CoMet: The Carbon Dioxide and Methane Mission for HALO

The lack of knowledge about the sources and sinks in the Global Carbon Cycle on all relevant temporal and spatial scales is currently recognized as the biggest deficit in understanding the processes of Global Change and developing solutions for adaptation measures. In order to reliably predict the climate on our planet throughout the 21st century and to support attaining emission targets in the framework of international climate agreements, research on the fluxes of the two most important anthropogenic greenhouse gases - carbon dioxide (CO2) and methane (CH4) - is indispensable. Here we will give an overview on primary objectives and first results from the HALO aircraft campaign CoMet (CO2 and Methane mission), which is planned in April-May 2017. During CoMet, a scientific payload consisting of the best currently available active (lidar) and passive remote sensing instruments will fly on HALO, supported by highly accurate in-situ measurements. The gained data sets will help to increase the knowledge about the variability of CO2 and CH4 on a subcontinental scale. The flights will be concentrated on Europe since the European continent is characterized by a very strong overlap between anthropogenic and biogenic sources. This will not only allow identifying local sources of emissions but also providing important input for the inverse models to infer regional budgets. A significant part of the HALO flights will be performed in coordination with two small Cessna aircraft that carry a passive remote sensor (MAMAP) and a suite of in-situ instrumentation and will concentrate on areas with strong localized sources. Through analyzing the CoMet data set the knowledge about the carbon dioxide and methane cycle shall be improved and new insight gained about the spatial and temporal variations of greenhouse gases. Moreover, the CoMet mission aims at preparing the validation activities for upcoming satellite missions such as the German-French Climate mission MERLIN (Methane Remote Sensing LIDAR Mission). Scheduled for Launch in 2021, this small satellite mission will measure the methane concentration in Earth's atmosphere to an unprecedented level of accuracy and thus further contribute to research into the causes of climate change.