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| Titel |
The dynamics of heat lows over flat terrain |
| VerfasserIn |
T. Spengler, R. K. Smith |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250020829
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| Zusammenfassung |
| The numerical model for a heat low developed by Racz and Smith (1999) is extended to
include a representation of radiative heating and cooling. The model is run with a higher
horizontal resolution than the original version and is used to investigate additional dynamical
aspects of the structure and evolution of a heat low over a subcontinental- or continental-scale
circular island surrounded by sea. Of particular interest is the diurnal and day-to-day
evolution of the upper- and lower-level circulations and the degree of balance that exists in
these. The heat low is surmounted by an anticyclone, the development of which is closely
tied to the outflow branch of the sea breeze. The anticyclone has a much smaller
diurnal variation than the heat low and, unlike the heat low is largely in balance,
except in the region affected by the upward-propagating gravity wave induced by the
inland-penetrating sea breeze. There is a strong analogy to certain aspects of tropical
cyclones, which have a warm core, a shallow unbalanced boundary layer, and which
are surmounted also by an anticyclone. Principles governing the absolute angular
momentum budget are the same as those relating to the tropical cyclones and to the
zonal-mean flow over Antarctica. Implications of these principles for obtaining a
realistic steady state in long-term integrations of axisymmetric models are discussed. |
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