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1. Direct imaging and spectroscopy of exoplanets with the ELT/HARMONI high-contrast module

Author

M. Houllé, Jean-François Sauvage, Gilles Otten, Elodie Choquet, Mark W. Phillips, Christoph Mordasini, Noah Schwartz, Isabelle Baraffe, Alexis Carlotti, Alexandre Emsenhuber, Faustine Cantalloube, Arthur Vigan, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, School of Physics and Astronomy [Exeter], University of Exeter, DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, UK Astronomy Technology Centre (UK ATC), Science and Technology Facilities Council (STFC), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Bern, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Max Planck Institute for Astronomy (MPIA), NASA GODDARD INSTITUTE FOR SPACE STUDIES NEW YORK USA, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Langages HUmanités Médiations Apprentissages Interactions Numérique (LHUMAIN), Université Paul-Valéry - Montpellier 3 (UPVM), DOTA, ONERA [Salon], ONERA, École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Center for Space and Habitability (CSH), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
planets and satellites: detection, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 530 Physics, Instrumentation, FOS: Physical sciences, Astrophysics, 7. Clean energy, law.invention, Telescope, Integral field spectrograph, instrumentation: high angular resolution, Planet, law, Extremely Large Telescope, infrared: planetary systems, Adaptive optics, Spectroscopy, Instrumentation and Methods for Astrophysics (astro-ph.IM), ComputingMilieux_MISCELLANEOUS, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 520 Astronomy, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Exoplanet, techniques: imaging spectroscopy, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract

Combining high-contrast imaging with medium-resolution spectroscopy has been shown to significantly boost the direct detection of exoplanets. HARMONI, one of the first-light instruments to be mounted on ESO's ELT, will be equipped with a single-conjugated adaptive optics system to reach the diffraction limit of the ELT in H and K bands, a high-contrast module dedicated to exoplanet imaging, and a medium-resolution (up to R = 17 000) optical and near-infrared integral field spectrograph. Combined together, these systems will provide unprecedented contrast limits at separations between 50 and 400 mas. In this paper, we estimate the capabilities of the HARMONI high-contrast module for the direct detection of young giant exoplanets. We use an end-to-end model of the instrument to simulate observations based on realistic observing scenarios and conditions. We analyze these data with the so-called "molecule mapping" technique combined to a matched-filter approach, in order to disentangle the companions from the host star and tellurics, and increase the S/N of the planetary signal. We detect planets above 5-sigma at contrasts up to 16 mag and separations down to 75 mas in several spectral configurations of the instrument. We show that molecule mapping allows the detection of companions up to 2.5 mag fainter compared to state-of-the-art high-contrast imaging techniques based on angular differential imaging. We also demonstrate that the performance is not strongly affected by the spectral type of the host star, and that we reach close sensitivities for the best three quartiles of observing conditions at Armazones, which means that HARMONI could be used in near-critical observations during 60 to 70% of telescope time at the ELT. Finally, we simulate planets from population synthesis models to further explore the parameter space that HARMONI and its high-contrast module will soon open., Accepted for publication in A&A (14 pages, 9 figures)

Published
2021
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2. Strong regional influence of climatic forcing datasets on global crop model ensembles

Author

Jonas Jägermeyr, Allard de Wit, Alex C. Ruane, Thomas A. M. Pugh, Wenfeng Liu, Joshua Elliott, Toshichika Iizumi, Gen Sakurai, Nikolay Khabarov, Peter Lawrence, Benjamin Sultan, Stefan Olin, Christoph Müller, Xuhui Wang, Hong Yang, A. Arneth, Juraj Balkovic, Delphine Deryng, Erwin Schmid, Christian Folberth, Robert C. Izaurralde, Meridell Phillips, Cynthia Rosenzweig, NASA Goddard Institute for Space Studies (GISS), NASA Goddard Space Flight Center (GSFC), NASA GODDARD INSTITUTE FOR SPACE STUDIES NEW YORK USA, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), University of Chicago, Potsdam Institute for Climate Impact Research (PIK), Institute of Geography, University of Edinburgh, International Institute for Applied Systems Analysis [Laxenburg] (IIASA), Tyndall Centre for Climate Change Research, University of East Anglia [Norwich] (UEA), Department of Geography, University of Liverpool, National Institute of Agro-Environmental Sciences (NIAES), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)

