Τίτλος:
The structure of katabatic flows down a simple slope
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
An analysis of the katabatic flow structure is presented, based on data
collected along a simple slope over a two-month period. Four
meteorological stations were deployed along the nearly two-dimensional
east slope of Mt. Hymettos in Greece. The study focuses on the momentum
and energy budgets of the flows during carefully selected stationary
periods with negligible ambient winds. In order to achieve a proper
selection, the mean features of the observed flows are presented along
with their response to external winds. The observed profiles are
successfully compared with the theoretical Prandtl profiles. Bulk
quantities of the katabatic layer are compared with proposed
experimental values in order to check the representativity of the
observed flows. These comparisons offer a further test of theoretical
considerations and assist in discussions of processes affecting
mean-flow features.
The flows were similar to 20 m deep, with velocities 1-2 m s(-1). During
steady-state periods the katabatic acceleration was mainly balanced by
the surface friction, the contribution of advective terms being small.
The estimated interfacial drag was less important than the surface drag,
which proved large compared with usually suggested values. Within the
experimental uncertainties, values of the drag coefficient of the order
of 10(-2) seem appropriate. The steady-state energy balance showed that
the downslope advection balanced the turbulent heat flux to the ground
surface.
Συγγραφείς:
Papadopoulos, KH
Helmis, CG
Soilemes, AT
Kalogiros, J and
Papageorgas, PG
Asimakopoulos, DN
Περιοδικό:
Quarterly Journal of the Royal Meteorological Society
Λέξεις-κλειδιά:
down-slope winds; mesoscale field-study; orography
DOI:
10.1002/qj.49712354207
