A systematic exploration of satellite radar coherence methods for rapid landslide detection Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-3197-2020 25 December 2020 Satellite radar could provide information on landslide locations within days of an earthquake or rainfall event anywhere on Earth, but until now there has been a lack of systematic testing of possible radar methods, and most methods have been demonstrated using a single case study event and data from a single satellite sensor. Here we test five methods on four events, demonstrating their wide applicability and making recommendations on when different methods should be applied in the future. Read more
New flood frequency estimates for the largest river in Norway based on the combination of short and long time series Hydrology and Earth System Sciences DOI 10.5194/hess-24-5595-2020 24 December 2020 We combine systematic, historical, and paleo information to obtain flood information from the last 10 300 years for the Glomma River in Norway. We identify periods with increased flood activity (4000–2000 years ago and the recent 1000 years) that correspond broadly to periods with low summer temperatures and glacier growth. The design floods in Glomma were more than 20 % higher during the 18th century than today. We suggest that trends in flood variability are linked to snow in late spring. Read more
Tectonic exhumation of the Central Alps recorded by detrital zircon in theMolasse Basin, Switzerland Solid Earth DOI 10.5194/se-11-2197-2020 23 December 2020 We present new U–Pb age data to provide insights into the source of sediment for the Molasse Sedimentary Basin in Switzerland. The paper aims to help shed light on the processes that built the Central Alpine Mountains between ~35 and ~15 Ma. A primary conclusion drawn from the results is that at ~21 Ma there was a significant change in the sediment sources for the basin. We feel this change indicates major tectonic changes within the Central Alps. Read more
Evaluation of Arctic warming in mid-Pliocene climate simulations Climate of the Past DOI 10.5194/cp-16-2325-2020 22 December 2020 The simulations for the past climate can inform us about the performance of climate models in different climate scenarios. Here, we analyse Arctic warming in an ensemble of 16 simulations of the mid-Pliocene Warm Period (mPWP), when the CO 2 level was comparable to today. The results highlight the importance of slow feedbacks in the model simulations and imply that we must be careful when using simulations of the mPWP as an analogue for future climate change. Read more
Sensitivity of the Southern Hemisphere circumpolar jet response to Antarctic ozone depletion: prescribed versus interactive chemistry Atmospheric Chemistry and Physics DOI 10.5194/acp-20-14043-2020 21 December 2020 Ozone depletion over Antarctica was shown to influence the tropospheric jet in the Southern Hemisphere. We investigate the atmospheric response to ozone depletion comparing climate model ensembles with interactive and prescribed ozone fields. We show that allowing feedbacks between ozone chemistry and model physics as well as including asymmetries in ozone leads to a strengthened ozone depletion signature in the stratosphere but does not significantly affect the tropospheric jet position. Read more
Distinguishing the impacts of ozone and ozone-depleting substanceson the recent increase in Antarctic surface mass balance The Cryosphere DOI 10.5194/tc-14-4135-2020 18 December 2020 The increase in Antarctic surface mass balance (SMB, precipitation vs. evaporation/sublimation) is projected to mitigate sea-level rise. Here we show that nearly half of this increase over the 20th century is attributed to stratospheric ozone depletion and ozone-depleting substance (ODS) emissions. Our results suggest that the phaseout of ODS by the Montreal Protocol, and the recovery of stratospheric ozone, will act to decrease the SMB over the 21st century and the mitigation of sea-level rise. Read more
Earth Girl Volcano: characterizing and conveying volcanic hazard complexity in an interactive casual game of disaster preparedness and response Geoscience Communication DOI 10.5194/gc-3-343-2020 17 December 2020 Earth Girl Volcano is a casual strategy interactive game about saving communities at risk of volcanic hazards. The easy-to-play game features a friendly animated visual style and an engaging simulation of volcanic events. The game was designed by a multidisciplinary team to appeal to mainstream non-technical audiences, and it was inspired by the experiences of disaster survivors and civil defense teams. Players can learn through gameplay about disaster preparedness and response. Read more
