Freney E.,CNRS Laboratory of Physics and Meteorology |
Freney E.,French National Center for Scientific Research |
Karine S.,CNRS Laboratory of Physics and Meteorology |
Karine S.,French National Center for Scientific Research |
And 16 more authors.
Aerosol and Air Quality Research | Year: 2016
Aerosol particles emitted by both natural and anthropogenic sources have direct and indirect radiative impacts. Within the planetary mixing layer (ML), these particles are subjected to a large number of removal processes, e.g., rain, sedimentation, coagulation, and thus have a relatively short lifetime. Once aerosols are transported into the free troposphere (FT), their atmospheric lifetime increases significantly and they tend to be representative of large spatial areas. The work presented here shows evidence of anthropogenic emissions being transported from the ML to the FT during a cold period in February 2012. Using a wide range of in-situ measurements of aerosol chemical and physical properties at the Puy de Dome (PUY) station, as well as LIDAR measurements (at the Cezeaux site) of atmospheric back scattering we studied the exchange between the ML and the FT. Criteria used to identify when the PUY station was sampling in the ML or in the FT included mixing layer height estimates from LIDAR measurements, trace gas measurements, and air mass trajectories. Within the FT, we observed a gradual change in aerosol physical properties with increases in aerosol mass concentrations of up to 2 times the starting concentration, as well as increases in the number of larger particles (particle diameter >150 nm). Aerosol chemical properties showed increases in organic and nitrate particles. A series of linear fits were made through the data providing information on how different parameters change as a function of time. The impact of these changing aerosol properties are discussed in relation to the potential influence on aerosol direct and indirect effects. This work presents a unique combination of observations, and provide valuable data for future model validation. © Taiwan Association for Aerosol Research. Source
Comment on "Trends and low frequency variability of extra-tropical cyclone activity in the ensemble of twentieth century reanalysis" by Xiaolan L. Wang, Y. Feng, G. P. Compo, V. R. Swail, F. W. Zwiers, R. J. Allan, and P. D. Sardeshmukh, Climate Dynamics, 2012
Krueger O.,University of Edinburgh |
Krueger O.,Helmholtz Center Geesthacht |
Feser F.,Helmholtz Center Geesthacht |
Barring L.,Rossby Center |
And 4 more authors.
Climate Dynamics | Year: 2014
The main subject of this article is to comment on the issue of storminess trends derived from the twentieth century reanalysis (20CR) and from observations in the North Atlantic region written about in Wang et al. (Clim Dyn 40(11-12):2775-2800, 2012). The statement that the 20CR estimates would be consistent with storminess derived from pressure-based proxies does not hold for the time prior to 1950. © 2013 Springer-Verlag Berlin Heidelberg. Source
Schulze E.D.,Max Planck Institute for Biogeochemistry |
Ciais P.,CEA Saclay Nuclear Research Center |
Luyssaert S.,CEA Saclay Nuclear Research Center |
Schrumpf M.,Max Planck Institute for Biogeochemistry |
And 21 more authors.
