The CarbonTracker Data Assimilation Shell (CTDAS) v1.0:
implementation and global carbon balance 2001–2015
Ingrid T. van der Laan-Luijkx1,2, Ivar R. van der Velde3,4,1,5, Emma van der Veen1, Aki Tsuruta6, Karolina Stanislawska7, Arne Babenhauserheide8, Hui Fang Zhang9,10, Yu Liu11, Wei He5,12, Huilin Chen5,4, Kenneth A. Masarie3,a, Maarten C. Krol1,2,13, and Wouter Peters1,51Wageningen University and Research, Environmental Sciences Group, Wageningen, the Netherlands 2Utrecht University, Institute for Marine and Atmospheric Research, Utrecht, the Netherlands 3Global Monitoring Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration (NOAA), Boulder, Colorado, USA 4University of Colorado, Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, Colorado, USA 5University of Groningen, Centre for Isotope Research, Groningen, the Netherlands 6Climate Research, Finnish Meteorological Institute, Helsinki, Finland 7Meteorological Research, Finnish Meteorological Institute, Helsinki, Finland 8IMK-ASF, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany 9State Key Laboratory of Resources and Environment Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China 10University of Chinese Academy of Sciences, Beijing, China 11Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, Zürich, Switzerland 12International Institute for Earth System Science, Nanjing University, Nanjing, China 13SRON Netherlands Institute for Space Research, Utrecht, the Netherlands acurrently at: SkyData Solutions LLC
Received: 24 Feb 2017 – Accepted for review: 19 Mar 2017 – Discussion started: 21 Mar 2017
Abstract. Data assimilation systems are used increasingly to constrain the budgets of reactive and long-lived gases measured in the atmosphere. Each trace gas has its own lifetime, dominant sources and sinks, and observational network (from flask sampling and in situ measurements to space-based remote sensing) and therefore comes with its own optimal configuration of the data assimilation. The CarbonTracker Europe data assimilation system for CO2 estimates global carbon sources and sinks, and updates are released annually and used in carbon cycle studies. CarbonTracker Europe simulations are performed using the new modular implementation of the data assimilation system which is called the CarbonTracker Data Assimilation Shell (CTDAS). Here, we present and document this redesign of the data assimilation code that forms the heart of CarbonTracker, specifically meant to enable easy extension and modification of the data assimilation system. This paper also presents the setup of the latest version of CarbonTracker Europe (CTE2016), including the use of the gridded state vector, and shows the resulting carbon flux estimates. We present the distribution of the carbon sinks over the hemispheres and between the land biosphere and the oceans. We show that with equal fossil fuel emissions, 2015 has a higher atmospheric CO2 growth rate compared to 2014, due to reduced land carbon uptake in later year. The European carbon sink is especially present in the forests, and is reduced during drought years. Finally, we also demonstrate the versatility of CTDAS by presenting an overview of the wide range of applications for which it has been used so far.
van der Laan-Luijkx, I. T., van der Velde, I. R., van der Veen, E., Tsuruta, A., Stanislawska, K., Babenhauserheide, A., Zhang, H. F., Liu, Y., He, W., Chen, H., Masarie, K. A., Krol, M. C., and Peters, W.: The CarbonTracker Data Assimilation Shell (CTDAS) v1.0:
implementation and global carbon balance 2001–2015, Geosci. Model Dev. Discuss., doi:10.5194/gmd-2017-45, in review, 2017.