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- ItemPotential and Actual impacts of deforestation and afforestation on land surface temperature(Hoboken, NJ : Blackwell Publishing Ltd, 2016) Li, Y.; Zhao, M.; Mildrexler, D.J.; Motesharrei, S.; Mu, Q.; Kalnay, E.; Zhao, F.; Li, S.; Wang, K.
- ItemModeling Antarctic tides in response to ice shelf thinning and retreat(Hoboken, NJ : Blackwell Publishing Ltd, 2014) Rosier, S.H.R.; Green, J.A.M.; Scourse, J.D.; Winkelmann, R.Tides play an important role in ice sheet dynamics by modulating ice stream velocity, fracturing, and moving ice shelves and mixing water beneath them. Any changes in ice shelf extent or thickness will alter the tidal dynamics through modification of water column thickness and coastal topography but these will in turn feed back onto the overall ice shelf stability. Here, we show that removal or reduction in extent and/or thickness of the Ross and Ronne-Filchner ice shelves would have a significant impact on the tides around Antarctica. The Ronne-Filchner appears particularly vulnerable, with an increase in M2 amplitude of over 0.5 m beneath much of the ice shelf potentially leading to tidally induced feedbacks on ice shelf/sheet dynamics. These results highlight the importance of understanding tidal feedbacks on ice shelves/streams due to their influence on ice sheet dynamics.
- ItemSPITFIRE within the MPI Earth system model: Model development and evaluation(Hoboken, NJ : Blackwell Publishing Ltd, 2014) Lasslop, G.; Thonicke, K.; Kloster, S.Quantification of the role of fire within the Earth system requires an adequate representation of fire as a climate-controlled process within an Earth system model. To be able to address questions on the interaction between fire and the Earth system, we implemented the mechanistic fire model SPITFIRE, in JSBACH, the land surface model of the MPI Earth system model. Here, we document the model implementation as well as model modifications. We evaluate our model results by comparing the simulation to the GFED version 3 satellite-based data set. In addition, we assess the sensitivity of the model to the meteorological forcing and to the spatial variability of a number of fire relevant model parameters. A first comparison of model results with burned area observations showed a strong correlation of the residuals with wind speed. Further analysis revealed that the response of the fire spread to wind speed was too strong for the application on global scale. Therefore, we developed an improved parametrization to account for this effect. The evaluation of the improved model shows that the model is able to capture the global gradients and the seasonality of burned area. Some areas of model-data mismatch can be explained by differences in vegetation cover compared to observations. We achieve benchmarking scores comparable to other state-of-the-art fire models. The global total burned area is sensitive to the meteorological forcing. Adjustment of parameters leads to similar model results for both forcing data sets with respect to spatial and seasonal patterns. Key Points The SPITFIRE fire model was evaluated within the JSBACH land surface model A modified wind speed response improved the spatial pattern of burned area Regional gradients in burned area are driven by vegetation and fuel properties.
- ItemHotspots of uncertainty in land-use and land-cover change projections: a global-scale model comparison(Hoboken, NJ : Blackwell Publishing Ltd, 2016) Prestele, R.; Alexander, P.; Rounsevell, M.D.A.; Arneth, A.; Calvin, K.; Doelman, J.; Eitelberg, D.A.; Engström, K.; Fujimori, S.; Hasegawa, T.; Havlik, P.; Humpenöder, F.; Jain, A.K.; Krisztin, T.; Kyle, P.; Meiyappan, P.; Popp, A.; Sands, R.D.; Schaldach, R.; Schüngel, J.; Stehfest, E.; Tabeau, A.; Van Meijl, H.; Van Vliet, J.; Verburg, P.H.