Subjects
Atmospheric Science, Earth Observation and Environmental Informatics, 010504 meteorology & atmospheric sciences, Global Gridded Crop Model Intercomparison (GGCMI), Forcing (mathematics), 01 natural sciences, Crop productivity, Crop, 03 medical and health sciences, Crop production, Climatic Forcing Datasets, Aardobservatie en omgevingsinformatica, Precipitation, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, 0105 earth and related environmental sciences, 2. Zero hunger, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 0303 health sciences, Global and Planetary Change, business.industry, Agroclimate, Extreme events, Forestry, Climate Impacts, PE&RC, Agricultural Model Intercomparison and Improvement Project (AgMIP), 13. Climate action, Agriculture, Climatology, Environmental science, business, Agronomy and Crop Science
Abstract

We present results from the Agricultural Model Intercomparison and Improvement Project (AgMIP) Global Gridded Crop Model Intercomparison (GGCMI) Phase I, which aligned 14 global gridded crop models (GGCMs) and 11 climatic forcing datasets (CFDs) in order to understand how the selection of climate data affects simulated historical crop productivity of maize, wheat, rice and soybean. Results show that CFDs demonstrate mean biases and differences in the probability of extreme events, with larger uncertainty around extreme precipitation and in regions where observational data for climate and crop systems are scarce. Countries where simulations correlate highly with reported FAO national production anomalies tend to have high correlations across most CFDs, whose influence we isolate using multi-GGCM ensembles for each CFD. Correlations compare favorably with the climate signal detected in other studies, although production in many countries is not primarily climate-limited (particularly for rice). Bias-adjusted CFDs most often were among the highest model-observation correlations, although all CFDs produced the highest correlation in at least one top-producing country. Analysis of larger multi-CFD-multi-GGCM ensembles (up to 91 members) shows benefits over the use of smaller subset of models in some regions and farming systems, although bigger is not always better. Our analysis suggests that global assessments should prioritize ensembles based on multiple crop models over multiple CFDs as long as a top-performing CFD is utilized for the focus region.

Published
2021
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3. The GGCMI Phase 2 experiment: global gridded crop model simulations under uniform changes in CO2 temperature, water, and nitrogen levels (protocol version 1.0)

Author

Franke, James A., Müller, Christoph, Elliott, Joshua, Ruane, Alex C., Jägermeyr, Jonas, Balkovic, Juraj, Ciais, Philippe, Dury, Marie, Falloon, Pete D., Folberth, Christian, François, Louis, Hank, Tobias, Hoffmann, Munir, Izaurralde, R. Cesar, Jacquemin, Ingrid, Jones, Curtis, Khabarov, Nikolay, Koch, Marian, Li, Michelle, Liu, Wenfeng, Olin, Stefan, Phillips, Meridel, Pugh, Thomas A. M., Reddy, Ashwan, Wang, Xuhui, Williams, Karina, Zabel, Florian, Moyer, Elisabeth J., Department of Geosciences, University of Chicago, Chicago, IL 60637, United States, Potsdam Institute for Climate Impact Research (PIK), University of Chicago, NASA Goddard Institute for Space Studies (GISS), NASA Goddard Space Flight Center (GSFC), International Institute for Applied Systems Analysis [Laxenburg] (IIASA), Comenius University in Bratislava, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Peking University [Beijing], ICOS-ATC (ICOS-ATC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Unité de Modélisation du Climat et des Cycles Biogéochimiques (UMCCB), Université de Liège, Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office [Exeter], Ludwig-Maximilians-Universität München (LMU), Tropical Plant Prodution and Agricultural Systems Modelling (TROPAGS), Georg-August-University = Georg-August-Universität Göttingen, INSTITUTE OF LANDSCAPE MATTER DYNAMICS LEIBNIZ CENTRE FOR AGRICULTURAL LANDSCAPE AND LAND USE RESEARCH ZALF MUNCHEBERG DEU, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Department of Geographical Sciences [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Tropical Plant Production and Agricultural Systems Modelling (TROPAGS), University of Chicago, Department of Statistics, Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland and ETH Zürich, Universitätstrasse 16, CH-8092 Zürich, Switzerland, DEPARTMENT OF PHYSICAL GEOGRAPHY AND ECOSYSTEM SCIENCE LUND UNIVERSITY SWE, NASA GODDARD INSTITUTE FOR SPACE STUDIES NEW YORK USA, Columbia University [New York], School of Geography, Earth and Environmental Sciences and Birmingham Institute of Forest Research, University of Birmingham [Birmingham], LUDWIG MAXIMILIANS UNIVERSITAT MUNCHEN DEPARTMENT OF GEOGRAPHY MUNICH DEU, European Project: 641811,H2020,H2020-WATER-2014-two-stage,IMPREX(2015), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Georg-August-University [Göttingen]

