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

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1 AMS - Boundary Layer and Turbulences 06/10/2014 Analysis of katabatic flow using infrared imaging at micro and meso scale Analysis of katabatic flow using infrared imaging at micro and meso scale Martina Grudzielanek Jan Cermak Roland Vogt Department of Geography Ruhr-Universität Bochum; Climatology University of Basel; Meteorology, Clomatology, Remote Sensing martina.grudzielanek@rub.de

2 Infrared imaging at micro scale Cold air drops Kaltluft-See Adapted from BENDIX

3 Experimental setup Analysis of katabatic flow using infrared imaging at micro and meso scale - micro scale - 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 2

4 - micro scale - Special feature: identifiication of new and only supposed phenomena Cold air drop with turbulences 3

5 height over ground [cm] IR temperature [ C] Analysis of katabatic flow using infrared imaging at micro and meso scale - micro scale - 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 Analysis as: - visualization - statistical time series analysis time [hours] 4

6 height over ground [cm] IR temperature [ C] height over ground [IR-Pixel] Analysis of katabatic flow using infrared imaging at micro and meso scale - micro scale - Observation of passing cold air drops and analysis of their vertical temperature gradients Hovmöller diagram for exemplary 10 minutes at cold air flow phase 8 time [hours] cold air drop peak IR temperature [ C] Classification of cold air drops in different types based on size, period, frequency and vertical temperature gradient is possible! 5

7 Infrared imaging at meso scale METCRAX II - The Meteor Crater Experiment II Dave Whiteman (PI, University of Utah) and Team of international scientists Barringer Meteor Crater, Arizona: meteorological measurements in Oct cold air flow into the crater Dynamic processes in and around the crater 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). 6

8 - meso scale - 7

9 - meso scale - 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 Cold air pool 3. Warm air intrusion (WAI) and resulting turbulences at the craters ground WAI 8

10 - meso scale - Turbulence in the crater, no steady inversion 9

11 - meso scale - Warm Air Intrusion at stable inversion at 10/22/2013 from 3 to 4 UTC 10

12 - meso scale - IR profile and Infrared profile diagram for the animated period 11

13 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 12

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18 height height Höhe height Höhe height Analysis of katabatic flow using infrared imaging at micro and meso scale Classification of cold air drops in different types based on: - size - period - frequency - - vertical temperature gradient: 1 2 temperature temperature 3 4 temperature temperature

19 height over ground [cm] IR temperature [ C] height over ground [IR-Pixel] Analysis of katabatic flow using infrared imaging at micro and meso scale Observation of individual passing cold air drops in time response Hovmöller diagram for an exemplary cold air drop passing the projection screen maximum of cold air drop time [hours] cold air drop moments IR temperature [ C]