- ItemVariation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models(Hoboken, NJ : Blackwell Publishing Ltd, 2016) Johnson, M.O.; Galbraith, D.; Gloor, M.; De Deurwaerder, H.; Guimberteau, M.; Rammig, A.; Thonicke, K.; Verbeeck, H.; von Randow, C.; Monteagudo, A.; Phillips, O.L.; Brienen, R.J.W.; Feldpausch, T.R.; Lopez Gonzalez, G.; Fauset, S.; Quesada, C.A.; Christoffersen, B.; Ciais, P.; Sampaio, G.; Kruijt, B.; Meir, P.; Moorcroft, P.; Zhang, K.; Alvarez-Davila, E.; Alves de Oliveira, A.; Amaral, I.; Andrade, A.; Aragao, L.E.O.C.; Araujo-Murakami, A.; Arets, E.J.M.M.; Arroyo, L.; Aymard, G.A.; Baraloto, C.; Barroso, J.; Bonal, D.; Boot, R.; Camargo, J.; Chave, J.; Cogollo, A.; Cornejo Valverde, F.; Lola da Costa, A.C.; Di Fiore, A.; Ferreira, L.; Higuchi, N.; Honorio, E.N.; Killeen, T.J.; Laurance, S.G.; Laurance, W.F.; Licona, J.; Lovejoy, T.; Malhi, Y.; Marimon, B.; Marimon, B.H. Jr.; Matos, D.C.L.; Mendoza, C.; Neill, D.A.; Pardo, G.; Peña-Claros, M.; Pitman, N.C.A.; Poorter, L.; Prieto, A.; Ramirez-Angulo, H.; Roopsind, A.; Rudas, A.; Salomao, R.P.; Silveira, M.; Stropp, J.; ter Steege, H.; Terborgh, J.; Thomas, R.; Toledo, M.; Torres-Lezama, A.; van der Heijden, G.M.F.; Vasquez, R.; Guimarães Vieira, I.C.; Vilanova, E.; Vos, V.A.; Baker, T.R.
- ItemInterglacials of the last 800,000 years(Hoboken, NJ : Blackwell Publishing Ltd, 2016) Berger, B.; Crucifix, M.; Hodell, D.A.; Mangili, C.; McManus, J.F.; Otto-Bliesner, B.; Pol, K.; Raynaud, D.; Skinner, L.C.; Tzedakis, P.C.; Wolff, E.W.; Yin, Q.Z.; Abe-Ouchi, A.; Barbante, C.; Brovkin, V.; Cacho, I.; Capron, E.; Ferretti, P.; Ganopolski, A.; Grimalt, J.O.; Hönisch, B.; Kawamura, K.A.; Landais, A.; Margari, V.; Martrat, B.; Masson-Delmotte, V.; Mokeddem, Z.; Parrenin, F.; Prokopenko, A.A.; Rashid, H.; Schulz, M.; Vazquez Riveiros, N.
- ItemCharacterizing half-a-degree difference: a review of methods for identifying regional climate responses to global warming targets(Hoboken, NJ : Blackwell Publishing Ltd, 2017) James, R.; Washington, R.; Schleussner, C.-F.; Rogelj, J.; Conway, D.The Paris Agreement long-term global temperature goal refers to two global warming levels: well below 2°C and 1.5°C above preindustrial. Regional climate signals at specific global warming levels, and especially the differences between 1.5°C and 2°C, are not well constrained, however. In particular, methodological challenges related to the assessment of such differences have received limited attention. This article reviews alternative approaches for identifying regional climate signals associated with global temperature limits, and evaluates the extent to which they constitute a sound basis for impacts analysis. Four methods are outlined, including comparing data from different greenhouse gas scenarios, sub-selecting climate models based on global temperature response, pattern scaling, and extracting anomalies at the time of each global temperature increment. These methods have rarely been applied to compare 2°C with 1.5°C, but some demonstrate potential avenues for useful research. Nevertheless, there are methodological challenges associated with the use of existing climate model experiments, which are generally designed to model responses to different levels of greenhouse gas forcing, rather than to model climate responses to a specific level of forcing that targets a given level of global temperature change. Novel approaches may be required to address policy questions, in particular: to differentiate between half degree warming increments while accounting for different sources of uncertainty; to examine mechanisms of regional climate change including the potential for nonlinear responses; and to explore the relevance of time-lagged processes in the climate system and declining emissions, and the resulting sensitivity to alternative mitigation pathways. WIREs Clim Change 2017, 8:e457. doi: 10.1002/wcc.457. For further resources related to this article, please visit the WIREs website.
- ItemValidation practices for satellite-based Earth observation data across communities(Hoboken, NJ : Blackwell Publishing Ltd, 2017) Loew, A.; Bell, W.; Brocca, L.; Bulgin, C.E.; Burdanowitz, J.; Calbet, X.; Donner, R.V.; Ghent, D.; Gruber, A.; Kaminski, T.; Kinzel, J.; Klepp, C.; Lambert, J.-C.; Schaepman-Strub, G.; Schröder, M.; Verhoelst, T.Assessing the inherent uncertainties in satellite data products is a challenging task. Different technical approaches have been developed in the Earth Observation (EO) communities to address the validation problem which results in a large variety of methods as well as terminology. This paper reviews state-of-the-art methods of satellite validation and documents their similarities and differences. First, the overall validation objectives and terminologies are specified, followed by a generic mathematical formulation of the validation problem. Metrics currently used as well as more advanced EO validation approaches are introduced thereafter. An outlook on the applicability and requirements of current EO validation approaches and targets is given.