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| Titel |
Revised identification of tropical oceanic cumulus congestus as viewed by CloudSat |
| VerfasserIn |
S. P. F. Casey, E. J. Fetzer, B. H. Kahn |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 3 ; Nr. 12, no. 3 (2012-02-13), S.1587-1595 |
| Datensatznummer |
250010648
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| Publikation (Nr.) |
 copernicus.org/acp-12-1587-2012.pdf |
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| Zusammenfassung |
| Congestus cloud convective features are examined in one year of tropical
oceanic cloud observations from the CloudSat/CALIPSO instruments. Two types
of convective clouds (cumulus and deep convective, based on classification
profiles from radar), and associated differences in radar reflectivity and
radar/lidar cloud-top height are considered. Congestus convective features
are defined as contiguous convective clouds with heights between 3 and 9 km.
Three criteria were used in previous studies to identify congestus: (1)
CloudSat and CALIPSO cloud-top heights less than 1 km apart; (2) CloudSat 0
dBZ echo-top height less than 1 km from CloudSat cloud-top height, and (3)
CloudSat 10 dBZ echo-top height less than 2 km from CloudSat cloud-top
height. A majority of congestus convective features satisfy the second and
third requirements. However, over 40% of convective features identified
had no associated CALIPSO cloud-top height, predominantly due to the
extinguishment of the lidar beam above the CloudSat-reported convective
cloud. For the remaining cells, approximately 56% of these satisfy all
three requirements; when considering the lidar beam-extinction issue, only
31% of congestus convective features are identified using these criteria.
This implies that while previous methods used to identify congestus clouds
may be accurate in finding vigorous convection (such as transient congestus
rising toward the tropopause), these criteria may miss almost 70% of the
total observed congestus convective features, suggesting a more general
approach should be used to describe congestus and its surrounding
environment. |
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