An increase in the amount of lightning and rainfall over the Houston area, compared
to the surrounding rural areas, has been well documented in previous studies. The
placement of a Shared Mobile Atmospheric Research and Teaching Radar (SMART-R)
in the Houston area during the summer season of 2005 presented a unique opportunity to
investigate the role of boundary-layer convergence in modulating convective frequency
and intensity and, thereby, likely causing the rainfall and lightning anomalies. The role
of the urban heat island (UHI) and the sea-breeze, as a source of low-level convergence
leading to enhanced convection over Houston, was examined.
Hourly average dual-Doppler wind and convergence maps were created on 1 X 1 km
grids for an eleven-week period. By using these images along with average lightning,
rainfall, and reflectivity for a large Houston-centered domain, it was possible to discern a
correlation between low-level convergence and convection. Also, past findings of
enhancement in lightning and rainfall over Houston and downwind of Houston were
validated. High convergence levels for the Houston area in the mid-morning were
followed closely by a peak in convection in the early afternoon. The enhancement of rainfall and lightning over and downwind of downtown was found to be primarily from a
large increase in frequency of deep convective events when compared to the surrounding
domain. Also, it was found that UHI, rather than sea-breeze, was likely the primary
causative mechanism in the development of convection over the Houston area because
of the lack of deep convection in areas equally affected by the sea-breeze and the timing
of the convection compared to time of peak sea-breeze. An area of weaker enhancement
south of Houston, not discussed in previous studies, was found to be present, possibly
from the interactions between the bay-breeze off of the Galveston Bay and the seabreeze.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/6005 |
| Date | 17 September 2007 |
| Creators | McNear, Veronica Ann |
| Contributors | Carey, Lawrence D. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | 10345030 bytes, electronic, application/pdf, born digital |
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