scholarly journals Recipes for Correcting the Impact of Effective Mesoscale Resolution on the Estimation of Extreme Winds

2012 ◽  
Vol 51 (3) ◽  
pp. 521-533 ◽  
Author(s):  
Xiaoli Guo Larsén ◽  
Søren Ott ◽  
Jake Badger ◽  
Andrea N. Hahmann ◽  
Jakob Mann
Keyword(s):  
High Frequency ◽  
Mesoscale Model ◽  
Energy Deficit ◽  
Smoothing Effect ◽  
Model Resolution ◽  
Extreme Wind ◽  
The Difference ◽  
Extreme Winds ◽  
The Impact ◽  
Good Agreement

AbstractExtreme winds derived from simulations using mesoscale models are underestimated because of the effective spatial and temporal resolutions. This is reflected in the spectral domain as an energy deficit in the mesoscale range. The energy deficit implies smaller spectral moments and thus underestimation in the extreme winds. The authors have developed two approaches for correcting the smoothing effect resulting from the mesoscale model resolution that impacts the extreme wind estimation by taking into account the difference between the modeled and measured spectra in the high-frequency range. Both approaches give estimates of the smoothing effect that are in good agreement with measurements from several sites in Denmark and Germany.

scholarly journals Fabric measurement along the NEEM ice core, Greenland, and comparison with GRIP and NGRIP ice cores

2014 ◽  
Vol 8 (1) ◽  
pp. 307-335 ◽  
Author(s):  
M. Montagnat ◽  
N. Azuma ◽  
D. Dahl-Jensen ◽  
J. Eichler ◽  
S. Fujita ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Cores ◽  
Deformation Pattern ◽  
Bottom Part ◽  
Single Maximum ◽  
Shear Component ◽  
Climatic Transition ◽  
The Difference ◽  
The Impact ◽  
Good Agreement

Abstract. Fabric (distribution of crystallographic orientations) profile along the full NEEM ice core, Greenland, is presented in this work. Data were measured in the field by an Automatic Ice Texture Analyzer every 10 m, from 33 m down to 2461 m depth. The fabric evolves from a slightly anisotropic fabric at the top, toward a strong single maximum at about 2300 m, which is typical of a deformation pattern mostly driven by uniaxial compression and simple shearing. A sharp increase in the fabric strengthening is observed at the Holocene to Wisconsin climatic transition. A similar strengthening, toward an anisotropic single maximum-type fabric, has been observed in several ice cores from Greenland and Antarctica, and can be attributed to a positive feedback between changes in ice viscosity at the climatic transition, and the impact of a shear component of stress. Centimeter scale abrupt texture (fabric and microstructure) variations are observed in the bottom part of the core. Their positions are in good agreement with the folding hypothesis used for a climatic reconstruction by Dahl-Jensen et al. (2013). Comparison is made to two others ice cores drilled along the same ridge; the GRIP ice core drilled at the summit of the ice sheet, and the NorthGRIP ice core, drilled 325 km to the NNW of the summit along the ridge, and 365 km upstream from NEEM. The fabric profile clearly reflects the increase in shear deformation when moving NW along the ridge from GRIP to NorthGRIP and NEEM. The difference in fabric profiles between NEEM and NorthGRIP also evidences a stronger lateral extension associated with a sharper ridge at NorthGRIP.

Fault Mechanism Analysis and Characteristic Extraction for Multi-Disc Clutch

2014 ◽  
Vol 526 ◽  
pp. 155-163
Author(s):  
Man Chen ◽  
He Yan Li ◽  
Biao Ma
Keyword(s):  
High Frequency ◽  
Initial Phase ◽  
Friction Pair ◽  
Vibration Signal ◽  
Coupling Model ◽  
Dynamics Simulation ◽  
Mechanism Analysis ◽  
The Difference ◽  
Vibration Signal Analysis ◽  
The Impact

