of both detectors’ radiances and derived products.
Posted or updated: Monday, March 7, 2016
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