Tropospheric aerosol extinction coefficient profiles derived from scanning lidar measurements over Tsukuba, Japan, from 1990 to 1993

1996 ◽  
Vol 35 (24) ◽  
pp. 4941 ◽  
Author(s):  
Yasuhiro Sasano
Keyword(s):  
Extinction Coefficient ◽  
Aerosol Extinction ◽  
Tropospheric Aerosol ◽  
Lidar Measurements ◽  
Scanning Lidar ◽  
Aerosol Extinction Coefficient

scholarly journals Impact of aerosol hygroscopic growth on retrieving aerosol extinction coefficient profiles from elastic-backscatter lidar signals

2017 ◽  
Author(s):  
Gang Zhao ◽  
Chunsheng Zhao ◽  
Ye Kuang ◽  
Jiangchuan Tao ◽  
Wangshu Tan ◽  
...  
Keyword(s):  
Extinction Coefficient ◽  
Enhancement Factor ◽  
Field Measurements ◽  
Relative Bias ◽  
Aerosol Extinction ◽  
Hygroscopic Growth ◽  
The North ◽  
True Value ◽  
Lidar Measurements ◽  
Aerosol Extinction Coefficient

Abstract. Light detection and ranging (lidar) measurements have been widely used to profile ambient aerosol extinction coefficient (σext). Particle extinction-to-backscatter ratio (lidar ratio, LR), which highly depends on aerosol dry particle number size distribution (PNSD) and aerosol hygroscopicity, is introduced to retrieve the σext profile from elastic-backscatter lidar signals. Conventionally, a constant column integrated LR that is estimated from aerosol optical depth is used by the retrieving algorithms. In this paper, the influences of aerosol PNSD, aerosol hygroscopic growth and relative humidity (RH) profiles on the variation of LR are investigated based on the datasets from field measurements in the North China Plain (NCP). Results show that LR has an enhancement factor of 2.2 when RH reaches 92 %. Simulation results indicate that both the magnitude and vertical structures of the σext profiles by using column-related LR method are significantly biased from the original σext profile. The relative bias, which is mainly influenced by RH and PNSD, can reach up to 40 % when RH at the top of the mixed layer is above 90 %. A new algorithm for retrieving σext profiles and a new scheme of LR enhancement factor by RH in the NCP are proposed in this study. The relative bias between the σext profile retrieved with this new algorithm and the ideal true value is reduced to below 13 %.

scholarly journals Impact of aerosol hygroscopic growth on retrieving aerosol extinction coefficient profiles from elastic-backscatter lidar signals

2017 ◽  
Vol 17 (19) ◽  
pp. 12133-12143 ◽  
Author(s):  
Gang Zhao ◽  
Chunsheng Zhao ◽  
Ye Kuang ◽  
Jiangchuan Tao ◽  
Wangshu Tan ◽  
...  
Keyword(s):  
Extinction Coefficient ◽  
Enhancement Factor ◽  
Field Measurements ◽  
Relative Bias ◽  
Aerosol Extinction ◽  
Hygroscopic Growth ◽  
The North ◽  
True Value ◽  
Lidar Measurements ◽  
Aerosol Extinction Coefficient

Abstract. Light detection and ranging (lidar) measurements have been widely used to profile the ambient aerosol extinction coefficient (σext). The particle extinction-to-backscatter ratio (lidar ratio, LR), which strongly depends on the aerosol dry particle number size distribution (PNSD) and aerosol hygroscopicity, is introduced to retrieve the σext profile from elastic-backscatter lidar signals. Conventionally, a constant column-integrated LR that is estimated from aerosol optical depth is used by the retrieving algorithms. In this paper, the influences of aerosol PNSD, aerosol hygroscopic growth and relative humidity (RH) profiles on the variation in LR are investigated based on the datasets from field measurements in the North China Plain (NCP). Results show that LR has an enhancement factor of 2.2 when RH reaches 92 %. Simulation results indicate that both the magnitude and vertical structures of the σext profiles by using the column-related LR method are significantly biased from the original σext profile. The relative bias, which is mainly influenced by RH and PNSD, can reach up to 40 % when RH at the top of the mixed layer is above 90 %. A new algorithm for retrieving σext profiles and a new scheme of LR enhancement factor by RH in the NCP are proposed in this study. The relative bias between the σext profile retrieved with this new algorithm and the ideal true value is reduced to below 13 %.

Lidar Measurements for Comparison of Atmospheric Aerosol Extinction and Scattering Properties over Lanzhou, China

2011 ◽  
Vol 137 ◽  
pp. 256-261 ◽  
Author(s):  
Xian Jie Cao ◽  
Lei Zhang ◽  
Xiao Jing Quan ◽  
Bi Zhou ◽  
Jing Bao ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Extinction Coefficient ◽  
Atmospheric Aerosol ◽  
Aerosol Extinction ◽  
Vertical Profiles ◽  
Lidar Measurements ◽  
The Difference ◽  
Aerosol Extinction Coefficient ◽  
Semi Arid

The aerosol comparison experiment was conducted in the Semi-Arid Climate and Environment Observatory of Lanzhou University since March to April 2007 with the measurements of two micro-pulse lidars MPL-4B and CE370-2. In the paper, the differences of aerosol extinction coefficient and optical depth retrieved from the observations of MPL-4B and CE370-2 are analyzed, and the results show: the aerosol extinction coefficient retrieved from the observation of MPL-4B is in general smaller than that from CE370-2, and the difference mainly exists in the low layer, while their trends of vertical profiles agree well; the aerosol optical depths from the observations of MPL-4B and CE370-2 correlate linearly rather well with the coefficient of 0.71, and the aerosol optical depth retrieved from the measurement of MPL-4B is less than that from CE370-2 in whole.