The baseline wander correction based on the improved ensemble empirical mode decomposition (EEMD) algorithm for groundedelectrical source airborne transient electromagnetic signals Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-9-443-2020 16 December 2020 The baseline wander has special characteristics, such as being low frequency, large amplitude, non-periodic, and non-stationary. It is caused by the receiving coil motion and always exists in the process of data acquisition. The proposed method can be used to solve similar problems. This paper has the following highlights: (1) the method can be used to process non-periodic and non-stationary signals; (2) the method is adaptive to satisfy the stopping criterion based on the measured signal. Read more
Millennial-scale atmospheric CO2 variations during the Marine Isotope Stage 6 period (190–135 ka) Climate of the Past DOI 10.5194/cp-16-2203-2020 15 December 2020 We reconstruct atmospheric CO 2 from the EPICA Dome C ice core during Marine Isotope Stage 6 (185–135 ka) to understand carbon mechanisms under the different boundary conditions of the climate system. The amplitude of CO 2 is highly determined by the Northern Hemisphere stadial duration. Carbon dioxide maxima show different lags with respect to the corresponding abrupt CH 4 jumps, the latter reflecting rapid warming in the Northern Hemisphere. Read more
Reduced global warming from CMIP6 projections when weighting models by performance and independence Earth System Dynamics DOI 10.5194/esd-11-995-2020 14 December 2020 In this study, we weight climate models by their performance with respect to simulating aspects of historical climate and their degree of interdependence. Our method is found to increase projection skill and to correct for structurally similar models. The weighted end-of-century mean warming (2081–2100 relative to 1995–2014) is 3.7 °C with a likely (66 %) range of 3.1 to 4.6 °C for the strong climate change scenario SSP5-8.5; this is a reduction of 0.4 °C compared with the unweighted mean. Read more
European daily precipitation according to EURO-CORDEX regionalclimate models (RCMs) andhigh-resolution globalclimate models (GCMs) from the High-Resolution Model Intercomparison Project (HighResMIP) Geoscientific Model Development DOI 10.5194/gmd-13-5485-2020 11 December 2020 Now that global climate models (GCMs) can run at similar resolutions to regional climate models (RCMs), one may wonder whether GCMs and RCMs provide similar regional climate information. We perform an evaluation for daily precipitation distribution in PRIMAVERA GCMs (25–50 km resolution) and CORDEX RCMs (12–50 km resolution) over Europe. We show that PRIMAVERA and CORDEX simulate similar distributions. Considering both datasets at such a resolution results in large benefits for impact studies. Read more
Validation of Aeolus wind products above the Atlantic Ocean Atmospheric Measurement Techniques DOI 10.5194/amt-13-6007-2020 10 December 2020 A first validation for the European satellite Aeolus is presented. Aeolus is the first satellite that can actively measure horizontal wind profiles from space. Radiosonde launches on board the German research vessel Polarstern have been utilized to validate Aeolus observations over the Atlantic Ocean, a region where almost no other reference measurements are available. It is shown that Aeolus is able to measure accurately atmospheric winds and thus may significantly improve weather forecasts. Read more
Review article: Geothermal heat flow in Antarctica: current and future directions The Cryosphere DOI 10.5194/tc-14-3843-2020 9 December 2020 The Antarctic ice sheet is the largest source for sea level rise. However, one key control on ice sheet flow remains poorly constrained: the effect of heat from the rocks beneath the ice sheet (known as geothermal heat flow). Although this may not seem like a lot of heat, beneath thick, slow ice this heat can control how well the ice flows and can lead to melting of the ice sheet. We discuss the methods used to estimate this heat, compile existing data, and recommend future research. Read more
