Congener-specific evaluation of biota-sediment accumulation factor model for HCHs and DDTs under small-scale in situ riverine condition

ABSTRACTFEBEX (Full-scale Engineered Barrier EXperiment) is a demonstration and research project dealing with the bentonite engineered barrier designed for sealing and containment of waste in a high level radioactive waste repository (HLWR). It includes two main experiments: an situ full-scale test performed at Grimsel (GTS) and a mock-up test operating since February 1997 at CIEMAT facilities in Madrid (Spain) [1,2,3]. One of the objectives of FEBEX is the development and testing of conceptual and numerical models for the thermal, hydrodynamic, and geochemical (THG) processes expected to take place in engineered clay barriers. A significant improvement in coupled THG modeling of the clay barrier has been achieved both in terms of a better understanding of THG processes and more sophisticated THG computer codes. The ability of these models to reproduce the observed THG patterns in a wide range of THG conditions enhances the confidence in their prediction capabilities. Numerical THG models of heating and hydration experiments performed on small-scale lab cells provide excellent results for temperatures, water inflow and final water content in the cells [3]. Calculated concentrations at the end of the experiments reproduce most of the patterns of measured data. In general, the fit of concentrations of dissolved species is better than that of exchanged cations. These models were later used to simulate the evolution of the large-scale experiments (in situ and mock-up). Some thermo-hydrodynamic hypotheses and bentonite parameters were slightly revised during TH calibration of the mock-up test. The results of the reference model reproduce simultaneously the observed water inflows and bentonite temperatures and relative humidities. Although the model is highly sensitive to one-at-a-time variations in model parameters, the possibility of parameter combinations leading to similar fits cannot be precluded. The TH model of the “in situ” test is based on the same bentonite TH parameters and assumptions as for the “mock-up” test. Granite parameters were slightly modified during the calibration process in order to reproduce the observed thermal and hydrodynamic evolution. The reference model captures properly relative humidities and temperatures in the bentonite [3]. It also reproduces the observed spatial distribution of water pressures and temperatures in the granite. Once calibrated the TH aspects of the model, predictions of the THG evolution of both tests were performed. Data from the dismantling of the in situ test, which is planned for the summer of 2001, will provide a unique opportunity to test and validate current THG models of the EBS.

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On the short-term variability of turbulence and temperature in the winter mesosphere

Annales Geophysicae ◽

10.5194/angeo-36-1099-2018 ◽

2018 ◽

Vol 36 (4) ◽

pp. 1099-1116

Author(s):

Gerald A. Lehmacher ◽

Miguel F. Larsen ◽

Richard L. Collins ◽

Aroh Barjatya ◽

Boris Strelnikov

Keyword(s):

Attitude Control ◽

Large Scale ◽

Lower Thermosphere ◽

Density Fluctuations ◽

Large Temperature ◽

Small Scale ◽

Spatial And Temporal Variability ◽

Temperature Structure ◽

Wind Shears

Abstract. Four mesosphere–lower thermosphere temperature and turbulence profiles were obtained in situ within ∼30 min and over an area of about 100 by 100 km during a sounding rocket experiment conducted on 26 January 2015 at Poker Flat Research Range in Alaska. In this paper we examine the spatial and temporal variability of mesospheric turbulence in relationship to the static stability of the background atmosphere. Using active payload attitude control, neutral density fluctuations, a tracer for turbulence, were observed with very little interference from the payload spin motion, and with high precision (<0.01 %) at sub-meter resolution. The large-scale vertical temperature structure was very consistent between the four soundings. The mesosphere was almost isothermal, which means more stratified, between 60 and 80 km, and again between 88 and 95 km. The stratified regions adjoined quasi-adiabatic regions assumed to be well mixed. Additional evidence of vertical transport and convective activity comes from sodium densities and trimethyl aluminum trail development, respectively, which were both observed simultaneously with the in situ measurements. We found considerable kilometer-scale temperature variability with amplitudes of 20 K in the stratified region below 80 km. Several thin turbulent layers were embedded in this region, differing in width and altitude for each profile. Energy dissipation rates varied between 0.1 and 10 mW kg−1, which is typical for the winter mesosphere. Very little turbulence was observed above 82 km, consistent with very weak small-scale gravity wave activity in the upper mesosphere during the launch night. On the other hand, above the cold and prominent mesopause at 102 km, large temperature excursions of +40 to +70 K were observed. Simultaneous wind measurements revealed extreme wind shears near 108 km, and combined with the observed temperature gradient, isolated regions of unstable Richardson numbers (0<Ri<0.25) were detected in the lower thermosphere. The experiment was launched into a bright auroral arc under moderately disturbed conditions (Kp∼5).

