Observation and Integrated Earth-System
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Observation and integrated Earth-system science: A roadmap for 2016–2025 Adrian Simmons, Jean-Louis Fellous, Venkatachalam Ramaswamy, Kevin Trenberth, Ghassem Asrar, Magdalena Balmaseda, John P. Burrows, Philippe Ciais, Mark Drinkwater, Pierre Friedlingstein, et al. To cite this version: Adrian Simmons, Jean-Louis Fellous, Venkatachalam Ramaswamy, Kevin Trenberth, Ghassem Asrar, et al.. Observation and integrated Earth-system science: A roadmap for 2016–2025. Advances in Space Research, Elsevier, 2016, 57 (10), pp.2037 - 2103. 10.1016/j.asr.2016.03.008. hal-01491811 HAL Id: hal-01491811 https://hal.archives-ouvertes.fr/hal-01491811 Submitted on 28 Jun 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Observation and Integrated Earth‐system Science: A roadmap for 2016‐2025 Adrian Simmons1 European Centre for Medium‐Range Weather Forecasts, Shinfield Park, Reading RG2 9AX, UK Jean‐Louis Fellous Committee on Space Research, c/o CNES, 2 place Maurice Quentin, 75039 Paris Cedex 01, France Venkatachalam Ramaswamy Geophysical Fluid Dynamics Laboratory/NOAA, Princeton, NJ 08540‐6649, USA Kevin Trenberth National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307, USA and fellow contributors from a Study Team of the Committee on Space Research: Ghassem Asrar (Univ. of Maryland), Magdalena Balmaseda (ECMWF), John P. Burrows (Univ. of Bremen), Philippe Ciais (IPSL/LSCE), Mark Drinkwater (ESA/ESTEC), Pierre Friedlingstein (Univ. of Exeter), Nadine Gobron (EC/JRC), Eric Guilyardi (IPSL/LOCEAN), David Halpern (NASA/JPL), Martin Heimann (MPI for Biogeochemistry), Johnny Johannessen (NERSC), Pieternel F. Levelt (KNMI and Univ. of Technology Delft), Ernesto Lopez‐Baeza (Univ. of Valencia), Joyce Penner (Univ. of Michigan), Robert Scholes (Univ. of the Witwatersrand) and Ted Shepherd (Univ. of Reading). Abstract This report is the response to a request by the Committee on Space Research of the International Council for Science to prepare a roadmap on observation and integrated Earth‐system science for the coming ten years. Its focus is on the combined use of observations and modelling to address the functioning, predictability and projected evolution of interacting components of the Earth system on timescales out to a century or so. It discusses how observations support integrated Earth‐system science and its applications, and identifies planned enhancements to the contributing observing systems and other requirements for observations and their processing. All types of observation are considered, but emphasis is placed on those made from space. The origins and development of the integrated view of the Earth system are outlined, noting the interactions between the main components that lead to requirements for integrated science and modelling, and for the observations that guide and support them. What constitutes an Earth‐system model is discussed. Summaries are given of key cycles within the Earth system. 1 Corresponding author; email: [email protected]; tel: +44 118 949 9700 Page 1 29 February 2016 The nature of Earth observation and the arrangements for international coordination essential for effective operation of global observing systems are introduced. Instances are given of present types of observation, what is already on the roadmap for 2016‐2025 and some of the issues to be faced. Observations that are organized on a systematic basis and observations that are made for process understanding and model development, or other research or demonstration purposes, are covered. Specific accounts are given for many of the variables of the Earth system. The current status and prospects for Earth‐system modelling are summarized. The evolution towards applying Earth‐system models for environmental monitoring and prediction as well as for climate simulation and projection is outlined. General aspects of the improvement of models, whether through refining the representations of processes that are already incorporated or through adding new processes or components, are discussed. Some important elements of Earth‐system models are considered more fully. Data assimilation is discussed not only because it uses observations and models to generate datasets for monitoring the Earth system and for initiating and evaluating predictions, in particular through reanalysis, but also because of the feedback it provides on the quality of both the observations and the models employed. Inverse methods for surface‐flux or model‐parameter estimation are also covered. Reviews are given of the way observations and the processed datasets based on them are used for evaluating models, and of the combined use of observations and models for monitoring and interpreting the behaviour of the Earth system and for predicting and projecting its future. A set of concluding discussions covers general developmental needs, requirements for continuity of space‐based observing systems, further long‐term requirements for observations and other data, technological advances and data challenges, and the importance of enhanced international co‐ operation. Page 2 29 February 2016 Contents 1 Introduction ..................................................................................................................... 6 2 The Earth system .............................................................................................................. 8 2.1 Development of the Earth‐system view ....................................................................... 8 2.2 Scope of this study ................................................................................................... 11 2.3 The climate system................................................................................................... 11 2.4 Integrated Earth‐system modelling............................................................................ 12 2.5 Energy, circulation and constituent cycles within the Earth system.............................. 13 2.5.1 Energy and circulation....................................................................................... 13 2.5.2 The hydrological cycle ....................................................................................... 14 2.5.3 The carbon cycle ............................................................................................... 16 2.5.4 Other constituent cycles and the link between air quality and climate.................. 18 3 Earth‐system observation ............................................................................................... 19 3.1 The nature of Earth observation ................................................................................ 19 3.2 International coordination of Earth observation ......................................................... 20 3.3 Sustained satellite observing systems for weather and climate ................................... 23 3.4 The Copernicus programme ...................................................................................... 24 3.5 Missions for research and development, and the challenges of continuity ................... 25 3.6 Observation of specific components of the Earth system ............................................ 28 3.6.1 Atmosphere ..................................................................................................... 28 3.6.2 Ocean .............................................................................................................. 34 3.6.3 Land................................................................................................................. 39 3.6.4 Cryosphere ....................................................................................................... 43 3.6.5 Carbon cycle ..................................................................................................... 45 4 Earth‐system modelling .................................................................................................. 46 4.1 “Seamless” modelling and prediction ........................................................................ 46 4.2 Limitations of models ............................................................................................... 48 4.3 Improvement of models ........................................................................................... 49 4.4 Resolution ............................................................................................................... 51 4.5 Clouds and aerosols.................................................................................................. 53 4.6 Hydrological cycle .................................................................................................... 54 4.7 Atmospheric chemistry ............................................................................................. 56 4.8 Land biogeochemistry .............................................................................................. 57 4.8.1 Nitrogen cycle .................................................................................................