Introducing hydrometeor orientation into all-sky microwave and submillimeter assimilation Atmospheric Measurement Techniques DOI 10.5194/amt-14-3427-2021 4 June 2021 Oriented nonspherical ice particles induce polarization that is ignored when cloud-sensitive satellite observations are used in numerical weather prediction systems. We present a simple approach for approximating particle orientation, requiring minor adaption of software and no additional calculation burden. With this approach, the system realistically simulates the observed polarization patterns, increasing the physical consistency between instruments with different polarizations. Read more
Captured cirrus ice particles in high definition Atmospheric Chemistry and Physics DOI 10.5194/acp-21-7171-2021 2 June 2021 The cryo-electron microscopy images and analysis in this paper result from the first balloon-borne capture, preservation, and high-resolution imaging of ice particles from cirrus clouds. The images show cirrus particle complexity in unprecedented detail, revealing unexpected morphology, a mixture of surface roughness scales and patterns, embedded aerosols, and a large variety of habits within a single cloud. The results should inform ongoing efforts to refine modeling of cirrus radiative impact. Read more
High-frequency monitoring of anomalous methane point sources with multispectral Sentinel-2 satellite observations Atmospheric Measurement Techniques DOI 10.5194/amt-14-2771-2021 31 May 2021 Satellites can detect methane emissions by measuring sunlight reflected from the Earth’s surface and atmosphere. Here we show that the European Space Agency’s Sentinel-2 twin satellites can be used to monitor anomalously large methane point sources around the world, with global coverage every 2–5 days and 20 m spatial resolution. We demonstrate this previously unreported capability through high-frequency Sentinel-2 monitoring of two strong methane point sources in Algeria and Turkmenistan. Read more
JlBox v1.1: a Julia-based multi-phase atmospheric chemistry box model Geoscientific Model Development DOI 10.5194/gmd-14-2187-2021 28 May 2021 As our knowledge and understanding of atmospheric aerosol particle evolution and impact grows, designing community mechanistic models requires an ability to capture increasing chemical, physical and therefore numerical complexity. As the landscape of computing software and hardware evolves, it is important to profile the usefulness of emerging platforms in tackling this complexity. With this in mind we present JlBox v1.1, written in Julia. Read more
Sudden large-volume detachments of low-angle mountain glaciers – more frequent than thought? The Cryosphere DOI 10.5194/tc-15-1751-2021 26 May 2021 Hardly recognized so far, giant catastrophic detachments of glaciers are a rare but great potential for loss of lives and massive damage in mountain regions. Several of the events compiled in our study involve volumes (up to 100 million m3 and more), avalanche speeds (up to 300 km/h), and reaches (tens of kilometres) that are hard to imagine. We show that current climate change is able to enhance associated hazards. For the first time, we elaborate a set of factors that could cause these events. Read more
African easterly waves in an idealized general circulation model: instability and wave packet diagnostics Weather and Climate Dynamics DOI 10.5194/wcd-2-311-2021 24 May 2021 Using a simple general circulation model, we examine the structure of waves in the mid-tropospheric jet over North Africa. We show that waves occur in near-stationary groups or wave packets. As they are not swept out of the jet, this may provide the opportunity for the packets to amplify via feedback from other energy sources like rain-producing cloud complexes and mineral dust that are known to operate here. Our results address the criticism that the easterly jet is too short to sustain waves. Read more
Medusa–Aqua system: simultaneous measurement and evaluation of novel potential halogenated transient tracers HCFCs, HFCs, and PFCs in the ocean Ocean Science DOI 10.5194/os-17-509-2021 21 May 2021 Observations of transient tracer distribution provide essential information on ocean ventilation. The use of several commonly used transient traces is limited as their atmospheric mole fractions do not monotonically change. Here we explore new potential oceanic transient tracers with an analytical system that simultaneously measures a large range of compounds. Combined with the known atmospheric history and seawater solubility, we discuss the utility of selected HCFCs, HFCs, and PFCs as tracers. Read more
