scholarly journals Retrieval of Eddy Dissipation Rate from Derived Equivalent Vertical Gust included in Aircraft Meteorological Data Relay (AMDAR)

2019 ◽  
Author(s):  
Soo-Hyun Kim ◽  
Hye-Yeong Chun ◽  
Jung-Hoon Kim ◽  
Robert D. Sharman ◽  
Matt Strahan
Keyword(s):  
Dissipation Rate ◽  
Meteorological Data ◽  
Civil Aviation ◽  
Cube Root ◽  
Control Procedures ◽  
Turbulence Data ◽  
Upper Level ◽  
Best Fit ◽  
Mapping Scheme

Abstract. Some of the Aircraft Meteorological Data Relay (AMDAR) data include a turbulence metric of the derived equivalent vertical gust (DEVG), in addition to wind and temperature. As the cube root of the eddy dissipation rate (EDR) is the International Civil Aviation Organization standard turbulence reporting metric, we attempt to retrieve the EDR from the DEVG for more reliable and consistent observations of aviation turbulence globally. Using the DEVG in the AMDAR archived from October 2015 to September 2018 covering a large portion of the Southern Hemisphere and North Pacific and North Atlantic Oceans, we convert the DEVG to the EDR using two methods, after conducting quality control procedures to remove suspicious turbulence reports in the DEVG. The first method is to remap the DEVG to the EDR using a lognormal mapping scheme, while the second one is using the best-fit curve between the EDR and DEVG developed in the previous study. The DEVG-derived EDRs obtained from the two methods are evaluated against in situ EDR data reported by United States-operated carriers. For two specified regions of the trans-Pacific Ocean and Europe, where both the DEVG-derived EDRs and in situ EDRs were available, the DEVG-derived EDRs obtained by the two methods are generally consistent with in situ EDRs, with slightly better statistics by the first method than the second one. This result is encouraging for extending the aviation turbulence data globally with the single preferred EDR metric, which will contribute to the improvement of global aviation turbulence forecasting as well as to the construction of the climatology of upper-level turbulence.

scholarly journals Retrieval of eddy dissipation rate from derived equivalent vertical gust included in Aircraft Meteorological Data Relay (AMDAR)

2020 ◽  
Vol 13 (3) ◽  
pp. 1373-1385 ◽  
Author(s):  
Soo-Hyun Kim ◽  
Hye-Yeong Chun ◽  
Jung-Hoon Kim ◽  
Robert D. Sharman ◽  
Matt Strahan
Keyword(s):  
Dissipation Rate ◽  
Meteorological Data ◽  
Civil Aviation ◽  
Cube Root ◽  
The Pacific ◽  
Control Procedures ◽  
Turbulence Data ◽  
The Pacific Ocean ◽  
Upper Level

Abstract. Some of the Aircraft Meteorological Data Relay (AMDAR) data include a turbulence metric of the derived equivalent vertical gust (DEVG), in addition to wind and temperature. As the cube root of the eddy dissipation rate (EDR) is the International Civil Aviation Organization standard turbulence reporting metric, we attempt to retrieve the EDR from the DEVG for more reliable and consistent observations of aviation turbulence globally. Using the DEVG in the AMDAR data archived from October 2015 to September 2018 covering a large portion of the Southern Hemisphere and North Pacific and North Atlantic oceans, we convert the DEVG to the EDR using two methods, after conducting quality control procedures to remove suspicious turbulence reports in the DEVG. The first method remaps the DEVG to the EDR using a lognormal mapping scheme, while the second one uses the best-fit curve between the EDR and DEVG developed in a previous study. The DEVG-derived EDRs obtained from the two methods are evaluated against in situ EDR data reported by US-operated carriers. For two specified regions of the Pacific Ocean and Europe, where both the DEVG-derived EDRs and in situ EDRs were available, the DEVG-derived EDRs obtained by the two methods were generally consistent with in situ EDRs, with slightly better statistics obtained by the first method than the second one. This result is encouraging for extending the aviation turbulence data globally with the single preferred EDR metric, which will contribute to the improvement of global aviation turbulence forecasting as well as to the construction of the climatology of upper-level turbulence.