Soil: the great connector of our lives now and beyond COVID-19 SOIL DOI 10.5194/soil-6-541-2020 8 December 2020 Humanity depends on the existence of healthy soils, both for the production of food and for ensuring a healthy, biodiverse environment. In the face of global crises like the COVID-19 pandemic, a sustainable soil management strategy is essential to ensure food security based on more diverse, locally oriented, and resilient food production systems through improving access to land, sound land use planning, sustainable soil management, enhanced research, and investment in education and extension. Read more
The pulse of a montane ecosystem: coupling between daily cycles in solar flux, snowmelt, transpiration, groundwater, and streamflow at Sagehen Creek and Independence Creek, Sierra Nevada, USA Hydrology and Earth System Sciences DOI 10.5194/hess-24-5095-2020 7 December 2020 Streams and groundwaters often show daily cycles in response to snowmelt and evapotranspiration. These typically have a roughly 6 h time lag, which is often interpreted as a travel-time lag. Here we show that it is instead primarily a phase lag that arises because aquifers integrate their inputs over time. We further show how these cycles shift seasonally, mirroring the springtime retreat of snow cover to higher elevations and the seasonal advance and retreat of photosynthetic activity. Read more
Long-term historical trends in air pollutant emissions in Asia: Regional Emission inventory in ASia (REAS) version 3 Atmospheric Chemistry and Physics DOI 10.5194/acp-20-12761-2020 4 December 2020 A long historical emission inventory of major air pollutants in Asia during 1950–2015 was developed as Regional Emission inventory in ASia version 3 (REASv3). Trends of emissions and changes in source contributions in countries and regions in Asia during these 6 decades were analyzed. REASv3 provides monthly gridded data with 0.25° by 0.25° resolution for major source categories as well as table of emissions by countries and sub-regions for major sectors and fuel types. Read more
The Pliocene Model Intercomparison Project Phase 2: large-scale climate features and climate sensitivity Climate of the Past DOI 10.5194/cp-16-2095-2020 3 December 2020 The large-scale features of middle Pliocene climate from the 16 models of PlioMIP Phase 2 are presented. The PlioMIP2 ensemble average was ~ 3.2 °C warmer and experienced ~ 7 % more precipitation than the pre-industrial era, although there are large regional variations. PlioMIP2 broadly agrees with a new proxy dataset of Pliocene sea surface temperatures. Combining PlioMIP2 and proxy data suggests that a doubling of atmospheric CO 2 would increase globally averaged temperature by 2.6–4.8 °C. Read more
Vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast Atlantic during CLARIFY-2017 Atmospheric Chemistry and Physics DOI 10.5194/acp-20-12697-2020 2 December 2020 Airborne measurements of highly aged biomass burning aerosols (BBAs) over the remote southeast Atlantic provide unique aerosol parameters for climate models. Our observations demonstrate the persistence of strongly absorbing BBAs across wide regions of the South Atlantic. We also found significant vertical variation in the single-scattering albedo of these BBAs, as a function of relative chemical composition and size. Aerosol properties in the marine BL are suggested to be separated from the FT. Read more
A microphysics guide to cirrus – Part 2:Climatologies of clouds and humidity from observations Atmospheric Chemistry and Physics DOI 10.5194/acp-20-12569-2020 1 December 2020 To improve the representations of cirrus clouds in climate predictions, extended knowledge of their properties and geographical distribution is required. This study presents extensive airborne in situ and satellite remote sensing climatologies of cirrus and humidity, which serve as a guide to cirrus clouds. Further, exemplary radiative characteristics of cirrus types and also in situ observations of tropical tropopause layer cirrus and humidity in the Asian monsoon anticyclone are shown. Read more
The Aarhus Chamber Campaign on Highly Oxygenated Organic Molecules andAerosols (ACCHA): particle formation, organic acids, and dimer esters fromα-pinene ozonolysis at different temperatures Atmospheric Chemistry and Physics DOI 10.5194/acp-20-12549-2020 30 November 2020 Atmospheric particles are important in relation to human health and the global climate. As the global temperature changes, so may the atmospheric chemistry controlling the formation of particles from reactions of naturally emitted volatile organic compounds (VOCs). In the current work, we show how temperatures influence the formation and chemical composition of atmospheric particles from α-pinene: a biogenic VOC largely emitted in high-latitude environments such as the boreal forests. Read more