Summary and synthesis of Changing Cold Regions Network (CCRN) research in the interior of western Canada – Part 2: Future change in cryosphere, vegetation, and hydrology Hydrology and Earth System Sciences DOI 10.5194/hess-25-1849-2021 19 May 2021 This article examines future changes in land cover and hydrological cycling across the interior of western Canada under climate conditions projected for the 21st century. Key insights into the mechanisms and interactions of Earth system and hydrological process responses are presented, and this understanding is used together with model application to provide a synthesis of future change. This has allowed more scientifically informed projections than have hitherto been available. Read more
Arctic Ocean acidification over the 21st century co-driven by anthropogenic carbon increases and freshening in the CMIP6 model ensemble Biogeosciences DOI 10.5194/bg-18-2221-2021 17 May 2021 The uptake of carbon, emitted as a result of human activities, results in ocean acidification. We analyse 21st-century projections of acidification in the Arctic Ocean, a region of particular vulnerability, using the latest generation of Earth system models. In this new generation of models there is a large decrease in the uncertainty associated with projections of Arctic Ocean acidification, with freshening playing a greater role in driving acidification than previously simulated. Read more
Airborne measurements of oxygen concentration from the surface to the lower stratosphere and pole to pole Atmospheric Measurement Techniques DOI 10.5194/amt-14-2543-2021 14 May 2021 We describe methods used to make high-precision global-scale airborne measurements of atmospheric oxygen concentrations over a period of 20 years in order to study the global carbon cycle. Our techniques include an in situ vacuum ultraviolet absorption instrument and a pressure- and flow-controlled, cryogenically dried, glass flask sampler. We have deployed these instruments in 15 airborne research campaigns spanning from the Earth’s surface to the lower stratosphere and from pole to pole. Read more
Evaluating stratospheric ozone and water vapour changes in CMIP6 models from 1850 to 2100 Atmospheric Chemistry and Physics DOI 10.5194/acp-21-5015-2021 12 May 2021 Stratospheric ozone and water vapour are key components of the Earth system; changes to both have important impacts on global and regional climate. We evaluate changes to these species from 1850 to 2100 in the new generation of CMIP6 models. There is good agreement between the multi-model mean and observations, although there is substantial variation between the individual models. The future evolution of both ozone and water vapour is strongly dependent on the assumed future emissions scenario. Read more
Diverging land-use projections cause large variability in their impacts on ecosystems and related indicators for ecosystem services Earth System Dynamics DOI 10.5194/esd-12-327-2021 10 May 2021 Many projections of future land-use/-cover exist. We evaluate a number of these and determine the variability they cause in ecosystems and their services. We found that projections differ a lot in regional patterns, with some patterns being at least questionable in a historical context. Across ecosystem service indicators, resulting variability until 2040 was highest in crop production. Results emphasize that such variability should be acknowledged in assessments of future ecosystem provisions. Read more
How Rossby wave breaking modulates the water cycle in the North Atlantic trade wind region Weather and Climate Dynamics DOI 10.5194/wcd-2-281-2021 7 May 2021 The interaction of clouds in the trade wind region with the atmospheric flow is complex and at the heart of uncertainties associated with climate projections. In this study, a natural tracer of atmospheric circulation is used to establish a link between air originating from dry regions of the midlatitudes and the occurrence of specific cloud patterns. Two pathways involving transport within midlatitude weather systems are identified, by which air is brought into the trades within 5–10 d. Read more
