Connecting regional aerosol emissions reductions to local and remote precipitation responses Atmospheric Chemistry and Physics DOI 10.5194/acp-18-12461-2018 28 August 2018 Small particles in Earth’s atmosphere (also referred to as atmospheric aerosols) emitted by human activities impact Earth’s climate in complex ways and play an important role in Earth’s water cycle. We use a climate modeling approach and find that aerosols from the United States and Europe can have substantial effects on rainfall in far-away regions such as Africa’s Sahel or the Mediterranean. Air pollution controls in these regions may help reduce the likelihood and severity of Sahel drought. Read more
Overflow of cold water across the Iceland–Faroe Ridge through the Western Valley Ocean Science DOI 10.5194/os-14-871-2018 27 August 2018 The Western Valley is one of the passages across the Iceland–Scotland Ridge through which a strong overflow of cold, dense water has been thought to feed the deep limb of the Atlantic Meridional Overturning Circulation (AMOC), but its strength has not been known. Based on a field experiment with instruments moored across the valley, we show that this overflow branch is much weaker than previously thought and that this is because it is suppressed by the warm countercurrent in the upper layers. Read more
Global fatal landslide occurrence from 2004 to 2016 Natural Hazards and Earth System Sciences DOI 10.5194/nhess-18-2161-2018 23 August 2018 Landslides are a hazard in terrestrial environments with slopes. This paper presents global analysis on patterns of fatal landsliding between 2004 and 2016, using a database collated from media reporting. The data show ~ 56 000 people were killed in 4862 landslide events. Active landslide years coincide with patterns of regional rainfall: most landslides were rainfall triggered. For the first time, analysis shows the number of landslides triggered by human activity increased with time. Read more
Dissolved Pb and Pb isotopes in the North Atlantic from the GEOVIDE transect (GEOTRACES GA-01) and their decadal evolution Biogeosciences DOI 10.5194/bg-15-4995-2018 22 August 2018 During a French cruise in the northern North Atlantic Ocean in 2014, seawater samples were collected for dissolved Pb and Pb isotope analysis. Lead concentrations were highest in subsurface water flowing out of the Mediterranean Sea. The recently formed Labrador Sea Water (LSW) is much lower in Pb concentration than older LSW found in the West European Basin. Comparison of North Atlantic data from 1981 to 2014 shows decreasing Pb concentrations down to ~ 2500 m depth. Read more
Estimating time-dependent vegetation biases in the SMAP soil moisture product Hydrology and Earth System Sciences DOI 10.5194/hess-22-4473-2018 22 August 2018 Satellite soil moisture products can provide critical information on incipient droughts and the interplay between vegetation and water availability. However, time-variant systematic errors in the soil moisture products may impede their usefulness. Using a novel statistical approach, we detect such errors (associated with changing vegetation) in the SMAP soil moisture product. The vegetation-associated biases impede drought detection and the quantification of vegetation–water interactions. Read more
Improving the representation of anthropogenic CO2 emissions in climate models: impact of a new parameterization for the Community Earth System Model (CESM) Earth System Dynamics DOI 10.5194/esd-9-1045-2018 21 August 2018 Earth system models provide simplified accounts of human–Earth interactions. Most current models treat CO2 emissions as a homogeneously distributed forcing. However, this paper presents a new parameterization, POPEM (POpulation Parameterization for Earth Models), that computes anthropogenic CO2 emissions at a grid point scale. A major advantage of this approach is the increased capacity to understand the potential effects of localized pollutant emissions on long-term global climate statistics. Read more
Developing a global operational seasonal hydro-meteorological forecasting system: GloFAS-Seasonal v1.0 Geoscientific Model Development DOI 10.5194/gmd-11-3327-2018 21 August 2018 Global overviews of upcoming flood and drought events are key for many applications from agriculture to disaster risk reduction. Seasonal forecasts are designed to provide early indications of such events weeks or even months in advance. This paper introduces GloFAS-Seasonal, the first operational global-scale seasonal hydro-meteorological forecasting system producing openly available forecasts of high and low river flow out to 4 months ahead. Read more
Climate impact on the development of Pre-Classic Maya civilisation Climate of the Past DOI 10.5194/cp-14-1253-2018 20 August 2018 We present two new palaeoclimatic records for the central Maya lowlands, adding valuable new insights to the impact of climate change on the development of Maya civilisation. Lake Tuspan’s diatom record is indicative of precipitation changes at a local scale, while a beach ridge elevation record from the world’s largest late Holocene beach ridge plain provides a regional picture. Read more
Extreme levels of Canadian wildfire smoke in the stratosphere over central Europe on 21–22 August 2017 Atmospheric Chemistry and Physics DOI 10.5194/acp-18-11831-2018 20 August 2018 Extremely large light extinction coefficients of 500 Mm-1, about 20 times higher than after the Pinatubo volcanic eruptions in 1991, were observed by EARLINET lidars in the stratosphere over central Europe from 21 to 22 August, 2017. This paper provides an overview based on ground-based (lidar, AERONET) and satellite (MODIS, OMI) remote sensing. Read more
A quantitative approach to evaluating the GWP timescale through implicit discount rates Earth System Dynamics DOI 10.5194/esd-9-1013-2018 17 August 2018 The 100-year GWP is the most widely used metric for comparing the climate impact of different gases such as methane and carbon dioxide. However, there have been recent arguments for the use of different timescales. This paper uses straightforward estimates of future damages to quantitatively determine the appropriate timescale as a function of how society discounts the future and finds that the 100-year timescale is consistent with commonly used discount rates. Read more