Description: The concurrence of atmospheric rivers and explosive cyclogenesis in the North Atlantic and North Pacific basins Jorge Eiras-Barca, Alexandre M. Ramos, Joaquim G. Pinto, Ricardo M. Trigo, Margarida L. R. Liberato, and Gonzalo Miguez-Macho Earth Syst. Dynam., 9, 91-102, https://doi.org/10.5194/esd-9-91-2018, 2018 This paper analyses the potential role of atmospheric rivers in the explosive cyclone deepening. Using ERA-Interim reanalysis data for 1979–2011, we analyse the concurrence of atmospheric rivers and explosive cyclogenesis over the North Atlantic and North Pacific basins for the extended winter months (ONDJFM).

Description: Contribution of atmospheric circulation to recent off-shore sea-level variations in the Baltic Sea and the North Sea Sitar Karabil, Eduardo Zorita, and Birgit Hünicke Earth Syst. Dynam., 9, 69-90, https://doi.org/10.5194/esd-9-69-2018, 2018 We analysed the contribution of atmospheric factors to interannual off-shore sea-level variability in the Baltic Sea region. We identified a different atmospheric circulation pattern that is more closely linked to sea-level variability than the NAO. The inverse barometer effect contributes to that link in the winter and summer seasons. Freshwater flux is connected to the link in summer and net heat flux in winter.The new atmospheric-pattern-related wind forcing plays an important role in summer.

Description: Causal dependences between the coupled ocean-atmosphere dynamics over the Tropical Pacific, the North Pacific and the North Atlantic Stéphane Vannitsem and Pierre Ekelmans Earth Syst. Dynam. Discuss., https//doi.org/10.5194/esd-2018-3,2018 Manuscript under review for ESD (discussion: open, 1 comment) The El-Nino-Southern-Oscillation phenomenon is a slow dynamics present in the coupled ocean-atmosphere tropical Pacific system which has important teleconnections with the northern extratropics. These teleconnections are usually believed to be the source of an enhanced predictability in the northern extratropics at seasonal to decadal time scales. This question is challenged by investigating the causality between these regions using an advanced technique known as Convergent Cross Mapping.

Description: Changes in tropical cyclones under stabilized 1.5 and 2.0 °C global warming scenarios as simulated by the Community Atmospheric Model under the HAPPI protocols Michael F. Wehner, Kevin A. Reed, Burlen Loring, Dáithí Stone, and Harinarayan Krishnan Earth Syst. Dynam., 9, 187-195, https://doi.org/10.5194/esd-9-187-2018, 2018 The United Nations Framework Convention on Climate Change invited the scientific community to explore the impacts of a world in which anthropogenic global warming is stabilized at only 1.5 °C above preindustrial average temperatures. We present a projection of future tropical cyclone statistics for both 1.5 and 2.0 °C stabilized warming scenarios using a high-resolution global climate model. We find more frequent and intense tropical cyclones, but a reduction in weaker storms.

Description: Quantification of the impacts of climate change and human agricultural activities on oasis water requirements in an arid region: a case study of the Heihe River basin, China Xingran Liu and Yanjun Shen Earth Syst. Dynam., 9, 211-225, https://doi.org/10.5194/esd-9-211-2018, 2018 The impacts of climate change and human activities on oasis water requirements in Heihe River basin were quantified with the methods of partial derivative and slope in this study. The results showed that the oasis water requirement increased sharply from 10.8 × 10 8 to 19.0 × 10 8  m 3 during 1986–2013. Human activities were the dominant driving forces. Changes in climate, land scale and structure contributed to the increase in water requirement at rates of 6.9, 58.1, and 25.3 %, respectively.

Description: Selecting a climate model subset to optimise key ensemble properties Nadja Herger, Gab Abramowitz, Reto Knutti, Oliver Angélil, Karsten Lehmann, and Benjamin M. Sanderson Earth Syst. Dynam., 9, 135-151, https://doi.org/10.5194/esd-9-135-2018, 2018 Users presented with large multi-model ensembles commonly use the equally weighted model mean as a best estimate, ignoring the issue of near replication of some climate models. We present an efficient and flexible tool that finds a subset of models with improved mean performance compared to the multi-model mean while at the same time maintaining the spread and addressing the problem of model interdependence. Out-of-sample skill and reliability are demonstrated using model-as-truth experiments.