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Microwave snow emission modeling uncertainties in boreal and subarctic environments

The Cryosphere Discussions ◽

10.5194/tcd-9-5719-2015 ◽

2015 ◽

Vol 9 (5) ◽

pp. 5719-5773

Author(s):

A. Roy ◽

A. Royer ◽

O. St-Jean-Rondeau ◽

B. Montpetit ◽

G. Picard ◽

...

Keyword(s):

Grain Size ◽

Spatial Variability ◽

Boreal Forest ◽

Frozen Soil ◽

Microwave Emission ◽

Small Scale ◽

Radiometric Measurements ◽

Snow Properties ◽

Modeling Uncertainties

Abstract. This study aims to better understand and quantify the uncertainties in microwave snow emission models using the Dense Media Radiative Theory-Multilayer model (DMRT-ML) with in situ measurements of snow properties. We use surface-based radiometric measurements at 10.67, 19 and 37 GHz in boreal forest and subarctic environments and a new in situ dataset of measurements of snow properties (profiles of density, snow grain size and temperature, soil characterization and ice lens detection) acquired in the James Bay and Umijuaq regions of Northern Québec, Canada. A snow excavation experiment – where snow was removed from the ground to measure the microwave emission of bare frozen ground – shows that small-scale spatial variability in the emission of frozen soil is small. Hence, variability in the emission of frozen soil has a small effect on snow-covered brightness temperature (TB). Grain size and density measurement errors can explain the errors at 37 GHz, while the sensitivity of TB at 19 GHz to snow increases during the winter because of the snow grain growth that leads to scattering. Furthermore, the inclusion of observed ice lenses in DMRT-ML leads to significant improvements in the simulations at horizontal polarization (H-pol) for the three frequencies (up to 20 K of root mean square error). However, the representation of the spatial variability of TB remains poor at 10.67 and 19 GHz at H-pol given the spatial variability of ice lens characteristics and the difficulty in simulating snowpack stratigraphy related to the snow crust. The results also show that for ground-based radiometric measurements, forest emission reflected by the surface leads to TB underestimation of up to 40 K if neglected. We perform a comprehensive analysis of the components that contribute to the snow-covered microwave signal, which will help to develop DMRT-ML and to improve the required field measurements. The analysis shows that a better consideration of ice lenses and snow crusts is essential to improve TB simulations in boreal forest and subarctic environments.

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A Case Study of Clear-Air Turbulence at Upper Levels

10.5194/ems2021-182 ◽

2021 ◽

Author(s):

Léo Rogel ◽

Didier Ricard ◽

Eric Bazile ◽

Irina Sandu

Keyword(s):

