Search results for "CLIMATE"
showing 10 items of 4934 documents
Soil carbon accumulation after agricultural abandonment. A Mediterranean case study.
2011
In the last decades, in Europe large agricultural areas have been abandoned. In absence of disturbance factors, renaturation of these areas is rapid due to secondary succession of vegetation communities. In the Mediterranean region, in the last years have been conducted studies on soil carbon accumulation after agricultural abandonment. Soil has to be regarded as the most considerable carbon (C) sink on a global level. CO2 emission compensation is guaranteed also by C uptake by plants and by organic matter accumulation in soils. The present study analyzes organic carbon stock in some soils of Southern Italy, in the Madonie Mountains in Sicily, where large areas are subject to secondary succ…
Multiple sediment proxies from Jaraguá cave, Brazil
2019
Multiple paleoclimate, paleovegetation and paleoenvironmental records from Jaraguá cave, located at center of South America. In this dataset that covers the last 28,000 year is included δ13C and δ18O values and 87Sr/86Sr ratios in stalagmites combined with XRF-derived elemental chemistry, δ13Corg, total organic carbon and total inorganic carbon (carbonate) in a sedimentary profile from the same cave.
Relations entre sociétés et environnement en Petite Seine du Mésolithique à la fin du Moyen Âge : nouvelles problématiques et résultats récents d’arc…
2021
Actes du colloque Arkéaube; International audience; This jointly authored paper encompasses several contributions which highlight new issues in environmental archaeology and incorporate palaeo-environmental data from preventiveexcavations. More specifically, it broaches three questions:-The evolution of the environment from the Late Glacial to the present day is analysed using faunal remains (malacofaunae—molluscs, etc.) and botanicalremains (pine trunks) preserved in the alluvial deposits of the river Seine;-Riverside occupations based on reconstructions of the hydrography and hydrographic functioning of the channels documented in the Pont-sur-Seine sector and in Bassée;-The marshes assume…
Heat in Normandy, types of atmospheric circulation and climate change (1970 - 2019)
2020
Heat in Normandy, synoptic circulation patterns and climate change (1970-2019). This article focuses on the role and the evolution of the different kinds of synoptic circulation patterns in the occurrence of hot days in Normandy. Heat is here, very dependent on the presence of action centres over central Europe as well as, air flow coming from NE and E. Contemporary climate change expresses itself by a rise in thermal efficiency of all synoptic circulation patterns (more heat for the same flow). Lastly, the north of Cotentin stands out by being a real “cool island” during summer because of its peninsula position which imposes on any air mass, regardless of its origin, a cooling from its bot…
Le sentiment des contributeurs de l’impact du changement climatique sur leur vie quotidienne (contributions en ligne au Grand Débat National - volet …
2019
Les données extraites pour cette analyse proviennent du site du Grand Débat National -volet Transition écologique.Nous utilisons les codes postaux renseignés par les contributeurs dans leurs propositions. Parmi les 134177 personnes ayant répondu au questionnaire "Transition écologique", 131472 ont donné un code postal exploitable permettant de les localiser.Concernant la question "Diriez-vous que votre vie quotidienne est aujourd’hui touchée par le changement climatique ?", 64% des contributeurs ont répondu oui, 29% ont répondu non et 7% n’ont pas répondu.Pour représenter le sentiment d’impact du changement climatique, nous exprimons ce dernier par un indice de sentiment estimer par la rela…
Tropical Temperate Toughs over southern Africa: mechanisms and evolution in response to climate change
2015
In the Southern Hemisphere, Southern Africa and the south-west Indian Ocean are one of the three preferred regions where interactions between the tropics and midlatitudes develop. This is the South Indian Convergence Zone (SICZ), where northwest-southeast oriented cloud bands form at the synoptic scale (between 3 and 5 days). These bands are mainly found during the austral summer and are commonly referred to as tropical temperate troughs (TTTs). This research aims at improving our knowledge related to TTTs, with a study on the dynamics associated with these systems, and an analysis of their possible evolution during the 21st century.The first part of this thesis aims at identifying favorab…
Initial approaches in benchmarking and round robin testing for proton exchange membrane water electrolyzers
2019
Abstract As ever-increasing amounts of renewable electricity enter the energy supply mix on a regional, national and international basis, greater emphasis is being placed on energy conversion and storage technologies to deal with the oscillations, excess and lack of electricity. Hydrogen generation via proton exchange membrane water electrolysis (PEMWE) is one technology that offers a pathway to store large amounts of electricity in the form of hydrogen. The challenges to widespread adoption of PEM water electrolyzers lie in their high capital and operating costs which both need to be reduced through R&D. An evaluation of reported PEMWE performance data in the literature reveals that there …
Comparative high-resolution chemostratigraphy of the Bonarelli Level from the reference Bottaccione section (Umbria-Marche Apennines) and from an equ…
2006
The Bonarelli Level (BL) from the upper Cenomanian portion of the reference Bottaccione section (central Italy) is characterized by the presence of black shales containing high TOC concentrations (up to 17%) and amounts of CaCO3 near to zero. In the absence of carbonate and, consequently, of relative carbon- and oxygen-isotopic data, the elemental geochemistry revealed to be a very useful tool to obtain information about the palaeoclimatic and palaeoceanographic evolution of the Tethys Ocean during the OAE2. Based on several geochemical proxies (Rb, V, Ni, Cr, Si, Ba), the BL is interpreted as a high-productivity event driven by increasingly warm and humid climatic conditions promoting an a…
Suppression of new particle formation from monoterpene oxidation by NO<sub>x</sub>
2014
Abstract. The impact of nitrogen oxides (NOx = NO + NO2) on new particle formation (NPF) and on photochemical ozone production from real plant volatile organic compound (BVOC) emissions was studied in a laboratory setup. At high NOx conditions ([BVOC] / [NOx] < 7, [NOx] > 23 ppb) new particle formation was suppressed. Instead, photochemical ozone formation was observed resulting in higher hydroxyl radical (OH) and lower nitrogen monoxide (NO) concentrations. When [NO] was reduced back to levels below 1 ppb by OH reactions, NPF was observed. Adding high amounts of NOx caused NPF to be slowed by orders of magnitude compared to analogous experiments at low NOx conditions ([NOx] ~300 ppt)…
In situ submicron organic aerosol characterization at a boreal forest research station during HUMPPA-COPEC 2010 using soft and hard ionization mass s…
2013
The chemical composition of submicron aerosol during the comprehensive field campaign HUMPPA-COPEC 2010 at Hyytiälä, Finland, is presented. The focus lies on online measurements of organic acids, which were achieved by using atmospheric pressure chemical ionization (APCI) ion trap mass spectrometry (IT-MS). These measurements were accompanied by aerosol mass spectrometry (AMS) measurements and Fourier transform infrared spectroscopy (FTIR) of filter samples, all showing a high degree of correlation. The soft ionization mass spectrometer alternated between gas-phase measurements solely and measuring the sum of gas and particle phase. The AMS measurements of C, H and O elemental composition s…