104 research outputs found
Sensitivity of surface fluxes in the ECMWF land surface model to the remotely sensed leaf area index and root distribution: Evaluation with tower flux data
The surface-atmosphere turbulent exchanges couple the water, energy and carbon budgets in the Earth system. The biosphere plays an important role in the evaporation process, and vegetation related parameters such as the leaf area index (LAI), vertical root distribution and stomatal resistance are poorly constrained due to sparse observations at the spatio-temporal scales at which land surface models (LSMs) operate. In this study, we use the Carbon Hydrology Tiled European Center for Medium-Range Weather Forecasts (ECMWF) Scheme for Surface Exchanges over Land (CHTESSEL) model and investigate the sensitivity of the simulated turbulent fluxes to these vegetation related parameters. Observed data from 17 FLUXNET towers were used to force and evaluate model simulations with different vegetation parameter configurations. The replacement of the current LAI climatology used by CHTESSEL, by a new high-resolution climatology, representative of the station’s location, has a small impact on the simulated fluxes. Instead, a revision of the root profile considering a uniform root distribution reduces the underestimation of evaporation during water stress conditions. Despite the limitations of using only one model and a limited number of stations, our results highlight the relevance of root distribution in controlling soil moisture stress, which is likely to be applicable to other LSMs
Poussée de maladie de Kaposi et élévation du CA 19-9: Penser à la tuberculose!
La maladie de Kaposi (MK) est une entité pathologique qui peut survenir chez les patients VIH positifs et dans le cadre d'une immunodépression, d'origine tuberculeuse très rarement. On décrit le cas d'une MK chez un patient VIH négatif au décours d'une tuberculose. Nous rapportons le cas d'un patient âgé de 81 ans, VIH négatif, ayant présenté deux nodules angiomateux de l'avant bras gauche dont la biopsie cutanée était en faveur d'une MK. L'évolution était marquée 2 mois plus tard, par l'apparition de placards angiomateux extensifs des deux membres supérieurs et d'adénopathies cervicales jugulo-carotidiennes bilatérales. La biopsie ganglionnaire était en faveur d'une tuberculose ganglionnaire. Par ailleurs, il avait un taux sérique élevé des CA 19-9. La régression de l'étendue des lésions au niveau des membres supérieurs et la normalisation du taux sérique des CA 19-9 ont été obtenues sous traitement anti-tuberculeux. Chez les patients atteints d'une MK avec une élévation des CA 19-9, il faut penser à la tuberculose
Tuberculous Duodenal Stenosis: Report of Two Cases
Duodenal tuberculosis is a rare clinical entity. The authors report and emphasize the lack of special clinical, radiological and endoscopic signs of duodenal tuberculosis. The diagnosis is affirmed, at laparotomy, out of the findings of peritoneal granulations or histology of lymphatic nodes. We report our experience of two cases of duodenal tuberculosis presenting with proximal intestinal obstruction and review the available literature
Climate model configurations of the ECMWF Integrated Forecasting System (ECMWF-IFS cycle 43r1) for HighResMIP
This paper presents atmosphere-only
and coupled climate model configurations of the European Centre for
Medium-Range Weather Forecasts Integrated Forecasting System (ECMWF-IFS) for
different combinations of ocean and atmosphere resolution. These
configurations are used to perform multi-decadal ensemble experiments
following the protocols of the High Resolution Model Intercomparison Project
(HighResMIP) and phase 6 of the Coupled Model Intercomparison Project
(CMIP6). These experiments are used to evaluate the sensitivity of major
biases in the atmosphere, ocean, and cryosphere to changes in atmosphere and
ocean resolution. All configurations successfully reproduce the observed
long-term trends in global mean surface temperature. Furthermore, following
an adjustment to account for drift in the subsurface ocean, coupled
configurations of ECMWF-IFS realistically reproduce observation-based
estimates of ocean heat content change since 1950. Climatological surface
biases in ECMWF-IFS are relatively insensitive to an increase in atmospheric
resolution from ∼ 50 to ∼ 25 km. However, increasing the horizontal
resolution of the atmosphere while maintaining the same vertical resolution
enhances the magnitude of a cold bias in the lower stratosphere. In coupled
configurations, there is a strong sensitivity to an increase in ocean model
resolution from 1 to 0.25°. However, this sensitivity to ocean
resolution takes many years to fully manifest and is less apparent in the
first year of integration. This result has implications for the ECMWF coupled
model development strategy that typically relies on the analysis of biases in
short ( < 1 year) ensemble (re)forecast data sets. The impacts of increased
ocean resolution are particularly evident in the North Atlantic and Arctic,
where they are associated with an improved Atlantic meridional overturning
circulation, increased meridional ocean heat transport, and more realistic
sea-ice cover. In the tropical Pacific, increased ocean resolution is
associated with improvements to the magnitude and asymmetry of El Niño–Southern
Oscillation (ENSO) variability and better representation of non-linear
sea surface temperature (SST)–radiation feedbacks
during warm events. However, increased ocean model resolution also increases
the magnitude of a warm bias in the Southern Ocean. Finally, there is
tentative evidence that both ocean coupling and increased atmospheric
resolution can improve teleconnections between tropical Pacific rainfall and
geopotential height anomalies in the North Atlantic.</p
Global nature run data with realistic high-resolution carbon weather for the year of the Paris agreement
Salicylic acid functionalized silica-coated magnetite nanoparticles for solid phase extraction and preconcentration of some heavy metal ions from various real samples