A process-based evaluation of the Intermediate Complexity Atmospheric Research Model (ICAR) 1.0.1 Geoscientific Model Development DOI 10.5194/gmd-14-1657-2021 3 May 2021 This study conducts an in-depth process-based evaluation of the Intermediate Complexity Atmospheric Research (ICAR) model, employing idealized simulations to increase the understanding of the model and develop recommendations to maximize the probability that its results are correct for the right reasons. The results show that when model skill is evaluated from statistical metrics based on comparisons to surface observations only, such an analysis may not reflect the skill of the model in capturing atmospheric processes like gravity waves and cloud formation. Read more
Similar importance of edaphic and climatic factors for controlling soil organic carbon stocks of the world Biogeosciences DOI 10.5194/bg-18-2063-2021 30 April 2021 Soil organic carbon (SOC) accounts for two-thirds of terrestrial carbon. Yet, the role of soil physicochemical properties in regulating SOC stocks is unclear, inhibiting reliable SOC predictions under land use and climatic changes. Using legacy observations from 141 584 soil profiles worldwide, we disentangle the effects of biotic, climatic and edaphic factors (a total of 31 variables) on the global spatial distribution of SOC stocks in four sequential soil layers down to 2 m. Read more
The behavior of high-CAPE (convective available potential energy) summer convection in large-domain large-eddy simulations with ICON Atmospheric Chemistry and Physics DOI 10.5194/acp-21-4285-2021 28 April 2021 Current state-of-the-art regional numerical weather prediction (NWP) models employ kilometer-scale horizontal grid resolutions, thereby simulating convection within the grey zone. Increasing resolution leads to resolving the 3D motion field and has been shown to improve the representation of clouds and precipitation. Using a hectometer-scale model in forecasting mode on a large domain therefore offers a chance to study processes that require the simulation of the 3D motion field at small horizontal scales. Read more
Do small and large floods have the same drivers of change? A regional attribution analysis in Europe Hydrology and Earth System Sciences DOI 10.5194/hess-25-1347-2021 26 April 2021 Recent studies have shown evidence of increasing and decreasing trends for average floods and flood quantiles across Europe. Studies attributing observed changes in flood peaks to their drivers have mostly focused on the average flood behaviour, without distinguishing small and large floods. This paper proposes a new framework for attributing flood changes to potential drivers, as a function of return period (T), in a regional context. Read more
Interhemispheric transport of metallic ions within ionospheric sporadic E layers by the lower thermospheric meridional circulation Atmospheric Chemistry and Physics DOI 10.5194/acp-21-4219-2021 23 April 2021 Here, we report a study of ionospheric irregularities using scintillation data from COSMIC satellites and identify a large-scale horizontal transport of long-lived metallic ions, combining the simulations of the Whole Atmosphere Community Climate Model with the chemistry of metals and ground-based observations from two meridional chains of stations from 1975–2016. Read more
Observed snow depth trends in the European Alps: 1971 to 2019 The Cryosphere DOI 10.5194/tc-15-1343-2021 9 April 2021 Here, we present an Alpine-wide analysis of snow depth from six Alpine countries – Austria, France, Germany, Italy, Slovenia, and Switzerland – including altogether more than 2000 stations of which more than 800 were used for the trend assessment. Linear trends of monthly mean snow depth between1971 and 2019 showed decreases in snow depth for most stations from November to May. Read more
The enigma of relict large sorted stone stripes in the tropical Ethiopian Highlands Earth Surface Dynamics DOI 10.5194/esurf-9-145-2021 7 April 2021 Large forms of sorted patterned ground belong to the most prominent geomorphic features of periglacial and permafrost environments of the mid-latitudes and polar regions, but they were hitherto unknown in the tropics. Here, we report on relict large sorted stone stripes (up to 1000 m long, 15 m wide, and 2 m deep) on the ca. 4000 m high central Sanetti Plateau of the tropical Bale Mountains in the southern Ethiopian Highlands. Read more
