Keyword

turbulence

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  • This dataset contains turbulent winds and sonic temperature measurements by the University of Leeds' Metek USA-100 sonic anemometer during the Arctic Cloud Summer Expedition (ACSE). The ACSE cruise took place in the Arctic during summer 2014. These data were obtained to complement a suite of other observations taken during the cruise. Those of the UK contribution, as well as selected other data, are available within the associated data collection in the Centre for Environmental Data Analysis (CEDA) archives. Other cruise data may be available in the NOAA ACSE and The Bolin Centre for Climate Research SWERUS (SWEdish-Russian-US) holdings - see online resources linked to this record. Measurements were made at 20Hz from which 20-minute average fluxes were then derived. The sonic anemometer was located on the foremast of the Icebreaker Oden ship at 20.58 m above the waterline. Data here includes the raw measurements and fully corrected turbulent winds (motion correction, flow distortion correction, etc), along with sonic temperature. For details of motion and flow distortion see the linked documentation. Note that while the Metek anemometer uses a left-handed reference frame, all measurements have been transformed to a right-handed frame here. The anemometer x-axis was rotated 30 deg anticlockwise from ship bow. The Arctic Cloud Summer Expedition (ACSE) was a collaboration between the University of Leeds, the University of Stockholm, and NOAA-CIRES. ACSE aimed to study the response of Arctic boundary layer cloud to changes in surface conditions in the Arctic Ocean as a working package of the larger Swedish-Russian-US Investigation of Climate, Cryosphere and Carbon interaction (SWERUS-C3) Expedition in Summer 2014. This expedition was a core component to the overall SWERUS-C3 programme and was supported by the Swedish Polar Research Secretariat. ACSE took place during a 3-month cruise of the Swedish Icebreaker Oden from Tromso, Norway to Barrow, Alaska and back over the summer of 2014. During this cruise ACSE scientists measured surface turbulent exchange, boundary layer structure, and cloud properties. Many of the measurements used remote sensing approaches - radar, lidar, and microwave radiometers - to retrieve vertical profiles of the dynamic and microphysical properties of the lower atmosphere and cloud. The UK participation of ACSE was funded by the Natural Environment Research Council (NERC, grant: NE/K011820/1) and involved instrumentation from the Atmospheric Measurement Facility of the UK's National Centre for Atmospheric Science (NCAS AMF). This dataset collection contains data mainy from the UK contribution with some additional data from other institutes also archived to complement the suite of meteorological measurements.

  • The ultimate aim of the CCOntrails Spreading into Cirrus (COSIC) project is, for the first time, to build a physically based parameterization of aviation induced cirrus to determine its role in climate change. The project aims to conduct studies of water vapour, ice crystal habit, turbulence and radiative properties of contrail as it either spreads into cirrus or dissipates. Boundary conditions for LEM studies of contrail lifecycles will be delivered and Measurements of radiative forcing from spreading contrail taken for comparison to other cases. Case studies for testing later contrail cirrus parameterization in the Unified Model will be also be considered.

  • This dataset contains estimates of turbulent heat and momentum fluxes calculated by applying the eddy covariance technique to the flux-components data product. Estimates are calculated over 15-minute and 30-minute averaging intervals, at two heights on the 15 m tower at Summit Station, Greenland. - ace-flux-1 are the lower level (~2 m above surface) calculations, from a Metek uSonic-3 scientific 3D sonic anemometer and Licor Li-7500 gas analyzer. - ace-flux-2 are the higher level measurements (~14 m above surface), from a Metek uSonic-3 scientific 3D sonic anemometer only (no latent heat flux). Also see the ICECAPS-ACE: surface turbulent heat flux components data product for the high resolution (10 Hz) data used to make these calculations. These data were collected as part of the joint Natural Environmental Research Council (NERC) and US National Science Foundation (NSF) -funded Integrated Characterisation of Energy, Clouds, Atmospheric state, and Precipitation at Summit - Aerosol Cloud Experiment (ICECAPS-ACE) project.

