The Global Land Carbon Cycle Simulated With ISBA‐CTRIP: Improvements Over the Last Decade

Delire, Christine; Séférian, Roland; Decharme, Bertrand; Alkama, Ramdane; Calvet, Jean‐Christophe; Carrer, Dominique; Gibelin, Anne-Laure; Joetzjer, Émilie; Morel, Xavier; Rocher, Matthias; Tzanos, Diane

doi:10.1029/2019ms001886

Cited by 59 publications

(46 citation statements)

References 126 publications

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“…Future analyses of the deforest-glob experiments could further focus on the seasonality of vegetation and climate variables (e.g. with regard to large-scale atmospheric circulation changes) to advance the understanding compared to previous studies (Bonan, 2008;Chen and Dirmeyer, 2020;Davin and de Noblet-Ducoudré, 2010;de Noblet-Ducoudré et al, 2012;Pitman et al, 2009). Additionally, the enhanced meridional temperature gradient may alter the large-scale atmospheric circulation that deserves future explorations.…”

Section: Discussionmentioning

confidence: 97%

“…With prescribed SSTs the mediating effect of the ocean on the land temperatures is missing, resulting in overestimated tropical warming and underestimated boreal cooling over deforested areas (Davin and de Noblet-Ducoudré, 2010).This setup assumes that the effect of large-scale circulation changes is small and can be ignored. Climatic effects of historical land use and land cover changes (LULCCs) studied in this setup show substantial differences among global climate models due to differences in land surface schemes and their implementation of changes in land cover to represent deforestation (Boisier et al, 2012;de Noblet-Ducoudré et al, 2012;Pitman et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Global climate response to idealized deforestation in CMIP6 models

et al. 2020

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Abstract. Changes in forest cover have a strong effect on climate through the alteration of surface biogeophysical and biogeochemical properties that affect energy, water and carbon exchange with the atmosphere. To quantify biogeophysical and biogeochemical effects of deforestation in a consistent setup, nine Earth system models (ESMs) carried out an idealized experiment in the framework of the Coupled Model Intercomparison Project, phase 6 (CMIP6). Starting from their pre-industrial state, models linearly replace 20×106 km2 of forest area in densely forested regions with grasslands over a period of 50 years followed by a stabilization period of 30 years. Most of the deforested area is in the tropics, with a secondary peak in the boreal region. The effect on global annual near-surface temperature ranges from no significant change to a cooling by 0.55 ∘C, with a multi-model mean of -0.22±0.21 ∘C. Five models simulate a temperature increase over deforested land in the tropics and a cooling over deforested boreal land. In these models, the latitude at which the temperature response changes sign ranges from 11 to 43∘ N, with a multi-model mean of 23∘ N. A multi-ensemble analysis reveals that the detection of near-surface temperature changes even under such a strong deforestation scenario may take decades and thus longer than current policy horizons. The observed changes emerge first in the centre of deforestation in tropical regions and propagate edges, indicating the influence of non-local effects. The biogeochemical effect of deforestation are land carbon losses of 259±80 PgC that emerge already within the first decade. Based on the transient climate response to cumulative emissions (TCRE) this would yield a warming by 0.46 ± 0.22 ∘C, suggesting a net warming effect of deforestation. Lastly, this study introduces the “forest sensitivity” (as a measure of climate or carbon change per fraction or area of deforestation), which has the potential to provide lookup tables for deforestation–climate emulators in the absence of strong non-local climate feedbacks. While there is general agreement across models in their response to deforestation in terms of change in global temperatures and land carbon pools, the underlying changes in energy and carbon fluxes diverge substantially across models and geographical regions. Future analyses of the global deforestation experiments could further explore the effect on changes in seasonality of the climate response as well as large-scale circulation changes to advance our understanding and quantification of deforestation effects in the ESM frameworks.

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Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Global climate response to idealized deforestation in CMIP6 models

et al. 2020

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“…Ocean carbon cycle is represented using the Canadian Model of Ocean Carbon (CMOC) which was developed for earlier versions of CanESM (Arora et al, 2011;Christian et al, 2010), and between the atmosphere, the ocean, the lakes and the land surface. Over the land surface, CNRM-ESM2-1 uses the ISBA-CTRIP land surface modeling system (http://www.umrcnrm.fr/spip.php?article1092&lang=en) to solve energy, carbon and water budgets at the land surface (Decharme et al, 2019;Delire et al, 2019). Its physical core explicitly solves the one- of the leaves.…”

Section: A53 Canadian Centre For Climate Modelling and Analysis (Ccmentioning

confidence: 99%

“…This dissolved organic carbon is transported by the rivers to the ocean. A detailed description of the terrestrial carbon cycle can be found in Delire et al (2019).…”

Section: A53 Canadian Centre For Climate Modelling and Analysis (Ccmentioning

confidence: 99%

Carbon-concentration and carbon-climate feedbacks in CMIP6 models, and their comparison to CMIP5 models

