On the alignment of velocity and magnetic fields within magnetosheath jets Annales Geophysicae DOI 10.5194/angeo-38-287-2020 12 March 2020 Jets of solar-wind plasma commonly hit the Earth’s magnetosphere. Using data from the four Magnetospheric Multiscale (MMS) spacecraft, we show statistically that within jets the magnetic field is more aligned with the plasma flow direction than outside of these jets. Our study confirms prior simulation results, but it also shows that the average effect is moderate. The jets’ magnetic field is important with respect to their impact on space weather. Read more
Earth system data cubes unravel global multivariate dynamics Earth System Dynamics DOI 10.5194/esd-11-201-2020 10 March 2020 The ever-growing availability of data streams on different subsystems of the Earth brings unprecedented scientific opportunities. However, researching a data-rich world brings novel challenges. We present the concept of Earth system data cubes to study the complex dynamics of multiple climate and ecosystem variables across space and time. Using a series of example studies, we highlight the potential of effectively considering the full multivariate nature of processes in the Earth system. Read more
Modelling global tropical cyclone wind footprints Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-567-2020 10 March 2020 Assessing tropical cyclone (TC) wind risk is challenging due to a lack of historical TC wind data. This paper presents a novel approach to simulating landfalling TC winds anywhere on Earth. It captures local features such as high winds over coastal hills and lulls over rough terrain. A dataset of over 700 global historical wind footprints has been generated to provide new views of historical events. This dataset can be used to advance our understanding of overland TC wind risk. Read more
The substructure of extremely hot summers in the Northern Hemisphere Weather and Climate Dynamics DOI 10.5194/wcd-1-45-2020 10 March 2020 In this study we quantify how much the coldest, middle and hottest third of all days during extremely hot summers contribute to their respective seasonal mean anomaly. This extreme-summer substructure varies substantially across the Northern Hemisphere and is directly related to the local physical drivers of extreme summers. Furthermore, comparing re-analysis (i.e. measurement-based) and climate model extreme-summer substructures reveals a remarkable level of agreement. Read more
Measuring compound flood potential from river discharge and storm surge extremes at the global scale Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-489-2020 3 March 2020 When a high river discharge coincides with a high storm surge level, this can exarcebate flood level, depth, and duration, resulting in a so-called compound flood event. These events are not currently included in global flood models. In this research, we analyse the timing and correlation between modelled discharge and storm surge level time series in deltas and estuaries. Our results provide a first indication of regions along the global coastline with a high compound flooding potential. Read more
TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI):motivations and protocol version 1.0 Geoscientific Model Development DOI 10.5194/gmd-13-707-2020 3 March 2020 Atmospheric characterization of rocky exoplanets orbiting within the habitable zone of nearby M dwarf stars is around the corner with the James Webb Space Telescope (JWST), expected to be launch in 2021. Global climate models (GCMs) are powerful tools to model exoplanet atmospheres and to predict their habitability. However, intrinsic differences between the models can lead to various predictions. This paper presents an experiment protocol to evaluate these differences. Read more
The 22 December 2018 Mount Anak Krakatau volcanogenic tsunami on SundaStrait coasts, Indonesia: tsunami and damage characteristics Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-549-2020 3 March 2020 On 22 December 2018, a tsunami was generated from the Mount Anak Krakatau area that was caused by volcanic flank failures. The tsunami had severe impacts on the western coasts of Banten and the southern coasts of Lampung in Indonesia. A series of surveys to measure the impacts of the tsunami was started 3 d after the tsunami and lasted for 10 d. This paper provides insights from the tsunami-affected area in terms of distribution of tsunami flow depths, boulders and building damage. Read more
No nitrogen fixation in the Bay of Bengal? Biogeosciences DOI 10.5194/bg-17-851-2020 27 February 2020 Oxygen minimum zones (OMZs) are ocean areas severely depleted in oxygen as a result of physical, chemical, and biological processes. Biologically, organic material is produced in the sea surface and exported to deeper waters, where it respires. In the Bay of Bengal (BoB), an OMZ is present, but there are traces of oxygen left. Our study now suggests that this is because one key process, nitrogen fixation, is absent in the BoB, thus preventing primary production and consecutive respiration. Read more
The millennium-old hydrogeology textbook The Extraction of Hidden Waters by the Persian mathematician and engineer Abubakr Mohammad Karaji (953 CE–1029 CE) Hydrology and Earth System Sciences DOI 10.5194/hess-24-761-2020 27 February 2020 We revisit and shed light on the textbook The Extraction of Hidden Waters by the Persian mathematician and engineer Abubakr Mohammad Karaji. Ground-breaking ideas and descriptions of hydrological and hydrogeological perceptions such as components of the hydrological cycle, groundwater quality and driving factors for groundwater flow were presented in the book. We speculate that Karaji’s book is the first of its kind to provide a construction and maintenance manual for an engineering project. Read more
Cryoconite: an efficient accumulator of radioactive fallout in glacialenvironments The Cryosphere DOI 10.5194/tc-14-657-2020 25 February 2020 Cryoconite is the sediment found on the surface of glaciers. The paper presents cryoconite as an environmental matrix able to accumulate natural and artificial radioactivity with unprecedented efficiency. Only samples from sites where nuclear accidents and explosions occurred present a stronger radioactive contamination. The peculiarities of glacial environments are responsible for this extreme feature, making cryoconite a useful tool tool for the monitoring of environmental radioactivity. Read more
