| Summary: | The mixing layer (ML) heights inferred from radiosondes, wind profilers,
airborne lidar, airborne microwave temperature profiler (MTP), and in-situ aircraft data
were compared during the Texas 2000 Air Quality Study in the Houston area. The
comparisons and resulting good agreement between the separate instruments allowed for
the spatial and temporal evolution of the ML height distribution to be determined across
the Houston area on September 1, 2000.
A benchmark method was created for determining ML heights from radiosonde
data. The ML heights determined using this method were compared to ML heights
determined using wind profiler data. The airborne lidar and MTP heights were also
compared to the wind profiler heights. This was the first time the MTP was used for
estimating ML heights. Because of this, the MTP heights were also compared to the ML
heights determined by in-situ aircraft data.
There was good agreement between the ML estimates when the instruments were
co-located. The comparisons between the benchmark method and the wind profilers
were independent of the quality of the profiler heights. The statistics for lidar and the
wind profilers were better for the inland profiler comparisons. Even so, the results for
coastal profilers were similar to the other comparisons. The results between the MTP
and the wind profilers were comparable with the results found between the other
instruments, and better, in that the statistics were similar for the both the inland and
coastal profilers. The results between the MTP and in-situ aircraft data provided
additional support for the use of MTP for determining ML heights.
The combination of the inland and coastal wind profilers with the airborne
instruments provided adequate information for the spatial and temporal evolution of the
ML height to be determined across the Houston area on September 1, 2000. By
analyzing the ML height distribution, major features were evident. These features
included the shallow ML heights associated with the marine air from Galveston Bay and
the Gulf of Mexico, and the sharp gradient of increasing ML heights north of Houston
associated with the variation in the inversion depth found on this day.
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