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| Titel |
Comparison of GEOS-5 AGCM planetary boundary layer depths computed with various definitions |
| VerfasserIn |
E. L. McGrath-Spangler, A. Molod |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 13 ; Nr. 14, no. 13 (2014-07-03), S.6717-6727 |
| Datensatznummer |
250118858
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| Publikation (Nr.) |
 copernicus.org/acp-14-6717-2014.pdf |
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| Zusammenfassung |
| Accurate models of planetary boundary layer (PBL) processes are important
for forecasting weather and climate. The present study compares seven
methods of calculating PBL depth in the GEOS-5 atmospheric general
circulation model (AGCM) over land. These methods depend on the eddy
diffusion coefficients, bulk and local Richardson numbers, and the turbulent
kinetic energy. The computed PBL depths are aggregated to the
Köppen–Geiger climate classes, and some limited comparisons are made
using radiosonde profiles. Most methods produce similar midday PBL depths,
although in the warm, moist climate classes the bulk Richardson number
method gives midday results that are lower than those given by the eddy
diffusion coefficient methods. Additional analysis revealed that methods
sensitive to turbulence driven by radiative cooling produce greater PBL
depths, this effect being most significant during the evening transition.
Nocturnal PBLs based on Richardson number methods are generally shallower than eddy
diffusion coefficient based estimates. The bulk Richardson number estimate
is recommended as the PBL height to inform the choice of the turbulent
length scale, based on the similarity to other methods during the day, and
the improved nighttime behavior. |
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