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

Concerns about food security under climate change motivate efforts to better understand future changes in crop yields. Process-based crop models, which represent plant physiological and soil processes, are necessary tools for this purpose since they allow representing future climate and management conditions not sampled in the historical record and new locations to which cultivation may shift. However, process-based crop models differ in many critical details, and their responses to different interacting factors remain only poorly understood. The Global Gridded Crop Model Intercomparison (GGCMI) Phase 2 experiment, an activity of the Agricultural Model Intercomparison and Improvement Project (AgMIP), is designed to provide a systematic parameter sweep focused on climate change factors and their interaction with overall soil fertility, to allow both evaluating model behavior and emulating model responses in impact assessment tools. In this paper we describe the GGCMI Phase 2 experimental protocol and its simulation data archive. A total of 12 crop models simulate five crops with systematic uniform perturbations of historical climate, varying CO2, temperature, water supply, and applied nitrogen (“CTWN”) for rainfed and irrigated agriculture, and a second set of simulations represents a type of adaptation by allowing the adjustment of growing season length. We present some crop yield results to illustrate general characteristics of the simulations and potential uses of the GGCMI Phase 2 archive. For example, in cases without adaptation, modeled yields show robust decreases to warmer temperatures in almost all regions, with a nonlinear dependence that means yields in warmer baseline locations have greater temperature sensitivity. Inter-model uncertainty is qualitatively similar across all the four input dimensions but is largest in high-latitude regions where crops may be grown in the future.

Published
2020
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4. Direct characterization of young giant exoplanets at high spectral resolution by coupling SPHERE and CRIRES+

Author

M. El Morsy, P. Cristofari, Jean-François Sauvage, M. Houllé, Anne Costille, C. Mordasini, Ulf Seemann, M. Lopez, R. Pourcelot, J. L. Beuzit, Ansgar Reiners, Gilles Otten, Reinhold J. Dorn, Y. Charles, Mark W. Phillips, Mamadou N'Diaye, Kjetil Dohlen, Arthur Vigan, Markus Kasper, Elodie Choquet, Isabelle Baraffe, Eduard Muslimov, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), NASA GODDARD INSTITUTE FOR SPACE STUDIES NEW YORK USA, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Physikalisches Institut [Bern], Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universität Bern [Bern] (UNIBE), and N'Diaye, Mamadou

Subjects
530 Physics, FOS: Physical sciences, Astrophysics, 01 natural sciences, [PHYS] Physics [physics], law.invention, [SDU] Sciences of the Universe [physics], 010309 optics, Apparent magnitude, instrumentation: high angular resolution, law, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Spectral resolution, infrared: planetary systems, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Coronagraph, Spectrograph, Astrophysics::Galaxy Astrophysics, instrumentation: spectrographs, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Physics, Very Large Telescope, 520 Astronomy, Astronomy and Astrophysics, 620 Engineering, Exoplanet, Stars, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract

Studies of atmospheres of directly imaged exoplanets with high-resolution spectrographs have shown that their characterization is predominantly limited by noise on the stellar halo at the location of the studied exoplanet. An instrumental combination of high-contrast imaging and high spectral resolution that suppresses this noise and resolves the spectral lines can therefore yield higher quality spectra. We study the performance of the proposed HiRISE fiber coupling between the SPHERE and CRIRES+ at the VLT for spectral characterization of directly imaged planets. Using end-to-end simulations of HiRISE we determine the S/N of the detection of molecular species for known exoplanets in $H$ and $K$ bands, and compare them to CRIRES+. We investigate the ultimate detection limits of HiRISE as a function of stellar magnitude, and we quantify the impact of different coronagraphs and of the system transmission. We find that HiRISE largely outperforms CRIRES+ for companions around bright hosts like $��$ Pic or 51 Eri. For an $H=3.5$ host, we observe a gain of a factor of up to 16 in observing time with HiRISE to reach the same S/N on a companion at 200 mas. More generally, HiRISE provides better performance than CRIRES+ in two-hour integration times between 50-350 mas for hosts with $H, 21 pages, 17 figures. 2 tables. Originally accepted for publication in A&A. Revised version after error in sky background was discovered (too high) and corrected in proofing stage. Revisions made in Abstract, Sections 3-6 and Figures 6-12,C1,C2 that address the changes in performance. Resubmitted to A&A