scholarly journals Description and Derived Climatologies of Automated In Situ Eddy-Dissipation-Rate Reports of Atmospheric Turbulence

2014 ◽  
Vol 53 (6) ◽  
pp. 1416-1432 ◽  
Author(s):  
R. D. Sharman ◽  
L. B. Cornman ◽  
G. Meymaris ◽  
J. Pearson ◽  
T. Farrar
Keyword(s):  
Atmospheric Turbulence ◽  
Dissipation Rate ◽  
Route Planning ◽  
Federal Aviation Administration ◽  
The United States ◽  
Commercial Aircraft ◽  
Upper Troposphere ◽  
Obvious Benefit ◽  
Turbulence Data

AbstractThe statistical properties of turbulence at upper levels in the atmosphere [upper troposphere and lower stratosphere (UTLS)] are still not well known, partly because of the lack of adequate routine observations. This is despite the obvious benefit that such observations would have for alerting aircraft of potentially hazardous conditions, either in real time or for route planning. To address this deficiency, a research project sponsored by the Federal Aviation Administration has developed a software package that automatically estimates and reports atmospheric turbulence intensity levels (as EDR ≡ ε1/3, where ε is the energy or eddy dissipation rate). The package has been tested and evaluated on commercial aircraft. The amount of turbulence data gathered from these in situ reports is unprecedented. As of January 2014, there are ~200 aircraft outfitted with this system, contributing to over 137 million archived records of EDR values through 2013, most of which were taken at cruise levels of commercial aircraft, that is, in the UTLS. In this paper, techniques used for estimating EDR are outlined and comparisons with pilot reports from the same or nearby aircraft are presented. These reports allow calibration of EDR in terms of traditionally reported intensity categories (“light,” “moderate,” or “severe”). The results of some statistical analyses of EDR values are also presented. These analyses are restricted to the United States for now, but, as this program is expanded to international carriers, such data will begin to become available over other areas of the globe.

scholarly journals Acceleration-Based In Situ Eddy Dissipation Rate Estimation with Flight Data

Atmosphere ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1247
Author(s):  
Zhenxing Gao ◽  
Haofeng Wang ◽  
Kai Qi ◽  
Zhiwei Xiang ◽  
Debao Wang
Keyword(s):  
Dissipation Rate ◽  
Civil Aviation ◽  
Vertical Acceleration ◽  
Acceleration Response ◽  
Lattice Method ◽  
Flight Data ◽  
Vortex Lattice Method ◽  
Vortex Lattices ◽  
Vertical Turbulence

Inducing civil aviation aircraft to bumpiness, atmospheric turbulence is a typical risk that seriously threatens flight safety. The Eddy Dissipation Rate (EDR) value, as an aircraft-independent turbulence severity indicator, is estimated by a vertical wind-based or aircraft vertical acceleration-based algorithm. Based on the flight data of civil aviation aircraft, the vertical turbulence component is obtained as the input of both algorithms. A new method of computing vertical acceleration response in turbulence is put forward through the Unsteady Vortex Lattice Method (UVLM). The lifting surface of the target aircraft is assumed to be a combination of wing and horizontal tail in a turbulent flight scenario. Vortex rings are assigned on the mean camber surface, forming a non-planar UVLM, to further improve the accuracy. Moreover, the neighboring vortex lattices are placed as close as possible to the structural edge of control surfaces. Thereby, a complete algorithm for estimating vertical acceleration and in situ EDR value from Quick Access Recorder (QAR) flight data is proposed. Experiments show that the aerodynamic performance is computed accurately by non-planar UVLM. The acceleration response by non-planar UVLM is able to track the recorded acceleration data with higher accuracy than that of the linear model. Different acceleration responses at different locations are also obtained. Furthermore, because the adverse effects of aircraft maneuvers are separated from turbulence-induced aircraft bumpiness, the new acceleration-based EDR algorithm shows better accuracy and stability.

scholarly journals Sub-Level Stoping in an Underground Limestone Quarry: An Analysis of the State of Stress in an Evolutionary Scenario

