Estimating random errors due to shot noise in backscatter lidar observations

Liu, Zhaoyan; Hunt, William H.; Vaughan, Mark; Hostetler, C. A.; McGill, Matthew J.; Powell, Kathleen A.; Winker, David M.; Hu, Yongxiang

doi:10.1364/ao.45.004437

Cited by 122 publications

(117 citation statements)

References 13 publications

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“…Random uncertainties in β' par [unc par ] and β' perp [unc perp ] due to shot noise are computed using the noise scale factor (NSF) approach introduced by Liu et al (2006) and described in detail for the CALIOP system by Hostetler et al (2006). The uncertainties are scaled by the inverse square root of the product of: the number of 15-m vertical bins being averaged, which is 12 in the case of our fixed 180-m vertical resolution, and the number of 1/3-km horizontal resolution laser shots being 20 averaged, which ranges from 15 to 405 in our successive horizontal averaging scheme.…”

Section: Random Measurement Uncertaintiesmentioning

confidence: 99%

Polar stratospheric cloud climatology based on CALIPSO spaceborne lidar measurements from 2006–2017

Pitts¹,

Poole²,

Gonzalez³

2018

Preprint

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Section: Random Measurement Uncertaintiesmentioning

confidence: 99%

Polar stratospheric cloud climatology based on CALIPSO spaceborne lidar measurements from 2006–2017

Pitts¹,

Poole²,

Gonzalez³

2018

Preprint

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“…(1), is then used to retrieve the level 2 lidar products, which include vertical profiles of aerosol/cloud backscatter and extinction, aerosol/cloud layer base and top heights, and integrated aerosol/cloud layer parameters (e.g., aerosol opti- cal depth). Also, since the 1064 nm signal is calibrated relative to the calibrated 532 nm total attenuated backscatter (Hostetler et al, 2006;Vaughan et al, 2010), the calibration of all data products is fundamentally dependent upon the calibration of the 532 nm parallel signal. The procedure for calibrating the 532 nm parallel component of the attenuated backscatter is described in detail in Powell et al (2009).…”

Section: Caliop Attenuated Backscattermentioning

confidence: 99%

“…Unless otherwise noted, this study uses the version 3.01 dataset (V3.01), released in early 2010. During nighttime measurements, the CALIOP 532 nm parallel signal is calibrated by determining the ratio between the measured signal (i.e., in digitizer counts) at a set altitude to the total backscatter estimated for that altitude from an atmospheric model Hostetler et al, 2006;Russell et al, 1979). The key to accurate calibration is to choose an altitude for which the atmospheric backscatter can be accurately estimated and the lidar signal has sufficient signal to noise ratio (SNR) and linearity.…”

Section: Caliop Attenuated Backscattermentioning

confidence: 99%

Assessment of the CALIPSO Lidar 532 nm attenuated backscatter calibration using the NASA LaRC airborne High Spectral Resolution Lidar

et al. 2011

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To better assess the range of conditions under which CALIOP data products are produced, these validation flights were conducted under both daytime and nighttime lighting conditions, in multiple seasons, and over a large range of latitudes and aerosol and cloud conditions. This paper presents a quantitative assessment of the CALIOP 532 nm calibration (through the 532 nm total attenuated backscatter) using internally calibrated airborne HSRL underflight data and is the most extensive study of CALIOP 532 nm calibration. Results show that HSRL and CALIOP 532 nm total attenuated backscatter agree on average within 2.7% ± 2.1% (CALIOP lower) at night and within 2.9% ± 3.9% (CALIOP lower) during the day, demonstrating the accuracy of the CALIOP 532 nm calibration algorithms. Additionally, comparisons with HSRL show consistency of the CALIOP calibration before and after the laser switch in 2009 as well as improvements in the daytime version 3.01 calibration scheme compared with the version 2 calibration scheme. Potential biases and uncertainties in the methodology relevant to validating satellite lidar measurements with an airborne lidar system are Correspondence to: R. R. Rogers (raymond.r.rogers@nasa.gov) discussed and found to be less than 4.5% ± 3.2% for this validation effort with HSRL. Results from this study are also compared with prior assessments of the CALIOP 532 nm attenuated backscatter calibration.

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“…The 1064 nm aerosol depolarization ratio is calculated at the same resolution as the aerosol backscatter product (∼1 km horizontal, 30 m vertical resolution). Random error estimates based on shot noise are provided for all HSRL products using a noise scale factor as detailed in Liu et al (2006).…”

Section: Hsrl Measurements During Milagromentioning

confidence: 99%

NASA LaRC airborne high spectral resolution lidar aerosol measurements during MILAGRO: observations and validation

et al. 2009

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Abstract. The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) measures vertical profiles of aerosol extinction, backscatter, and depolarization at both 532 nm and 1064 nm. In March of 2006 the HSRL participated in the Megacity Initiative: Local and Global Research Observations (MILAGRO) campaign along with several other suites of instruments deployed on both aircraft and ground based platforms. This paper presents high spatial and vertical resolution HSRL measurements of aerosol extinction and optical depth from MILAGRO and comparisons of those measurements with similar measurements from other sensors and model predictions. HSRL measurements coincident with airborne in situ aerosol scattering and absorption measurements from two different instrument suites on the C-130 and G-1 aircraft, airborne aerosol optical depth (AOD) and extinction measurements from an airborne tracking sunphotometer on the J-31 aircraft, and AOD from a network of ground based Aerosol Robotic Network (AERONET) sun photometers are presented as a validation of the HSRL aerosol extinction and optical depth products. Regarding the extinction validation, we find bias differences between HSRL and these instruments to be less than 3% (0.01 km −1 ) at 532 nm, the wavelength at which the HSRL technique is employed. The rms differences at 532 nm were less than 50% (0.015 km −1 ). To our knowledge this is the Correspondence to: R. R. Rogers (raymond.r.rogers@nasa.gov) most comprehensive validation of the HSRL measurement of aerosol extinction and optical depth to date. The observed bias differences in ambient aerosol extinction between HSRL and other measurements is within 15-20% at visible wavelengths, found by previous studies to be the differences observed with current state-of-the-art instrumentation .

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Estimating random errors due to shot noise in backscatter lidar observations

Cited by 122 publications

References 13 publications

Polar stratospheric cloud climatology based on CALIPSO spaceborne lidar measurements from 2006–2017

Polar stratospheric cloud climatology based on CALIPSO spaceborne lidar measurements from 2006–2017

Assessment of the CALIPSO Lidar 532 nm attenuated backscatter calibration using the NASA LaRC airborne High Spectral Resolution Lidar

NASA LaRC airborne high spectral resolution lidar aerosol measurements during MILAGRO: observations and validation

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