geoChronR – an R package to model, analyze, and visualize age-uncertain data Geochronology DOI 10.5194/gchron-3-149-2021 5 April 2021 Chronological uncertainty is a hallmark of the paleoenvironmental sciences and geosciences. While many tools have been made available to researchers to quantify age uncertainties suitable for various settings and assumptions, disparate tools and output formats often discourage integrative approaches. Here, we describe geoChronR, an open-source R package to facilitate these tasks. Read more
Sensitivities to biological aerosol particle properties and ageing processes: potential implications for aerosol–cloud interactions and optical properties Atmospheric Chemistry and Physics DOI 10.5194/acp-21-3699-2021 2 April 2021 Primary biological aerosol particles (PBAPs), such as bacteria, viruses, fungi, and pollen, represent a small fraction of the total aerosol burden. Given that PBAPs are highly efficient atmospheric ice nuclei (IN) at T > -10 ∘C, we suggest that small changes in their sizes or surface properties due to chemical, physical, or biological processing might translate into large impacts on ice initiation in clouds. Read more
High-resolution optical constants of crystalline ammonium nitrate forinfrared remote sensing of the Asian Tropopause Aerosol Layer Atmospheric Measurement Techniques DOI 10.5194/amt-14-1977-2021 31 March 2021 In this work, we have retrieved the first low-temperature data set of optical constants for crystalline AN in the 800–6000 cm-1 wave number range with a spectral resolution of 0.5 cm-1. We show that our data accurately fit aircraft-borne infrared measurements of ammonium nitrate particles in the upper tropospheric aerosol layer, which is formed during the Asian summer monsoon period. Read more
A statistical–parametric model of tropical cyclones for hazard assessment Natural Hazards and Earth System Sciences DOI 10.5194/nhess-21-893-2021 30 March 2021 We present the formulation of an open-source, statistical–parametric model of tropical cyclones (TCs) for use in hazard and risk assessment applications. We demonstrate the capability of the model to replicate observed behaviour of TCs, including coastal landfall rates which are of significant importance for risk assessments. Read more
A global climatological perspective on the importance of Rossby wavebreaking and intense moisture transport for extreme precipitation events Weather and Climate Dynamics DOI 10.5194/wcd-2-129-2021 29 March 2021 Extreme precipitation events (EPEs) frequently cause flooding with dramatic socioeconomic impacts in many parts of the world.Previous studies considered two synoptic-scale processes, Rossby wave breaking and intense moisture transport, typically in isolation, and their linkage to such EPEs in several regions. This study presents for the first time a global and systematic climatological analysis of these two synoptic-scale processes, in tandem and in isolation, for the occurrence of EPEs. Read more
Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard Annales Geophysicae DOI 10.5194/angeo-39-277-2021 26 March 2021 This study analyses the observations of a new type of small-scale aurora-like feature, which is further referred to as fragmented aurora-like emission(s) (FAEs). One possible explanation for this is Farley–Buneman instabilities of strong local currents. In the present study, we provide an overview of the observations and discuss their characteristics and potential generation mechanisms. Read more
Model physics and chemistry causing intermodel disagreement within the VolMIP-Tambora Interactive Stratospheric Aerosol ensemble Atmospheric Chemistry and Physics DOI 10.5194/acp-21-3317-2021 25 March 2021 As part of the Model Intercomparison Project on the climatic response to Volcanic forcing (VolMIP), several climate modeling centers performed a coordinated pre-study experiment with interactive stratospheric aerosol models simulating the volcanic aerosol cloud from an eruption resembling the 1815 Mt. Tambora eruption (VolMIP-Tambora ISA ensemble). Read more
Comparison of ozone measurement methods in biomass burning smoke: anevaluation under field and laboratory conditions Atmospheric Measurement Techniques DOI 10.5194/amt-14-1783-2021 24 March 2021 In recent years wildland fires in the United States have had significant impacts on local and regional air quality and negative human health outcomes. Although the primary health concerns from wildland fires come from fine particulate matter (PM2.5), large increases in ozone (O3 have been observed downwind of wildland fire plumes. The chemiluminescence FRM method is highly recommended for accurate measurements of O3 in wildland fire plume studies and at regulatory ambient monitoring sites frequently impacted by wildland firesmoke. Read more
