Balanced estimate and uncertainty assessment of European climate change using the large EURO-CORDEX regional climate model ensemble Earth System Dynamics DOI 10.5194/esd-12-1543-2021 30 March 2022 This research paper proposes an assessment of mean climate change responses and related uncertainties over Europe for mean seasonal temperature and total seasonal precipitation. An advanced statistical approach is applied to a large ensemble of 87 high-resolution EURO-CORDEX projections. For the first time, we provide a comprehensive estimation of the relative contribution of GCMs and RCMs, RCP scenarios, and internal variability to the total variance of a very large ensemble. Read more
The ESA MIPAS/Envisat level2-v8 dataset: 10 years of measurements retrieved with ORM v8.22 Atmospheric Measurement Techniques DOI 10.5194/amt-14-7975-2021 28 March 2022 The level-2 v8 database from the measurements of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), aboard the European Space Agency Envisat satellite, containing atmospheric fields of pressure, temperature, and volume mixing ratio of 21 trace gases, is described in this paper. The database covers all the measurements acquired by MIPAS (from July 2002 to April 2012). The number of species included makes it of particular importance for the studies of stratospheric chemistry. Read more
A simple model of ozone–temperature coupling in the tropical lower stratosphere Atmospheric Chemistry and Physics DOI 10.5194/acp-21-18531-2021 25 March 2022 Balloon and satellite observations show strong coupling between large-scale ozone and temperature fields in the tropical lower stratosphere, spanning timescales of days to years. We present a simple interpretation of this behaviour based on an idealized model of transport by the tropical stratospheric circulation, and good quantitative agreement with observations demonstrates that this is a useful simplification. The results provide simple understanding of observed atmospheric behaviour. Read more
Secondary ice production during the break-up of freezing water drops on impact with ice particles Atmospheric Chemistry and Physics DOI 10.5194/acp-21-18519-2021 23 March 2022 Secondary ice production (SIP) plays an important role in ice formation within mixed-phase clouds. We present a laboratory investigation of a potentially new SIP mechanism involving the collisions of supercooled water drops with ice particles. At impact, the supercooled water drop fragments form smaller secondary drops. Approximately 30 % of the secondary drops formed during the retraction phase of the supercooled water drop impact freeze over a temperature range of -4 °C to -12 °C. Read more
Deep oceanic submarine fieldwork with undergraduate students: an immersive experience with the Minerve software Solid Earth DOI 10.5194/se-12-2789-2021 21 March 2022 We use the Minerve virtual reality software to bring undergraduate students to an unusual field trip at 1200 m below sea level in the Lesser Antilles area. This region is located above an active subduction zone responsible for intense volcanic and seismic activity. In particular, we focus on the Roseau submarine fault that ruptured during the Mw 6.3 Les Saintes earthquake and presented a fresh scarp that the students can analyse and map in VR. They compile their results in a GIS project. Read more
Impact of the melt–albedo feedback on the future evolution of the Greenland Ice Sheet with PISM-dEBM-simple The Cryosphere DOI 10.5194/tc-15-5739-2021 18 March 2022 With the increasing melt of the Greenland Ice Sheet, which contributes to sea level rise, the surface of the ice darkens. The dark surfaces absorb more radiation and thus experience increased melt, resulting in the melt–albedo feedback. Using a simple surface melt model, we estimate that this positive feedback contributes to an additional 60 % ice loss in a high-warming scenario and additional 90 % ice loss for moderate warming. Albedo changes are important for Greenland’s future ice loss. Read more
The blue suns of 1831: was the eruption of Ferdinandea, near Sicily, one of the largest volcanic climate forcing events of the nineteenth century? Climate of the Past DOI 10.5194/cp-17-2607-2021 16 March 2022 An unidentified eruption in 1831 was one of the largest volcanic climate forcing events of the nineteenth century. We use reported observations of a blue sun to reconstruct the transport of an aerosol plume from that eruption and, hence, identify it as the 1831 eruption of Ferdinandea, near Sicily. We propose that, although it was only a modest eruption, its volcanic plume was enriched with sulphur from sedimentary deposits and that meteorological conditions helped it reach the stratosphere. Read more
Brief communication: A roadmap towards credible projections of ice sheet contribution to sea level The Cryosphere DOI 10.5194/tc-15-5705-2021 14 March 2022 Estimating how much ice loss from Greenland and Antarctica will contribute to sea level rise is of critical societal importance. However, our analysis shows that recent efforts are not trustworthy because the models fail at reproducing contemporary ice melt. Here we present a roadmap towards making more credible estimates of ice sheet melt. Read more
Options to correct local turbulent flux measurements for large-scale fluxes using an approach based on large-eddy simulation Atmospheric Measurement Techniques DOI 10.5194/amt-14-7835-2021 11 March 2022 Turbulent flux measurements suffer from a general systematic underestimation. One reason for this bias is non-local transport by large-scale circulations. A recently developed model for this additional transport of sensible and latent energy is evaluated for three different test sites. Different options on how to apply this correction are presented, and the results are evaluated against independent measurements. Read more
Dynamics of variable dusk–dawn flow associated with magnetotail current sheet flapping Annales Geophysicae DOI 10.5194/angeo-39-1037-2021 9 March 2022 The sun’s magnetic field is carried across space by the solar wind – a hot plasma “stream” of ions and electrons – forming the interplanetary magnetic field (IMF). The IMF can introduce asymmetries in the Earth’s magnetic field, giving plasma flowing within it a direction dependent on IMF orientation. Electric currents in near-Earth space can also influence these plasma flows. We investigate these two competing mechanisms and find that the currents can prevent the IMF from controlling the flow. Read more
