Inversion of lidar signals with the slope method

Kunz, G.J.; Leeuw, G. de

doi:10.1364/ao.32.003249

Cited by 95 publications

(51 citation statements)

References 3 publications

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“…The overlap function is estimated using the procedure explained by Pelon et al (2008). We performed horizontal observations for clear (low optical depth) conditions and the overlap function is derived using the slope method (Kunz and de Leeuw, 1993) function is complete (100%) at 2 km. The correction remains large (20% of overlap) up to 600 m and the error is about 10% above 600 m while it is up to 50% close to the ground.…”

Section: Instrumentation and Methodologymentioning

confidence: 99%

Aerosol vertical distribution and optical properties over M'Bour (16.96° W; 14.39° N), Senegal from 2006 to 2008

et al. 2009

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Abstract. We present ground-based measurements of aerosol mass, optical properties and vertical extinction profiles acquired in M'Bour, Senegal (16.96° W; 14.39° N) from January 2006 to September 2008. This place of the world is all year long affected by the export of mineral dust as it moves westward to the north Atlantic ocean. The maximum in the dust activity is observed in summer (June–July), corresponding to a maximum in the aerosol optical thickness (above 0.5) and single scattering albedo (above 0.95). It also corresponds to a maximum in the top altitude of the transported aerosol layer (up to 6 km) and aerosol optical thickness scale height (up to 3.5 km) due to the presence of the Saharan Air Layer located between 2 and 6 km. The late summer shows an additional low level aerosol layer that increases in thickness in autumn. Severe dust storms are also systematically observed in spring (March) but with a lower vertical development and a stronger impact (factor 2 to 3) on the ground-level mass compared to summer. Sporadic events of biomass burning aerosols are observed in winter (January) and particularly in January 2006 when the biomass burning aerosol are advected between 1.5 and 3.5 km high. On average, the seasonal signal in the aerosol optical properties and vertical distribution is very similar from year to year over our 3 year monitoring.

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Section: Instrumentation and Methodologymentioning

confidence: 99%

Aerosol vertical distribution and optical properties over M'Bour (16.96° W; 14.39° N), Senegal from 2006 to 2008

et al. 2009

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“…Anderson et al, 2000), by Raman lidar systems (e.g. Pappalardo et al, 2002) or from a horizontal lidar measurement assuming horizontal stratification (Kunz and de Leeuw, 1993). However, the choice of a fixed LR is to some extent arbitrary and can lead to significant errors in the lidar retrievals (e.g.…”

Section: Lidarmentioning

confidence: 99%

Aerosol stratification, optical properties and radiative forcing in Venice (Italy) during ADRIEX

Barnaba

Gobbi

Leeuw

2007

Q.J.R. Meteorol. Soc.

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This study presents ground-based measurements of aerosol optical properties and solar radiation performed in Venice (Italy) within the Aerosol Direct Radiative Impact Experiment (ADRIEX). The measurement site is of particular interest due to its location at the eastern border of the polluted Po Valley and constituting the northern edge of the Mediterranean basin. Lidar observations showed a stratified structure of aerosols in the lower troposphere (0-4 km), with more than 40% of the aerosol optical depth due to aerosol above the local planetary boundary layer (about 1 km thick). Different aerosol vertical distributions and optical and microphysical properties were observed to develop under the influence of the various advection regimes encountered during ADRIEX. Sunphotometer measurements indicated fine particles (radius <1 µm) as dominating the light extinction, confirming the main aerosol source in the region as anthropogenic. Photometric data also revealed a relatively low aerosol absorption (i.e. a single-scattering albedo >0.92 at 440 nm), this being comparable to those found in other urban/industrial sites in Europe and USA, and slightly lower than those characterizing central America and Asia. Overall, the aerosol optical properties measured at Venice during ADRIEX translate into a summertime mean daily aerosol forcing between −10 and −14 W m −2 at the surface and between −4 and −8 W m −2 at the top of the atmosphere.

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“…Other applications of the slope method in inhomogeneous atmospheres encompass boundary calibration of Klett's method 3,5 and the so-called slice method of inversion, which is merely an extremely close variant of the slope method but applied to successive range intervals. 6 As originally reported by Kunz and Leeuw,7 although the simplicity and straightforwardness of the slope method is advantageous, its biased estimation for low SNR's, caused by samples of the return signal approaching the noise floor ͓n͑R͒ Ϸ ϪP͑R͒ in Eq. ͑2͔͒, emerges as the main drawback of the algorithm.…”

Section: P͑r͒mentioning

confidence: 95%

Statistics of the slope-method estimator

2000

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The slope method has customarily been used and is still used for inversion of atmospheric optical parameters, extinction, and backscatter in homogeneous atmospheres from lidar returns. Our aim is to study the underlying statistics of the old slope method and ultimately to compare its inversion performance with that of the present-day nonlinear least-squares solution ͑the so-called exponential-curve fitting͒. The contents are twofold: First, an analytical study is conducted to characterize the bias and the mean-square-estimation error of the regression operator, which permits estimation of the optical parameters from the logarithm of the range-compensated lidar return. Second, universal plots for most short-and far-range tropospheric backscatter lidars are presented as a rule of thumb for obtaining the optimum regression interval length that yields unbiased estimates. As a result, the simple graphic basis of the slope method is still maintained, and its inversion performance improves up to that of the present-day computer-oriented exponential-curve fitting, which ends the controversy between these two algorithms.

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Inversion of lidar signals with the slope method

Cited by 95 publications

References 3 publications

Aerosol vertical distribution and optical properties over M'Bour (16.96° W; 14.39° N), Senegal from 2006 to 2008

Aerosol vertical distribution and optical properties over M'Bour (16.96° W; 14.39° N), Senegal from 2006 to 2008

Aerosol stratification, optical properties and radiative forcing in Venice (Italy) during ADRIEX

Statistics of the slope-method estimator

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