scholarly journals Dual-wavelength aerosol vertical profile measurements by MAX-DOAS at Tsukuba, Japan

2009 ◽  
Vol 9 (8) ◽  
pp. 2741-2749 ◽  
Author(s):  
H. Irie ◽  
Y. Kanaya ◽  
H. Akimoto ◽  
H. Iwabuchi ◽  
A. Shimizu ◽  
...  
Keyword(s):  
Extinction Coefficient ◽  
Optical Absorption Spectroscopy ◽  
Aerosol Extinction ◽  
Measurement Sensitivity ◽  
Extinction Coefficients ◽  
Quantitative Studies ◽  
Lidar Measurements ◽  
Dependent Measurement ◽  
Aerosol Extinction Coefficient ◽  
Measurement Period

Abstract. We present vertical profiles of the aerosol extinction coefficient retrieved from ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements at Tsukuba, Japan (36.1° N, 140.1° E), from November 2006 to March 2007. Retrievals utilizing absorption by the oxygen collision complex O4 are first made at two wavelengths, 354 and 476 nm. A robust assessment of the MAX-DOAS aerosol data is then made using coincident lidar measurements throughout the period. Agreement between aerosol extinction coefficients measured by MAX-DOAS and the lidar tends to be better at the longer wavelength and at lower altitudes. At 476 nm, the best agreement, to within 30%, is found at altitudes of 0–1 km, confirming results from a literature assessment for a two-month measurement period. These findings are supported by comparisons between aerosol optical depths derived from MAX-DOAS and sky radiometer measurements and are further explained by differences in the altitude-dependent measurement sensitivity to the aerosol extinction coefficient between 354 and 476 nm. Thus, uncertainty in MAX-DOAS aerosol measurements is well quantified and characterized, providing a basis for quantitative studies using MAX-DOAS measurements.

scholarly journals Evidence for the predictability of changes in the stratospheric aerosol size following volcanic eruptions of diverse magnitudes using space-based instruments

2020 ◽  
Author(s):  
Larry W. Thomason ◽  
Mahesh Kovilakam ◽  
Anja Schmidt ◽  
Christian von Savigny ◽  
Travis Knepp ◽  
...  
Keyword(s):  
Size Distribution ◽  
Extinction Coefficient ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Global Climate Models ◽  
Aerosol Size Distribution ◽  
Aerosol Layer ◽  
Aerosol Extinction ◽  
Volcanic Event ◽  
Aerosol Extinction Coefficient

Abstract. An analysis of multiwavelength stratospheric aerosol extinction coefficient data from the Stratospheric Aerosol and Gas Experiment II and III/ISS instruments is used to demonstrate a coherent relationship between the perturbation in extinction coefficient in an eruption's main aerosol layer and an apparent change in aerosol size distribution that spans multiple orders of magnitude in the stratospheric impact of a volcanic event. The relationship is measurement-based and does not rely on assumptions about the aerosol size distribution. We note limitations on this analysis including that the presence of significant amounts of ash in the main aerosol layer may significantly modulate these results. Despite this limitation, these findings represent a unique opportunity to verify the performance of interactive aerosol models used in Global Climate Models and Earth System Model and may suggest an avenue for improving aerosol extinction coefficient measurements from single channel observations such the Optical Spectrograph and Infrared Imager System as they rely on a priori assumptions about particle size.

scholarly journals An evaluation of the SAGE III Version 4 aerosol extinction coefficient and water vapor data products

2009 ◽  
Vol 9 (5) ◽  
pp. 22177-22222
Author(s):  
L. W. Thomason ◽  
J. R. Moore ◽  
M. C. Pitts ◽  
J. M. Zawodny ◽  
E.-W. Chiou
Keyword(s):  
Water Vapor ◽  
Extinction Coefficient ◽  
Stratospheric Aerosol ◽  
Data Sets ◽  
Aerosol Extinction ◽  
Data Products ◽  
Mean Differences ◽  
Aerosol Extinction Coefficient ◽  
Polar Ozone

Abstract. Herein, we provide an assessment of the data quality of Stratospheric Aerosol and Gas Experiment (SAGE III) Version 4 aerosol extinction coefficient and water vapor data products. The evaluation is based on comparisons with data from four instruments: SAGE II, the Polar Ozone and Aerosol Measurement (POAM III), the Halogen Occultation Experiment (HALOE), and the Microwave Limb Sounder (MLS). Since only about half of the SAGE III channels have a direct comparison with measurements by other instruments, we have employed some empirical techniques to evaluate measurements at some wavelengths. We find that the aerosol extinction coefficient measurements at 449, 520, 755, 869, and 1021 nm are reliable with accuracies and precisions on the order of 10% in the primary aerosol range of 15 to 25 km. We also believe this to be true of the aerosol measurements at 1545 nm though we cannot exclude some positive bias below 15 km. We recommend use of the 385 nm measurements above 16 km where the accuracy is on par with other aerosol channels. The 601 nm measurement is much noisier (~20%) than other channels and we suggest caution in the use of these data. We believe that the 676 nm data are clearly defective particularly above 20 km (accuracy as poor as 50%) and the precision is also low (~30%). We suggest excluding this channel under most circumstances. The SAGE III Version 4 water vapor data product appears to be high quality and is recommended for science applications in the stratosphere below 45 km. In this altitude range, the mean differences with all four corroborative data sets are no bigger than 15% and often less than 10% with exceptional agreement with POAM III and MLS. Above 45 km, it seems likely that SAGE III water vapor values are increasingly too large and should be used cautiously or avoided. We believe that SAGE III meets its preflight goal of 15% accuracy and 10% precision between 15 and 45 km. We do not currently recommend limiting the SAGE III water vapor data utility in the stratosphere by aerosol loading.

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