Description: Thermodynamics of saline and fresh water mixing in estuaries Zhilin Zhang and Hubert H. G. Savenije Earth Syst. Dynam., 9, 241-247, https://doi.org/10.5194/esd-9-241-2018, 2018 This paper presents a new equation for the dispersion of salinity in alluvial estuaries based on the maximum power concept. The new equation is physically based and replaces previous empirical equations. It is very useful for application in practice because in contrast to previous methods it no longer requires a calibration parameter, turning the method into a predictive method. The paper presents successful applications in more than 23 estuaries in different parts of the world.

Description: Using Network Theory and Machine Learning to predict El Niño Peter D. Nooteboom, Qing Yi Feng, Cristóbal López, Emilio Hernández-García, and Henk A. Dijkstra Earth Syst. Dynam. Discuss., https//doi.org/10.5194/esd-2018-13,2018 Manuscript under review for ESD (discussion: open, 0 comments) The prediction of the El Niño phenomenon, an increased sea surface temperature in the eastern Pacific, fascinates people for a long time. El Niño is associated with natural disasters, such as droughts and floods. Current methods can make a reliable prediction of this phenomenon up to six months ahead. However, this article presents a method which combines network theory and machine learning and predicts El Niño up to one year ahead.

Description: Regional scaling of annual mean precipitation and water availability with global temperature change Peter Greve, Lukas Gudmundsson, and Sonia I. Seneviratne Earth Syst. Dynam., 9, 227-240, https://doi.org/10.5194/esd-9-227-2018, 2018 Assessing projected hydroclimatological changes is crucial, but associated with large uncertainties. We statistically assess here the response of precipitation and water availability to global temperature change, enabling us to estimate the significance of drying/wetting tendencies under anthropogenic climate change. We further show that opting for a 1.5 K warming target just slightly influences the mean response but could substantially reduce the risk of experiencing extreme changes.

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: A new moisture tagging capability in the Weather Research and Forecasting model: formulation, validation and application to the 2014 Great Lake-effect snowstorm Damián Insua-Costa and Gonzalo Miguez-Macho Earth Syst. Dynam., 9, 167-185, https://doi.org/10.5194/esd-9-167-2018, 2018 We present here a newly implemented water vapor tracer tool into the WRF meteorological model (WRF-WVT). A detailed validation shows high accuracy, with an error of much less than 1 % in moisture traceability. As an example application, we show that for the 2014 Great Lake-effect snowstorm, above 30 % of precipitation in the regions immediately downwind originated from lake evaporation, with contributions exceeding 50 % in the areas with highest snowfall accumulations.

Description: The biomass burning contribution to climate-carbon cycle feedback Sandy P. Harrison, Patrick J. Bartlein, Victor Brovkin, Sander Houweling, Silvia Kloster, and I. Colin Prentice Earth Syst. Dynam. Discuss., https//doi.org/10.5194/esd-2018-11,2018 Manuscript under review for ESD (discussion: open, 0 comments) Temperature exerts strong controls on the incidence and severity of fire. Warming is thus expected to increase fire-related carbon emissions, and thereby atmospheric CO 2 . But the magnitude of this feedback is very poorly known. We use a single-box model of the land biosphere to quantify this positive feedback from satellite-based estimates of biomass burning emissions for 2000–2014 CE, and from sedimentary charcoal records for the millennium before the industrial period. We derive an estimate of the centennial-scale feedback strength of 6.5 ± 3.4 ppm CO 2 per degree of land temperature increase, based on the satellite data. However, this estimate is poorly constrained, and is largely driven by the well-documented dependence of tropical deforestation and peat fires on climate variability patterns linked to the El Niño-Southern Oscillation. Palaeodata from pre-industrial times provide the opportunity to assess the fire-related climate-carbon cycle feedback over a longer period, with less pervasive human impacts. Past biomass burning can be quantified based on variations in either the concentration and isotopic composition of methane in ice cores (with assumptions about the isotopic signatures of different methane sources) or the abundances of charcoal preserved in sediments, which reflect landscape-scale changes in burnt biomass. These two data sources are shown here to be coherent with one another. The more numerous data from sedimentary charcoal, expressed as normalized anomalies (fractional deviations from the long-term mean), are then used – together with an estimate of mean biomass burning derived from methane isotope data – to infer a feedback strength of 5.6 ± 3.2 ppm CO 2 per degree of land temperature and (for a climate sensitivity of 2.8 K) a gain of 0.09 ± 0.05. This finding indicates that the positive feedback from increased fire provides a substantial contribution to the overall climate-carbon cycle feedback on centennial time scales.

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: How intermittency affects the rate at which rainfall extremes respond to changes in temperature Marc Schleiss Earth Syst. Dynam. Discuss., https//doi.org/10.5194/esd-2018-4,2018 Manuscript under review for ESD (discussion: open, 1 comment) The present study aims at shedding new light on the importance of intermittency and how it modulates the rate at which precipitation extremes (in current climate) depend on temperature. The analysis of 99 stations in the United States reveals that rapid increases or decreases in intermittency cause extremes to respond differently to changes in temperature than expected from Clausius–Clapeyron. A new model is proposed to help better anticipate changes across scales.

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: Earth system modelling with complex dynamic human societies: the copan:CORE World-Earth modeling framework Jonathan F. Donges, Jobst Heitzig, Wolfram Barfuss, Johannes A. Kassel, Tim Kittel, Jakob J. Kolb, Till Kolster, Finn Müller-Hansen, Ilona M. Otto, Marc Wiedermann, Kilian B. Zimmerer, and Wolfgang Lucht Earth Syst. Dynam. Discuss., https//doi.org/10.5194/esd-2017-126,2018 Manuscript under review for ESD (discussion: open, 0 comments) We present an open source software library for developing so-called World-Earth models that link physical, chemical and biological processes with social, economic and cultural processes to study the Earth system's future in the Anthropocene. Due to its modular structure, the software allows interdisciplinary studies of global change and sustainable development that combine stylized model components from Earth system science, climatology, economics, ecology, or sociology.