thumbnail

Measurements of thermal updraft intensity over complex terrain using American white pelicans and a simple boundary-layer forecast model

Boundary-Layer Meteorology

By:
, , , , and

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time
  • Download citation as: RIS

Abstract

An examination of boundary-layer meteorological and avian aerodynamic theories suggests that soaring birds can be used to measure the magnitude of vertical air motions within the boundary layer. These theories are applied to obtain mixed-layer normalized thermal updraft intensity over both flat and complex terrain from the climb rates of soaring American white pelicans and from diagnostic boundary-layer model-produced estimates of the boundary-layer depth zi and the convective velocity scale w*. Comparison of the flatland data with the profiles of normalized updraft velocity obtained from previous studies reveals that the pelican-derived measurements of thermal updraft intensity are in close agreement with those obtained using traditional research aircraft and large eddy simulation (LES) in the height range of 0.2 to 0.8 zi. Given the success of this method, the profiles of thermal vertical velocity over the flatland and the nearby mountains are compared. This comparison shows that these profiles are statistically indistinguishable over this height range, indicating that the profile for thermal updraft intensity varies little over this sample of complex terrain. These observations support the findings of a recent LES study that explored the turbulent structure of the boundary layer using a range of terrain specifications. For terrain similar in scale to that encountered in this study, results of the LES suggest that the terrain caused less than an 11% variation in the standard deviation of vertical velocity.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Measurements of thermal updraft intensity over complex terrain using American white pelicans and a simple boundary-layer forecast model
Series title:
Boundary-Layer Meteorology
Volume
104
Issue:
2
Year Published:
2003
Language:
English
Contributing office(s):
Forest and Rangeland Ecosystem Science Center
Description:
p. 167-199
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Boundary-Layer Meteorology
First page:
167
Last page:
199