Project

Discipline

greenhouse gases; climate change; measurement network; atmospheric transport modeling; biosphere-atmosphere exchange; inverse modeling; carbon dioxide; methane

Lead
Lay summary
CarboCount CH will investigate human-related emissions and natural exchange between atmosphere and biosphere of the two most important long-lived greenhouse gases carbon dioxide (CO2) and methane (CH4) in Europe and especially in Switzerland. As one of the signatory nations of the Kyoto Protocol, Switzerland is obliged to report to the protocol and urge the reduction of its man-made greenhouse gas emissions including CO2 and CH4. CO2, which is emitted in vast amounts through the burning of fossil fuels, is partially absorbed by oceans and partially by the biosphere which uses CO2 for the production of biomass via photosynthesis. Atmospheric CO2 levels are therefore increasing only about half as rapidly as they would if all emitted CO2 remained in the atmosphere. It is highly uncertain, however, how the storage capacity of oceans and biosphere will evolve in the future under a changing climate. CH4 is also emitted from a variety of both anthropogenic and natural sources and future levels of CH4 are similarly difficult to predict as those of CO2. The project CarboCount CH will improve our understanding of biosphere-atmosphere exchange processes in a regional environment typical of the northern mid-latitudes. In addition, CarboCount CH will provide quantitative estimates of CO2 and CH4 fluxes in Switzerland through a unique combination of information from observations and models. These estimates will provide invaluable input to Swiss policy makers in the context of climate change, particularly for the ongoing post-Kyoto negotiations. To achieve its goals, CarboCount CH will setup a network of four new atmospheric CO2 and CH4 measurement sites which will complement existing networks such as the CO2 flux network Swiss Fluxnet. The retired Beromünster radio tower will be the flagship of this network where CO2 and CH4 will be measured at several different altitudes above ground providing crucial data for flux estimation. The project will also explore new avenues in modeling: The COSMO weather forecast model of MeteoSwiss will be extended with new modules to simulate transport of CO2 and CH4 in the atmosphere and to describe the exchange of CO2 between atmosphere and biosphere. Observations and model simulations will finally be combined in a so-called inverse modeling framework for a better quantification of greenhouse gas fluxes and emissions in Switzerland.

Direct link to Lay Summary

Last update: 21.02.2013

Active participation

Self-organised

Communication	Title	Media	Place	Year

Title	Year

Number	Title	Start	Funding scheme

CarboCount CH aims to develop a prototype modelling and observing system for CO2 and CH4 at the regional scale with the objective to quantify and understand CO2 and CH4 fluxes and their sensitivity to recent and current climate variability. The system will provide real time flux estimates allowing to verify their compliance with national regulations and international treaties independently and to provide support for policy makers in the context of climate change. Our approach is to integrate so-called “top-down” methods based on atmospheric measurements and models with “bottom-up” methods based on local (e.g. flux) measurements, process-based models of natural fluxes, and statistical information on anthropogenic emissions. We will focus on central Europe and especially central Switzerland where (i) there exists a strong basis for building a CO2/CH4 measurement network, (ii) rich and detailed data sets are available to provide input and independent verification, and (iii) the heterogeneity of the region provides the challenge needed to test such a system.Our integrated project stands methodologically on three pillars: First, the development of an integrated atmospheric CO2/CH4 measurement network in central Switzerland, consisting of existing flux and concentration measurement sites that will be partially augmented, and four new representative sites on hill tops and towers all equipped with continuous instruments measuring (at least) CO2, CH4, and water vapor. Second, the establishment of high resolution bottom-up driven data products based on process-based ecosystem modeling, direct flux measurements, forest inventories, and geostatistical data of anthropogenic CO2 and CH4 emissions. Third, the development and application of high-resolution regional to local models of atmospheric transport and atmosphere-biosphere exchange of CO2 and CH4, used in forward and inverse (data assimilation) modes.CarboCount CH will study the 1992-2012 period, with a focus on the later years when all observations are in place. Particular questions that will be addressed are: What was the impact of the 2003 heat wave/drought and other drought episodes on the carbon balance in central Europe/Switzerland? How well do we understand atmosphere-biosphere exchange of different vegetation types and their diurnal, seasonal and interannual variability? What are the limitations for the modeling of these fluxes including the limitations imposed by our observation network? How well do bottom-up and top-down estimates agree? What are the main restrictions and uncertainties of the top-down approach to constrain the fluxes?