Improving the understanding of flood risk in the Alsatian region by knowledge capitalization: the ORRION participative observatory Natural Hazards and Earth System Sciences DOI 10.5194/nhess-19-1653-2019 7 August 2019 The article presents the Alsatian regional flood risk observatory ORRION, a participative online platform on which information is shared between individuals, stakeholders, engineers, and scientists. This maximizes knowledge capitalization and contributes to building a common knowledge base for flood risk. From this information, long chronicles of floods are derived for the Rhine, and most of its main Alsatian tributaries and their main characteristics are identified and analysed. Read more
Past climate and continentality inferred from ice wedges at Batagay megaslump in the Northern Hemisphere’s most continental region, Yana Highlands, interior Yakutia Climate of the Past DOI 10.5194/cp-15-1443-2019 2 August 2019 To reconstruct past winter climate, we studied ice wedges at two sites in the Yana Highlands, interior Yakutia (Russia), the most continental region of the Northern Hemisphere. Our ice wedges of the upper ice complex unit of the Batagay megaslump and a river terrace show much more depleted stable-isotope compositions than other study sites in coastal and central Yakutia, reflecting lower winter temperatures and a higher continentality of the study region during Marine Isotope Stages 3 and 1. Read more
A salinity module for SWAT to simulate salt ion fate and transport at the watershed scale Hydrology and Earth System Sciences DOI 10.5194/hess-23-3155-2019 31 July 2019 Salinity is one of the most common water quality threats in river basins and irrigated regions worldwide. Available watershed models, however, do not simulate the fate and transport of salt species. This paper presents a modified version of the popular SWAT watershed model that simulates the transport of major salt ions in a watershed system. Salt is transported via surface runoff, soil percolation, groundwater flow, and streamflow. The model can be used in salt-affected watersheds worldwide. Read more
Global soil–climate–biome diagram: linking surface soil properties to climate and biota Biogeosciences DOI 10.5194/bg-16-2857-2019 25 July 2019 Surface soils interact strongly with both climate and biota and provide fundamental ecosystem services. However, the quantitative linkages between soil, climate, and biota remain unclear at a global scale. By compiling a large global soil database, we mapped eight major soil properties based on machine learning algorithms and developed a global soil–climate–biome diagram. Our results suggest shifts in soil properties under global climate and land cover change. Read more
Assessing the characteristics and drivers of compound flooding events around the UK coast Hydrology and Earth System Sciences DOI 10.5194/hess-23-3117-2019 23 July 2019 Flooding can arise from multiple sources, including waves, extreme sea levels, rivers, and severe rainfall. When two or more sources combine, the consequences can be greatly multiplied. We find the potential for the joint occurrence of extreme sea levels and river discharge to be greater on the western coast of the UK compared to the eastern coast. This is due to the weather conditions generating each flood source around the UK. These results will help increase our flood forecasting ability. Read more
Early instrumental meteorological measurements in Switzerland Climate of the Past DOI 10.5194/cp-15-1345-2019 22 July 2019 The 18th and early 19th centuries saw pronounced climatic variations with impacts on the environment and society. Although instrumental meteorological data for that period exist, only a small fraction has been the subject of research. This study provides an overview of early instrumental meteorological records in Switzerland resulting from an archive survey and demonstrates the great potential of such data. It is accompanied by the online publication of the imaged data series and metadata. Read more
Converging photospheric vortex flows close to the polarity inversion line of a fully emerged active region Annales Geophysicae DOI 10.5194/angeo-37-603-2019 22 July 2019 We describe a technique used to locate and classify critical points in 2-D flow fields at the solar photosphere obtained from the evolution of the line-of-sight magnetic field in a region close to the magnetic polarity inversion line of a fully emerged active region. We apply this technique to locate a particular kind of critical point associated to vortex flows, which are considered important, since they can twist and interweave the foot points of flux tubes and generate magnetic reconnection. Read more
Towards monitoring localized CO2 emissions from space: co-located regional CO2 and NO2 enhancements observed by the OCO-2 and S5P satellites Atmospheric Chemistry and Physics DOI 10.5194/acp-19-9371-2019 22 July 2019 The quantification of anthropogenic emissions with current CO2 satellite sensors is difficult, but NO2 is co-emitted, making it a suitable tracer of recently emitted CO2. We analyze enhancements of CO2 and NO2 observed by OCO-2 and S5P and estimate the CO2plume cross-sectional fluxes that we compare with emission databases. Our results demonstrate the usefulness of simultaneous satellite observations of CO2 and NO2 as envisaged for the European Copernicus anthropogenic CO2 monitoring mission Read more
Brief communication: Updated GAMDAM glacier inventory over high-mountain Asia The Cryosphere DOI 10.5194/tc-13-2043-2019 19 July 2019 The Glacier Area Mapping for Discharge from the Asian Mountains (GAMDAM) glacier inventory was updated to revise the underestimated glacier area in the first version. The total number and area of glaciers are 134 770 and 100 693 ± 11 790 km2 from 453 Landsat images, which were carefully selected for the period from 1990 to 2010, to avoid mountain shadow, cloud cover, and seasonal snow cover. Read more
Quantification of water vapour transport from the Asian monsoon to the stratosphere Atmospheric Chemistry and Physics DOI 10.5194/acp-19-8947-2019 12 July 2019 We investigate the transport pathways of water vapour from the upper troposphere in the Asian monsoon region to the stratosphere. In the employed chemistry-transport model we use a tagging method, such that the impact of different source regions on the stratospheric water vapour budget can be quantified. A key finding is that the Asian monsoon (compared to other source regions) is very efficient in transporting air masses and water vapour to the tropical and extratropical stratosphere. Read more