Description: Tagging moisture sources with Lagrangian and inertial tracers: Application to intense atmospheric river events Vicente Pérez-Muñuzuri, Jorge Eiras-Barca, and Daniel Garaboa-Paz Earth Syst. Dynam. Discuss., https//doi.org/10.5194/esd-2018-8,2018 Manuscript under review for ESD (discussion: open, 1 comment) Two Lagrangian tracers tools are evaluated for studies on atmospheric moisture sources and pathways. Usual Lagrangian methods consider the initial moisture volume to remain constant and the particle follows flow path lines exactly. In a different approach, the initial volume can be considered to depend on time as it is advected by the flow, due to thermodynamic processes. Drag and buoyancy forces must be considered then.

Description: A framework for modelling the complexities of food and water security under globalisation Brian J. Dermody, Murugesu Sivapalan, Elke Stehfest, Detlef P. van Vuuren, Martin J. Wassen, Marc F. P. Bierkens, and Stefan C. Dekker Earth Syst. Dynam., 9, 103-118, https://doi.org/10.5194/esd-9-103-2018, 2018 Ensuring sustainable food and water security is an urgent and complex challenge. As the world becomes increasingly globalised and interdependent, food and water management policies may have unintended consequences across regions, sectors and scales. Current decision-making tools do not capture these complexities and thus miss important dynamics. We present a modelling framework to capture regional and sectoral interdependence and cross-scale feedbacks within the global food system.

Description: Assessing the Impact of a Future Volcanic Eruption on Decadal Predictions Sebastian Illing, Christopher Kadow, Holger Pohlmann, and Claudia Timmreck Earth Syst. Dynam. Discuss., https//doi.org/10.5194/esd-2018-5,2018 Manuscript under review for ESD (discussion: open, 0 comments) The likelihood of a large volcanic eruption in the future provides the largest uncertainty concerning the evolution of the climate system on the time scale of a few years; but also an excellent opportunity to learn about the behavior of the climate system, and our models thereof. So the question emerges how predictable is the response of the climate system to future eruptions? By this we mean, to what extent will the volcanic perturbation affect decadal climate predictions and how does the pre-eruption climate state influence the impact of the volcanic signal on the predictions? To address these questions, we performed decadal forecasts with the MiKlip prediction system in the low-resolution configuration for the initialization years 2012 and 2014, which differ in the Pacific Decadal Oscillation (PDO) phase among other things. Each forecast contains an artificial Pinatubo-like eruption starting in June of the first prediction year. For the construction of the aerosol radiative forcing, we used the global aerosol model ECHAM5-HAM in a version adapted for volcanic eruptions. We investigate the response of different climate variables, including near-surface air temperature, precipitation, frost days, and sea ice area fraction. Our results show that the average global cooling response over four years of about 0.2 K and the precipitation decrease of about 0.025 mm/day, is relatively robust throughout the different experiments and seemingly independent of the initialization state. However, on a regional scale, we find substantial differences between the initializations. The cooling effect in the North Atlantic and Europe lasts longer and the Arctic sea ice increase is stronger than in the simulations initialized in 2014. In contrast, the forecast initialized with a negative PDO shows a prolonged cooling in the North Pacific basin.

Description: Systematic Correlation Matrix Evaluation (SCoMaE) – a bottom–up, science-led approach to identifying indicators Nadine Mengis, David P. Keller, and Andreas Oschlies Earth Syst. Dynam., 9, 15-31, https://doi.org/10.5194/esd-9-15-2018, 2018 The Systematic Correlation Matrix Evaluation (SCoMaE) method applies statistical information to systematically select, transparent, nonredundant indicators for a comprehensive assessment of the Earth system state. We show that due to changing climate forcing, such as anthropogenic climate change, the ad hoc assessment indicators might need to be reevaluated. Within an iterative process, this method would allow us to select scientifically consistent and societally relevant assessment indicators.