A5007445726- Meteorological Phenomena and Simulations
- Atmospheric and Environmental Gas Dynamics
- Plant Water Relations and Carbon Dynamics
- Wind and Air Flow Studies
- Fluid Dynamics and Turbulent Flows
- Atmospheric chemistry and aerosols
- Atmospheric aerosols and clouds
- Climate variability and models
- Aeolian processes and effects
- Atmospheric Ozone and Climate
- Wind Energy Research and Development
- Geophysics and Gravity Measurements
- Oceanographic and Atmospheric Processes
- Icing and De-icing Technologies
- Ionosphere and magnetosphere dynamics
- Flow Measurement and Analysis
- Air Quality and Health Impacts
- Aerodynamics and Acoustics in Jet Flows
- Air Quality Monitoring and Forecasting
- Geology and Paleoclimatology Research
- Particle Dynamics in Fluid Flows
- Greenhouse Technology and Climate Control
- Remote Sensing and LiDAR Applications
- Plant responses to elevated CO2
- Arctic and Antarctic ice dynamics
NSF National Center for Atmospheric Research
2014-2024
University of Ontario Institute of Technology
2023
University of Utah
2023
University of Notre Dame
2023
SA Photonics (United States)
2023
Earth Observing Laboratory
2020
Colorado State University
2009
University of Colorado Boulder
2009
Washington State University
2009
Campo Arqueologico de Mertola
2009
A method is proposed to measure scalar fluxes using conditional sampling. Only the mean concentrations of updraft and downdraft samples, standard deviation vertical velocity, a coefficient proportionality, b, need be known. The has been simulated from existing time series wind component, temperature, humidity in surface layer. It found that b an almost constant value 0.6 for both scalars over wide stability range. This result encourages application other suggests may used beyond atmospheric...
Abstract This paper describes important characteristics of an uncoupled high-resolution land data assimilation system (HRLDAS) and presents a systematic evaluation 18-month-long HRLDAS numerical experiments, conducted in two nested domains (with 12- 4-km grid spacing) for the period from 1 January 2001 to 30 June 2002, context International H2O Project (IHOP_2002). was developed at National Center Atmospheric Research (NCAR) initialize land-state variables coupled Weather Forecasting...
Abstract A grand challenge from the wind energy industry is to provide reliable forecasts on mountain winds several hours in advance at microscale (∼100 m) resolution. This requires better wind-energy physics included forecasting tools, for which field observations are imperative. While mesoscale (∼1 km) measurements abound, processes not monitored practice nor do plentiful exist this scale. After a decade of preparation, group European and U.S. collaborators conducted campaign during 1...
An atmospheric surface-layer experiment over a nearly uniform plowed field was performed to determine the constants in flux-profile similarity formulas, particularly von Kármán constant. New instruments were constructed minimize flow distortion effects on turbulence measurements and provide high-resolution gradient measurements. In addition, hot-wire anemometer directly measured turbulent kinetic energy dissipation rate. average value of constant 0.365 ± 0.015 obtained from 91 runs (31 h)...
Perturbations of mean and turbulent wind characteristics by large turbines modify fluxes between the vegetated surface lower boundary layer. While simulations have suggested that farms could significantly change heat, momentum, moisture, CO2 over hundreds square kilometers, little observational evidence exists to test these predictions. Quantifying influences “turbine layer” is necessary quantify how are modified better forecast energy production a farm. Changes in particularly important...
Abstract The Chequamegon Heterogeneous Ecosystem Energy-Balance Study Enabled by a High-Density Extensive Array of Detectors 2019 (CHEESEHEAD19) is an ongoing National Science Foundation project based on intensive field campaign that occurred from June to October 2019. purpose the study examine how atmospheric boundary layer (ABL) responds spatial heterogeneity in surface energy fluxes. One main objectives test whether lack balance closure measured eddy covariance (EC) towers related...
Abstract To assess current capabilities for measuring flow within the atmospheric boundary layer, including wind farms, U.S. Department of Energy sponsored eXperimental Planetary layer Instrumentation Assessment (XPIA) campaign at Boulder Atmospheric Observatory (BAO) in spring 2015. Herein, we summarize XPIA field experiment, highlight novel measurement approaches, and quantify uncertainties associated with these methods. Line-of-sight velocities measured by scanning lidars radars exhibit...
