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| Titel |
Effect of explicit urban land surface representation on the simulation of the 26 July 2005 heavy rain event over Mumbai, India |
| VerfasserIn |
M. Lei, D. Niyogi, C. Kishtawal, R. A. Pielke, A. Beltrán-Przekurat, T. E. Nobis, S. S. Vaidya |
| 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 ; 8, no. 20 ; Nr. 8, no. 20 (2008-10-16), S.5975-5995 |
| Datensatznummer |
250006409
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| Publikation (Nr.) |
 copernicus.org/acp-8-5975-2008.pdf |
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| Zusammenfassung |
| We investigate whether explicit representation of the urban land surface
improves the simulation of the record-breaking 24-h heavy rain event that
occurred over Mumbai, India on 26 July 2005 as the event has been poorly
simulated by operational weather forecasting models. We conducted
experiments using the Regional Atmosphere modeling system (RAMS 4.3),
coupled with and without explicit urban energy balance model-town energy
budget (TEB) to study the role of urban land – atmosphere interactions in
modulating the heavy rain event over the Indian monsoon region. The impact
of including an explicit urban energy balance on surface thermodynamic,
boundary layer, and circulation changes are analyzed. The results indicate
that even for this synoptically active rainfall event, the vertical wind and
precipitation are significantly influenced by heterogeneity in surface
temperatures due to urbanization, and the effect is more significant during
the storm initiation. Interestingly, precipitation in the upwind region of
Mumbai city is increased in the simulation, possibly as a feedback from the
sea breeze – urban landscape convergence. We find that even with the active
monsoon, the representation of urbanization contributes to local heavy
precipitation and mesoscale precipitation distribution over the Indian
monsoon region. Additional experiments within a statistical dynamical
framework show that an urban model by itself is not the dominant factor for
the enhanced rainfall for a Mumbai heavy rain event; the combination of
updated SST fields using Tropical Rainfall Measurement Mission (TRMM) data
with the detailed representation of urban effects simulated by the TEB model
created realistic gradients that successfully maintained the convergence
zone over Mumbai. Further research will require more detailed morphology
data for simulating weather events in such urban regions. The results
suggest that urbanization can significantly contribute to extremes in
monsoonal rain events that have been reported to be on the rise. |
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