TURBULENT SURFACE FLUXES ON KILOMETER SCALE OBTAINED ...

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XVI International Conference on Computational Methods in Water Resources (CMWR-XVI) Ingeniørhuset

TURBULENT SURFACE FLUXES ON KILOMETER SCALE OBTAINED WITH SCINTILLOMETRY; A REVIEW.
Paper
Author:Hendrik, A. R. De Bruin <henk.debruin@wur.nl> (Wageningen University, Meteorology and Air Quality Group, 6701 AP Wageningen, Netherlands)
Wouter, M. L. Meijninger <wouter.meijninger@wur.nl> (Wageningen University, Meteorology and Air Quality Group)
Wim Kohsiek <wim.kohsiek@casema.nl> (Royal Dutch Meteorological Society (KNMI), De Bilt, Netherlands)
Frank Beyrich <frank.beyrich@dwd.de> (Deutsche Wetter Dienst (DWD), Lindenberg, Germany)
Arnold, F. Moene <arnold.moene@wur.nl> (Wageningen University, Netherlands, Meteorology and Air Quality Group)
Oscar, K. Hartogensis <oscar.hartogensis@wur.nl> (Wageningen University, Netherlands, Meteorology and Air Quality Group)
Presenter:Hendrik, A. R. De Bruin <henk.debruin@wur.nl> (Wageningen University, Meteorology and Air Quality Group, 6701 AP Wageningen, Netherlands)
Date: 2006-06-18     Track: Special Sessions     Session: Field measurements and simulations of land-atmosphere interaction
DOI:10.4122/1.1000000561
DOI:10.4122/1.1000000562

A review will be presented of scintillometry work carried out by the Wageningen University in collaboration with others. A scintillometer consists of a transmitter and a receiver. The transmitter produces a parallel beam of light (here wavelengths of about 1 micron and/or 1 mm) and the receiver detects light intensity fluctuations cause by atmospheric turbulent motions. The latter are related to surface fluxes. First, the performance of a large aperture scintillometer (LAS) over different surface types, e.g. heterogeneous terrain types (Flevopolder, the Netherlands; LITTFASS, Germany), grass (Cabauw, the Netherlands), savannah (GLOWA, Ghana) and forest (LITFASS, Germany; Marrakech, Morocco), using path lengths between 1 and 10 km, will be discussed. Note that a LAS provides the sensible heat flux only. Evaporation can be estimated next from a simplified energy balance equation. The so- called saturation effect appears to limit the maximum path length of a LAS. Recently developed saturation correction procedures will be presented. Next, the performance of a LAS combined with a millimeter wave scintillometer (MWS) for estimating both the surface fluxes of sensible and latent heat over natural landscape will be dealt with. Results of the Flevopolder and LITFASS-2003 field experiments will be shown, where a LAS-MWS system was installed over a heterogeneous landscape over a path length of 2.1 and 4.7 km respectively. The scintillometer derived surface fluxes will be compared with aggregated eddy-covariance (EC) measurements. It is our aim also to discuss the question whether and how the scintillometer method can be used in hydrology and agriculture.