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Comparison of two different vertical diffusion schemes in amplitude and phase of the diurnal variation and its impact on a GCM
Author(s) -
Shin SunHee,
Kimoto Masahide,
Ha KyungJa
Publication year - 2009
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl039414
Subject(s) - amplitude , diurnal temperature variation , mixing (physics) , atmospheric sciences , daytime , atmosphere (unit) , gcm transcription factors , environmental science , diffusion , diurnal cycle , climatology , variation (astronomy) , intensity (physics) , phase (matter) , turbulence , nocturnal , meteorology , geology , physics , climate change , thermodynamics , general circulation model , optics , oceanography , quantum mechanics , astronomy , astrophysics
The diurnal variation in an AGCM is evaluated by comparing the land‐ocean contrast in amplitude and phase using two different diffusion schemes; the Mellor and Yamada level‐2(MY) and Holtslag and Boville(HB) schemes. Although both schemes utilize almost the same surface conditions and show similar mean values in vertical mixing, they produce different amplitudes and phases for vertical mixing. The differences in the diurnal variation over the land and ocean as well as their linkages to the atmosphere are closely associated with the characteristics of the two schemes. The HB scheme responds more quickly to surface heating and is related more closely to the intensity of surface fluxes. It can also transport the physical quantities from the surface to the atmosphere during the daytime. The MY scheme tends to reproduce the apparent vertical mixing by the mechanical turbulent mixing during the nocturnal period. Hence, it affects the daily minimum value.