Structure of a Midlatitude Squall Line Formed in Strong Unidirectional Shear
| Autor: | G. M. Barnes, James C. Fankhauser, Margaret A. LeMone |
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| Rok vydání: | 1992 |
| Předmět: | |
| Zdroj: | Monthly Weather Review. 120:237-260 |
| ISSN: | 1520-0493 0027-0644 |
| Popis: | Data from five Doppler radars, the surface mesonet, aircraft, and rawinsondes from the Cooperative Convective Precipitation Experiment (CCOPE) are used to document the structure and evolution of a squall line with unusually persistent cells and an anvil that spreads downwind in strong upper-level westerlies. The environmental sounding showed linear shear of ∼4 m s−1 km−1 through the troposphere, a convective available potential energy of 600 m2 s−2, and a convective Richardson number of 10, based on the wind in the lowest 6 km. The orientation of the squall line, comprised of high-reflectivity centers spaced 20–40 km apart, changed with time. Initially, the squall-line axis was normal to the environmental shear, but with time it became parallel to the shear vector, as the northeastern portion of the subcloud cold dome merged with cold air generated by individual storms that had formed ahead of the line. The intensity of the cells within the squads line diminished as its axis became more parallel ... |
| Databáze: | OpenAIRE |
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