HR: 10:20h
AN: B52B-01    [Abstracts]
TI: WRF-VPRM Modeling System And Its Role In Predicting Regional Carbon Budget
AU: * Ahmadov, R
EM: rahmadov@bgc-jena.mpg.de
AF: Max-Planck-Institute for Biogeochemistry, Hans-Knoell-str. 10, Jena, 07745, Germany
AU: Gerbig, C
EM: cgerbig@bgc-jena.mpg.de
AF: Max-Planck-Institute for Biogeochemistry, Hans-Knoell-str. 10, Jena, 07745, Germany
AU: Dhanya, K
EM: kdhanya@bgc-jena.mpg.de
AF: Max-Planck-Institute for Biogeochemistry, Hans-Knoell-str. 10, Jena, 07745, Germany
AU: Kretschmer, R
EM: rkretsch@bgc-jena.mpg.de
AF: Max-Planck-Institute for Biogeochemistry, Hans-Knoell-str. 10, Jena, 07745, Germany
AU: Koerner, S
EM: Stefan.Koerner@bgc-jena.mpg.de
AF: Max-Planck-Institute for Biogeochemistry, Hans-Knoell-str. 10, Jena, 07745, Germany
AU: Neininger, B
EM: bruno.neininger@metair.ch
AF: MetAir AG, Sonnenberg 27, Menzingen, CH-6313, Switzerland
AB: One of the key questions in climate science is to estimate a carbon budget of a given region. Atmospheric measurements of CO2 from global networks, mostly consisting of remote sites are used in combination with inverse modeling to estimate exchange fluxes of carbon between land and ocean biosphere and the atmosphere. Enhanced spatial resolution of such estimates is targeted with increasing density of the network, with a significant fraction of observations made in the continental boundary layer. These continental measurement sites, close to variable sources and sinks of CO2, are often located in meteorologically complex areas: terrain induced mesoscale phenomena such as sea-land, (lake, river, forest, etc.) breezes and mountain-valley circulations make the representation in global scale coarse resolution atmospheric models that are used in the inversions quite difficult. We setup a modeling system which combines a mesoscale meteorological model, the Weather Research and Forecasting (WRF) model with a diagnostic biospheric model, the Vegetation Photosynthesis and Respiration (VPRM). VRPM uses EVI and LSWI vegetation indices from MODIS satellite. In addition VPRM uses four parameters for each vegetation class, also temperature and radiation to produce biospheric CO2 fluxes. The WRF-VPRM modeling system was designed to realistically simulate atmospheric CO2 concentration fields at mesoscales, starting at 2km. Here we present our simulation results for different domains – SW France and SE Germany, where we have continuous measurement sites. The first domain contains ocean, land and mountains in the south and the east, while the second domain is the Ochsenkopf, a ~1 km tall hill in northern Bavaria. This gives us an opportunity to study the different kind of local mesoscale circulations and their influence on CO2 distribution. The study shows that in order to interpret local concentration measurements one has to perform high-resolution simulations which resolve local effects. The coastal station (Biscarosse tower in SW France) detects the remarkable variations in CO2 concentration due to sea-land breeze. This mesoscale effect leads to average CO2 concentration over land near the coast being higher than further inland (3D rectifier effect). The different kind of meteorological data obtained by ground and aircraft measurements allows us to investigate transport model deficiencies in detail and improve our models for using these fields in inversions. For performing inversions we're coupling Stochastic Time-Inverted Lagrangian Transport Model (STILT) to WRF-VPRM. The limited number of parameters in VPRM allows optimizing them against CO2 mixing ratio measurements in atmospheric inversion by using adjoint transport model - STILT. This provides a test for upscaling methods from flux towers to regional scales. The WRF-VPRM system provides the basis for a model-data-fusion system that simultaneously assimilates fluxes and concentrations to estimate high resolution regional scale biospheric CO2 fluxes over long-time periods.
DE: 0466 Modeling
DE: 3329 Mesoscale meteorology
SC: Biogeosciences [B]
MN: 2007 Fall Meeting