Conservative finite-volume forms of the Saint-Venant equations for hydrology and urban drainage Hydrology and Earth System Sciences DOI 10.5194/hess-23-1281-2019 7 March 2019 A new derivation of the equations for one-dimensional open-channel flow in rivers and storm drainage systems has been developed. The new approach solves some long-standing problems for obtaining well-behaved solutions with conservation forms of the equations. This research was motivated by the need for highly accurate models of large-scale river networks and the storm drainage systems in megacities. Such models are difficult to create with existing equation forms. Read more
Seasonal origins of soil water used by trees Hydrology and Earth System Sciences DOI 10.5194/hess-23-1199-2019 1 March 2019 We used stable isotopes of xylem water to study differences in the seasonal origin of water in more than 900 individual trees from three dominant species in 182 Swiss forested sites. We discovered that midsummer transpiration was mostly supplied by winter precipitation across diverse humid climates. Our findings provide new insights into tree vulnerability to droughts, transport of water (and thus solutes) in soils, and the climatic information conveyed by plant-tissue isotopes. Read more
The Reference Elevation Model of Antarctica The Cryosphere DOI 10.5194/tc-13-665-2019 26 February 2019 The Reference Elevation Model of Antarctica (REMA) is the first continental-scale terrain map at less than 10 m resolution, and the first with a time stamp, enabling measurements of elevation change. REMA is constructed from over 300 000 individual stereoscopic elevation models (DEMs) extracted from submeter-resolution satellite imagery. REMA is vertically registered to satellite altimetry, resulting in errors of less than 1 m over most of its area and relative uncertainties of decimeters. Read more
Revisiting the differential freezing nucleus spectra derived from drop-freezing experiments: methods of calculation, applications, and confidence limits Atmospheric Measurement Techniques DOI 10.5194/amt-12-1219-2019 26 February 2019 The abundance of freezing nuclei in water samples is routinely determined by experiments involving the cooling of sample drops and observing the temperatures at which the drops freeze. This is used for characterizing the nucleating abilities of materials in laboratory preparations or to determine the numbers of nucleating particles in rain, snow, river water or other natural waters. The evaluation of drop-freezing experiments in terms of differential nucleus spectra is advocated in the paper. Read more
The role of moisture transport for precipitation in the inter-annual and inter-daily fluctuations of the Arctic sea ice extension Earth System Dynamics DOI 10.5194/esd-10-121-2019 21 February 2019 Ice melting at the scale of inter-annual fluctuations against the trend is favoured by an increase in moisture transport in summer, autumn, and winter and a decrease in spring. On a daily basis extreme humidity transport increases the formation of ice in winter and decreases it in spring, summer, and autumn; in these three seasons it thus contributes to Arctic sea ice melting. These patterns differ sharply from that linked to decline, especially in summer when the opposite trend applies. Read more
Identifying and improving AGU collaborations using network analysis and scientometrics Geoscience Communication DOI 10.5194/gc-2-55-2019 20 February 2019 The American Geophysical Union (AGU) is an Earth and space science professional society. Research conducted by AGU members ranges from the Earth’s deep interior to the outer planets of our solar system. However, little research exists on the AGU meeting itself. We apply network analysis and scientometrics to 17 years of AGU Fall Meetings to examine the network structure of the AGU and explore how data science can facilitate better scientific communication and collaboration. Read more
Harmonising plant functional type distributions for evaluating Earth system models Climate of the Past DOI 10.5194/cp-15-335-2019 18 February 2019 A simple but powerful method for the biomisation of plant functional type distributions is introduced and tested for six different dynamic global vegetation models based on pre-industrial and palaeo-simulations. The method facilitates the direct comparison between vegetation distributions simulated by different Earth system models and between model results and the pollen-based biome reconstructions. It is therefore a powerful tool for the evaluation of Earth system models. Read more
Thaw processes in ice-rich permafrost landscapes represented with laterally coupled tiles in a land surface model The Cryosphere DOI 10.5194/tc-13-591-2019 18 February 2019 Many permafrost landscapes contain large amounts of excess ground ice, which gives rise to small-scale elevation differences. This results in lateral fluxes of snow, water, and heat, which we investigate and show how it can be accounted for in large-scale models. Using a novel model technique which can account for these differences, we are able to model both the current state of permafrost and how these landscapes change as permafrost thaws, in a way that could not previously be achieved. Read more
Towards a more complete quantification of the global carbon cycle Biogeosciences DOI 10.5194/bg-16-831-2019 14 February 2019 Globally, C is added to the atmosphere from fossil fuels and deforestation, balanced by ocean uptake and atmospheric increase. The difference (residual sink) is equated to plant uptake. But this omits cement carbonation; transport to oceans by dust; riverine organic C and volatile organics; and increased C in plastic, bitumen, wood, landfills, and lakes. Their inclusion reduces the residual sink from 3.6 to 2.1 GtC yr-1 and thus the inferred ability of the biosphere to alter human C emissions. Read more
A simple topography-driven and calibration-free runoff generation module Hydrology and Earth System Sciences DOI 10.5194/hess-23-787-2019 13 February 2019 Supported by large-sample ecological observations, a novel, simple and topography-driven runoff generation module (HSC-MCT) was created. The HSC-MCT is calibration-free, and therefore it can be used to predict in ungauged basins, and has great potential to be generalized at the global scale. Also, it allows us to reproduce the variation of saturation areas, which has great potential to be used for broader hydrological, ecological, climatological, and biogeochemical studies. Read more
