zentralanstalt für meteorologie und geodynamik a re-evaluation of the role of subsidence in valley...

15
Zentralanstalt für Meteorologie und Geodynamik A re-evaluation of the role of subsidence in valley and basin warming Thomas Haiden

Upload: kayleigh-topham

Post on 28-Mar-2015

215 views

Category:

Documents


2 download

TRANSCRIPT

Page 1: Zentralanstalt für Meteorologie und Geodynamik A re-evaluation of the role of subsidence in valley and basin warming Thomas Haiden

Zentralanstalt für Meteorologie und Geodynamik

A re-evaluation of the role of subsidence in valley and basin warming

Thomas Haiden

Page 2: 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

Page 3: 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

Subsidence

Upper Inn valley

slope flow

subsidence

Page 4: 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

Mass budget

Uw

b D

DUbw

Page 5: 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

Heat budget

0sin

zU

Dc

H

t p

U

H

Slope

Valleyz

wt

w

Page 6: 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

Heat budget

0sin

zU

Dc

H

t p

U

H

Slope

Prandtl type ‘equilibrium’ flow

w

Page 7: 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

Heat budget

1

sin

zc

HDU

p

U

H

constraint on upslope mass-flux

w

Page 8: 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

Heat budget

H

equivalent to direct horizontal heat input

vp HH

tbc

sin

Page 9: 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

Heat budget

Temperature evolution in valley atmosphere can be modelled without explicitly simulating slope wind layer

Page 10: 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

Meteor Crater

Test of ‘horizontal heat input’ concept under near-ideal conditions

Page 11: 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

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

Page 12: 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

Meteor Crater

Subsidence signal

Page 13: 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

Heating modes

Same warming at all heights

Strongest warming in stable layer

Upslopemass-flux

in EQ

Upslopemass-flux

Non-EQ

Page 14: 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

Heating modes

Page 15: 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

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