Identifying community values related to heat: recommendations for forecast and health risk communication Geoscience Communication DOI 10.5194/gc-4-517-2021 7 March 2022 This paper presents an analysis of public responses to U.S. National Weather Service heat-related Facebook posts for the Phoenix (Arizona) County Warning Area to identify community norms that may present challenges to the effectiveness of heat risk communication. Findings suggest that local audiences tend to view heat as normal and the ability to withstand heat as a marker of community identity. Recommendations are provided for harnessing those norms to promote positive behavioural change. Read more
Modelling the volcanic ash plume from Eyjafjallajökull eruption (May 2010) over Europe: evaluation of the benefit of source term improvements and of the assimilation of aerosol measurements Natural Hazards and Earth System Sciences DOI 10.5194/nhess-21-3731-2021 4 March 2022 Volcanic eruptions that spread out ash over large areas, like Eyjafjallajökull in 2010, may have huge economic consequences due to flight cancellations. In this article, we demonstrate the benefits of source term improvement and of data assimilation for quantifying volcanic ash concentrations. The work, which was supported by the EUNADICS-AV project, is the first one, to our knowledge, that demonstrates the benefit of the assimilation of ground-based lidar data over Europe during an eruption. Read more
Ubiquity of human-induced changes in climate variability Earth System Dynamics DOI 10.5194/esd-12-1393-2021 2 March 2022 A large ensemble of simulations with 100 members has been conducted with the state-of-the-art CESM2 Earth system model, using historical and SSP3-7.0 forcing. Our main finding is that there are significant changes in the variance of the Earth system in response to anthropogenic forcing, with these changes spanning a broad range of variables important to impacts for human populations and ecosystems. Read more
SELF v1.0: a minimal physical model for predicting time of freeze-up in lakes Geoscientific Model Development DOI 10.5194/gmd-14-7527-2021 28 February 2022 The time when lakes freeze varies considerably from year to year. A common way to predict it is to use negative degree days, i.e., the sum of air temperatures below 0°C, a proxy for the heat lost to the atmosphere. Here, we show that this is insufficient as the mixing of the surface layer induced by wind tends to delay the formation of ice. To do so, we developed a minimal model based on a simplified energy balance, which can be used both for large-scale analyses and short-term predictions. Read more
Annual exposure to polycyclic aromatic hydrocarbons in urban environments linked to wintertime wood-burning episodes Atmospheric Chemistry and Physics DOI 10.5194/acp-21-17865-2021 25 February 2022 We analyse observations from year-long measurements at Athens, Greece. Nighttime wintertime PAH levels are 4 times higher than daytime, and wintertime values are 15 times higher than summertime. Biomass burning aerosol during wintertime pollution events is responsible for these significant wintertime enhancements and accounts for 43 % of the population exposure to PAH carcinogenic risk. Biomass burning poses additional health risks beyond those associated with the high PM levels that develop. Read more
Assessing the dependence structure between oceanographic, fluvial, and pluvial flooding drivers along the United States coastline Hydrology and Earth System Sciences DOI 10.5194/hess-25-6203-2021 23 February 2022 We analyse dependences between different flooding drivers around the USA coastline, where the Gulf of Mexico and the southeastern and southwestern coasts are regions of high dependence between flooding drivers. Dependence is higher during the tropical season in the Gulf and at some locations on the East Coast but higher during the extratropical season on the West Coast. The analysis gives new insights on locations, driver combinations, and the time of the year when compound flooding is likely. Read more
Extreme metrics from large ensembles: investigating the effects of ensemble size on their estimates Earth Surface Dynamics DOI 10.5194/esd-12-1427-2021 21 February 2022 We address the question of how large an initial condition ensemble of climate model simulations should be if we are concerned with accurately projecting future changes in temperature and precipitation extremes. We find that for most cases (and both models considered), an ensemble of 20-25 members is sufficient for many extreme metrics, spatial scales and time horizons. This may leave computational resources to tackle other uncertainties in climate model simulations with our ensembles. Read more
Tracking aerosols and SO2 clouds from the Raikoke eruption: 3D view from satellite observations Atmospheric Measurement Techniques DOI 10.5194/amt-14-7545-2021 18 February 2022 The 21 June 2019 eruption of the Raikoke volcano produced significant amounts of volcanic aerosols (sulfate and ash) and sulfur dioxide (SO2) gas that penetrated into the lower stratosphere. We showed that the amount of SO2 decreases with a characteristic period of 8–18 d and the peak of sulfate aerosol lags the initial peak of SO2 by 1.5 months. We also examined the dynamics of an unusual stratospheric coherent circular cloud of SO2 and aerosol observed from 18 July to 22 September 2019. Read more
Rectified tidal transport in Lofoten–Vesterålen, northern Norway Ocean Science DOI 10.5194/os-17-1753-2021 16 February 2022 Non-linear tidal dynamics can produce prominent time-mean transport in coastal regions where strong tidal currents interact with topography. We investigate tidal-induced transport using a tidally driven ocean model for Lofoten-Vesterålen in northern Norway and find that both tidal pumping and tidal rectification can play an important role for time-mean transport in the region. The study emphasizes the importance of non-linear tidal dynamics for time-mean transport in complex coastal regions. Read more
Assessment of the ParFlow–CLM CONUS 1.0 integrated hydrologic model: evaluation of hyper-resolution water balance components across the contiguous United States Geoscientific Model Development DOI 10.5194/gmd-14-7223-2021 14 February 2022 Modeling the hydrologic cycle at high resolution and at large spatial scales is an incredible opportunity and challenge for hydrologists. In this paper, we present the results of a high-resolution hydrologic simulation configured over the contiguous United States. We discuss simulated water fluxes through groundwater, soil, plants, and over land, and we compare model results to in situ observations and satellite products in order to build confidence and guide future model development. Read more