Cryptotephra from the Icelandic Veiðivötn 1477 CE eruption in a Greenland ice core: confirming the dating of volcanic events in the 1450s CE and assessing the eruption’s climatic impact Climate of the Past DOI 10.5194/cp-17-565-2021 23 March 2021 Volcanic eruptions are a key source of climatic variability, and reconstructing their past impact can improve our understanding of the operation of the climate system and increase the accuracy of future climate projections. While many chronological mismatches have been resolved, the precise timing and climatic impact of two major sulfate-emitting volcanic eruptions during the 1450s CE, including the largest atmospheric sulfate-loading event in the last 700 years, have not been constrained. Here we explore this issue through a combination of tephrochronological evidence and high-resolution ice-core chemistry measurements from a Greenland ice core, the TUNU2013 record. Read more
The case of a southern European glacier which survived Roman and medieval warm periods but is disappearing under recent warming The Cryosphere DOI 10.5194/tc-15-1157-2021 22 March 2021 We present here the first chronological study of a glacier located in the Central Pyrenees (NE Spain), Monte Perdido Glacier (MPG),carried out by different radiochronological techniques and a comparison with geochemical proxies from neighbouring palaeoclimate records. The chronological model evidences that the glacier persisted during the Roman period and the Medieval Climate Anomaly. The apparent absence of ice in the past∼ 600 years suggests that any ice accumulated during the Little Ice Age has since ablated. Read more
Diverging responses of high-latitude CO2 and CH4 emissions in idealized climate change scenarios The Cryosphere DOI 10.5194/tc-15-1097-2021 19 March 2021 The present study investigates the response of the high-latitude carbon cycle to changes in atmospheric greenhouse gas (GHG) concentrations in idealized climate change scenarios. We find that at a global mean temperature of roughly 1.75 K (±0.5 K) above pre-industrial levels the high-latitude ecosystem turns from a CO2 sink into a source of atmospheric carbon, with the net fluxes into the atmosphere increasing substantially with rising atmospheric GHG concentrations. This is very different from scenario simulations with the standard version of the MPI-ESM, in which the region continues to take up atmospheric CO2 throughout the entire 21st century. Read more
A dynamical systems characterization of atmospheric jet regimes Earth System Dynamics DOI 10.5194/esd-12-233-2021 18 March 2021 Atmospheric jet streams are typically separated into primarily “eddy-driven” (or polar-front) jets and primarily “thermally driven” (or subtropical) jets. Here, we link the current understanding of dynamical jet maintenance mechanisms, mostly arising from conceptual or idealized models, to the phenomena observed in reanalysis data. Read more
Lower oceanic δ13C during the last interglacial period compared to the Holocene Climate of the Past DOI 10.5194/cp-17-507-2021 17 March 2021 The last time in Earth’s history when high latitudes were warmer than during pre-industrial times was the last interglacial period (LIG, 129–116 ka BP). Since the LIG is the most recent and best documented interglacial, it can provide insights into climate processes in a warmer world. However, some key features of the LIG are not well constrained, notably the oceanic circulation and the global carbon cycle. Here, we use a new database of LIG benthic δ13C to investigate these two aspects. Read more
Mapping avalanches with satellites – evaluation of performance andcompleteness The Cryosphere DOI 10.5194/tc-15-983-2021 16 March 2021 The spatial distribution and size of avalanches are essential parameters for avalanche warning, avalanche documentation, mitigation measure design and hazard zonation. Despite its importance, this information is incomplete today and only available for limited areas and limited time periods. Read more
