Wetropolis extreme rainfall and flood demonstrator: from mathematical design to outreach Hydrology and Earth System Sciences DOI 10.5194/hess-24-2483-2020 28 May 2020 Wetropolis is a table-top demonstration model with extreme rainfall and flooding, including random rainfall, river flow, flood plains, an upland reservoir, a porous moor, and a city which can flood. It lets the viewer experience extreme rainfall and flood events in a physical model on reduced spatial and temporal scales with an event return period of 6.06 min rather than, say, 200 years. We disseminate its mathematical design and how it has been shown most prominently to over 500 flood victims. Read more
Rapid collaborative knowledge building via Twitter after significantgeohazard events Geoscience Communication DOI 10.5194/gc-3-129-2020 28 May 2020 Among social media platforms, Twitter is valued by scholars to disseminate scientific information. Using two 2018 geohazard events as examples, we show that collaborative open data sharing and discussion on Twitter promote very rapid building of knowledge. This breaks down the traditional ivory tower of academia, making science accessible to nonacademics who can follow the discussion. It also presents the opportunity for a new type of scientific approach within global virtual teams. Read more
Microwave and submillimeter wave scattering of oriented ice particles Atmospheric Measurement Techniques DOI 10.5194/amt-13-2309-2020 26 May 2020 Microwave dual-polarization observations consistently show that larger atmospheric ice particles tend to have a preferred orientation. We provide a publicly available database of microwave and submillimeter wave scattering properties of oriented ice particles based on discrete dipole approximation scattering calculations. Detailed radiative transfer simulations, recreating observed polarization patterns, are additionally presented in this study. Read more
Dynamic projection of anthropogenic emissions in China: methodology and 2015–2050 emission pathways under a range of socio-economic, climate policy, and pollution control scenarios Atmospheric Chemistry and Physics DOI 10.5194/acp-20-5729-2020 26 May 2020 Future trends in air pollution and greenhouse gas emissions in China are of great concern to the community. Here we developed a sophisticated dynamic projection model to understand 2015–2050 emission pathways under a range of socio-economic, climate policy, and pollution control scenarios. By coupling strong low-carbon transitions and clean air policy, emissions of major air pollutants in China will be reduced by 58–87 % during 2015–2050. This work can support future co-governance policy design. Read more
A machine-learning-based cloud detection and thermodynamic-phaseclassification algorithm using passive spectral observations Atmospheric Measurement Techniques DOI 10.5194/amt-13-2257-2020 21 May 2020 A machine-learning (ML)-based approach that can be used for cloud mask and phase detection is developed. An all-day model that uses infrared (IR) observations and a daytime model that uses shortwave and IR observations from a passive instrument are trained separately for different surface types. The training datasets are selected by using reference pixel types from collocated space lidar. The ML approach is validated carefully and the overall performance is better than traditional methods. Read more
The catastrophic thermokarst lake drainage events of 2018 in northwestern Alaska: Fast-forward into the future The Cryosphere DOI 10.5194/tc-2020-106 21 May 2020 Northwestern Alaska has been highly affected by changing climatic patterns with new temperature and precipitation maxima over the recent years. In particular, the Baldwin and northern Seward peninsulas are characterized by an abundance of thermokarst lakes that are highly dynamic and prone to lake drainage, like many other regions at the southern margins of continuous permafrost. We used Sentinel-1 synthetic aperture radar (SAR) and Planet CubeSat optical remote sensing data to analyze recently observed widespread lake drainage. Read more
Quantification of seasonal and diurnal dynamics of subglacial channels using seismic observations on an Alpine glacier The Cryosphere DOI 10.5194/tc-14-1475-2020 19 May 2020 Our study addresses key questions on the subglacial drainage system physics through a novel observational approach that overcomes traditional limitations. We conducted, over 2 years, measurements of the subglacial water-flow-induced seismic noise and of glacier basal sliding speeds. We then inverted for the subglacial channel’s hydraulic pressure gradient and hydraulic radius and investigated the links between the equilibrium state of subglacial channels and glacier basal sliding. Read more
Summarizing the state of the terrestrial biosphere in few dimensions Biogeosciences DOI 10.5194/bg-17-2397-2020 19 May 2020 To closely monitor the state of our planet, we require systems that can monitor the observation of many different properties at the same time. We create indicators that resemble the behavior of many different simultaneous observations. We apply the method to create indicators representing the Earth’s biosphere. The indicators show a productivity gradient and a water gradient. The resulting indicators can detect a large number of changes and extremes in the Earth system. Read more
Intercomparison of wind observations from the European Space Agency’s Aeolus satellite mission and the ALADIN Airborne Demonstrator Atmospheric Measurement Techniques DOI 10.5194/amt-13-2075-2020 14 May 2020 This work reports on the first airborne validation campaign of ESA’s Earth Explorer mission Aeolus, conducted in central Europe during the commissioning phase in November 2018. After presenting the methodology used to compare the data sets from the satellite, the airborne wind lidar and the ECWMF model, the wind results from the underflights performed are analyzed and discussed, providing a first assessment of the accuracy and precision of the preliminary Aeolus wind data. Read more
The acidity of atmospheric particles and clouds Atmospheric Chemistry and Physics DOI 10.5194/acp-20-4809-2020 14 May 2020 Acid rain is recognized for its impacts on human health and ecosystems, and programs to mitigate these effects have had implications for atmospheric acidity. Historical measurements indicate that cloud and fog droplet acidity has changed in recent decades in response to controls on emissions from human activity, while the limited trend data for suspended particles indicate acidity may be relatively constant. This review synthesizes knowledge on the acidity of atmospheric particles and clouds. Read more