Lidar Observations of Banded Convection during BLX83

Ferrare, R. A.; Schols, J. L.; Eloranta, E. W.; Coulter, R. L.

doi:10.1175/1520-0450(1991)030<0312:loobcd>2.0.co;2

Cited by 38 publications

(28 citation statements)

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“…A backscattering Lidar can thus provide information on the Planetary Boundary Layer (PBL) mixed depth, entrainment zones and convective cell structure, aerosol distribution, clear air layering, cloud-top altitudes, cloud statistics, atmospheric transport processes and other inferences of air motion [17][18][19][20]. The Lidar system is a single-wavelength backscatter system pointing vertically to the zenith and operating in the coaxial mode.…”

Section: Elastic Backscatter Lidar System (Msp-lidar)mentioning

confidence: 99%

Impacts of Biomass Burning in the Atmosphere of the Southeastern Region of Brazil Using Remote Sensing Systems

Lopes¹,

Mariano²,

Landulfo³

et al. 2012

Atmospheric Aerosols - Regional Characteristics - Chemistry and Physics

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Section: Elastic Backscatter Lidar System (Msp-lidar)mentioning

confidence: 99%

Impacts of Biomass Burning in the Atmosphere of the Southeastern Region of Brazil Using Remote Sensing Systems

Lopes¹,

Mariano²,

Landulfo³

et al. 2012

Atmospheric Aerosols - Regional Characteristics - Chemistry and Physics

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“…These may take the form of convective roll vortices (e.g. Ferrare et al 1991) or polygonal patterns of convection cells, which occur when shear across the CBL is small (e.g. Melfi et al 1985).…”

Section: The Cbl As a Complex Dynamical Systemmentioning

confidence: 99%

Scaling Properties of Temperature Spectra and Heat-Flux Cospectra in the Surface Friction Layer Beneath an Unstable Outer Layer

Laubach

McNaughton

2009

Boundary-Layer Meteorol

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Temperature variance and temperature power spectra in the unstable surface layer have always presented a problem to the standard Monin-Obukhov similarity model. Recently that problem has intensified with the demonstration by Smedman et al. (2007, Q J Roy Meteorol Soc 133: 37-51) that temperature spectra and heat-flux cospectra can have two distinct peaks in slightly unstable conditions, and by McNaughton et al. (2007, Nonlinear Process Geophys 14: 257-271) who showed that the wavenumber of the peak of temperature spectra in a convective boundary layer (CBL), closely above the surface friction layer (SFL), can be sensitive to the CBL depth, z i . Neither the two-peak form at slight instability nor the dependence of peak position on z i at large instability is compatible with the MoninObukhov model. Here we examine the properties of temperature spectra and heat-flux cospectra from between these extremes, i.e. from within the unstable SFL, in two experiments. The analysis is based on McNaughton's model of the turbulence structure in the SFL. According to this model, heat is transported through most of the SFL by sheet plumes, created by the action of impinging outer eddies. The smallest and most effective of these outer eddies have sizes that scale on SFL depth, z s . The z s -scale eddies and plumes are organised within the overall convection pattern in the CBL, and in turn they organise the motion of smaller eddies within the SFL, whose sizes scale on height, z. The main experimental results are: (1) the peak amplitudes of the temperature spectra in the SFL are collapsed with a scaling factor (z s z) 1/3 ε 2/3 o divided by the square of the surface temperature flux, where ε o is the dissipation rate of turbulent energy in the outer CBL (above the SFL); (2) the peak wavenumbers J. Laubach (B) Manaaki Whenua -Landcare Research, of the temperature spectra are collapsed with the mixed length scale (z i z s ) 1/2 ; (3) the peak wavenumbers of the heat-flux cospectra are collapsed with the doubly-mixed length scale (z i z s ) 1/4 z 1/2 ; (4) for z/z s < 0.03, the peak in the cospectrum is replaced by another peak at a wavenumber about a magnitude larger. This peak's position scales on z; (5) all these findings are consistent with the observations of Smedman et al.

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“…The LIDAR technique, through its high temporal (from seconds to minutes) and spatial (3-15 m) resolution, is a powerful tool to visualize in real time, the structure of the PBL using the aerosols as passive tracers of the atmospheric dynamic processes. A backscattering LIDAR can thus provide information on the PBL's mixed layer depth, entrainment zones and convective cells structure, aerosol distribution, clear air layering, cloud-top altitudes, cloud statistics, atmospheric transport processes and other inferences of air motion (Ferrare et al 1991, Melfi et al 1985, Crum et al 1987, Balis et al 2000.…”

Section: Introductionmentioning

confidence: 99%

Synergetic measurements of aerosols over São Paulo, Brazil using LIDAR, sunphotometer and satellite data during the dry season

Landulfo

Papayannis

Artaxo³

et al. 2003

Atmos. Chem. Phys.

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Abstract.A backscattering LIDAR system, the first of this kind in Brazil, has been set-up in a suburban area in the city of São Paulo (23 • 33' S, 46 • 44' W) to provide the vertical profile of the aerosol backscatter coefficient at 532 nm up to an altitude of 4-6 km above sea level (asl). The measurements have been carried out during the second half of the so-called Brazilian dry season, September and October 2001 and during the first half of the dry season in August and September 2002. The LIDAR data are presented and analysed in synergy with aerosol optical thickness (AOT) measurements obtained by a CIMEL sun-tracking photometer in the visible spectral region and with satellite measurements obtained by the MODIS sensor. This synergetic approach has been used, not only to validate the LIDAR data, but also to derive a typical value (45 sr) of the so-called extinction-tobackscatter ratio (LIDAR ratio) during the dry season. The satellite data analysis offers additional information on the spatial distribution of aerosols over Brazil including the determination of aerosol source regions over the country. The LIDAR data were also used to retrieve the Planetary Boundary Layer (PBL) height, aerosol layering and the structure of the lower troposphere over the city of São Paulo. These first LIDAR measurements over the city of São Paulo during the dry season showed a significant variability of the AOT in the lower troposphere (0.5-5 km) at 532 nm. It was also found that the aerosol load is maximized in the 1-3 km height region, although up to 3 km thick aerosol layers were also detected in the 2.5-5.5 km region in certain cases. Threedimensional 96-hours air mass back-trajectory analysis was also performed in selected cases to determine the source regions of aerosols around São Paulo during the dry season.

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Lidar Observations of Banded Convection during BLX83

Cited by 38 publications

References 0 publications

Impacts of Biomass Burning in the Atmosphere of the Southeastern Region of Brazil Using Remote Sensing Systems

Impacts of Biomass Burning in the Atmosphere of the Southeastern Region of Brazil Using Remote Sensing Systems

Scaling Properties of Temperature Spectra and Heat-Flux Cospectra in the Surface Friction Layer Beneath an Unstable Outer Layer

Synergetic measurements of aerosols over São Paulo, Brazil using LIDAR, sunphotometer and satellite data during the dry season

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