A-Train estimates of the sensitivity of the cloud-to-rainwater ratio to cloud size, relative humidity, and aerosols Atmospheric Chemistry and Physics DOI 10.5194/acp-21-2765-2021 15 March 2021 Precipitation efficiency has been found to play an important role in constraining the sensitivity of the climate through its role in controlling cloud cover, yet its controls are not fully understood. Here we use CloudSat observations to identify individual contiguous shallow cumulus cloud objects and compute the ratio of cloud water path to rainwater (WRR) path as a proxy for warm-rain efficiency. Read more
Development of a MetUM (v 11.1) and NEMO (v 3.6) coupled operational forecastmodel for the Maritime Continent – Part 1: Evaluation of ocean forecasts Geoscientific Model Development DOI 10.5194/gmd-14-1081-2021 12 March 2021 This article describes the development and ocean forecast evaluation of an atmosphere–ocean coupled prediction system for the Maritime Continent (MC) domain, which includes the eastern Indian and western Pacific oceans. Overall, the model forecast deviation of SST, SSH, and subsurface temperature and salinity fields relative to observation is within acceptable error limits of operational forecast models. Read more
Long-term global ground heat flux and continental heat storage from geothermal data Climate of the Past DOI 10.5194/cp-17-451-2021 11 March 2021 Here, we provide new global estimates of changes in ground surface temperature, ground surface heat flux, and continental heat storage derived from geothermal data using an expanded database and new techniques. Read more
Radar-based assessment of hail frequency in Europe Natural Hazards and Earth System Sciences DOI 10.5194/nhess-21-683-2021 10 March 2021 In this study we present a unique 10 year climatology of severe convective storm tracks for a large European area covering Germany, France, Belgium and Luxembourg. For the period 2005–2014, a high-resolution hail potential composite of 1×1 km2 is produced from two-dimensional radar reflectivity and lightning data. Read more
In situ cosmogenic 10Be–14C–26Al measurements from recently deglaciated bedrock as a new tool to decipher changes in Greenland Ice Sheet size Climate of the Past DOI 10.5194/cp-17-419-2021 9 March 2021 Sometime during the middle to late Holocene (8.2 ka to ∼ 1850–1900 CE), the Greenland Ice Sheet (GrIS) was smaller than its current configuration. Contemporary retreat of the GrIS from its historical maximum extent in southwestern Greenland is exposing a landscape that holds clues regarding the configuration and timing of past ice-sheet minima. Read more
Reviews and syntheses: Impacts of plant-silica–herbivore interactions onterrestrial biogeochemical cycling Biogeosciences DOI 10.5194/bg-18-1259-2021 8 March 2021 Researchers have known for decades that silicon plays a major role in biogeochemical and plant–soil processes in terrestrial systems. We review and synthesize 119 available studies directly investigating silicon and herbivory to summarize key trends and highlight research gaps and opportunities. Read more
Response of tidal flow regime and sediment transport in North Malé Atoll, Maldives, to coastal modification and sea level rise Ocean Science DOI 10.5194/os-17-319-2021 5 March 2021 Changes to coastlines and bathymetry alter tidal dynamics and associated sediment transport processes, impacting upon a number of threats facing coastal regions, including flood risk and erosion. Especially vulnerable are coral atolls such as those that make up the Maldives archipelago, which has undergone significant land reclamation in recent years and decades and is also particularly exposed to sea level rise. Read more
Assessment of a full-field initialized decadal climate prediction system with the CMIP6 version of EC-Earth Earth System Dynamics DOI 10.5194/esd-12-173-2021 4 March 2021 In this paper, we present and evaluate the skill of an EC-Earth 3.3 decadal prediction system contributing to the Decadal Climate Prediction Project – Component A (DCPP-A). This prediction system is capable of skilfully simulating past global mean surface temperature variations at interannual and decadal forecast times as well as the local surface temperature in regions such as the tropical Atlantic, the Indian Ocean and most of the continental areas, although most of the skill comes from the representation of the external radiative forcings. Read more