The thermo-elastic coupling model of clutch friction pair is established by the thermoelastic instability theory to acquire the basic process of friction disc warp due to hot agglomeration; according to this process, thought of reflecting initial phase clutch fault by observing the partial deformation generated by hot spots is proposed in this paper. And based on this thought, the multi-disc clutch dynamics simulation model is established to acquire the dynamic characteristics existing on the friction pair when tiny deformation happens; according to vibration characteristics of this characteristics and the feature that the interference noise of the high frequency section of the transmission system is comparatively light, and based on the analysis on the difference of frequency spectrum of the high frequency section before and after shifting gears, a new kind of initial phase multi-disc clutch fault diagnosing method based on vibration signal analysis is proposed. The test results further prove that, this method can be used to extract the impact vibration generated by tiny deformation happened on the friction pair, and is hopeful to be used in the practical engineering of initial phase multi-disc clutch fault diagnosing.

scholarly journals Quantifying the Impact of the Covid-19 Lockdown Measures on Nitrogen Dioxide Levels throughout Europe

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 131
Author(s):  
Sverre Solberg ◽  
Sam-Erik Walker ◽  
Philipp Schneider ◽  
Cristina Guerreiro
Keyword(s):  
Nitrogen Dioxide ◽  
Temporal Trends ◽  
Measurement Data ◽  
Additive Model ◽  
Generalised Additive Model ◽  
The Difference ◽  
The One ◽  
The Impact ◽  
Good Agreement ◽  
Model Approach

In this paper, the effect of the lockdown measures on nitrogen dioxide (NO2) in Europe is analysed by a statistical model approach based on a generalised additive model (GAM). The GAM is designed to find relationships between various meteorological parameters and temporal metrics (day of week, season, etc.) on the one hand and the level of pollutants on the other. The model is first trained on measurement data from almost 2000 monitoring stations during 2015–2019 and then applied to the same stations in 2020, providing predictions of expected concentrations in the absence of a lockdown. The difference between the modelled levels and the actual measurements from 2020 is used to calculate the impact of the lockdown measures adjusted for confounding effects, such as meteorology and temporal trends. The study is focused on April 2020, the month with the strongest reductions in NO2, as well as on the gradual recovery until the end of July. Significant differences between the countries are identified, with the largest NO2 reductions in Spain, France, Italy, Great Britain and Portugal and the smallest in eastern countries (Poland and Hungary). The model is found to perform best for urban and suburban sites. A comparison between the found relative changes in urban surface NO2 data during the lockdown and the corresponding changes in tropospheric vertical NO2 column density as observed by the TROPOMI instrument on Sentinel-5P revealed good agreement despite substantial differences in the observing method.

scholarly journals Validation of XCH<sub>4</sub> derived from SWIR spectra of GOSAT TANSO-FTS with aircraft measurement data

2014 ◽  
Vol 7 (5) ◽  
pp. 4729-4774
Author(s):  
M. Inoue ◽  
I. Morino ◽  
O. Uchino ◽  
Y. Miyamoto ◽  
T. Saeki ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Measurement Data ◽  
Department Of Energy ◽  
Aircraft Measurement ◽  
The Us ◽  
Temporal Interpolation ◽  
The Difference ◽  
The Impact ◽  
Data Screening ◽  
Good Agreement

Abstract. Column-averaged dry-air mole fractions of methane (XCH4), retrieved from Greenhouse gases Observing SATellite (GOSAT) Short-Wavelength InfraRed (SWIR) spectra, were validated by using aircraft measurement data from the National Oceanic and Atmospheric Administration (NOAA), the US Department of Energy (DOE), the National Institute for Environmental Studies (NIES), the HIAPER Pole-to-Pole Observations (HIPPO) program, and the GOSAT validation aircraft observation campaign over Japan. In the calculation of XCH4 from aircraft measurements (aircraft-based XCH4), other satellite data were used for the CH4 profiles above the tropopause. We proposed a data-screening scheme for aircraft-based XCH4 for reliable validation of GOSAT XCH4. Further, we examined the impact of GOSAT SWIR column averaging kernels (CAK) on the aircraft-based XCH4 calculation and found that the difference between aircraft-based XCH4 with and without the application of the GOSAT CAK was less than ±9 ppb at maximum, with an average difference of −0.5 ppb. We compared GOSAT XCH4 Ver. 02.00 data retrieved within ±2° or ±5° latitude/longitude boxes centered at each aircraft measurement site with aircraft-based XCH4 measured on a GOSAT overpass day. In general, GOSAT XCH4 was in good agreement with aircraft-based XCH4. However, over land, the GOSAT data showed a positive bias of 1.5 ppb (2.0 ppb) with a standard deviation of 14.9 ppb (16.0 ppb) within the ±2° (±5°) boxes, and over ocean, the average bias was 4.1 ppb (6.5 ppb) with a standard deviation of 9.4 ppb (8.8 ppb) within the ±2° (±5°) boxes. In addition, we obtained similar results when we used an aircraft-based XCH4 time series obtained by curve fitting with temporal interpolation for comparison with GOSAT data.

