Search results for "Atmosphere"

Ecohydrology in Mediterranean areas: a numerical model to describe growing seasons out of phase with precipitations

2008

The probabilistic description of soil moisture dynamics is a relatively new topic in hydrology. The most common ecohydrological models start from a stochastic differential equation describing the soil water balance, where the unknown quantity, the soil moisture, depends both on spaces and time. Most of the solutions existing in literature are obtained in a probabilistic framework and under steady-state condition; even if this last condition allows the analytical handling of the problem, it has considerably simplified the same problem by subtracting generalities from it. <br><br> The steady-state hypothesis, appears perfectly applicable in arid and semiarid climatic areas like th…

Aerosol optical properties and instantaneous radiative forcing based on high temporospatial resolution CARSNET ground-based measurements over eastern…

2017

Abstract. Variations in the optical properties of aerosols and their radiative forcing were investigated based on long-term synchronous observations made at three-minute intervals from 2011 to 2015 over seven adjacent CARSNET (China Aerosol Remote Sensing NETwork) urban (Hangzhou), suburban (Xiaoshan, Fuyang, LinAn, Tonglu, Jiande) and rural (ChunAn) stations in the Yangtze River Delta region, eastern China. The aerosol optical depth (AOD) varied from 0.68 to 0.76, with two peaks in June and September, and decreased from the eastern coast to western inland areas. The ratio of the AOD of fine-mode particles to the total AOD was > 0.90 and the extinction Angström exponent was > 1.20 thr…

Architectures “on ruins” and ambiguous transparency: the glass in preservation and communication of archaeology

2008

Abstract The contemporary architecture is characterized by an even more marked transparency, as a result of a continuous experimentation all directed towards the search of the built “lightness”, that is towards the “dematerialization” of the architecture and the consequent loss of weight connected to the excess of form. It is in 1851 that a New Architectural Age springs because of the realization of the Crystal Palace, in London – that has addressed towards the experimentation of the glass as an architectural, structural element and of design. Today, part of this experimentation has been applied for some interventions of coverage, protection and communication in situ of the archaeological r…

N2O emission in maize-crops fertilized with pig slurry, matured pig manure or ammonium nitrate in Brittany

2008

International audience; N2O is a potent greenhouse gas and solutions have to be sought to reduce its emission from agriculture. This work evaluates N2O emission from maize-crop (Zea mays) fields submitted to different organic or mineral fertilizers (pig slurry, matured pig manure or ammonium nitrate) in Brittany (France). N2O emission was evaluated along a year in two experimental sites receiving 110 or 180 kg N ha−1 as ammonium nitrate or pig slurry and 180 or 132 kg N ha−1 as ammonium nitrate or matured pig manure at Champ Noel and Le Rheu experimental plots, respectively. N2O emission was evaluated by interpolation method of periodic fluxes on the field scale and by simulation with NOE a…

2017

Abstract. Hydroxyl (OH) radical reactivity (kOH) has been measured for 18 years with different measurement techniques. In order to compare the performances of instruments deployed in the field, two campaigns were conducted performing experiments in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich in October 2015 and April 2016. Chemical conditions were chosen either to be representative of the atmosphere or to test potential limitations of instruments. All types of instruments that are currently used for atmospheric measurements were used in one of the two campaigns. The results of these campaigns demonstrate that OH reactivity can be accurately measured for a wide rang…

Performance of a thermoelectric module based on n-type (La0.12Sr0.88)0.95TiO3-δ and p-type Ca3Co4-xO9+δ

2020

Here, we present the performance of a thermoelectric (TE) module consisting of n-type (La0.12Sr0.88)0.95TiO3 and p-type Ca3Co4-xO9+δ materials. The main challenge in this investigation was operation of TE module in different atmosphere conditions, since n-type has its optimum TE-performance at reducing, while p-type at oxidizing conditions. The TE module was exposed to two different atmospheres and demonstrated higher stability in N2 atmosphere than in air. The maximum electrical power output decreased after 40 h when the hot side was exposed to N2 at 600 °C, while only 1 h at 400 °C in ambient air was enough to oxidize (La0.12Sr0.88)0.95TiO3 followed by a reduced electrical power output. T…

Impact of Noah-LSM Parameterizations on WRF Mesoscale Simulations: Case Study of Prevailing Summer Atmospheric Conditions over a Typical Semi-Arid Re…

2021

The current study evaluates the ability of the Weather Research and Forecasting Model (WRF) to forecast surface energy fluxes over a region in Eastern Spain. Focusing on the sensitivity of the model to Land Surface Model (LSM) parameterizations, we compare the simulations provided by the original Noah LSM and the Noah LSM with multiple physics options (Noah-MP). Furthermore, we assess the WRF sensitivity to different Noah-MP physics schemes, namely the calculation of canopy stomatal resistance (OPT_CRS), the soil moisture factor for stomatal resistance (OPT_BTR), and the surface layer drag coefficient (OPT_SFC). It has been found that these physics options strongly affect the energy partiti…

La microbiologie moléculaire environnementale : historique, limites et potentialités

2017

prod 2017-237c INRA EA BIOmE; Résumé de la brochure : Dans une société où il devient urgent de réduire l'empreinte environnementale des activités humaines, la première étape est de pouvoir faire un diagnostic de la qualité de notre environnement et des différentes matrices le constituant (eau, sol, atmosphère, déchets). Les microorganismes, de par leur petite taille, leur énorme diversité taxonomique et génétique, leur réactivité aux perturbations ainsi que par leur forte implication dans les cycles biogéochimiques gérant les flux de matière et d'énergie, sont des candidats incontournables pour élaborer ce diagnostic. Ceci est d'autant plus vrai que depuis une vingtaine d'années les fortes …

Trace gas composition in the Asian summer monsoon anticyclone: a case study based on aircraft observations and model simulations

2017

We present in situ measurements of the trace gas composition of the upper tropospheric (UT) Asian summer monsoon anticyclone (ASMA) performed with the High Altitude and Long Range Research Aircraft (HALO) in the frame of the Earth System Model Validation (ESMVal) campaign. Air masses with enhanced O3 mixing ratios were encountered after entering the ASMA at its southern edge at about 150 hPa on 18 September 2012. This is in contrast to the presumption that the anticyclone's interior is dominated by recently uplifted air with low O3 in the monsoon season. We also observed enhanced CO and HCl in the ASMA, which are tracers for boundary layer pollution and tropopause layer (TL) air or stratosp…

X-Raying the Dark Side of Venus - Scatter from Venus Magnetotail?

2016

This work analyzes the X-ray, EUV and UV emission apparently coming from the Earth-facing (dark) side of Venus as observed with Hinode/XRT and SDO/AIA during a transit across the solar disk occurred in 2012. We have measured significant X-Ray, EUV and UV flux from Venus dark side. As a check we have also analyzed a Mercury transit across the solar disk, observed with Hinode/XRT in 2006. We have used the latest version of the Hinode/XRT Point Spread Function (PSF) to deconvolve Venus and Mercury X-ray images, in order to remove possible instrumental scattering. Even after deconvolution, the flux from Venus shadow remains significant while in the case of Mercury it becomes negligible. Since s…