{"id":1202,"date":"2018-04-04T16:23:41","date_gmt":"2018-04-04T16:23:41","guid":{"rendered":"https:\/\/www.essl.org\/cwg-satellite-guidance\/?page_id=1202"},"modified":"2018-04-06T07:13:36","modified_gmt":"2018-04-06T07:13:36","slug":"optimal-cloud-analysis-oca","status":"publish","type":"page","link":"https:\/\/www.essl.org\/cwg-satellite-guidance\/optimal-cloud-analysis-oca\/","title":{"rendered":"Optimal Cloud Analysis (OCA)"},"content":{"rendered":"

Optimal Cloud Analysis (OCA)<\/h1>\n

Demonstrational product by EUMETSAT.<\/p>\n

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Application:<\/h2>\n

Optimal Cloud Analysis provides cloud microphysical and bulk properties from the MSG SEVIRI instrument. Basic parameters provided are:
\n\u2022 Phase (ice\/liquid\/Multi-layer)
\n\u2022 Optical Depth
\n\u2022 Effective Radius
\n\u2022 Top pressure<\/p>\n

In the Multi-layer case parameters are provided for upper (assumed ice phase) and lower (assumed liquid phase) layers. Currently effective radius is not available for the lower layer.<\/p>\n

With all parameters there is an associated error estimate and an overall quality measure indicates the confidence in the retrieval (per pixel).<\/p>\n

The product can be used in applications requiring cloud properties from medium spatial resolution (3-~6 km) and high temporal resolution (15 minutes): Nowcasting, model verification, precipitation estimation (as a derived product), etc.<\/p>\n<\/div>\n

Advantages:<\/h2>\n
\u2713 Availability 3 km @Sub-Satellite-Point every 15 minutes.<\/span>
\n\u2713 Two-layer capability (most other products limit to a single layer).<\/span>
\n\u2713 Error estimates<\/span>.
\n\u2713 Permits overshooting tops (some other products limit to tropopause).<\/span><\/p>\n

Limitations:<\/h2>\n

X Nighttime product inferior to daytime as all channels used in solar illumination.
\nX Multi-layer conditions only detected for moderate cirrus optical depths (<~4-5).
\nX Complex compared to single layer analogues \u2013 attention to error estimates!
\n<\/span><\/p>\n<\/div><\/div>\n

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