A comparison of the Cloud Top Height Product (CTOP) and cloud-top heights derived from satellite, rawinsonde and radar

The Cloud Top Height (CTOP) product, developed by the Oceanic Weather Product Development Team (OW PDT) of the Federal Aviation Administration's Aviation Weather Research Program (FAA/AWRP), has recently received experimental status through the Aviation Weather Technology Transfer (AWTT) process. The CTOP diagnoses combine GOES IR data and Global Forecast System (GFS) profiles to estimate the heights of cloud tops over the open ocean for both day- and night-time hours.

As part of the AWTT process, the CTOP was extensively compared to cloud-top estimates based on a variety of types of observations. This paper compares CTOP-diagnosed heights with several other types of inferred cloud-top heights in coastal and island regions, and over the continental U.S. (CONUS). The other inferred cloud-top values used in the intercomparison include cloud top values based on land- and ship-based rawinsondes, WSR-88D radar echo tops (ET), and the NESDIS cloud-top pressure product (NCTP). The comparisons are presented for two periods: 12 February-23 April and 15 August – 15 September 2004 for the Pacific, North Pacific, and Gulf of Mexico domains; and 15 August – 15 September 2004 for the CONUS. Results of the comparisons indicate the CTOP is generally consistent with the cloud-top heights determined from ground-based observations below 30,000 ft and with the NCTP. This intercomparison of cloud-top values is a companion to a study in which the CTOP was extensively compared to gridded NCTP values, where similar results were obtained.