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Scintillometry Henk de Bruin

HAR de Bruin Freelnce consultant. Scintillometry Henk de Bruin. Associate Professor Emeritus. Presented by Massimo Menenti. Features scintillometry. Meteorological and hydrological models need as boundary conditions the surface fluxes of sensible heat ( H ) and water vapor ( ET ),

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Scintillometry Henk de Bruin

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  1. HAR de Bruin Freelnce consultant ScintillometryHenk de Bruin Associate Professor Emeritus Presented by Massimo Menenti NASA - USDA Workshop on Evapotranspiration, Silver Spring Md.

  2. Features scintillometry • Meteorological and hydrological models need as boundary conditions the surface fluxes of sensible heat (H) and water vapor (ET), • The horizontal spatial scale of a grid box used in these models is at least several kilometers • At this scale most land surface are heterogeneous • Conventional techniques concern point observations • Long-path scintillometry provides H and ET over heterogeneous terrain on km scales • PM Not discussed here:Short path scintillometers provide, besides H, momentum flux also and indirectly, ET and CO2, for short time intervals NASA - USDA Workshop on Evapotranspiration, Silver Spring Md.

  3. Dutch history of scintillometry De Bruin, 2009. BAMS • Idea: Wesely (1976) • Renaissance: EFEDA experiment Spain 1991 with Wim Kohsiek • 1994: mirror-type LAS built in Wageningen De Bruin et al (1995, 1996) • Experiments:Green at al. (1994), McAneney et al. (1995), Lagouarde et al. (1996, 2002) • Further developments in Wageningen: Messera valley - Crete (1996?), Jornada (1997), Montestigliano, Tuscany (1998, RESMEDES) • Tibet: Naqu and Everest (2009 – 2010) • Prototype improved, Kipp & Zonen, … NASA - USDA Workshop on Evapotranspiration, Silver Spring Md.

  4. Transmitter Receiver Scintillometer D Wavelength l L = path length z NASA - USDA Workshop on Evapotranspiration, Silver Spring Md.

  5. Definitions NASA - USDA Workshop on Evapotranspiration, Silver Spring Md.

  6. Overview different scintillometer types Atmospheric turbulence characterized by outer and inner scale: L0utand l0 NASA - USDA Workshop on Evapotranspiration, Silver Spring Md.

  7. Results LAS and MWS scintillometer to measure H and ET Micro Wave Scintillometer (MWS), Univ. Of Bern receivers transmitters Large Aperture Scintillometer (LAS), Wageningen Univ. NASA - USDA Workshop on Evapotranspiration, Silver Spring Md. Path length about 5 km

  8. Example performance long-path scintillometryFluxes over Different Vegetation near Lindenberg, Germany Forest Arable crops and lakes NASA - USDA Workshop on Evapotranspiration, Silver Spring Md.

  9. EC-Area-averaged Fluxes versus scintillometer measurements Sensible heat flux, H Latent heat flux, ET Scintillometer W/m2 Scintillometer W/m2 Weighed averaged fluxes derived from eddy-correlation (EC) network W/m2 NASA - USDA Workshop on Evapotranspiration, Silver Spring Md.

  10. Do we have anything better to validate RS estimates of heat fluxes at km - scale? NASA - USDA Workshop on Evapotranspiration, Silver Spring Md.

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