A New Method for Aerosol Retrieval Based on Lidar Observations in Beijing

AbstractA new automatic mixing layer height detection method for lidar observations of aerosol backscatter profiles is presented and evaluated for robustness. The new detection method incorporates the strengths of Steyn et al.’s error function–ideal profile (ERF) method and Davis et al.’s wavelet covariance transform (WCT) method. These two methods are critical components of the new method, and their robustness is also evaluated and then contrasted to the new method. The new method is applied to aerosol backscatter observations in two ways: 1) by looking for the most realistic mixing height throughout the entire profile and 2) by searching for mixing height below significant elevated obscurations (e.g., clouds or aerosol layers). The first approach is referred to as the hybrid method and the second as the hybrid-lowest method. Coincident radiosounding observations of mixing heights are used to independently reference the lidar-based estimates.There were 4030 cases examined over a 5-yr period for mixing heights. The efficacy of the lidar-based methods was determined based on diurnal, seasonal, stability, and sky obscuration conditions. Of these conditions, the hybrid method performed best for unstable and cloudy situations. It determined mixing heights reliably (less than ±0.30-km bias) for close to 70% of those cases. The hybrid-lowest method performed best in stable and clear-sky conditions; it determined mixing heights reliably for over 70% of those cases. The WCT method performed the best overall.

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A new method for estimating the noise scale factor (NSF) and random errors in lidar observations

Applied Physics B ◽

10.1007/s00340-021-07572-2 ◽

2021 ◽

Vol 127 (2) ◽

Author(s):

Ming Zhao ◽

Tijian Wang ◽

Hao Wu ◽

Dongyang Nie ◽

Mengmeng Li ◽

...

Keyword(s):

Scale Factor ◽

New Method ◽

Random Errors ◽

Lidar Observations

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Using Combined 532 NM HSRL and 1064 NM Elastic-Scatter Lidar Observations to Verify and Update CRAM Dual-Wavelength Aerosol Retrieval Models

IGARSS 2008 - 2008 IEEE International Geoscience and Remote Sensing Symposium ◽

10.1109/igarss.2008.4779055 ◽

2008 ◽

Cited By ~ 5

Author(s):

John A. Reagan ◽

Christopher J. McPherson ◽

Richard Ferrare ◽

Chris Hostetler ◽

Johnathan Hair

Keyword(s):

Dual Wavelength ◽

Retrieval Models ◽

Aerosol Retrieval ◽

Elastic Scatter ◽

Lidar Observations ◽

532 Nm

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A new method for improving the MODIS aerosol retrieval over coastal water

10.1117/12.900580 ◽

2011 ◽

Author(s):

Jiacheng Wang

Keyword(s):

Coastal Water ◽

New Method ◽

Aerosol Retrieval

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Implementation of a 2D Wavelet Method to Probe Mixed Layer Height Using Lidar Observations

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16142516 ◽

2019 ◽

Vol 16 (14) ◽

pp. 2516 ◽

Cited By ~ 1

Author(s):

Ning Zhang ◽

Fuyan Yang ◽

Yan Chen

Keyword(s):

Mixed Layer ◽

Early Morning ◽

New Method ◽

Data Quality Control ◽

Wavelet Method ◽

Wavelet Filters ◽

Radiosonde Observation ◽

Variation Characteristics ◽

Mixed Layer Height ◽

Lidar Observations

A new method was developed to estimate mixed layer (ML) height with light detection and ranging (lidar) observations using a 2Dimensional (2D) wavelet method, which can consider the diurnal variation characteristics of ML height. Ideal signals and real lidar observations in Shanghai, China were used to evaluate the new method. The results showed that the new method is insensitive to the type of wavelet filters. The estimated ML heights obtained by the 2D wavelet method agreed well with both of the previous methods developed for the ML height probing using lidar, including the gradient method, the 1D-wavelet method, the standard deviation method, and the conventional radiosonde method. The primary differences among the results obtained via the different lidar methods occurred in the early morning or later afternoon; when the ML is well mixed, very small differences were observed among the different lidar methods. The new method showed better determination skills than other methods when compared to the radiosonde observation results. It also performed well when there were missing profiles or observation errors and it made the new method suitable for operations where data quality control may be missed.

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Selective Sampling and Orientation of Non-Homogeneous Tissues

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100238 ◽

1968 ◽

Vol 26 ◽

pp. 98-99

Author(s):

C. C. Clawson ◽

L. W. Anderson ◽

R. A. Good

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Light Microscopy ◽

Random Sampling ◽

New Method ◽

Microscope Examination ◽

Small Areas ◽

Selective Sampling ◽

Large Numbers ◽

Specific Orientation

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.

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