2016 ◽  
Vol 61 (1) ◽  
pp. 199-216 ◽  
Author(s):  
Marilena Cardu ◽  
Sergio Dipietromaria ◽  
Pierpaolo Oreste
Keyword(s):  
Numerical Models ◽  
The State ◽  
In Situ Tests ◽  
Future Scenario ◽  
Limestone Quarry ◽  
Geomechanical Properties ◽  
State Of Stress ◽  
Upper Level ◽  
Pillar Structure

Abstract The aim of this study was to evaluate the state of stress of a „voids-pillar“ structure excavated by means of the sub-level stoping method in an underground limestone quarry near Bergamo (Italy). Both the current structure of the quarry (i.e. the rooms exploited till now) and a possible future scenario were analysed using the (FDM) FLAC 2D code. The quarry has been in operation since 1927; at present, exploitation is carried out underground via the sub-level stoping method. Exploitation involves two levels, with 5 rooms on the upper level and 9 rooms on the lower level. After analysing data obtained from laboratory and in situ tests carried out on rock samples and natural discontinuities, the geomechanical properties of the medium, knowledge of which is essential in order to establish the parameters that must be included in the numerical model, were evaluated. The implementation of three numerical models made it possible to study both the present conditions of quarry exploitation and the evolution of the exploited rooms, as well as a possible expansion involving a third level of rooms. Using the results obtained regarding the stress-strain present in the pillars, a potential change in room geometry was proposed aimed at reducing the stress state inside the pillars, decreasing plasticity and increasing overall quarry safety.

scholarly journals Multi-source SO<sub>2</sub> emissions retrievals and consistency of satellite and surface measurements with reported emissions

2017 ◽  
Author(s):  
Vitali Fioletov ◽  
Chris A. McLinden ◽  
Shailesh K. Kharol ◽  
Nickolay A. Krotkov ◽  
Can Li ◽  
...  
Keyword(s):  
Point Source ◽  
Single Point ◽  
Control Measures ◽  
Ozone Monitoring Instrument ◽  
So2 Emissions ◽  
Vertical Column ◽  
Wind Speeds ◽  
Surface Measurements ◽  
Best Fit

Abstract. Reported sulfur dioxide (SO2) emissions from U.S. and Canadian sources have declined dramatically since the 1990s as a result of emissions control measures. Observations from the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite and ground-based in-situ measurements are examined to verify whether the observed changes from SO2 abundance measurements are quantitatively consistent with the reported changes in emissions. To make this connection, a new method to link SO2 emissions and satellite SO2 measurements was developed. The method is based on fitting satellite SO2 vertical column densities (VCDs) to a set of functions of OMI pixel coordinates and wind speeds, where each function represents a statistical model of a plume from a single point source. The concept is first demonstrated using sources in North America, and then applied to Europe. The correlation coefficient between OMI-measured VCDs (with a local bias removed) and SO2 VCDs derived here using reported emissions for 1° by 1° gridded data is 0.91 and the best-fit line has a slope near unity, confirming a very good agreement between observed SO2 VCDs and reported emissions. Having demonstrated their consistency, seasonal and annual mean SO2 VCD distributions are calculated, based on reported point-source emissions for the period 1980–2015, as would have been seen by OMI. This consistency is further substantiated as the emissions-derived VCDs also show a high correlation with annual mean SO2 surface concentrations at 50 regional monitoring stations.

scholarly journals Remote sensing of ecosystem light use efficiency with MODIS-based PRI

2011 ◽  
Vol 8 (1) ◽  
pp. 189-202 ◽  
Author(s):  
A. Goerner ◽  
M. Reichstein ◽  
E. Tomelleri ◽  
N. Hanan ◽  
S. Rambal ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Vapour Pressure Deficit ◽  
Ground Truth ◽  
Light Use Efficiency ◽  
Wide Range ◽  
Evaluation Exercise ◽  
Use Efficiency ◽  
Study Sites ◽  
Absorbed Photosynthetically Active Radiation

