Investigation of sooting flames by color-ratio pyrometry with a consumer-grade  DSLR camera

Abstract. To study cloud/aerosol features in the upper troposphere and lower stratosphere (UT/LS) with the NASA's A-Train sensors, a research algorithm is developed for a re-gridded CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) Level 1 (L1) backscatter dataset. This paper provides a detailed analysis of the measurement noise of this re-gridded dataset in order to compare the lidar measurements with other collocated measurements (e.g., CloudSat, Microwave Limb Sounder). The re-gridded dataset has a manageable data volume for multi-year analysis. It has a fixed (5 km) horizontal resolution, and the measurement error is derived empirically from the background-corrected backscatter profile on a profile-by-profile basis. The 532-nm and 1064-nm measurement noises, determined from the data at altitudes above 19 km, are analyzed and characterized in terms of the mean (μ), standard deviation (σ), and normalized probability density function (PDF). These noises show a larger variance over landmasses and bright surfaces during day, and in regions with enhanced flux of energetic particles during night, where the instrument's ability for feature detection is slightly degraded. An increasing trend in the nighttime 1064-nm σ appears to be significant, which likely causes the increasing differences in cloud occurrence frequency between the 532-nm and 1064-nm channels. Most of the CALIOP backscatter noise distributions exhibit a Gaussian-like behavior but the nighttime 532-nm perpendicular measurements show multi-Gaussian characteristics. We apply σ – based thresholds to detect cloud/aerosol features in the UT/LS from the subset L1 data. The observed morphology is similar to that from the Level 2 (L2) 05km_CLAY+05km_ALAY product, but the occurrence frequency obtained in this study is slightly lower than the L2 product due to differences in spatial averaging and detection threshold. In the case where the measurement noises of two data sets are different, the normalized PDF has proven useful for quantifying the day-night difference of the CALIOP backscatters, showing higher daytime cloud occurrence frequency in the tropical UT/LS. Other cloud/aerosol properties, such as depolarization ratio and color ratio, can be also evaluated with the PDF method.

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Airborne measurements of aerosol optical properties related to early spring transport of mid-latitude sources into the Arctic

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-5011-2010 ◽

2010 ◽

Vol 10 (11) ◽

pp. 5011-5030 ◽

Cited By ~ 48

Author(s):

R. A. de Villiers ◽

G. Ancellet ◽

J. Pelon ◽

B. Quennehen ◽

A. Schwarzenboeck ◽

...

Keyword(s):

Optical Properties ◽

The Arctic ◽

Depolarization Ratio ◽

Aerosol Optical Properties ◽

Accumulation Mode ◽

Color Ratio ◽

Aerosol Sources ◽

Aerosol Backscatter ◽

532 Nm

Abstract. Airborne lidar and in-situ measurements of the aerosol properties were conducted between Svalbard Island and Scandinavia in April 2008. Evidence of aerosol transport from Europe and Asia is given. The analysis of the aerosol optical properties based on a multiwavelength lidar (355, 532, 1064 nm) including volume depolarization at 355 nm aims at distinguishing the role of the different aerosol sources (Siberian wild fires, Eastern Asia and European anthropogenic emissions). Combining, first aircraft measurements, second FLEXPART simulations with a calculation of the PBL air fraction originating from the three different mid-latitude source regions, and third level-2 CALIPSO data products (i.e. backscatter coefficient 532 nm,volume depolarization and color ratio between 1064 and 532 nm in aerosol layers) along the transport pathways, appears a valuable approach to identify the role of the different aerosol sources even after a transport time larger than 4 days. Optical depth of the aerosol layers are always rather small (<4%) while transported over the Arctic and ratio of the total attenuated backscatter (i.e. including molecular contribution) provide more stable result than conventional aerosol backscatter ratio. Above Asia, CALIPSO data indicate more depolarization (up to 15%) and largest color ratio (>0.5) for the northeastern Asia emissions (i.e. an expected mixture of Asian pollution and dust), while low depolarization together with smaller and quasi constant color ratio (≈0.3) are observed for the Siberian biomass burning emissions. A similar difference is visible between two layers observed by the aircraft above Scandinavia. The analysis of the time evolution of the aerosol optical properties revealed by CALIPSO between Asia and Scandinavia shows a gradual decrease of the aerosol backscatter, depolarization ratio and color ratio which suggests the removal of the largest particles in the accumulation mode. A similar study conducted for a European plume has shown aerosol optical properties intermediate between the two Asian sources with color ratio never exceeding 0.4 and moderate depolarization ratio being always less than 8%, i.e. less aerosol from the accumulation mode.

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Robust Visual Tracking with Channel Weighted Color Ratio Feature

2019 IEEE 4th International Conference on Image, Vision and Computing (ICIVC) ◽

10.1109/icivc47709.2019.8980966 ◽

2019 ◽

Author(s):

Shan Jiang ◽

Shuxiao Li ◽

Chengfei Zhu ◽

Xiaosong Lan

Keyword(s):

Visual Tracking ◽

Color Ratio

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Aerosol classification using airborne High Spectral Resolution Lidar measurements – methodology and examples

Atmospheric Measurement Techniques ◽

10.5194/amt-5-73-2012 ◽

2012 ◽

Vol 5 (1) ◽

pp. 73-98 ◽

Cited By ~ 252

Author(s):

S. P. Burton ◽

R. A. Ferrare ◽

C. A. Hostetler ◽

J. W. Hair ◽

R. R. Rogers ◽

...

Keyword(s):

Spectral Resolution ◽

High Spectral Resolution ◽

Color Ratio ◽

Lidar Measurements ◽

Aerosol Classification ◽

Langley Research Center ◽

High Spectral Resolution Lidar ◽

Aerosol Types ◽

532 Nm ◽

Aerosol Type

Abstract. The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) on the NASA B200 aircraft has acquired extensive datasets of aerosol extinction (532 nm), aerosol optical depth (AOD) (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm) profiles during 18 field missions that have been conducted over North America since 2006. The lidar measurements of aerosol intensive parameters (lidar ratio, depolarization, backscatter color ratio, and spectral depolarization ratio) are shown to vary with location and aerosol type. A methodology based on observations of known aerosol types is used to qualitatively classify the extensive set of HSRL aerosol measurements into eight separate types. Several examples are presented showing how the aerosol intensive parameters vary with aerosol type and how these aerosols are classified according to this new methodology. The HSRL-based classification reveals vertical variability of aerosol types during the NASA ARCTAS field experiment conducted over Alaska and northwest Canada during 2008. In two examples derived from flights conducted during ARCTAS, the HSRL classification of biomass burning smoke is shown to be consistent with aerosol types derived from coincident airborne in situ measurements of particle size and composition. The HSRL retrievals of AOD and inferences of aerosol types are used to apportion AOD to aerosol type; results of this analysis are shown for several experiments.

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