Kármán–Howarth solutions of homogeneous isotropic turbulence

2021 ◽  
Vol 932 ◽  
Author(s):  
L. Djenidi ◽  
R.A. Antonia
Keyword(s):  
Reynolds Number ◽  
Large Scale ◽  
Isotropic Turbulence ◽  
Three Dimensional ◽  
Order Moment ◽  
Homogeneous Isotropic Turbulence ◽  
The Difference ◽  
Decaying Turbulence ◽  
The Impact ◽  
Good Agreement

The Kármán–Howarth equation (KHEq) is solved using a closure model to obtain solutions of the second-order moment of the velocity increment, $S_2$ , in homogeneous isotropic turbulence (HIT). The results are in good agreement with experimental data for decaying turbulence and are also consistent with calculations based on the three-dimensional energy spectrum for decaying HIT. They differ, however, from those for forced HIT, the difference occurring mainly at large scales. This difference is attributed to the fact that the forcing generates large-scale motions which are not compatible with the KHEq. As the Reynolds number increases, the impact of forcing on the small scales decreases, thus allowing the KHEq and spectrally based solutions to agree well in the range of scales unaffected by forcing. Finally, the results show that the two-thirds law is compatible with the KHEq solutions as the Reynolds number increases to very large, if not infinite, values.

scholarly journals Impact of Model Resolution and Initial/Boundary Conditions in Forecasting Flood-Causing Precipitations

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 592
Author(s):  
Francesco Ferrari ◽  
Federico Cassola ◽  
Peter Enos Tuju ◽  
Alessandro Stocchino ◽  
Paolo Brotto ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Mesoscale Model ◽  
Flash Flood ◽  
Late Summer ◽  
Initial Boundary ◽  
Small Scale ◽  
Topographic Effects ◽  
Model Resolution ◽  
Convective Systems ◽  
The Impact

In late summer and autumn Mediterranean coastal regions are quite regularly affected by small-scale, flood-producing convective systems. The complexity of mesoscale triggering mechanisms, related to low-level temperature gradients, moisture convergence, and topographic effects contributes to limit the predictability of such phenomena. In the present work, a severe convection episode associated to a flash flood occurred in Cannes (southern France) in October 2015, is investigated by means of numerical simulations with a state-of-the-art nonhydrostatic mesoscale model. In the modelling configuration operational at the University of Genoa precipitation maxima were underestimated and misplaced. The impact of model resolution as well as initial and boundary conditions on the quantitative precipitation forecasts is analyzed and discussed. In particular, the effect of ingesting a high-resolution satellite-derived sea surface temperature field is proven to be beneficial in terms of precipitation intensity and localization, especially when also associated with the most accurate lateral boundary conditions.

scholarly journals Validation of XCH<sub>4</sub> derived from SWIR spectra of GOSAT TANSO-FTS with aircraft measurement data

2014 ◽  
Vol 7 (9) ◽  
pp. 2987-3005 ◽  
Author(s):  
M. Inoue ◽  
I. Morino ◽  
O. Uchino ◽  
Y. Miyamoto ◽  
T. Saeki ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Measurement Data ◽  
Department Of Energy ◽  
Aircraft Measurement ◽  
The Us ◽  
Temporal Interpolation ◽  
The Difference ◽  
The Impact ◽  
Data Screening ◽  
Good Agreement