Abstract. Several studies sustained the possibility that a photochemical reflectance index (PRI) directly obtained from satellite data can be used as a proxy for ecosystem light use efficiency (LUE) in diagnostic models of gross primary productivity. This modelling approach would avoid the complications that are involved in using meteorological data as constraints for a fixed maximum LUE. However, no unifying model predicting LUE across climate zones and time based on MODIS PRI has been published to date. In this study, we evaluate the effectiveness with which MODIS-based PRI can be used to estimate ecosystem light use efficiency at study sites of different plant functional types and vegetation densities. Our objective is to examine if known limitations such as dependence on viewing and illumination geometry can be overcome and a single PRI-based model of LUE (i.e. based on the same reference band) can be applied under a wide range of conditions. Furthermore, we were interested in the effect of using different faPAR (fraction of absorbed photosynthetically active radiation) products on the in-situ LUE used as ground truth and thus on the whole evaluation exercise. We found that estimating LUE at site-level based on PRI reduces uncertainty compared to the approaches relying on a maximum LUE reduced by minimum temperature and vapour pressure deficit. Despite the advantages of using PRI to estimate LUE at site-level, we could not establish an universally applicable light use efficiency model based on MODIS PRI. Models that were optimised for a pool of data from several sites did not perform well.

scholarly journals Meteorological Conditions at Racetrack Playa, Death Valley National Park: Implications for Rock Production and Transport

2011 ◽  
Vol 50 (12) ◽  
pp. 2361-2375 ◽  
Author(s):  
Ralph D. Lorenz ◽  
Brian K. Jackson ◽  
Jason W. Barnes ◽  
Joseph N. Spitale ◽  
Jani Radebaugh ◽  
...  
Keyword(s):  
National Park ◽  
Probability Distributions ◽  
Meteorological Data ◽  
Time Lapse ◽  
Meteorological Conditions ◽  
Death Valley ◽  
Trail Formation ◽  
Strong Winds ◽  
Death Valley National Park

AbstractThree decades of weather records at meteorological stations near Death Valley National Park are analyzed in an attempt to gauge the frequency of conditions that might form and erase the famous trails of wind-blown rocks in the mud of Racetrack Playa. Trail formation requires the playa to be wet, followed by strong winds and/or freezing conditions. Weather records are compared with a limited set of meteorological data that were acquired in situ at the playa over three winters and that indicate freezing on 50, 29, and 15 nights during the winters of 2007/08–09/10, respectively, as well as with the hydrological condition of the playa as determined by time-lapse cameras that observed flooding over ~1, ~5, and ~40 days, respectively, during those winters. Measurements at the nearby Panamint and Hunter Mountain stations are found to be a useful, if imperfect (~50%), indicator of Racetrack Playa conditions and give some features of Racetrack Playa’s micrometeorological behavior. Wind speed probability distributions suggest that winds that are fast enough to cause unassisted rock motion are rare and therefore that freezing of water on the playa has a role in a significant fraction of movement events.

scholarly journals Study of Clear Air Turbulence Related to Tropopause Folding over the Romanian Airspace

Atmosphere ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1099
Author(s):  
Sabina Ștefan ◽  
Bogdan Antonescu ◽  
Ana Denisa Urlea ◽  
Livius Buzdugan ◽  
Meda Daniela Andrei ◽  
...  
Keyword(s):  
Large Scale ◽  
Lower Stratosphere ◽  
Meteorological Data ◽  
Horizontal Temperature Gradient ◽  
Jet Streams ◽  
Mountain Waves ◽  
Upper Troposphere ◽  
Air Turbulence ◽  
Upper Level ◽  
Tropopause Folding