Turbulent Flow ◽

Partial Information ◽

Weather Prediction ◽

Turbulent Fluxes ◽

Small Scale ◽

Mixing Length ◽

Vertical Resolution ◽

Stable Conditions ◽

Study Results

Because of the technical difficulties of achieving measurements at high altitudes, it is not clear how well turbulent phenomena are represented in the upper levels of current Numerical Weather Prediction (NWP) operational models. Indeed, turbulence in strongly stable conditions near the tropopause is known to be particularly difficult to correctly parameterize. The constraining buoyancy forces on the vertical lead to anisotropic turbulence, potentially inhibiting turbulent production in NWP models. Partial information for high altitude turbulence events is nonetheless available in the form of in-situ measurements from aircrafts. However, it only allows for qualitative comparisons with model outputs. This study focuses on a turbulent episode induced by a winter upper-level jet above east Belgium on January 27, 2018, for which in-situ EDR (Eddy Dissipation Rate) reports indicate moderate-or-greater turbulence levels. Numerical simulations are performed with the M&#233;t&#233;o-France operational model AROME, and with the mesoscale research model MesoNH (Laero/CNRM), at the same horizontal grid resolution (1.3km). These two models also use the eddy-diffusivity turbulence scheme of Cuxart et al (2000), a 1.5 order closure scheme based on a prognostic Turbulent Kinetic Energy (TKE) evolution equation, with a diagnostic computation of the mixing length. TKE budgets, as well as stability indices and gradient-based quantities (Richardson number, vertical wind shear) are computed from the model outputs, and qualitative comparison with in-situ data is presented. Time evolution of the turbulent event over Belgium is well captured by both models, agreeing with EDR data. Several sensitivity tests on the vertical resolution, on the mixing length formulation and on the parameters of the TKE equation are then performed. Most notably, the use of an increased vertical resolution near the tropopause greatly enhances the turbulent fluxes in both operational and research models. Secondly, comparison of various expressions of the mixing length shows that the Bougeault and Lacarrere (1989) formulation produces the higher amount of subgrid TKE and turbulent mixing. A decreased turbulent dissipation parameter also significantly increases the amount of subgrid TKE. On the contrary, the use of a 3D turbulence scheme appears to have very limited impacts on the turbulent flow at this kilometer-scale horizontal resolution. On a second part of this study, results from ongoing Large Eddy Simulations (LES) will be presented. These simulations aim at representing small-scale features of the turbulent flow. They will be used as a reference for the computation of turbulent fluxes at kilometer-scale resolution using a coarse-graining method, allowing for a comparison with the parameterized fluxes from the turbulence scheme. In particular, the dissipation term of the TKE equation will be examined. These results are expected to give insight on the leading turbulent mechanisms for which the current turbulence parameterization can be improved in stable conditions.

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The standard characterization of the Romanian onion landrace ‘Roșie de Făgăraș’

Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca Horticulture ◽

10.15835/buasvmcn-hort:12227 ◽

2016 ◽

Vol 73 (2) ◽

pp. 101

Author(s):

Mihaela Antofie ◽

Camelia Sand Sava

Keyword(s):

In Situ Conservation ◽

Political Support ◽

Medium Size ◽

Small Scale ◽

The European Union ◽

Market Place ◽

Food And Agriculture ◽

Land Cultivation

‘Roșie de Făgăraș’ is a red onion landrace originating from the old region Făgăraș Country situated in South East Transylvania. It was officially included in the National Official Catalogue for cultivars and hybrids in 1952, for almost 50 years, and erased before 2004 without applying in situ conservation measures. However, food security depends on the appropriate management of all genetic resources for food and agriculture (PGRFA). Thus they have to be conserved and sustainable used and efforts have to be done for the recognition of this landrace as a PGRFA and therefore to be maintained "under conservation" into the Official Catalogue. The study focused on analysing data from three localities recognized for cultivating ‘Roșie de Făgăraș’, in order to evaluate morphometric characteristics of mature onion bulbs according to the UPOV Standard TG/46/7, productivity, land cultivation and socio-economic vulnerabilities. The analysis of morphometric measurements results support that ‘Roșie de Făgăraș’ is a medium size red onion that may have the chance to enter the market place, at least at the small scale, according to the current regulatory framework of the European Union regarding the conservation of landraces and provided by: Directive 2008/62/EC, Directive 2009/145/EC and Directive 2010/60/EU. The analysis of productivity, and land cultivation revealed dramatic land use change associated with the decline of cultivated area as following: 76.27% in Mândra, 50% in Recea and 33.34% in Beclean. With an increasing aging population, lack of political support for entering the market place, decrease of landowners cultivating ‘Roșie de Făgăraș’ for trade will increase vulnerability of traditional knowledge related to the conservation of this landrace.