  • The Natural Environment Research Council (NERC) Mesosphere-Stratosphere-Troposphere (MST) Radar is operated by the Science and Technology Facilities Council (STFC) at the Radar Facility's (MSTRF's) site in Capel Dewi, near Aberystwyth, Mid-Wales. This dataset contains time-series of vertical profiles of derived atmospheric dynamics (wind speed, direction) and structure (indications of refractive index structures and turbulence) from observations taken from the 46.5 MHz pulsed Doppler radar. It is primarily used for making atmospheric observations over the approximate altitude range 2 - 20 km, i.e. of the free troposphere (above the boundary layer) and the lower stratosphere, known as the "ST-mode". Additional observations are made over the approximate altitude range 56 - 96 km, i.e. covering the mesosphere - known as the "M-mode" (see related dataset); hence the term "MST" radar. The instrument has been in operation, using the Doppler Beam Swinging technique (see linked documentation for further details), since late 1989. It was initially operated on a campaign basis, but switched to quasi-continuous observations (i.e. close to 24-7 operation) in late 1997. In 2011 the radar system underwent renovation with significant improvements in radar performance. The version 4.0 (v4.0) data processing scheme is closely related to the version 3 (v3) scheme and uses v3 Cartesian files as input. The main difference is that the horizontal wind components in the v4 Cardinal files represent time averages, which have a smaller random measurement error compared to the single cycle estimates in the v3 Cartesian files. Data products available from the v4 Cardinal files include time-series profiles of: - eastward wind - northward wind - upward wind - (radar return) signal power (giving an indication of atmospheric structure) - also known as echo power - (beam broadening) corrected spectral width (giving a measure of turbulence intensity) - tropopause altitude and sharpness A full list of variables will be added to this record in due course. Quick look plots for these data are available - see related links under the "docs" tab below. Note - some files are released marked as '-suspect'. These have been released to permit early access to the data where the majority of data are known to pass quality control, but a small, limited part of the data have been identified as being 'suspect'. An internal remark about the suspect data may be found within the file's metadata 'comments' attribute.

  • This dataset collection contains in situ atmospheric and aerosol measurements collected at Summit Station, Greenland. These data were collected as part of the joint Natural Environmental Research Council (NERC) and US National Science Foundation (NSF) -funded Integrated Characterisation of Energy, Clouds, Atmospheric state, and Precipitation at Summit - Aerosol Cloud Experiment (ICECAPS-ACE) project. Since 2010, the ICECAPS project has been monitoring cloud-atmosphere-energy interactions at Summit Station, in the centre of the Greenland Ice Sheet (GrIS), using a comprehensive suite of ground-based remote sensing instruments and twice daily radiosonde profiles. In 2018, the Aerosol Cloud Experiment (ACE) expansion of ICECAPS saw the addition of a new series of instruments to measure surface aerosol concentrations and turbulent heat fluxes over the ice sheet. Combined with the original ICECAPS instrumentation, the ACE instruments allow for the study of cloud-aerosol-energy interactions over the central GrIS. This dataset collection contains the measurements collected as part of the ACE component of ICECAPS-ACE, which includes the following: 1) Surface-temperature-profile: A near surface temperature profile from four temperature/ humidity sensors distributed on the 15 m tower at Summit. 2) Surface-moisture-profile: A near surface moisture profile from four temperature/ humidity sensors distributed on the 15 m tower at Summit. 3) Surface-winds-profile: A near surface wind profile from four sonic anemometers distributed on the 15 m tower at Summit. 4) Snow-height: The distance to the snow surface from the lowest level of instruments on the 15 m tower at Summit, detected by a sonic-ranging sensor. 5) Skin-temperature: The brightness temperature of the snow surface as detected by an infrared radiation thermometer. 6) Aerosol-concentration: The concentration of condensation nuclei (> 5nm diameter) measured at the surface using a Condensation Particle Counter. 7) Aerosol-size-distribution: The size-resolved concentration of surface aerosol particles between 0.25 and 6.5 um in diameter measured using an Optical Particle Counter. 8) Flux-components: High resolution temperature, humidity and wind fluctuations that can be used to estimate turbulent fluxes using eddy covariance, located at two levels on the 15 m tower at Summit. 9) Flux-estimates: Estimates of turbulent heat and momentum fluxes by applying the eddy covariance technique to flux-components. Other ICECAPS data are available here: https://psl.noaa.gov/arctic/observatories/summit/