Clear air turbulence (CAT) poses a significant threat to aviation. CAT usually occurs in the lower stratosphere and the upper troposphere. It is generally associated with large scale waves, mountain waves, jet streams, upper-level fronts and tropopause folds. Aircraft can experience CAT when flying in proximity of a tropopause fold. To better understand and diagnose tropopause fold- associated CAT we selected a series of cases from among those reported by pilots between June 2017 and December 2018 in the Romanian airspace. Data on turbulence were used in conjunction with meteorological data, satellite imagery, and vertical profiles. Additionally, a set of indices as Ellrod, horizontal temperature gradient, Dutton, and Brown were computed to diagnose CAT associated with tropopause folding. These indices were also analyzed to test the physics mechanisms that may explain the occurrence of severe turbulence. Results show that out of the 420 cases announced by pilots, severe turbulence was reported in 80 cases of which 13 were associated with tropopause folding.

scholarly journals A New Air Quality Prediction Framework for Airports Developed with a Hybrid Supervised Learning Method

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Yong Tian ◽  
Weifang Huang ◽  
Bojia Ye ◽  
Minhao Yang
Keyword(s):  
Air Quality ◽  
Supervised Learning ◽  
Meteorological Data ◽  
Accurate Prediction ◽  
Civil Aviation ◽  
Assessment Procedure ◽  
Learning Methods ◽  
Air Quality Prediction ◽  
Flight Operations ◽  
Standard Assessment

In order to reduce the air pollution impacts by aircraft operations around airports, a fast and accurate prediction of air quality related to aircraft operations is an essential prerequisite. This article proposes a new framework with a combination of the standard assessment procedure and machine learning methods for fast and accurate prediction of air quality in airports. Instead of taking some specific pollutant as concerned metric, we introduce the air quality index (AQI) for the first time to evaluate the air quality in airports. Then, following the standard assessment procedure proposed by International Civil Aviation Organization (ICAO), the airports AQIs in different scenarios are classified with consideration of the airport configuration, actual flight operations, aircraft performance, and related meteorological data. Taking the AQI classification results as sample data, several popular supervised learning methods are investigated for accurately predicting air quality in airports. The numerical tests implicate that the accuracy rate of prediction could reach more than 95% with only 0.022 sec; the proposed framework and the results could be used as the foundation for improving air quality impacts around airports.

In situ ground based measurements of low level clouds during 10 years of Pallas cloud experiments.

2020 ◽  
Author(s):  
Konstantinos Doulgeris ◽  
David Brus
Keyword(s):  
Water Content ◽  
Liquid Water ◽  
Meteorological Data ◽  
Liquid Water Content ◽  
Data Set ◽  
Radiative Balance ◽  
Low Level ◽  
Major Factors

&lt;p&gt;Clouds and their interaction with aerosols are considered one of the major factors that are connected with uncertainties in predictions of climate change and are highly associated with earth radiative balance. Semi long term in-situ measurements of Arctic low-level clouds have been conducted during last 10 year (2009 - 2019) autumns at Sammaltunturi station (67&amp;#9702;58&amp;#180;N, 24&amp;#9702;07&amp;#180;E, and 560 m a.s.l.), the part of Pallas Atmosphere - Ecosystem Supersite and Global Atmosphere Watch (GAW) programme. During these years a unique data set of continuous and detailed ground-based cloud observations over the sub-Arctic area was obtained. The in-situ cloud measurements were made using two cloud probes that were installed on the roof of the station: the Cloud, Aerosol and Precipitation Spectrometer probe (CAPS) and the Forward Scattering Spectrometer Probe&lt;strong&gt; (&lt;/strong&gt;FSSP&lt;strong&gt;)&lt;/strong&gt;, both made by droplet measurement technologies (DMT, Longmont, CO, USA). CAPS in&amp;#173;cludes three instruments: the Cloud Imaging Probe (CIP, 12.5 &amp;#956;m-1.55 mm), the Cloud and Aerosol Spectrometer (CAS-DPOL, 0.51-50 &amp;#956;m) with depolarization feature and the Hotwire Liquid Water Content Sensor (Hotwire LWC, 0 - 3 g/m&lt;sup&gt;3&lt;/sup&gt;). Vaisala FD12P weather sensor was used to measure all the meteorological data. The essential cloud microphysical parameters we investigated during this work were the size distributions, the total number concentrations, the effective radius of cloud droplets and the cloud liquid water content. The year to year comparison and correlations among semi long term in situ cloud measurements and meteorology are presented.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document