Micrometeorological Transitions in the Morning Boundary Layer over Rolling Terrain.
Abstract
Six years of temperature and wind data from two 60m micrometeorological towers in the piedmont of the Carolinas were analyzed. One tower was near a large lake, the other in mostly-forested terrain. Statistics of the basic tower measurements were generated and their time evolution was described for the morning transition period near sunrise. A stepwise regression model was developed and tested to predict the daily transition time at each site based on tower variables. To determine large-scale influences on the local inversion and its morning transition, the local tower data from each site were then related to the synoptic-scale pressure field over the eastern one-third of the United States. To accomplish the comparison, an objective typing scheme was developed in which the gridded daily sea-level pressure field was expressed in terms of eigenvector types. Results document the average morning transition sequence in terms of systematic changes in radiation, wind and temperatures. The regression models are quite similar at both sites and predict transition time with a least-squared regression of 0.76 for clear mornings at the forested site. The eigenvector analysis successfully categorized each day's pressure field into ten types. These showed very close association with the local inversion intensity at sunrise, but had very little relation to morning transition time at each site. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 20, 1986
- Accession Number
- ADA169237
Entities
People
- Allen J. Riordan
- Jerry M. Davis
Organizations
- North Carolina State University