Geoökologisches Kolloquium SS 2007

All lecture dates

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Prof Dr. T. Weidinger
Universität Budapest, Department of Meteorology
Thursday, 14.06.2007 16:16 H6

Measurement and modeling of energy budget components and trace gases fluxes between atmosphere and different types of ecosystems of Hungary

After a presentation of the brief history and the present status of
micrometeorological research activities in Hungary our field
measurement programs, instrumentation and flux calculation
methodology are presented. The research group consists of people
from the Hungarian Meteorological Service and different universities,
who work in close international cooperation.
Field experiments using the gradient and the profile methods
have been started 17 years ago. First, the daily and annual
variations of deposition velocities and fluxes of ozone, nitrogen
oxides and sulfur dioxide were investigated above grassland and
spruce forest. Based on this measured data set an ozone deposition
model for Hungary was also developed and tested.
Measurement and modeling of deposition processes of
nitrogen compounds, first of all that of ammonia were investigated in
Hortobágy puszta in the frame of the EU4-GRAMINAE program
(1999-2002). Ammonia bi-directional flux shows net deposition in
annual time scale. Net emission of ammonia was detected daytime,
during the vegetation period when the stomata are open.
Measurements and model calculations suggest, ammonia is emitted
mostly through stomata since the soil emission is limited below the
soil pH 8, where all of ammonia exists in the form of ammonium ion.
The effect of high nitrogen load (application of mineral fertilizer) was
also investigated. High ammonia emission was detected daytime for
few weeks of application of fertilizer.
Continuous energy, water, carbon and nitrogen budget
measurements have been carried out in the frame of the EU5
GREENGRASS and EU6 NitroEurope projects in the central part of
the country (Bugac puszta) above a semi-natural grassland, since
2002. One of the main aim of these investigations was to reduce the
large uncertainties in CO2, N2O and CH4-fluxes within the atmosphere
and grassland under different climate conditions. Meteorological
data were collected on the basis of 30 minute average. The eddy-
covariance system used for calculation of momentum, CO2, sensible
and latent heat fluxes consisted of a sonic anemometer and a Li-Cor
7500 open path CO2/H2O infrared gas analyzer. Nitrous oxide and
methane emissions are also measured using static soil chambers.
Profile measurements of ozone and nitrogen oxides (NO, NOx) and
dynamic chamber measurements for nitric oxide have been started
in 2006. Nitric oxide and nitrous oxide soil emissions amount
approximately 10% of the total (wet and dry) deposition of nitrogen
compounds.
In the last part of the presentation the development of a new
Hungarian reference climate network is illustrated, to detect the
possible effects of future climate change, consists of both regular
standard measurement program for climate stations and soil,
radiation as well as energy budget measurements.


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