Published
2021
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5. On the Dependence of Cloud Feedbacks on Physical Parameterizations in WRF Aquaplanet Simulations

Author

Cesana, Grégory, Suselj, Kay, Brient, Florent, Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, USA, NASA GODDARD INSTITUTE FOR SPACE STUDIES NEW YORK USA, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017
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6. Suivi des dynamiques d'inondation à l'échelle globale sur une décennie

Author

Papa, F., Prigent, Cybill, Aires, F., Rossow, W.B., Kosuth, Pascal, NASA GODDARD INSTITUTE FOR SPACE STUDIES NEW YORK USA, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Observatoire de Paris, Université Paris sciences et lettres (PSL), Université Pierre et Marie Curie - Paris 6 (UPMC), Territoires, Environnement, Télédétection et Information Spatiale (UMR TETIS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and Irstea Publications, Migration

Subjects
[SDE] Environmental Sciences, [SDE]Environmental Sciences, FLOODPLAIN
Abstract

[Departement_IRSTEA]DS [TR1_IRSTEA]METHODO / SYNERGIE; Although they only cover ~6% of the Earth's ice-free land surfaces (~8.6 millions km2), natural wetlands and rice paddies play a key role in climate and hydrological processes. Firstly, they represent the world's largest methane source (CH4), the only one dominated by climate variations and account for ~40% of CH4 emitted annually to the atmosphere. In addition, wetlands play a major role for local hydrological system as they contribute in part of the fresh water input in the Oceans by river discharge that greatly influences the ocean circulation through the evolution of the Sea Surface Temperature. Approximately 60% of wetlands are only inundated at some period in the year leading to large uncertainties on their seasonal and inter-annual extents. This is particularly the case for tropical regions subject to the annual rain season as well as Boreal regions subject to the snow melt period. Despite the recognition of their role in climate and hydrological process, as well as their importance in water resources management, wetlands extent and dynamic databases still suffer of a lack of reliable information at global or regional scales over long time period. Characterizing wetlands and their dynamics over large geographical region has been investigated using different techniques with varying degrees of success. Datasets based on soil and vegetation observations represent realistic global wetland distributions, but unfortunately they suffer from a lack of information on temporal and spatial dynamics. In that context, satellite observations provide a means of monitoring wetlands and their dynamics at global and regional scales over long time periods. The objective of this study is to present a new globally applicable remote sensing technique, considering a suite of complementary satellite observations developed to quantify spatial and temporal dynamics of wetlands. The technique it self is based on the detection of inundations at the global scale using the passive microwave land-surfaces emissivities estimated from SSM/I observations, and the use of ERS scatterometer and AVHRR visible and near infrared reflectances to estimate the vegetation contribution to the passive microwave signal. Monthly wetlands extents are now estimated at the global scale over the 9-years 93-2001 period and analyzed regarding to spatial patterns and temporal evolutions. A first results evaluation is made using independent datasets such as land surfaces databases, rain fall rate from GPCP products and water level from radar altimeter measurements. The spatial and temporal wetlands estimations, comprising natural wetlands, irrigated rice culture and lake/river are relevant when compare to static wetlands observations databases. Over the globe, the results show also a high correlation with the GPCP rain data product over the 9 years of study. The correlation over specific regions will be discussed. When focusing around specific areas such as the river basins of the Ganges, the Amazon or Parana Rivers or the Congo-Niger regions, the analysis based on the comparison with water river levels derived from radar altimeter observations show a similar seasonal cycle over the 9 years. These results are encouraging and future studies could now focus on wetlands dynamics as a proxy to study for instance the impacts of ENSO or the monsoons regimes on continental processes. A promising synergy with radar altimetry that could also bring new information related to hydrological parameters, such as river discharges, is under now investigation. Finally, this study stresses the need for development of quality longer satellite estimated wetlands dynamics till upcoming days.

