Geometrical form factor in the laser radar equation: an experimental determination

Sasano, Yasuhiro; Shimizu, Hiroshi; Takeuchi, Nobuo; Okuda, Michio

doi:10.1364/ao.18.003908

Cited by 102 publications

(60 citation statements)

References 4 publications

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“…We estimate that the full overlap is achieved at 150 m. Comparing the AECL results in the few lowest range bins against the in-situ (flight-level) data requires careful consideration of the incomplete overlap problem. In this work, we have used the method of [5] to correct the signal below 150 m by using calibration data in clear air. Despite the correction, we acknowledge that evaluating lidar data in the overlap region can be problematic and associated with a source of error.…”

Section: Figure 1 Aecl Design With a Rotatable Beam Bendermentioning

confidence: 99%

Retrievals of ice-water content from an airborne elastic lidar in tropical convective clouds

et al. 2018

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Ice water content (IWC) is one of the critical parameters in determining the cloud radiative impact. In this work lidar-based IWC retrievals obtained in tropical mesoscale convective systems are evaluated in the context of an extensive in-situ and remote sensing instrumentation suite. Based on a test case of May 27, 2015 lidar-derived IWC values at 50 m above the aircraft were on average within 25% of the in-situ IWC measurements obtained using an isokinetic probe.

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Section: Figure 1 Aecl Design With a Rotatable Beam Bendermentioning

confidence: 99%

Retrievals of ice-water content from an airborne elastic lidar in tropical convective clouds

et al. 2018

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“…Several methods have been used to determine the profile of the overlap factor [37][38][39][40][41]. Our overlap correction is determined by experimental methods such as those described by Sasano et al [37]. The final variable NRB can be expressed as [42]:…”

Section: Measurement Site Instruments and Datamentioning

confidence: 99%

Application of Convective Condensation Level Limiter in Convective Boundary Layer Height Retrieval Based on Lidar Data

Yang

et al. 2017

Atmosphere

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Abstract:Micro pulse lidar is a promising tool for retrieving the convective boundary layer height (CBLH), but its application has been hindered by sharp extinction of the signal in high humidity conditions, e.g., clouds. To remedy this, we developed an effective and simple limiter to obtain more accurate estimates of the CBLH. The limiter is based on the algorithm for the convective condensation level (CCL) and is aimed at limiting the vertical extent of the lidar backscatter profile used in lidar methods to search for the CBLH. Four lidar methods (i.e., the gradient method, the idealized backscatter method, and two forms of the wavelet covariance methods) are used to calculate the CBLH with (or without) the limiter added. Compared to the CBLH calculated by the parcel method from microwave radiometer temperature data, more accurate retrieval of the CBLH is carried out with the limiter applied in four cloudy cases.

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“…Each vertical scan duration was about 2 min, corresponding to an average of 50-100 shots per profile (Table 3). The theoretical lidar blind distance r 0 for optimal nearfield overlap is about 250 m. In order to reduce the blind distance from the lidar, a geometrical form factor (GFF) has been deduced by using horizontal profile measurements in the direction of a south (from the burning site) homogeneous clear atmosphere area before the start of the burning (Sasano et al, 1979). The GFF, deduced experimentally, has been applied in each profile obtained during the burning period, to reduce the blind distance from 250 m to 105 m.…”

Section: Scanning Lidar Experimental Setupmentioning

confidence: 99%

Evaluation of wildland fire smoke plume dynamics and aerosol load using UV scanning lidar and fire–atmosphere modelling during the Mediterranean Letia 2010 experiment

Leroy-Cancellieri

Augustin

Filippi

et al. 2014

Nat. Hazards Earth Syst. Sci.

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Abstract. Vegetation fires emit large amount of gases and aerosols which are detrimental to human health. Smoke exposure near and downwind of fires depends on the fire propagation, the atmospheric circulations and the burnt vegetation. A better knowledge of the interaction between wildfire and atmosphere is a primary requirement to investigate fire smoke and particle transport. The purpose of this paper is to highlight the usefulness of an UV scanning lidar to characterise the fire smoke plume and consequently validate fireatmosphere model simulations.An instrumented burn was conducted in a Mediterranean area typical of ones frequently subject to wildfire with low dense shrubs. Using lidar measurements positioned near the experimental site, fire smoke plume was thoroughly characterised by its optical properties, edge and dynamics. These parameters were obtained by combining methods based on lidar inversion technique, wavelet edge detection and a backscatter barycentre technique. The smoke plume displacement was determined using a digital video camera coupled with the lidar.The simulation was performed using a mesoscale atmospheric model in a large eddy simulation configuration (Meso-NH) coupled to a fire propagation physical model (ForeFire), taking into account the effect of wind, slope and fuel properties. A passive numerical scalar tracer was injected in the model at fire location to mimic the smoke plume. The simulated fire smoke plume width remained within the edge smoke plume obtained from lidar measurements. The maximum smoke injection derived from lidar backscatter coefficients and the simulated passive tracer was around 200 m. The vertical position of the simulated plume barycentre was systematically below the barycentre derived from the lidar backscatter coefficients due to the oversimplified properties of the passive tracer compared to real aerosol particles. Simulated speed and horizontal location of the plume compared well with the observations derived from the videography and lidar method, suggesting that fire convection and advection were correctly taken into account.

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Geometrical form factor in the laser radar equation: an experimental determination

Cited by 102 publications

References 4 publications

Retrievals of ice-water content from an airborne elastic lidar in tropical convective clouds

Retrievals of ice-water content from an airborne elastic lidar in tropical convective clouds

Application of Convective Condensation Level Limiter in Convective Boundary Layer Height Retrieval Based on Lidar Data

Evaluation of wildland fire smoke plume dynamics and aerosol load using UV scanning lidar and fire–atmosphere modelling during the Mediterranean Letia 2010 experiment

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