Schmid, H.P.

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Schmid, H. P.

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Seeing the City for all the BuildingsHaPe Schmid, Institute for Meteorology and Climate Research, Research Centre Kalsruhe, Garmisch-Partenkirchen (Germany)Gibbs Roundsavall: "suburban sprawl" (detail) 19" x 24", enamel on aluminium, 2005Duluth, MN, neighborhood Timbouctou, Mali, neighborhoodPattern:     Spatial ScalesThe atmosphere sometimes organizes into patterns and distinct spatial scalesHomogeneous heatingRorationHeating gradient(from: Album of Fluid Dynamics)Cultivated Landscape:Imposes Pattern and ScaleCultivated Landscape:Imposes Pattern and ScaleCultivated Landscape:Imposes Pattern and ScaleMexico City (source: Google) Measured Variability depends on Resolution: the Scale of MeasurementHomogeneous FieldSchmid 1994 (Boundary-Layer Meteorol., 67, 293-318)Flux Footprint = spatial filter, “field of view”(convolution of the source distribution, QS, with the footprint, f )sensorInputs:• zm• z0• h• u*• σw• σv      ffs sQF d Q       x x x x xVancouver, B.C., Canada: Summer 1986Schmid et al., BLM 1991Does the Footprint Concept Actually Work?(after Schmid et al. 1991) "Field of View" / Footprint Varies with Time• Turns with wind direction• Small in unstable conditions• Larger in neutral/stable conditionsat full resolution (from airborne IR scanner)as "seen" by a flux sensor at 30 m in unstable conditions as "seen" by a flux sensor at 30 m in near-neutral conditions Vancouver Temperature Distribution variability reduced to 18% variability reduced to 4%Is the Vancouver Suburban Study Area Homogeneous?(regarding a turbulent flux sensor at 30 m)• in unstable conditions: expect spatial variability• in near-neutral/stable conditions: expect homogeneitySize of 0.5-level Source Area (m2 )104 1050510152025303540Inter -Site PeriodCalibration PeriodMeasured Spatial Variability of Sensible Heat Flux (QH)in Residential Vancouver Area (1986)Schmid et al., BLM 1991; Schmid, AgForMet 1997QH variations within ~ 1 kminstrument uncertaintyQH variations decrease with increasing source area (= effective spatial averaging)spatial representativenessLynn Basa: "Sprawl", acrylic on canvas, 12" x 12", 2007• Surface patterns impose atmospheric scales• Averaging over at least a pattern-unit provides a "scale of homoeneity"• Measurements at scales of homogneity are basis for generalisation (e.g., at the micro-, local-, or suburban-scale)ConclusionsTen urban climate doctoral graduates: (L to R, back row) Rachel Spronken-Smith ‘94, Jamie Voogt ‘95, Matthias Roth ‘91, Hans Peter Schmid ’88, Helen Cleugh ‘90, Sue Grimmond ‘88, Manuel Nunez ‘74, Tim Oke, (L to R, front row) Kathy Runnalls ‘02, Kat Richards ‘99, Andres Soux [Photo – 1998]Thanks to...Tim Oke's sprawled urban climate team!

Seeing the city for all the buildings

https://publikationen.bibliothek.kit.edu/230075878/3815484

Seeing the city for all the buildings

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