Search results for "Climate"

Timing and patterns of the ENSO signal in Africa over the last 30 years: insights from normalized difference vegetation index data.

2014

Abstract A more complete picture of the timing and patterns of the ENSO signal during the seasonal cycle for the whole of Africa over the three last decades is provided using the normalized difference vegetation index (NDVI). Indeed, NDVI has a higher spatial resolution and is more frequently updated than in situ climate databases, and highlights the impact of ENSO on vegetation dynamics as a combined result of ENSO on rainfall, solar radiation, and temperature. The month-by-month NDVI–Niño-3.4 correlation patterns evolve as follows. From July to September, negative correlations are observed over the Sahel, the Gulf of Guinea coast, and regions from the northern Democratic Republic of Congo…

Reactive species formed upon interaction of water with fine particulate matter from remote forest and polluted urban air

2020

Interaction of water with fine particulate matter leads to the formation of reactive species (RS) that may influence the aging, properties, and health effects of atmospheric aerosols. In this study, we explore the RS yields of fine PM from remote forest (Hyytiälä, Finland) and polluted urban air (Mainz, Germany and Beijing, China) and relate these yields to different chemical constituents and reaction mechanisms. Ultrahigh-resolution mass spectrometry was used to characterize organic aerosol composition, electron paramagnetic resonance (EPR) spectroscopy with a spin-trapping technique was used to determine the concentrations •OH, O2•−, and carbon- or oxygen-centered organic radicals, …

Trapping AsPh3 via reaction with NiS/γ-Al2O3 in the presence of H2: Reaction mechanism and kinetics

2021

International audience; Removal of As from petroleum feedstocks is an important process which can be realized using As trapping mass containing supported nickel sulfide. In order to understand the mechanism of the trapping we studied the reaction of AsPh3 with NiS/γ-Al2O3 in the presence of H2 in a batch reactor in toluene solution at 230 °C. This reaction results in formation of NiAs, benzene and H2S. Also, the intermediate species, thiophenol and diphenylsulfide, were observed. Despite formation of NiAs layer in the course of reaction, the rate of AsPh3 decomposition is not affected by the solid state diffusion up to ∼ 50 % of nickel conversion. The rate determining step in these conditio…

Investigation of electrode material – redox couple systems for reverse electrodialysis processes. Part II: Experiments in a stack with 10–50 cell pai…

2013

Abstract The performances of reverse electrodialysis depend on several factors, including the nature of the electrode material and of the redox processes adopted to make possible the conversion between chemical potential and electric power. In this paper the possible utilization of various redox processes (reduction/oxidation of iron species, oxidation and reduction of water, oxidation of chlorine and reduction of water) was studied in a stack equipped with 10–50 cell pairs and by focused electrolyses in a three compartment cell. The effect of selected redox processes on power density output and eventual contamination of saline solutions flowing in the stack was evaluated in detail. The eff…

Impact of the environmental taxes on reduction of emission from transport in Latvia

2021

Transport has a significant contribution to climate change and many post-Soviet republics, including Latvia, struggle to decrease these emissions to reach carbon neutrality by 2050. In this paper, ...

Dataset of a globally relevant stock of soil nitrogen in the Yedoma permafrost domain

2022

This dataset merges nitrogen data from the Yedoma domain. It includes numerous fieldwork campaigns, which take place since 1998. In total 467 samples from the active layer (seasonally thawed layer), 175 samples from perennially frozen Holocene cover deposits, 479 samples from thermokarst deposits in drained thermokarst, 175 in-situ thawed, diagenetically (anaerobic microbial decomposition possible during unfrozen phase) altered Yedoma deposits (called Taberite), and 917 samples from frozen Yedoma deposits are included. Moreover it includes a NH4+ and NO3- quantification basing on of 658 samples, including 378 data points for NH4+ (active layer, 93; Holocene cover, 108; thermokarst sediment,…

Soil organic carbon stocks assessment in Mediterranean natural areas: A comparison of entire soil profiles and soil control sections

2015

Soil organic carbon (SOC) is an important part of the global carbon (C) cycle. In addition, SOC is a soil property subject to changes and highly variable in space and time. Over time, some researches have analyzed entire soil profile (ESP) by pedogenetic horizons and other researches have analyzed soil control sections (SCS) to different thickness. However, very few studies compare both methods (ESP versus SCS). This research sought to analyze the SOC stock (SOCS) variability using both methods (ESP and SCS) in The Despeñaperros Natural Park, a nature reserve that consists of a 76.8 km(2) forested area in southern Spain. Thirty-four sampling points were selected in the study zone. Each samp…

Green taxes, quotas and equality : preserving social justice whilst averting climate change

2016

The need for green fiscal reform is urgent in the face of climate change. Some oppose it, however, arguing that such reforms disproportionately burden poorer individuals whose emissions are far smaller than those of wealthier individuals. Defusing these criticisms, this paper argues that this is not an inevitable feature of green fiscal reform. We should adopt a more scientific attitude not only towards climate change but towards testing fiscal proposals to mitigate it, and avoid dividing, with rushed assumptions, responsible voters who care about both equality and climate change.

2019

Abstract The long-term relationship between temperature and hydroclimate has remained uncertain due to the short length of instrumental measurements and inconsistent results from climate model simulations. This lack of understanding is particularly critical with regard to projected drought and flood risks. Here we assess warm-season co-variability patterns between temperature and hydroclimate over Europe back to 850 CE using instrumental measurements, tree-ring based reconstructions, and climate model simulations. We find that the temperature–hydroclimate relationship in both the instrumental and reconstructed data turns more positive at lower frequencies, but less so in model simulations, …

Data sets for energy rating of photovoltaic modules

2013

Abstract A proposal for generating standard climatic data sets for use in energy rating of photovoltaic (PV) modules is presented which will give a good comparability between different technologies. The current proposal of standard data sets consisting of “typical days” do not give realistic estimates of PV performance and thus is not sufficient as a rating standard. A dataset striking the balance between being significant for any location but does not consisting of too much data is required. A method to generate such a dataset is presented, meeting all the requirements of an international standard while being sufficiently accurate to differentiate between different devices of different man…