Arora¹,

Katavouta²,

Williams³

et al. 2019

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Abstract. Results from the fully-, biogeochemically-, and radiatively-coupled simulations in which CO2 increases at a rate of 1&#8201;% per year (1pctCO2) from its pre-industrial value are analyzed to quantify the magnitude of two feedback parameters which characterize the coupled carbon-climate system. These feedback parameters quantify the response of ocean and terrestrial carbon pools to changes in atmospheric CO2 concentration and the resulting change in global climate. The results are based on eight comprehensive Earth system models from the fifth Coupled Model Intercomparison Project (CMIP5) and eleven models from the sixth CMIP (CMIP6). The comparison of model results from two CMIP phases shows that, for both land and ocean, the model mean values of the feedback parameters and their multi-model spread has not changed significantly across the two CMIP phases. The absolute values of feedback parameters are lower for land with models that include a representation of nitrogen cycle. The sensitivity of feedback parameters to the three different ways in which they may be calculated is shown and, consistent with existing studies, the most relevant definition is that calculated using results from the fully- and biogeochemically-coupled configurations. Based on these two simulations simplified expressions for the feedback parameters are obtained when the small temperature change in the biogeochemically-coupled simulation is ignored. Decomposition of the terms of these simplified expressions for the feedback parameters allows identification of the reasons for differing responses among ocean and land carbon cycle models.

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“…The most significant results show improvements in the river discharge simulations, the snowpack representation and the land surface evapotranspiration (Decharme et al, 2019). Recently, the updated version of ISBA-CTRIP, considering improvements such as wild fires and land cover changes (Séférian et al, 2019), has also shown a better representation of global-scale carbon pools and fluxes (Delire et al, 2020).…”

Section: Isba-ctrip Systemmentioning

confidence: 99%

Parametrization of lakes water dynamics in the ISBA-CTRIP land surface system (SURFEX v8.1)

Guinaldo¹,

Munier²,

Moigne³

et al. 2020

Preprint

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Abstract. Lakes are of fundamental importance in the Earth system as they support essential environmental and economic services such as freshwater supply. They also modify the local hydro-meteorological continuum as a lower boundary of the atmosphere. Sentinels of climate change and anthropization, these open water bodies are facing disruptions of their equilibrium generally leading to a notable reduction of their levels worldwide. Stream-flow variability and temporal evolution are impacted by the presence of lakes in the river network, therefore any change in the lake state can induce a modification of the regional hydrological regime. Despite the importance of the impact of lakes on hydrological fluxes and the water balance, a representation of the mass budget is generally not included in climate models and global scale hydrological modeling platforms. The goal of this study is to introduce a new lake mass module, MLake (Mass-Lake model), into the river routing model CTRIP to resolve the specific mass-balance of open water bodies. Based on the inherent CTRIP parameters, the development of the non-calibrated MLake model was introduced to examine the influence of such hydrological buffer areas on the global scale river routing performances. In the current study, an off-line evaluation was performed for four river networks using a set of state-of-the-art quality atmospheric forcings and a combination of in situ and satellite measurements for river discharge and lake level observations. The results reveal a general improvement in CTRIP simulated discharge and its variability, while also generating realistic lake level variations. MLake produces more realistic streamflows both in terms of daily and seasonal correlation. Excluding the specific case of Lake Victoria having low performances, the mean skill score of Kling-Gupta Efficiency (KGE) is 0.41 while the Normalized Information Contribution (NIC) shows a mean improvement of 0.56 (ranging from 0.15 to 0.94). Streamflow results are spatially scale-dependent, with better scores associated with larger lakes, and increased sensitivity to the width of the lake outlet. Regarding lake levels variations, results indicate a good agreement between observations and simulations with a mean correlation of 0.56 (ranging from 0.07 to 0.92) which is linked to the capability of the model to retrieve seasonal variations. Discrepancies in the results are mainly explained by the anthropization of the selected lakes which introduces high-frequency variations in both streamflows and lake levels that degraded the scores. Anthropization effects are prevalent in most of the lakes studied, but they are predominant for Lake Victoria and are the main cause for relatively low statistical scores for this river. However, results on the Angara and the Neva rivers also depend on the inherent gap of ISBA-CTRIP processes representation which relies on further development such as the partitioned energy budget between the snow and the canopy over a Boreal zone. The study is a first step towards a global coupled land system that will help to qualitatively assess the evolution of future global water resources leading to improvements in flood risk and drought forecasting.

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The Global Land Carbon Cycle Simulated With ISBA‐CTRIP: Improvements Over the Last Decade

Cited by 59 publications

References 126 publications

Global climate response to idealized deforestation in CMIP6 models

Global climate response to idealized deforestation in CMIP6 models

Carbon-concentration and carbon-climate feedbacks in CMIP6 models, and their comparison to CMIP5 models

Parametrization of lakes water dynamics in the ISBA-CTRIP land surface system (SURFEX v8.1)

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