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. EURO-CORDEX regionalclimate models (RCMs) andhigh-resolution globalclimate models (GCMs) from the High-Resolution Model Intercomparison Project (HighResMIP)">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. COVID-19">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. USA">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. REAS) version 3">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. CLARIFY-2017">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