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Small-scale spatial variations of gaseous air pollutants – A comparison of path-integrated and in situ measurement methods

Atmospheric Environment ◽

10.1016/j.atmosenv.2014.01.062 ◽

2014 ◽

Vol 92 ◽

pp. 566-575 ◽

Cited By ~ 1

Author(s):

Hong Ling ◽

Klaus Schäfer ◽

Jinyuan Xin ◽

Min Qin ◽

Peter Suppan ◽

...

Keyword(s):

Air Pollutants ◽

Measurement Methods ◽

Spatial Variations ◽

In Situ Measurement ◽

Small Scale

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In-Situ TEM Straining Experiments: Recent Progress in Stages and Small-Scale Mechanics

In-Situ Electron Microscopy ◽

10.1002/9783527652167.ch10 ◽

2012 ◽

pp. 227-254

Author(s):

Gerhard Dehm ◽

Marc Legros ◽

Daniel Kiener

Keyword(s):

Recent Progress ◽

Small Scale ◽

In Situ Tem

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The Copernicus global 1/12° oceanic and sea ice reanalysis

10.5194/egusphere-egu21-14961 ◽

2021 ◽

Author(s):

Jean-Michel Lellouche ◽

Romain Bourdalle-Badie ◽

Eric Greiner ◽

Gilles Garric ◽

Angelique Melet ◽

...

Keyword(s):

Sea Ice ◽

Real Time ◽

Sea Level ◽

Observation System ◽

Small Scale ◽

Free Access ◽

In Situ Observation ◽

Seasonal Forecasts ◽

Concentration Data

The GLORYS12V1 system is a global eddy-resolving physical ocean and sea ice reanalysis at 1/12&#176; resolution covering the 1993-present altimetry period, designed and implemented in the framework of the Copernicus Marine Environment Monitoring Service (CMEMS). All the essential ocean physical variables from this reanalysis are available with free access through the CMEMS data portal.The GLORYS12V1 reanalysis is based on the current CMEMS global real-time forecasting system, apart from a few specificities that are detailed in this manuscript. The model component is the NEMO platform driven at the surface by atmospheric conditions from the ECMWF ERA-Interim reanalysis. Ocean observations are assimilated by means of a reduced-order Kalman filter. Along track altimeter sea level anomaly, satellite sea surface temperature and sea ice concentration data and in situ temperature and salinity (T/S) vertical profiles are jointly assimilated. A 3D-VAR scheme provides an additional correction for the slowly-evolving large-scale biases in temperature and salinity.The performance of the reanalysis is first addressed in the space of the assimilated observations and shows a clear dependency on the time-dependent in situ observation system, which is intrinsic to most reanalyses. The general assessment of GLORYS12V1 highlights a level of performance at the state-of-the-art and the reliability of the system to correctly capture the main expected climatic interannual variability signals for ocean and sea ice, the general circulation and the inter-basins exchanges. In terms of trends, GLORYS12V1 shows a higher than observed&#160; warming trend together with a lower than observed global mean sea level rise.Comparisons made with an experiment carried out on the same platform without assimilation show the benefit of data assimilation in controlling water masses properties and their low frequency variability. Examination of the deep signals below 2000 m depth shows that the reanalysis does not suffer from artificial signals even in the pre-Argo period.Moreover, GLORYS12V1 represents particularly well the small-scale variability of surface dynamics and compares well with independent (non-assimilated) data. Comparisons made with a twin experiment carried out at &#188;&#176; resolution allows characterizing and quantifying the strengthened contribution of the 1/12&#176; resolution onto the downscaled dynamics.In conclusion, GLORYS12V1 provides a reliable physical ocean state for climate variability and supports applications such as seasonal forecasts. In addition, this reanalysis has strong assets to serve regional applications and should provide relevant physical conditions for applications such as marine biogeochemistry. In a near future, GLORYS12V1 will be maintained to be as close as possible to real time and could therefore provide a relevant reference statistical framework for many operational applications.

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