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High‐resolution numerical‐model integrations to validate gravity‐wave‐drag parametrization schemes: A case‐study
Author(s) -
Broad Adrian S.
Publication year - 1996
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49712253508
Subject(s) - parametrization (atmospheric modeling) , drag , hydrostatic equilibrium , wave drag , gravity wave , geology , mechanics , physics , amplitude , wave model , meteorology , geodesy , gravitational wave , drag coefficient , quantum mechanics , radiative transfer , astrophysics
A three‐dimensional non‐hydrostatic numerical model is used to simulate the lee‐wave event IOP3 (1800 GMT 14 October 1990 to 1200 GMT 15 October 1990) from the PYREX mountain experiment. Using high resolution with a horizontal gridlength of 1.5 km and a realistic terrain‐height specification the resulting model vertical‐velocity fields are compared directly with observations from aircraft flights. The overall agreement of the model‐simulated wave structure with the aircraft data is very encouraging, particularly given the high degree of nonlinearity and finite amplitude wave activity observed during this event. Given the very restrictive three‐dimensional coverage of the observations from the field experiment, the numerical‐model results are used as surrogate observational data to give exhaustive three‐dimensional data over the whole model volume. The model integrations are subsequently used to compute areally averaged surface‐pressure drags and height profiles of the vertical flux of horizontal momentum. Assuming these wave stresses to be an accurate representation of the real atmospheric stresses, they are compared, as a validation procedure, against grid‐box flux values taken from a gravity‐wave‐drag parametrization scheme in a model with resolution 2.5° latitude by 3.75° longitude. The drag scheme in question compares favourably with the model domain‐averaged stresses.