Vapor plumes in a tropical wet forest: spotting the invisible evaporation Hydrology and Earth System Sciences DOI 10.5194/hess-25-619-2021 3 March 2021 Forest evaporation exports a vast amount of water vapor from land ecosystems into the atmosphere. This work describes the formation process of vapor plumes in a tropical wet forest as evidence of evaporation processes happening during rain events. Read more
Low-NO atmospheric oxidation pathways in a polluted megacity Atmospheric Chemistry and Physics DOI 10.5194/acp-21-1613-2021 2 March 2021 The impact of emissions of volatile organic compounds (VOCs) to the atmosphere on the production of secondary pollutants, such as ozone and secondary organic aerosol (SOA), is mediated by the concentration of nitric oxide (NO). Polluted urban atmospheres are typically considered to be high-NO” environments, while remote regions such as rainforests, with minimal anthropogenic influences, are considered to be “low NO”. However, our observations from central Beijing show that this simplistic separation of regimes is flawed. Read more
A limited effect of sub-tropical typhoons on phytoplankton dynamics Biogeosciences DOI 10.5194/bg-18-849-2021 1 March 2021 Typhoons are assumed to stimulate primary ocean production through the upward mixing of nutrients into the ocean surface. This assumption is based largely on observations of increased surface chlorophyll concentrations following the passage of typhoons. This surface chlorophyll enhancement, occasionally detected by satellites, is often undetected due to intense cloud coverage. Read more
Volcanoes in video games: the portrayal of volcanoes incommercial off-the-shelf (COTS) video games and their learning potential Geoscience Communication DOI 10.5194/gc-4-11-2021 26 February 2021 Volcanoes are a very common staple in mainstream video games. Particularly within the action–adventure genres, entire missions or even full storylines can require players to traverse an active volcano. Therefore, players can spend a lot of time immersed within the detailed graphics and unknowingly learn about volcanic traits while playing. Read more
Mass accommodation and gas–particle partitioning in secondary organicaerosols: dependence on diffusivity, volatility, particle-phase reactions,and penetration depth Atmospheric Chemistry and Physics DOI 10.5194/acp-21-1565-2021 25 February 2021 Mass accommodation is an essential process for gas–particle partitioning of organic compounds in secondary organic aerosols (SOA). The mass accommodation coefficient is commonly described as the probability of a gas molecule colliding with the surface to enter the particle phase. It is often applied, however, without specifying if and how deep a molecule has to penetrate beneath the surface to be regarded as being incorporated into the condensed phase (adsorption vs. absorption). Read more
A new view of heat wave dynamics and predictability over the easternMediterranean Earth System Dynamics DOI 10.5194/esd-12-133-2021 24 February 2021 Skillful forecasts of extreme weather events have a major socioeconomic relevance. Here, we compare two complementary approaches to diagnose the predictability of extreme weather: recent developments in dynamical systems theory and numerical ensemble weather forecasts. Read more
An overview of the ORACLES (ObseRvations of Aerosols above CLouds and theirintEractionS) project: aerosol–cloud–radiation interactions in the southeastAtlantic basin Atmospheric Chemistry and Physics DOI 10.5194/acp-21-1507-2021 23 February 2021 Southern Africa produces almost a third of the Earth’s biomass burning (BB) aerosol particles, yet the fate of these particles and their influence on regional and global climate is poorly understood. ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) is a 5-year NASA EVS-2 (Earth Venture Suborbital-2) investigation with three intensive observation periods designed to study key atmospheric processes that determine the climate impacts of these aerosols. Read more
Synchronized spatial shifts of Hadley and Walker circulations Earth System Dynamics DOI 10.5194/esd-12-121-2021 22 February 2021 Here, by examining the spatiotemporal relationship between Hadley and Walker cells in observations and climate model experiments, we demonstrate that the seasonally evolving warm-pool sea surface temperature (SST) anomalies in the decay phase of an El Niño event generate a meridionally asymmetric Walker circulation response, which couples the zonal and meridional atmospheric overturning circulations. Read more