Mikrometeorologische Bestimmung des Energiehaushaltes einer Magerwiese in komplexem Gelände

In 1993, the Swiss national science foundation
launched the integrated project "biodiversity".
The investigations focused on the role of variability
as a driving force in the evolution and
maintenance of life systems from the molecular
to the landscape scale. Within this framework,
an extensive micrometeorological data set could
be collected on the main investigation site
1HQ]OLQJHU� :HLGH from August 1994 until
December 1996. The 1HQ]OLQJHU�:HLGH� is situated
on a southwest exposed slope with a tilt of
about 17 °. The surrounding is characterized by
single trees and forest.
One goal of the presented investigation is to
recognize the location-specific influence of the
measurement site on the turbulent exchange
between surface and planetary boundary layer.
This will be done using the theory developed
for horizontal and homogeneous terrain. Due to
thermally and mechanically effective inhomogeneities
in the surrounding of the measurement
site the influence of the slope can not be
judged independently.
On the other hand it is shown that eddycovariance
measurements can be used to determine
the sensible heat fluxes in most complex
terrain with reliable results. Flux contributions
due to advection frequently results in an underestimation
of the measured flux values. They
can be corrected however as a function of the
available energy. In order to consider the sensor
response of the assigned measuring system a
correction-model was developed. The corrections
will be discussed.
Finally the energy budget for the entire investigation
period is analysed. Dependence between
radiative fluxes, soil heat flux, sensible and
latent heat fluxes as well as relations to water
regime, cloudiness and vegetation are discussed.
The evaporation correlates well with the
radiation balance. The radiation balance values
must be converted previous from the horizontal
into a slope-parallel coordinate system. The
model used is presented. The modelled values
agree well with comparative measurements.
Further it can be stated that the diversity of
plant species affects the energy budget at 1HQ�
]OLQJHU�:HLGH�compensatorily.