Analysis of katabatic flow using infrared imaging at micro ...€¦ · Analysis of katabatic flow using infrared imaging at micro and meso scale Experimental setup Setup design on

Martina Grudzielanek, Roland Vogt, Jan Cermak | [email protected] | www.climate.rub.de | AMS - Boundary Layer and Turbulences 10/06/2014

Analysis of katabatic flow using infrared imaging at micro and meso scale


Martina Grudzielanek Jan Cermak Department of Geography Ruhr-Universität Bochum; Climatology Roland Vogt University of Basel; Meteorology, Clomatology, Remote Sensing

[email protected] www.climate.rub.de

AMS - Boundary Layer and Turbulences 06/10/2014



Infrared imaging at micro scale

Adapted from BENDIX 2004

Kaltluft-See

Cold air drops

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Experimental setup

Setup design on sloping grassland Infrared-Camera: VarioCam

384x288 IR pixel; 7,5 – 14 μm

Evaluation of the Infrared (IR) method by cross-correlation of Infrared temperatures and sensor temperatures at almost identical locations

- micro scale -

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Special feature: identifiication of new and only supposed phenomena

Cold air drop with turbulences

- micro scale -

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IR data analysis Observation of near ground inversion in time response

Hovmöller diagram for IR_Profil1 for two hours of measurement at cold air flow phase

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IR t

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time [hours]

Analysis as: - visualization - statistical time series analysis

- micro scale -

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8 Hovmöller diagram for exemplary 10 minutes at cold air flow phase

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[cm

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[IR

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IR t

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IR temperature [°C] cold air drop peak

time [hours]

Observation of passing cold air drops and analysis of their vertical temperature gradients

Classification of cold air drops in different types based on size, period, frequency and vertical temperature gradient is possible!

- micro scale -

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METCRAX II - The Meteor Crater Experiment II http://www.inscc.utah.edu/~whiteman/metcrax2/

Barringer Meteor Crater, Arizona: meteorological measurements in Oct. 2013 cold air flow into the crater Dynamic processes in and around the

crater

Dave Whiteman (PI, University of Utah) and Team of international scientists

Infrared imaging at meso scale

5 Infrared Cameras: VarioCams; 7,5 – 14 μm

384x288 IR pixel, 640 x 480 IR pixel

1022 x 766 IR-Pixel

Thanks for technical support and additional IR cameras to Matthias Krauß (InfraTec), Andrea Pitacco (University of Padova and Christian Bernhofer (University of Dresden).

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Analysis of katabatic flow using infrared imaging at micro and meso scale - meso scale -

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Exemplary research questions at METCRAX II, wich are additionally analysed with the IR method:

1. Identification and dynamics of the cold and warm air inflow into the craters south rim

2. Thickness of the cold air pool in the crater over the night and at special flow dynamic situations

3. Warm air intrusion (WAI) and resulting turbulences at the craters ground WAI

Cold air pool

- meso scale -

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Turbulence in the crater, no steady inversion

- meso scale -

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Warm Air Intrusion at stable inversion at 10/22/2013 from 3 to 4 UTC

- meso scale -

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IR profile and Infrared profile diagram for the animated period

- meso scale -

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IR method for the analysis of dynamic air processes like catabatic flows

What is possible? - Analysis of air mass processes, which are attended by air temperature changes - Analysis in different scales - data collection as time sequenced IR data - Combination with other data are possible - Data analysis as

1. visualisation 2. time series statistical analysis

What has to be considered? - The recorded surfaces have to be dry and temperatur reactive the surface has to react fast with air temperature changes

- surface properties can be different in one recorded IR investigation area emissivity, angle of IR Cam view, humidity (near ground condensation), temperature reactivity and heat storage

- …

Big benefit for dynamic air process understanding by additional IR method

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Classification of cold air drops in different types based on: - size - period - frequency - … - vertical temperature gradient:

Hö

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Hö

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temperature

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temperature

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temperature

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temperature

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Hovmöller diagram for an exemplary cold air drop passing the projection screen

IR t

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[°C

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hei

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[cm

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hei

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[IR

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IR temperature [°C] cold air drop moments

maximum of cold air drop

time [hours]

Observation of individual passing cold air drops in time response

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Analysis of katabatic flow using infrared imaging at micro ...€¦ · Analysis of katabatic flow using infrared imaging at micro and meso scale Experimental setup Setup design on