  • This dataset contains high resolution measurements of temperature, humidity and wind fluctuations from Summit Station, Greenland. These measurements and derived quantities can be used to estimate turbulent fluxes using eddy covariance. The data are collected at 10 Hz resolution and statistical properties have been calculated over both 15-minute and 30-minute flux averaging intervals (separate files). The measurements are located at two levels on the 15 m tower: - ace-flux-1 are the lower level (~2 m above surface) measurements, from a Metek uSonic-3 scientific 3D sonic anemometer and Licor Li-7500 gas analyzer. - ace-flux-2 are the higher level measurements (~14 m above surface), from a Metek uSonic-3 scientific 3D sonic anemometer only (no humidity measurements). Also see the ICECAPS-ACE: surface turbulent heat flux estimates data product for estimations of latent and sensible heat flux calculated from these components. These data were collected as part of the joint Natural Environmental Research Council (NERC) and US National Science Foundation (NSF) -funded Integrated Characterisation of Energy, Clouds, Atmospheric state, and Precipitation at Summit - Aerosol Cloud Experiment (ICECAPS-ACE) project.

  • Comprehensive measurements were taken on the Larsen C Ice Shelf and used to compute the Surface Energy Budget (SEB). Data were collected from two automatic weather stations (AWS) put in place in January 2009. Parallel to the AWS measurements, high-quality spectral and broadband radiation measurements were carried out, as well as direct measurements of turbulent fluxes. A special part of the field experiment focused on the direct measurement of liquid water content in the snowpack, using time-domain reflectometry (TDR).

  • The DIAMET project aimed to better the understanding and prediction of mesoscale structures in synoptic-scale storms. Such structures include fronts, rain bands, secondary cyclones, sting jets etc, and are important because much of the extreme weather we experience (e.g. strong winds, heavy rain) comes from such regions. Weather forecasting models are able to capture some of this activity correctly, but there is much still to learn. By a combination of measurements and modelling, mainly using the Met Office Unified Model (UM), the project worked to better understand how mesoscale processes in cyclones give rise to severe weather and how they can be better represented in models and better forecast. This dataset contains wind profile measurements which were taken by the Facility for Ground-based Atmospheric Measurements' (FGAM) 1290 MHz Degreane Mobile Wind Profiler, operated by the University of Manchester,as part of the DIAMET (Diabatic influences on mesoscale structures in extratropical storms) project from 9th August 2011 to 17th February 2012. During this period the instrument was deployed at the Natural Environment Research Council (NERC) Mesosphere-Stratosphere-Troposphere (MST) Radar Facility, Capel Dewi, UK. These data are available in netCDF and include wind speed, wind direction, signal to noise ratio and spectral width.

  • This dataset contains vertical profiles of horizontal and vertical wind components as well as signal-to-noise (SNR) and spectral width measurements were collected at the Davidstow Airfield and Cornwall at War Museum, Cornwall, between June and August 2013 as part of the MICROphysicS of COnvective PrEcipitation (MICROSCOPE) project. These data were collected by the National Centre for Atmospheric Science (NCAS) Atmospheric Measurement Facility's (AMF) 1290 MHz Mobile Wind Profiler, owned and operated by the University of Manchester and previously known as the aber-radar-1290mhz. The data are available at 15 minute intervals as netCDF files to all MICROSCOPE project participants.

  • The University of Wales, Aberystwyth 1290 MHz mobile wind profiler, deployed as part of a suite of instrument from NCAS's Universities Facility for Atmospheric Measurements (UFAM), was sited at Ashmansworth for the duration of the Convective Storm Initiation Project (CSIP)'s pilot field campaign. The instrument was operated throughout the campaign, producing vertical profiles of wind speed and direction (horizontal and vertical components), signal to noise ratio and spectral width measurements 6th to 22nd July 2004 . This instrument is now referred to as the University of Manchester mobile wind profiler (man-radar-1290mhz).