Abstract. Column-averaged dry-air mole fractions of methane (XCH4), retrieved from Greenhouse gases Observing SATellite (GOSAT) short-wavelength infrared (SWIR) spectra, were validated by using aircraft measurement data from the National Oceanic and Atmospheric Administration (NOAA), the US Department of Energy (DOE), the National Institute for Environmental Studies (NIES), the HIAPER Pole-to-Pole Observations (HIPPO) program, and the GOSAT validation aircraft observation campaign over Japan. In the calculation of XCH4 from aircraft measurements (aircraft-based XCH4), other satellite data were used for the CH4 profiles above the tropopause. We proposed a data-screening scheme for aircraft-based XCH4 for reliable validation of GOSAT XCH4. Further, we examined the impact of GOSAT SWIR column averaging kernels (CAK) on the aircraft-based XCH4 calculation and found that the difference between aircraft-based XCH4 with and without the application of the GOSAT CAK was less than ±9 ppb at maximum, with an average difference of −0.5 ppb. We compared GOSAT XCH4 Ver. 02.00 data retrieved within ±2° or ±5° latitude–longitude boxes centered at each aircraft measurement site with aircraft-based XCH4 measured on a GOSAT overpass day. In general, GOSAT XCH4 was in good agreement with aircraft-based XCH4. However, over land, the GOSAT data showed a positive bias of 1.5 ppb (2.0 ppb) with a standard deviation of 14.9 ppb (16.0 ppb) within the ±2° (±5°) boxes, and over ocean, the average bias was 4.1 ppb (6.5 ppb) with a standard deviation of 9.4 ppb (8.8 ppb) within the ±2° (±5°) boxes. In addition, we obtained similar results when we used an aircraft-based XCH4 time series obtained by curve fitting with temporal interpolation for comparison with GOSAT data.

Comparison of In-the-Ear and Over-the-Ear Hearing Aid Fittings

1986 ◽  
Vol 51 (4) ◽  
pp. 362-369 ◽  
Author(s):  
Donna M. Risberg ◽  
Robyn M. Cox
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Comparative Evaluation ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Hearing Aid Fitting ◽  
The Difference ◽  
Functional Gain ◽  
The Relationship

A custom in-the-ear (ITE) hearing aid fitting was compared to two over-the-ear (OTE) hearing aid fittings for each of 9 subjects with mild to moderately severe hearing losses. Speech intelligibility via the three instruments was compared using the Speech Intelligibility Rating (SIR) test. The relationship between functional gain and coupler gain was compared for the ITE and the higher rated OTE instruments. The difference in input received at the microphone locations of the two types of hearing aids was measured for 10 different subjects and compared to the functional gain data. It was concluded that (a) for persons with mild to moderately severe hearing losses, appropriately adjusted custom ITE fittings typically yield speech intelligibility that is equal to the better OTE fitting identified in a comparative evaluation; and (b) gain prescriptions for ITE hearing aids should be adjusted to account for the high-frequency emphasis associated with in-the-concha microphone placement.

Evaluation of the impact of public investment programs on social and economic performance of territories

2019 ◽  
pp. 109-123
Author(s):  
I. E. Limonov ◽  
M. V. Nesena
Keyword(s):  
Bayesian Modeling ◽  
Positive Impact ◽  
Public Investment ◽  
Difference In Differences ◽  
The Public ◽  
Export Activity ◽  
Regional Investment ◽  
The Difference ◽  
The Impact ◽  
Development Institution

The purpose of this study is to evaluate the impact of public investment programs on the socio-economic development of territories. As a case, the federal target programs for the development of regions and investment programs of the financial development institution — Vnesheconombank, designed to solve the problems of regional development are considered. The impact of the public interventions were evaluated by the “difference in differences” method using Bayesian modeling. The results of the evaluation suggest the positive impact of federal target programs on the total factor productivity of regions and on innovation; and that regional investment programs of Vnesheconombank are improving the export activity. All of the investments considered are likely to have contributed to the reduction of unemployment, but their implementation has been accompanied by an increase in social inequality.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

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