Global Change Biology | Year: 2010
Overviewing the European carbon (C), greenhouse gas (GHG), and non-GHG fluxes, gross primary productivity (GPP) is about 9.3 Pg yr-1, and fossil fuel imports are 1.6 Pg yr-1. GPP is about 1.25% of solar radiation, containing about 360 × 1018 J energy - five times the energy content of annual fossil fuel use. Net primary production (NPP) is 50%, terrestrial net biome productivity, NBP, 3%, and the net GHG balance, NGB, 0.3% of GPP. Human harvest uses 20% of NPP or 10% of GPP, or alternatively 1‰ of solar radiation after accounting for the inherent cost of agriculture and forestry, for production of pesticides and fertilizer, the return of organic fertilizer, and for the C equivalent cost of GHG emissions. C equivalents are defined on a global warming potential with a 100-year time horizon. The equivalent of about 2.4% of the mineral fertilizer input is emitted as N2O. Agricultural emissions to the atmosphere are about 40% of total methane, 60% of total NO-N, 70% of total N2O-N, and 95% of total NH3-N emissions of Europe. European soils are a net C sink (114 Tg yr-1), but considering the emissions of GHGs, soils are a source of about 26 Tg CO2 C-equivalent yr-1. Forest, grassland and sediment C sinks are offset by GHG emissions from croplands, peatlands and inland waters. Non-GHGs (NH3, NOx) interact significantly with the GHG and the C cycle through ammonium nitrate aerosols and dry deposition. Wet deposition of nitrogen (N) supports about 50% of forest timber growth. Land use change is regionally important. The absolute flux values total about 50 Tg C yr-1. Nevertheless, for the European trace-gas balance, land-use intensity is more important than land-use change. This study shows that emissions of GHGs and non-GHGs significantly distort the C cycle and eliminate apparent C sinks. © 2010 Blackwell Publishing Ltd. Source
Panagos P.,European Commission - Joint Research Center Ispra |
Borrelli P.,European Commission - Joint Research Center Ispra |
Spinoni J.,European Commission - Joint Research Center Ispra |
Ballabio C.,European Commission - Joint Research Center Ispra |
And 17 more authors.
Water (Switzerland) | Year: 2016
As a follow up and an advancement of the recently published Rainfall Erosivity Database at European Scale (REDES) and the respective mean annual R-factor map, the monthly aspect of rainfall erosivity has been added to REDES. Rainfall erosivity is crucial to be considered at a monthly resolution, for the optimization of land management (seasonal variation of vegetation cover and agricultural support practices) as well as natural hazard protection (landslides and flood prediction). We expanded REDES by 140 rainfall stations, thus covering areas where monthly R-factor values were missing (Slovakia, Poland) or former data density was not satisfactory (Austria, France, and Spain). The different time resolutions (from 5 to 60 min) of high temporal data require a conversion of monthly R-factor based on a pool of stations with available data at all time resolutions. Because the conversion factors show smaller monthly variability in winter (January: 1.54) than in summer (August: 2.13), applying conversion factors on a monthly basis is suggested. The estimated monthly conversion factors allow transferring the R-factor to the desired time resolution at a European scale. The June to September period contributes to 53% of the annual rainfall erosivity in Europe, with different spatial and temporal patterns depending on the region. The study also investigated the heterogeneous seasonal patterns in different regions of Europe: on average, the Northern and Central European countries exhibit the largest R-factor values in summer, while the Southern European countries do so from October to January. In almost all countries (excluding Ireland, United Kingdom and North France), the seasonal variability of rainfall erosivity is high. Very few areas (mainly located in Spain and France) show the largest from February to April. The average monthly erosivity density is very large in August (1.67) and July (1.63), while very small in January and February (0.37). This study addresses the need to develop monthly calibration factors for seasonal estimation of rainfall erosivity and presents the spatial patterns of monthly rainfall erosivity in European Union and Switzerland. Moreover, the study presents the regions and seasons under threat of rainfall erosivity. © 2016 by the authors. Source
Malnes E.,NORUT |
Buanes A.,NORUT |
Nagler T.,ENVEO |
Bippus G.,ENVEO |
And 8 more authors.
Cryosphere | Year: 2015
CryoLand (2011-2015) is a project carried out within the 7th Framework of the European Commission aimed at developing downstream services for monitoring seasonal snow, glaciers and lake/river ice primarily based on satellite remote sensing. The services target private and public users from a wide variety of application areas, and aim to develop sustainable services after the project is completed. The project has performed a thorough user requirement survey in order to derive targeted requirements for the service and provide recommendations for the design and priorities of the service. In this paper we describe the methods used, the major findings in this user survey, and how we used the results to design and specify the CryoLand snow and land ice service. The user requirement analysis shows that a European operational snow and land ice service is required and that there exists developed cryosphere products that can meet the specific needs. The majority of the users were mainly interested not only in the snow services, but also the lake/river ice products and the glacier products were desired. © Author(s) 2015. Source