Search results for "CLIMAT"
showing 10 items of 5990 documents
Les vagues de chaleur au Sahel : caractérisation, mécanismes, prévisibilité.
2016
The mechanisms controlling Sahelian heat wave (HW) variability are examined on the period 1979-2014 using the GSOD observational database and ERA-Interim reanalyses. HW events are analyzed through all terms of the atmospheric energy balance, showing a predominant role of incoming shortwave radiation on daily maximum temperature (Tx) and atmospheric water vapor on minimum temperature (Tn). The low-frequency warming trend, not explained by the previous terms, is thought to relate to the increase of greenhouse gases concentrations, due to anthropogenic emissions. The predictability of Sahelian HW events is assessed for lead times reaching up to 15 days. The model's skill, biases and uncertaint…
Les Local Climate Zones face à la canicule de 2018 à Dijon.
2019
Air temperatures measured by the MUSTARDijon network are analyzed during the summer 2018 (July 24 - August 8) heat wave. The WUDAPT method is applied to Dijon to identify Local Climate Zones (LCZs). Diurnal rhythms and nighttime mean temperatures are analyzed according to LCZs as well as to altitude and distance to the city center. During warm nights, altitude plays a negligible role. The temperatures depend to the distance of the city center. They are also associated to the anthropization summarized by the LCZs. Form of the building and vegetation are the two keys to understand and modulate the night temperatures which have the greatest impact on human health during heat waves.
Radar-rain gauges intercomparison for the estimation of high resolution rainfall.
2015
An accurate rainfall estimation is essential for many applications like precision viticulture. Rainfall is most of the time estimated by two methods:radar and rain gauges. High resolution rain gauges network Hydravitis was installed in 2014. Data coming from radar,composite product and the network was extracted for the 2014 3 to 4 November event. Data from the network were kriged tocompare with the other products. Results show that PANTHERE radar image well reproduces the spatial variability ofrainfall but underestimates rainfall amounts over a 4 mm/h intensité. Composite product ANTILOPE gives a goodvisualization of spatial variability and intensity of rainfall. Expectations of viticulture…
Vidusskolēnu uztvertā skolas klimata un depresijas simptomu sakarība
2020
Šī bakalaura darba mērķis bija noskaidrot uztvertā skolas klimata un depresijas simptomu sakarības vidusskolēniem vecuma grupā no 16-18 gadiem. Tika analizēta teorētiskā literatūra, jaunāko zinātnisko pētījumu rezultāti un veikts praktisks pētījums. Tika noskaidrots, ka skolas klimats un depresijas veidošanās ir pētīti dažādos pētījumu kontekstos. Tika iegūti apstiprinājumi ka pētnieki ir nonākuši pie secinājumiem, ka skolas klimats var ietekmēt skolēnu garīgo un fizisko veselību. Ir pierādīts, ka skolas klimats ietekmē vidusskolēnu pašnovērtējumu, mazina paškritikas negatīvo ietekmi, un sniedz ieguldījumu garīgajā veselībā. Pētījumā tika izvirzīti divi pētījuma jautājumi: 1.Kāda saistība p…
Statistical upscaling of ecosystem CO2 fluxes across the terrestrial tundra and boreal domain: Regional patterns and uncertainties
2021
The regional variability in tundra and boreal carbon dioxide (CO2) fluxes can be high, complicating efforts to quantify sink-source patterns across the entire region. Statistical models are increasingly used to predict (i.e., upscale) CO2 fluxes across large spatial domains, but the reliability of different modeling techniques, each with different specifications and assumptions, has not been assessed in detail. Here, we compile eddy covariance and chamber measurements of annual and growing season CO2 fluxes of gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE) during 1990–2015 from 148 terrestrial high-latitude (i.e., tundra and boreal) sites to a…
Applicability and consequences of the integration of alternative models for CO2 transfer velocity into a process-based lake model
2019
Freshwater lakes are important in carbon cycling, especially in the boreal zone where many lakes are supersaturated with the greenhouse gas carbon dioxide (CO2) and emit it to the atmosphere, thus ventilating carbon originally fixed by the terrestrial system. The exchange of CO2 between water and the atmosphere is commonly estimated using simple wind-based parameterizations or models of gas transfer velocity (k). More complex surface renewal models, however, have been shown to yield more correct estimates of k in comparison with direct CO2 flux measurements. We incorporated four gas exchange models with different complexity into a vertical process-based physico-biochemical lake model, MyLak…
Right to Food and Geoengineering
2023
AbstractClimate change poses grave risks to food security, and mitigation and adaptation actions have so far been insufficient to lessen the risk of climate-induced violations of the right to food. Could safeguarding the right to food, then, justify some forms of geoengineering? This article examines geoengineering through the analytical lens of the right to food. We look at the components of food security and consider how the acceptability of geoengineering relates to the right to food via its impacts on these components. Our examination shows that results vary greatly between different forms of geoengineering: while some forms of geoengineering fail to respect the right to food, certain o…
Review of carbon emissions offsetting guidelines using instructional criteria
2023
Abstract Purpose Carbon offsetting is one of the tools that companies can use to achieve their climate targets. The ability of a company to offset its emissions successfully depends on the availability and quality of guidance on the subject. This study explores how well existing offsetting guidelines equip corporations to achieve successful emissions offsetting. Methods Instructional criteria were developed and used to evaluate seven guidelines. The contents of each guideline were assessed based on how they instruct a company to achieve emissions offsetting that fulfills five criteria for appropriate offsetting: target affiliation, Paris compatibility, effectiveness, prioritizing removals, …
Water-use efficiency and transpiration across European forests during the Anthropocene
2015
Considering the combined effects of CO2 fertilization and climate change drivers on plant physiology leads to a modest increase in simulated European forest transpiration in spite of the effects of CO2-induced stomatal closure. The Earth’s carbon and hydrologic cycles are intimately coupled by gas exchange through plant stomata1,2,3. However, uncertainties in the magnitude4,5,6 and consequences7,8 of the physiological responses9,10 of plants to elevated CO2 in natural environments hinders modelling of terrestrial water cycling and carbon storage11. Here we use annually resolved long-term δ13C tree-ring measurements across a European forest network to reconstruct the physiologically driven r…
The ABCflux database: Arctic-boreal CO2flux observations and ancillary information aggregated to monthly time steps across terrestrial ecosystems
2022
Past efforts to synthesize and quantify the magnitude and change in carbon dioxide (CO2) fluxes in terrestrial ecosystems across the rapidly warming Arctic–boreal zone (ABZ) have provided valuable information but were limited in their geographical and temporal coverage. Furthermore, these efforts have been based on data aggregated over varying time periods, often with only minimal site ancillary data, thus limiting their potential to be used in large-scale carbon budget assessments. To bridge these gaps, we developed a standardized monthly database of Arctic–boreal CO2 fluxes (ABCflux) that aggregates in situ measurements of terrestrial net ecosystem CO2 exchange and its derived partitioned…