Welcome to AEROCENTER
Aerosol research is one of the nine cross-cutting themes of the Earth Sciences Division at NASA's Goddard Space Flight Center. AeroCenter is an interdisciplinary union of researchers at NASA Goddard and other organizations in the Washington DC metropolitan area (including NOAA, University of Maryland, and other insititutions) who are interested in many facets of atmospheric aerosols. Interests include aerosol effects on radiative transfer, clouds and precipitation, climate, the biosphere, and atmospheric chemistry the aerosol role in air quality and human health; and the atmospheric correction of aerosol blurring of satellite imagery of the ground. Our regular activities include strong collaborations among aerosol community, informal weekly AeroCenter Forum (seminars, discussions, posters, and paper reviews) and annual aerosol research update.
Featured Aerocenter Highlight
We are planning our next AeroCenter update, to be held in late May or early June. The goal is to provide updates on the latest progress on the instrument/model/algorithm/network/mission of the AeroCenter members. The format will be similar in previous years: a 10minute talk and 5 minute Q&A.
Please let us know if you have any topic in mind that you would like to see covered during the AeroCenter update.
The Aerocenter Committee
Valentina Aquila, David Giles, John Yorks, & Tianle Yuan
Posted April 15, 2015
Cho, H. M. et al. (2015), Frequency and causes of failed MODIS cloud property retrievals for liquid phase clouds over global oceans, J. Geophys. Res., in press, doi:10.1002/2015JD023161. http://onlinelibrary.wiley.com/wol1/doi/10.1002/2015JD023161/abstract
MODIS retrieves cloud droplet effective radius (re) and optical thickness (τ) by projecting observed cloud reflectances onto a pre-computed look-up-table (LUT). When observations fall outside of the LUT, the retrieval is considered “failed” because no combination of τ and re within the LUT can explain the observed cloud reflectances. In this study, the frequency and potential causes of failed MODIS retrievals for marine liquid phase (MLP) clouds are analyzed based on one year of Aqua MODIS Collection 6 products and collocated CALIOP and CloudSat observations. The retrieval based on the 0.86μm and 2.1μm MODIS channel combination has an overall failure rate of about 16% (10% for the 0.86μm and 3.7μm combination). The failure rates are lower over stratocumulus regimes and higher over the broken trade-wind cumulus regimes. The leading type of failure is the “re too large” failure accounting for 60%~85% of all failed retrievals. The rest is mostly due to the “re too small” or τ retrieval failures. Enhanced retrieval failure rates are found when MLP cloud pixels are partially cloudy or have high sub-pixel inhomogeneity, are located at special sun-satellite viewing geometries such as sunglint, large viewing or solar zenith angles, or cloudbow and glory angles, or are subject to cloud masking, cloud overlapping and/or cloud phase retrieval issues. The majority (more than 84%) of failed retrievals along the CALIPSO track can be attributed to at least one or more of these potential reasons. The collocated CloudSat radar reflectivity observations reveal that the remaining failed retrievals are often precipitating. It remains an open question whether the extremely large re values observed in these clouds are the consequence of true cloud microphysics or still due to artifacts not included in this study.
Dr. Yoram Kaufman
Abstract and title of the seminar are coming.…
Winter storms in California’s Sierra Nevada increase seasonal snowpack and provide critical water resources and hydropower for the state. Thus, the mechanisms influencing precipitation in thi…
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