Atmospheric and Earth System Research with HALO

(High Altitude and Long Range Research Aircraft)

Carbon Dioxide and Methane Mission for HALO - CoMet

Mission Time Period: May - June 2018, Mission completed

Principle Investigators

Partner Institutions

Confronting Climate Change is one of the paramount societal challenges of our time. The main cause for global warming is the increase of greenhouse gases (GHGs) in the Earth’s atmosphere. Together, carbon dioxide (CO2) and methane (CH4), being the two most important anthropogenic GHGs, globally contribute to about 81% of the anthropogenic radiative forcing.

However, there are still significant deficits in the knowledge about the budgets of these two major GHGs such that the ability to accurately predict our future climate remains substantially compromised. Different feedback mechanisms which are insufficiently understood have significant impact on the quality of climate projections. In order to accurately predict future climate of our planet and support observing emission targets in the framework of international agreements, the investigation of sources and sinks of the GHGs and their feedback mechanisms is indispensable.

In the past years, inverse modelling has emerged as a key method for obtaining quantitative information on the sources and sinks of the GHGs. However, this technique requires the availability of sufficient amounts of precise and independent data on various spatial scales. Therefore, observing the atmospheric concentrations of the GHGs is of significant importance for this purpose. In contrast to point measurements, airborne instruments are able to provide regional-scale data of GHGs which are urgently required, though currently lacking.

Therefore, CoMet aims at constraining the sources and sinks of these two most important anthropogenic GHGs on regional to sub-continental scales. This goal shall be pursued by accurate airborne measurements using both active and passive remote sensing and supported by in-situ observations, in conjunction with ground–based as well as spaceborne instruments and inverse models.

The goal of CoMet is to combine - for the first time - a suite of the best currently available active (lidar) and passive remote sensors as well as in-situ instruments to collect new data sets and knowledge about the variability of CO2 and CH4 on a subcontinental scale. The flights will be concentrated on Europe, partly because of logistic reasons but also because 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 budget by means of remote sensing and in-situ data. Through analysing 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 the GHGs. Moreover, the project also aims at developing new methodologies for the measurement of GHGs and shall promote the development of technologies for future generations of Earth observing satellites.

For CoMet, an intensive measurement period of 4 weeks is planned at the beginning of the growing season in April-May 2017. Within approximately 60 hours of flight operation, optimized research flights on HALO will comprise:

  • extended latitudinal transects to capture the GHG gradients,
  • flights over known regions of strong emissions (such as the hard coal mining areas in Upper Silesia),
  • comparison overflights over the ground–based remote sensing sites of the TCCON network.

Part of the HALO flights will be performed in coordination with small Cessna aircraft that will concentrate on strong localized sources.

Further Information