Published
2006

7. Scientific data from precipitation driver response model intercomparison project.

Author

Myhre G, Samset B, Forster PM, Hodnebrog Ø, Sandstad M, Mohr CW, Sillmann J, Stjern CW, Andrews T, Boucher O, Faluvegi G, Iversen T, Lamarque JF, Kasoar M, Kirkevåg A, Kramer R, Liu L, Mülmenstädt J, Olivié D, Quaas J, Richardson TB, Shawki D, Shindell D, Smith C, Stier P, Tang T, Takemura T, Voulgarakis A, and Watson-Parris D

Abstract

This data descriptor reports the main scientific values from General Circulation Models (GCMs) in the Precipitation Driver and Response Model Intercomparison Project (PDRMIP). The purpose of the GCM simulations has been to enhance the scientific understanding of how changes in greenhouse gases, aerosols, and incoming solar radiation perturb the Earth's radiation balance and its climate response in terms of changes in temperature and precipitation. Here we provide global and annual mean results for a large set of coupled atmospheric-ocean GCM simulations and a description of how to easily extract files from the dataset. The simulations consist of single idealized perturbations to the climate system and have been shown to achieve important insight in complex climate simulations. We therefore expect this data set to be valuable and highly used to understand simulations from complex GCMs and Earth System Models for various phases of the Coupled Model Intercomparison Project., (© 2022. The Author(s).)

Published
2022
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8. Tracking Improvement in Simulated Marine Biogeochemistry Between CMIP5 and CMIP6.

Author

Séférian R, Berthet S, Yool A, Palmiéri J, Bopp L, Tagliabue A, Kwiatkowski L, Aumont O, Christian J, Dunne J, Gehlen M, Ilyina T, John JG, Li H, Long MC, Luo JY, Nakano H, Romanou A, Schwinger J, Stock C, Santana-Falcón Y, Takano Y, Tjiputra J, Tsujino H, Watanabe M, Wu T, Wu F, and Yamamoto A

Abstract

Purpose of Review: The changes or updates in ocean biogeochemistry component have been mapped between CMIP5 and CMIP6 model versions, and an assessment made of how far these have led to improvements in the simulated mean state of marine biogeochemical models within the current generation of Earth system models (ESMs)., Recent Findings: The representation of marine biogeochemistry has progressed within the current generation of Earth system models. However, it remains difficult to identify which model updates are responsible for a given improvement. In addition, the full potential of marine biogeochemistry in terms of Earth system interactions and climate feedback remains poorly examined in the current generation of Earth system models., Summary: Increasing availability of ocean biogeochemical data, as well as an improved understanding of the underlying processes, allows advances in the marine biogeochemical components of the current generation of ESMs. The present study scrutinizes the extent to which marine biogeochemistry components of ESMs have progressed between the 5th and the 6th phases of the Coupled Model Intercomparison Project (CMIP)., Competing Interests: Conflict of InterestOn behalf of all authors, the corresponding author states that there is no conflict of interest., (© The Author(s) 2020.)

Published
2020
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9. A PDRMIP multi-model study on the impacts of regional aerosol forcings on global and regional precipitation.

Author

Liu L, Shawki D, Voulgarakis A, Kasoar M, Samset BH, Myhre G, Forster PM, Hodnebrog Ø, Sillmann J, Aalbergsjø SG, Boucher O, Faluvegi G, Iversen T, Kirkevåg A, Lamarque JF, Olivié D, Richardson T, Shindell D, and Takemura T