The exchange of various trace species and energy at the earth's surface plays an important role in climate, ecology, human health welfare. Surface measurements can be difficult to obtain yet are understand physical processes, assess environmental global change impacts, develop robust parameterizations atmospheric processes. physics turbulent structure boundary layer reviewed as they contribute dry rates (fluxes). Micrometeorological, budget, enclosure techniques used measure or estimate...
To improve the quality of scalar-flux measurements, two-point covariance between vertical velocity w̃ and a scalar s̃, separated in space both horizontally vertically, is studied. The measurements such covariances temperature with horizontal separations show good agreement symmetric turbulence model when displacement horizontal. However, similar does not work for displacements because up–down asymmetry exists; that is, there lack reflection symmetry function. second-order equation...
The Canopy Horizontal Array Turbulence Study (CHATS) took place in spring 2007 and is the third series of (HATS) experiments. HATS experiments have been instrumental testing developing subfilterscale (SFS) models for large-eddy simulation (LES) planetary boundary layer (PBL) turbulence. CHATS campaign a deciduous walnut orchard near Dixon, California, was designed to examine impacts vegetation on SFS Measurements were collected both prior following leafout capture impact leaves turbulence,...
Abstract. Measurements of turbulence are essential to understand and quantify the transport dispersal heat, moisture, momentum, trace gases within planetary boundary layer (PBL). Through years, various techniques measure using Doppler lidar observations have been proposed. However, accuracy these measurements has rarely validated against trusted in situ instrumentation. Herein, data from eXperimental Planetary Instrumentation Assessment (XPIA) used verify profiles through comparison with...
Abstract. Results from a recent field campaign are used to assess the accuracy of wind speed and direction precision estimates produced by Doppler lidar retrieval algorithm. The algorithm, which is based on traditional velocity-azimuth-display (VAD) technique, measurement using standard error propagation techniques, assuming input data (i.e., radial velocities) be contaminated random, zero-mean, errors. For this study, was configured execute an 8-beam plan-position-indicator (PPI) scan once...
"Experimental Equipment: A Supplement to The Summertime Arctic Atmosphere: Meteorological Measurements during the Ocean Experiment 2001" published on Sep 2004 by American Society.
This paper describes the development of Cooperative Atmosphere Surface Exchange Study (CASES), its synergism with Boundary Layer Experiments (ABLE) and related efforts, CASES field programs, some early results, future plans opportunities. is a grassroots multidisciplinary effort to study interaction lower atmosphere land surface, subsurface, vegetation over timescales ranging from nearly instantaneous years. scientists developed consensus that observations should be taken in watershed...
This report summarizes presentations and discussions that occurred at a workshop held in conjunction with the XIXth General Assembly of European Geophysical Society (EGS) from 22 to 24 April 1994. The purpose this was define state art micrometeorological flux measurements, identify problem areas, any additional data must be taken solve these problems. organized response proposal made 1993 EGS conference by T. Foken, Delany (National Center for Atmospheric Research), S. Oncley, L. Tsvang...
Characteristics of turbulence in the inertial range are experimentally studied atmospheric surface layer over Taylor microscale based Reynolds number Rλ≊(2.8–12.7)×103 and a large wind tunnel (in mixing at Rλ≊2.0×103 return channel Rλ≊3.2×103). The intermittency exponent μ, estimated from correlation function energy dissipation Rεε(r)=〈ε(x)ε(x+r)〉∝r−μ, is found to be independent approximately equal 0.20. No ‘‘measurable’’ deviation −5/3 ‘‘five-thirds’’ law found. On other hand, Kolmogorov...
Field and numerical studies of the evolution atmosphere in near-ideal, basinshaped crater have led to an ex tensive dataset exhibiting many stable boundar y layer phenomena their interactions with background flows.
Abstract. Accurate three-dimensional information of wind flow fields can be an important tool in not only visualizing complex but also understanding the underlying physical processes and improving modeling. However, a thorough analysis measurement uncertainties is required to properly interpret results. The XPIA (eXperimental Planetary boundary layer Instrumentation Assessment) field campaign conducted at Boulder Atmospheric Observatory (BAO) Erie, CO, from 2 March 31 May 2015 brought...
Abstract. Scanning Doppler lidars have great potential for reducing uncertainty of wind resource estimation in complex terrain. Due to their scanning capabilities, they can measure at multiple locations over large areas. We demonstrate this ability with dual-Doppler lidar measurements flow two parallel ridges. The data been collected using pairs operated a mode during the Perdigão 2017 measurement campaign. There mapped 80 m above ground level along ridges, which are considered favorable...