Recorded presentation7A.4
ARMOR And MAX Radar Observations Of The Lake Breeze Generated By A Small Anthropogenic Lake
Salvi Asefi, University of Alabama, Huntsville, AL; and K. Knupp, U. S. Nair, R. M. Welch, and D. Phillips
The present study reports the analysis of radar observations of the lake breeze front from a small lake. The ARMOR (Advanced Radar for Meteorological and Operational Research) facility at Huntsville International Airport is located about 30 km distance from the lake. ARMOR observations showed that during synoptic condition of low wind and high pressure a lake-breeze circulation forced by Wheeler Reservoir generates significant flow perturbations in the convective boundary layer which sometimes are significant enough to produce convective initiation, cloud formation and precipitation.
The lake breeze front may develop either on the north or the south side of Wheeler Lake, and occasionally on both sides. Sometimes the lake breeze develops mesoscale circulations along the lake that trace the detailed shape of the lake, and other times circulations develop in scattered patches. Sometimes the lake breeze persists for extended periods of time, sometimes it appears to be stationary, other times it advects away, and sometimes convective initiation is followed by cumulus cloud formation and precipitation. The goal was to understand the reasons for these various scenarios.
ARMOR radar radial velocity measurements (May 2005, 2006 and 2007) provide the means to understand the various aspects of the lake breeze front development and dissipation. Specifically, the lake-breeze formation, size, orientation, strength and stability has a direct association to the direction and strength of the background wind versus the orientation of the lake as well as temperature gradient. Under appropriate situations convective initiation, cumulus cloud formation and precipitation can occur. In order to measure the strength of the perturbations caused by the lake breeze the VAD (Velocity Azimuth Display) technique was used. TREC (Tracking Radar Echoes by Correlation) is used in order to derive the local wind properties.
In order to verify our measurements and also to understand the behavior of the boundary layer during such atmospheric activities, we performed one day of field measurements in June 9th 2008 using MAX (Mobile Alabama X-Band) radar, MIPS (Mobile Integrated Profiling System ) and M3V (Mobile Meteorological Measurements Vehicle) provided by University of Alabama in Huntsville. On this day we captured the lake breeze boundaries on both shores, cumulus cloud formation as well as convective initiation and precipitation. Analysis and results from this day is described in the presented study.
Session 7A, Hydrological Impacts of Land Use Change
Wednesday, 14 January 2009, 1:30 PM-2:30 PM, Room 127B
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