zentralanstalt für meteorologie und geodynamik a re-evaluation of the role of subsidence in valley...
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Zentralanstalt für Meteorologie und Geodynamik
A re-evaluation of the role of subsidence in valley and basin warming
Thomas Haiden
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Two concepts in mountain CBL theory
Compensating subsidence
Equilibrium slope flow (Prandtl-type)
Additional insights into valley and basin warming
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Subsidence
Upper Inn valley
slope flow
subsidence
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Mass budget
Uw
b D
DUbw
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Heat budget
0sin
zU
Dc
H
t p
U
H
Slope
Valleyz
wt
w
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Heat budget
0sin
zU
Dc
H
t p
U
H
Slope
Prandtl type ‘equilibrium’ flow
w
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Heat budget
1
sin
zc
HDU
p
U
H
constraint on upslope mass-flux
w
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Heat budget
H
equivalent to direct horizontal heat input
vp HH
tbc
sin
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Heat budget
Temperature evolution in valley atmosphere can be modelled without explicitly simulating slope wind layer
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Meteor Crater
Test of ‘horizontal heat input’ concept under near-ideal conditions
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Meteor Crater
The model (1.5-D) Simple horizontal heat input model, with dry-adiabatic adjustment Realistic area-height distribution of the crater Sensible heat flux parameterized based on detailed radiation distribution
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Meteor Crater
Subsidence signal
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Heating modes
Same warming at all heights
Strongest warming in stable layer
Upslopemass-flux
in EQ
Upslopemass-flux
Non-EQ
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Heating modes
08-18-200913th AMS MESO Conf
Zentralanstalt für Meteorologie und Geodynamik
Conclusions
‘Horizontal heat input’ is good approximation
Can be applied to realistic topography
If not fulfilled, deviation from Prandtl-type equilibrium flow
Slope flow non-local
Slope flow ‘uses up’ surplus temperature to remain continuous
Stable layer more of an obstacle over steeper slope
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