Abstract

Atmospheric aerosols such as sulfate and black carbon (BC) generate inhomogeneous radiative forcing and can affect precipitation in distinct ways compared to greenhouse gases (GHGs). Their regional effects on the atmospheric energy budget and circulation can be important for understanding and predicting global and regional precipitation changes, which act on top of the background GHG-induced hydrological changes. Under the framework of the Precipitation Driver Response Model Inter-comparison Project (PDRMIP), multiple models were used for the first time to simulate the influence of regional (Asian and European) sulfate and BC forcing on global and regional precipitation. The results show that, as in the case of global aerosol forcing, the global fast precipitation response to regional aerosol forcing scales with global atmospheric absorption, and the slow precipitation response scales with global surface temperature response. Asian sulphate aerosols appear to be a stronger driver of global temperature and precipitation change compared to European aerosols, but when the responses are normalised by unit radiative forcing or by aerosol burden change, the picture reverses, with European aerosols being more efficient in driving global change. The global apparent hydrological sensitivities of these regional forcing experiments are again consistent with those for corresponding global aerosol forcings found in the literature. However, the regional responses and regional apparent hydrological sensitivities do not align with the corresponding global values. Through a holistic approach involving analysis of the energy budget combined with exploring changes in atmospheric dynamics, we provide a framework for explaining the global and regional precipitation responses to regional aerosol forcing.

Published
2018
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10. Rapid adjustments cause weak surface temperature response to increased black carbon concentrations.

Author

Stjern CW, Samset BH, Myhre G, Forster PM, Hodnebrog Ø, Andrews T, Boucher O, Faluvegi G, Iversen T, Kasoar M, Kharin V, Kirkevåg A, Lamarque JF, Olivié D, Richardson T, Shawki D, Shindell D, Smith CJ, Takemura T, and Voulgarakis A

Abstract

We investigate the climate response to increased concentrations of black carbon (BC), as part of the Precipitation Driver Response Model Intercomparison Project (PDRMIP). A tenfold increase in BC is simulated by 9 global coupled-climate models, producing a model-median effective radiative forcing (ERF) of 0.82 (ranging from 0.41 to 2.91) Wm -2 , and a warming of 0.67 (0.16 to 1.66) K globally and 1.24 (0.26 to 4.31) K in the Arctic. A strong positive instantaneous radiative forcing (median of 2.10 Wm -2 based on five of the models) is countered by negative rapid adjustments (-0.64 Wm -2 for the same five models), which dampen the total surface temperature signal. Unlike other drivers of climate change, the response of temperature and cloud profiles to the BC forcing is dominated by rapid adjustments. Low-level cloud amounts increase for all models, while higher-level clouds are diminished. The rapid temperature response is particularly strong above 400 hPa, where increased atmospheric stabilization and reduced cloud cover contrast the response pattern of the other drivers. In conclusion, we find that this substantial increase in BC concentrations does have considerable impacts on important aspects of the climate system. However, some of these effects tend to offset one another, leaving a relatively small global warming of 0.47 K per Wm -2 - about 20 % lower than the response to a doubling of CO 2 . Translating the tenfold increase in BC to the present-day impact of anthropogenic BC (given the emissions used in this work) would leave a warming of merely 0.07 K.

Published
2017
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11. Intercomparison of global river discharge simulations focusing on dam operation - Part II: Multiple models analysis in two case-study river basins, Missouri-Mississippi and Green-Colorado.

Author

Masaki Y, Hanasaki N, Biemans H, Schmied HM, Tang Q, Wada Y, Gosling SN, Takahashi K, and Hijioka Y

Abstract

We performed a twofold intercomparison of river discharge regulated by dams under multiple meteorological forcings among multiple global hydrological models for a historical period by simulation. Paper II provides an intercomparison of river discharge simulated by five hydrological models under four meteorological forcings. This is the first global multimodel intercomparison study on dam-regulated river flow. Although the simulations were conducted globally, the Missouri-Mississippi and Green- Colorado Rivers were chosen as case-study sites in this study. The hydrological models incorporate generic schemes of dam operation, not specific to a certain dam. We examined river discharge on a longitudinal section of river channels to investigate the effects of dams on simulated discharge, especially at the seasonal time scale. We found that the magnitude of dam regulation differed considerably among the hydrological models. The difference was attributable not only to dam operation schemes but also to the magnitude of simulated river discharge flowing into dams. That is, although a similar algorithm of dam operation schemes was incorporated in different hydrological models, the magnitude of dam regulation substantially differed among the models. Intermodel discrepancies tended to decrease toward the lower reaches of these river basins, which means model dependence is less significant toward lower reaches. These case-study results imply that, intermodel comparisons of river discharge should be made at different locations along the river's course to critically examine the performance of hydrological models because the performance can vary with the locations.