Evaluating post-glacial bedrock erosion and surface exposure duration by coupling in situ optically stimulated luminescence and 10Be dating Earth Surface Dynamics DOI 10.5194/esurf-7-633-2019 11 July 2019 Assessing the impact of glaciation at the Earth’s surface requires simultaneous quantification of the impact of climate variability on past glacier fluctuations and on bedrock erosion. Here we present a new approach for evaluating post-glacial bedrock surface erosion in mountainous environments by combining two different surface exposure dating methods. This approach can be used to estimate how bedrock erosion rates vary spatially and temporally since glacier retreat in an alpine environment. Read more
Dissolved organic matter at the fluvial–marine transition in the Laptev Sea using in situ data and ocean colour remote sensing Biogeosciences DOI 10.5194/bg-16-2693-2019 11 July 2019 In this article, we present the variability and characteristics of dissolved organic matter at the fluvial–marine transition in the Laptev Sea from a unique dataset collected during 11 Arctic expeditions. We develop a new relationship between dissolved organic carbon (DOC) and coloured dissolved organic matter absorption, which is used to estimate surface water DOC concentration from space. We believe that our findings help current efforts to monitor ongoing changes in the Arctic carbon cycle. Read more
Atmospheric measurements of the terrestrial O2:CO2 exchange ratio of a midlatitude forest Atmospheric Chemistry and Physics DOI 10.5194/acp-19-8687-2019 10 July 2019 Predictions of global warming require predictions of how much CO2 will be taken up by the oceans, how much by land plants, and how much will stay in the atmosphere. Measurements of atmospheric oxygen (O2) help with these predictions if we also know the ratio of O2 release to CO2 uptake in land plants. We have measured this ratio in a midlatitude forest and find a lower value than the one in wide use. If truly applicable, our results call for a modest adjustment in the global carbon budget. Read more
Evaluation of global simulations of aerosol particle and cloud condensation nuclei number, with implications for cloud droplet formation Atmospheric Chemistry and Physics DOI 10.5194/acp-19-8591-2019 8 July 2019 Effects of aerosols on clouds are important for climate studies but are among the largest uncertainties in climate projections. This study evaluates the skill of global models to simulate aerosol, cloud condensation nuclei (CCN) and cloud droplet number concentrations (CDNCs). Model results show reduced spread in CDNC compared to CCN due to the negative correlation between the sensitivities of CDNC to aerosol number concentration (air pollution) and updraft velocity (atmospheric dynamics). Read more
Flood risk in a range of spatial perspectives – from global to local scales Natural Hazards and Earth System Sciences DOI 10.5194/nhess-19-1319-2019 5 July 2019 Considering flood risk composed of hazard, exposure, and vulnerability from global to local scales, this paper reviews and presents increasing observed flood losses and projections of flood hazard and losses. We acknowledge existence of multiple driving factors and of considerable uncertainty, in particular with regards to projections for the future. Finally, this paper analyses options for flood risk reduction from a global framework to regional and local scales. Read more
Description of a formaldehyde retrieval algorithm for the Geostationary Environment Monitoring Spectrometer (GEMS) Atmospheric Measurement Techniques DOI 10.5194/amt-12-3551-2019 4 July 2019 The Geostationary Environment Monitoring Spectrometer (GEMS) will be launched by South Korea in 2019, and it will measure radiances ranging from 300 to 500 nm every hour with a fine spatial resolution of 7 km x 8 km over Seoul in South Korea to monitor column concentrations of air pollutants including O3, NO2, SO2, and HCHO, as well as aerosol optical properties. This paper describes a GEMS formaldehyde retrieval algorithm including a number of sensitivity tests for algorithm evaluation. Read more
Converting snow depth to snow water equivalent using climatological variables The Cryosphere DOI 10.5194/tc-13-1767-2019 4 July 2019 We present a new statistical model for converting snow depths to water equivalent. The only variables required are snow depth, day of year, and location. We use the location to look up climatological parameters such as mean winter precipitation and mean temperature difference (difference between hottest month and coldest month). The model is simple by design so that it can be applied to depth measurements anywhere, anytime. The model is shown to perform better than other widely used approaches. Read more
Emission of trace gases and aerosols from biomass burning – an updated assessment Atmospheric Chemistry and Physics DOI 10.5194/acp-19-8523-2019 4 July 2019 Biomass burning is one of the largest sources of atmospheric pollutants worldwide. This paper presents an up-to-date compilation of emission factors for over 120 trace gas and aerosol species from the different forms of open vegetation fires and domestic biofuel use, based on an analysis of over 370 published studies. Using these emission factors and current global burning activity data, the annual emissions of important species released by the various types of biomass burning are estimated. Read more
Mid-Holocene climate change over China: model–data discrepancy Climate of the Past DOI 10.5194/cp-15-1223-2019 2 July 2019 The mid-Holocene has been an excellent target for comparing models and data. This work shows that, over China, all the ocean–atmosphere general circulation models involved in PMIP3 show a very large discrepancy with pollen data reconstruction when comparing annual and seasonal temperature. It demonstrates that to reconcile models and data and to capture the signature of seasonal thermal response, it is necessary to integrate non-linear processes, particularly those related to vegetation changes. Read more
Alluvial channel response to environmental perturbations: fill-terrace formation and sediment-signal disruption Earth Surface Dynamics DOI 10.5194/esurf-7-609-2019 1 July 2019 We performed seven physical experiments to explore terrace formation and sediment export from a braided alluvial river system that is perturbed by changes in water discharge, sediment supply, or base level. Each perturbation differently affects (1) the geometry of terraces and channels, (2) the timing of terrace formation, and (3) the transient response of sediment discharge. Our findings provide guidelines for interpreting fill terraces and sediment export from fluvial systems. Read more