A method for the preconcentration of trace heavy metal ions in environmental samples has been reported. The presented method is based on the sorption of Cu(II), Cd(II), Ni(II) and Cr(III) ions with salicylic acid as respective chelate on silica-coated magnetite nanoparticles. Prepared adsorbent was characterized by XRD, SEM, BET and FT-IR measurements. The metals content of the sorbed complexes are eluted using 4.0 mL of 1.0 mol L-1 nitric acid. The influences of the analytical parameters including pH, amount of solid phase and condition of eluting solution, the effects of matrix ions on the retention of the analytes were examined. The accuracy and precision of suggested method were tested by analyzing of certified reference materials. The detection limits (3Sb/m, N = 8) for Cu(II), Cd(II), Ni(II) and Cr(III) ions are 0.22, 0.11, 0.27 and 0.15 μg L-1, respectively, and the maximum preconcentration factor is 200. The method was successfully applied to the evaluation of these trace and toxic metals in various waters, foods and other samples
The EC-Earth3 Earth system model for the Coupled Model Intercomparison Project 6
The Earth system model EC-Earth3 for contributions to CMIP6 is documented here, with its flexible coupling framework, major model configurations, a methodology for ensuring the simulations are comparable across different high-performance computing (HPC) systems, and with the physical performance of base configurations over the historical period. The variety of possible configurations and sub-models reflects the broad interests in the EC-Earth community. EC-Earth3 key performance metrics demonstrate physical behavior and biases well within the frame known from recent CMIP models. With improved physical and dynamic features, new Earth system model (ESM) components, community tools, and largely improved physical performance compared to the CMIP5 version, EC-Earth3 represents a clear step forward for the only European community ESM. We demonstrate here that EC-Earth3 is suited for a range of tasks in CMIP6 and beyond
Gene Expression Rhythms in the Mussel Mytilus galloprovincialis (Lam.) across an Annual Cycle
Seasonal environmental changes may affect the physiology of Mytilus
galloprovincialis (Lam.), an intertidal filter-feeder bivalve
occurring commonly in Mediterranean and Atlantic coastal areas. We investigated
seasonal variations in relative transcript abundance of the digestive gland and
the mantle (gonads) of males and females. To identify gene expression trends
– in terms of relative mRNA abundance- we used a medium-density cDNA
microarray (1.7 K probes) in dual-color competitive hybridization analyses.
Hierarchical clustering of digestive gland microarray data showed two main
branches, distinguishing profiles associated with the “hot” months
(May–August) from the other months. Genes involved in chitin metabolism,
associated with mussel nutrition and digestion showed higher mRNA levels during
summer. Moreover, we found different gene transcriptomic patterns in the
digestive glands of males when compared to females, during the four stages of
mussel gonadal development. Microarray data from gonadal transcripts also
displayed clear patterns during the different developmental phases respect to
the resting period (stage I) with peak relative mRNA abundance at the ripe phase
(stage III) for both sexes. These data showed a clear temporal pattern in
transcriptomic profiles of mussels sampled over an annual cycle. Physiological
response to thermal variation, food availability, and reproductive status across
months may contribute to variation in relative mRNA abundance
Satellite and in situ observations for advancing global Earth surface modelling: a review
In this paper, we review the use of satellite-based remote sensing in combination with in situ data to inform Earth surface modelling. This involves verification and optimization methods that can handle both random and systematic errors and result in effective model improvement for both surface monitoring and prediction applications. The reasons for diverse remote sensing data and products include (i) their complementary areal and temporal coverage, (ii) their diverse and covariant information content, and (iii) their ability to complement in situ observations, which are often sparse and only locally representative. To improve our understanding of the complex behavior of the Earth system at the surface and sub-surface, we need large volumes of data from high-resolution modelling and remote sensing, since the Earth surface exhibits a high degree of heterogeneity and discontinuities in space and time. The spatial and temporal variability of the biosphere, hydrosphere, cryosphere and anthroposphere calls for an increased use of Earth observation (EO) data attaining volumes previously considered prohibitive. We review data availability and discuss recent examples where satellite remote sensing is used to infer observable surface quantities directly or indirectly, with particular emphasis on key parameters necessary for weather and climate prediction. Coordinated high-resolution remote-sensing and modelling/assimilation capabilities for the Earth surface are required to support an international application-focused effort
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Hyperresolution information and hyperresolution ignorance in modelling the hydrology of the land surface
There is a strong drive towards hyperresolution earth system models in order to resolve finer scales of motion in the atmosphere. The problem of obtaining more realistic representation of terrestrial fluxes of heat and water, however, is not just a problem of moving to hyperresolution grid scales. It is much more a question of a lack of knowledge about the parameterisation of processes at whatever grid scale is being used for a wider modelling problem. Hyperresolution grid scales cannot alone solve the problem of this hyperresolution ignorance. This paper discusses these issues in more detail with specific reference to land surface parameterisations and flood inundation models. The importance of making local hyperresolution model predictions available for evaluation by local stakeholders is stressed. It is expected that this will be a major driving force for improving model performance in the future.
Keith BEVEN, Hannah CLOKE, Florian PAPPENBERGER, Rob LAMB, Neil HUNTE
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