Published
2017
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12. Multimodel uncertainty changes in simulated river flows induced by human impact parameterizations.

Author

Liu X, Tang Q, Cui H, Mu M, Gerten D, Gosling S, Masaki Y, Satoh Y, and Wada Y

Abstract

Human impacts increasingly affect the global hydrological cycle and indeed dominate hydrological changes in some regions. Hydrologists have sought to identify the human-impact-induced hydrological variations via parameterizing anthropogenic water uses in global hydrological models (GHMs). The consequently increased model complexity is likely to introduce additional uncertainty among GHMs. Here, using four GHMs, between-model uncertainties are quantified in terms of the ratio of signal to noise (SNR) for average river flow during 1971-2000 simulated in two experiments, with representation of human impacts (VARSOC) and without (NOSOC). It is the first quantitative investigation of between-model uncertainty resulted from the inclusion of human impact parameterizations. Results show that the between-model uncertainties in terms of SNRs in the VARSOC annual flow are larger (about 2% for global and varied magnitude for different basins) than those in the NOSOC, which are particularly significant in most areas of Asia and northern areas to the Mediterranean Sea. The SNR differences are mostly negative (-20% to 5%, indicating higher uncertainty) for basin-averaged annual flow. The VARSOC high flow shows slightly lower uncertainties than NOSOC simulations, with SNR differences mostly ranging from -20% to 20%. The uncertainty differences between the two experiments are significantly related to the fraction of irrigation areas of basins. The large additional uncertainties in VARSOC simulations introduced by the inclusion of parameterizations of human impacts raise the urgent need of GHMs development regarding a better understanding of human impacts. Differences in the parameterizations of irrigation, reservoir regulation and water withdrawals are discussed towards potential directions of improvements for future GHM development. We also discuss the advantages of statistical approaches to reduce the between-model uncertainties, and the importance of calibration of GHMs for not only better performances of historical simulations but also more robust and confidential future projections of hydrological changes under a changing environment.

Published
2017
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13. Net primary productivity estimates and environmental variables in the Arctic Ocean: An assessment of coupled physical-biogeochemical models.

Author

Lee YJ, Matrai PA, Friedrichs MAM, Saba VS, Aumont O, Babin M, Buitenhuis ET, Chevallier M, de Mora L, Dessert M, Dunne JP, Ellingsen IH, Feldman D, Frouin R, Gehlen M, Gorgues T, Ilyina T, Jin M, John JG, Lawrence J, Manizza M, Menkes CE, Perruche C, Le Fouest V, Popova EE, Romanou A, Samuelsen A, Schwinger J, Séférian R, Stock CA, Tjiputra J, Tremblay LB, Ueyoshi K, Vichi M, Yool A, and Zhang J

Abstract

The relative skill of 21 regional and global biogeochemical models was assessed in terms of how well the models reproduced observed net primary productivity (NPP) and environmental variables such as nitrate concentration (NO 3 ), mixed layer depth (MLD), euphotic layer depth (Z eu ), and sea ice concentration, by comparing results against a newly updated, quality-controlled in situ NPP database for the Arctic Ocean (1959-2011). The models broadly captured the spatial features of integrated NPP (iNPP) on a pan-Arctic scale. Most models underestimated iNPP by varying degrees in spite of overestimating surface NO 3 , MLD, and Z eu throughout the regions. Among the models, iNPP exhibited little difference over sea ice condition (ice-free versus ice-influenced) and bottom depth (shelf versus deep ocean). The models performed relatively well for the most recent decade and toward the end of Arctic summer. In the Barents and Greenland Seas, regional model skill of surface NO 3 was best associated with how well MLD was reproduced. Regionally, iNPP was relatively well simulated in the Beaufort Sea and the central Arctic Basin, where in situ NPP is low and nutrients are mostly depleted. Models performed less well at simulating iNPP in the Greenland and Chukchi Seas, despite the higher model skill in MLD and sea ice concentration, respectively. iNPP model skill was constrained by different factors in different Arctic Ocean regions. Our study suggests that better parameterization of biological and ecological microbial rates (phytoplankton growth and zooplankton grazing) are needed for improved Arctic Ocean biogeochemical modeling.

Published
2016
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