Classification of particle shapes from lidar depolarization ratio in convective ice clouds compared to in situ observations during CRYSTAL-FACE

Abstract. This paper presents a comparison of lidar ratios and volume extinction coefficients in tropical ice clouds, retrieved using observations from two instruments: the 532-nm Cloud Physics Lidar (CPL), and the in-situ Cloud Integrating Nephelometer (CIN) probe. Both instruments were mounted on airborne platforms during the CRYSTAL-FACE campaign and took measurements up to 17 km. Coincident observations from two cases of ice clouds located on top of deep convective systems are compared. First, lidar ratios are retrieved from CPL observations of attenuated backscatter, using a retrieval algorithm for opaque cloud similar to one used in the soon-to-be launched CALIPSO mission, and compared to results from the regular CPL algorithm. These lidar ratios are used to retrieve extinction coefficient profiles, which are compared to actual observations from the CIN in-situ probe, putting the emphasis on their vertical variability. When observations coincide, retrievals from both instruments are very similar. Differences are generally variations around the average profiles, and general trends on larger spatial scales are usually well reproduced. The two instruments agree well, with an average difference of less than 11% on optical depth retrievals. Results suggest the CALIPSO Deep Convection algorithm can be trusted to deliver realistic estimates of the lidar ratio, leading to good retrievals of extinction coefficients.

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Growth of monoatomic layer terraces on a (111) lead crystal face: In situ observations in dark field by UHV-TEM

Surface Science Letters ◽

10.1016/0167-2584(85)91121-1 ◽

1985 ◽

Vol 155 (1) ◽

pp. A259

Author(s):

J.J. Métois ◽

K. Takayanagi ◽

Y. Tanishiro

Keyword(s):

Dark Field ◽

Lead Crystal ◽

Crystal Face ◽

In Situ Observations

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Relative Humidity in Liquid, Mixed-Phase, and Ice Clouds

Journal of the Atmospheric Sciences ◽

10.1175/jas3784.1 ◽

2006 ◽

Vol 63 (11) ◽

pp. 2865-2880 ◽

Cited By ~ 64

Author(s):

Alexei Korolev ◽

George A. Isaac

Keyword(s):

Relative Humidity ◽

Research Council ◽

Large Fraction ◽

National Research Council ◽

Mixed Phase ◽

Ice Clouds ◽

In Situ Observations ◽

Frontal Systems ◽

Mixed Phase Clouds

Abstract The results of in situ observations of the relative humidity in liquid, mixed, and ice clouds typically stratiform in nature and associated with mesoscale frontal systems at temperatures −45°C < Ta < −5°C are presented. The data were collected with the help of instrumentation deployed on the National Research Council (NRC) Convair-580. The length of sampled in-cloud space is approximately 23 × 103 km. The liquid sensor was calibrated in liquid clouds with the assumption that the air in liquid clouds is saturated with respect to water. It was found that the relative humidity in mixed-phase clouds is close to saturation over water in the temperature range from −5° to −35°C for an averaging scale of 100 m. In ice clouds the relative humidity over ice is not necessarily equal to 100%, and it may be either lower or higher than saturation over ice, but it is always lower than saturation over water. On average the relative humidity in ice clouds increases with a decrease of temperature. At −40°C the relative humidity over ice is midway between saturation over ice and liquid. A parameterization for the relative humidity in ice clouds is suggested. A large fraction of ice clouds was found to be undersaturated with respect to ice. The fraction of ice clouds undersaturated with respect to ice increases toward warmer temperatures.

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CAPACITY BUILDING FOR HIGH-RESOLUTION LAND COVER INTERCOMPARISON AND VALIDATION: WHAT IS AVAILABLE AND WHAT IS NEEDED

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-4-w8-15-2018 ◽

2018 ◽

Vol XLII-4/W8 ◽

pp. 15-22

Author(s):

M. A. Brovelli ◽

M. Minghini ◽

M. E. Molinari ◽

H. Wu ◽

X. Zheng ◽

...

Keyword(s):

High Resolution ◽

Land Cover ◽

Capacity Building ◽

Ad Hoc ◽

Educational Material ◽

Reference Dataset ◽

Training Material ◽

In Situ Observations

Abstract. Land Cover (LC) maps are fundamental products for a wide variety of applications. The workflow for their production is composed of classification of satellite imagery and validation against a reference dataset. Different LC maps as well as multiple versions in time of the same LC map can be also compared with one another to assess LC changes. Since the current richness of both space and in-situ observations makes it quite easy to produce LC maps, it is fundamental to assess their accuracy before using them for real applications. This paper focuses on education and capacity building on the intercomparison and validation of global (i.e. covering the whole world) and high-resolution (i.e. with a spatial resolution of at least 30m) LC maps. The availability of Free and Open Source for Geospatial (FOSS4G) technology capable to process LC maps, as well as the existence of ad hoc educational material, is carefully assessed. In parallel, an ad hoc survey has showed that users, especially in developing countries, often lack awareness about the need to validate them and are not aware about the existence of training material. With this premise, a new project presented in the paper aims to produce new, openly licensed and FOSS4G-based training material on the intercomparison and validation of global high-resolution LC maps.

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Extinction coefficients retrieved in deep tropical ice clouds from lidar observations using a CALIPSO-like algorithm compared to in-situ measurements from the cloud integrating nephelometer during CRYSTAL-FACE

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-1415-2007 ◽

2007 ◽

Vol 7 (5) ◽

pp. 1415-1422 ◽

Cited By ~ 15

Author(s):

V. Noel ◽

D. M. Winker ◽

T. J. Garrett ◽

M. McGill

Keyword(s):

Spatial Scales ◽

Deep Convection ◽

Retrieval Algorithm ◽

Crystal Face ◽

Ice Clouds ◽

Extinction Coefficients ◽

Convective Systems ◽

Lidar Ratio ◽

Integrating Nephelometer

Abstract. This paper presents a comparison of lidar ratios and volume extinction coefficients in tropical ice clouds, retrieved using observations from two instruments: the 532-nm Cloud Physics Lidar (CPL), and the in-situ Cloud Integrating Nephelometer (CIN) probe. Both instruments were mounted on airborne platforms during the CRYSTAL-FACE campaign and took measurements up to 17 km. Coincident observations from two cases of ice clouds located on top of deep convective systems are compared. First, lidar ratios are retrieved from CPL observations of attenuated backscatter, using a retrieval algorithm for opaque cloud similar to one used in the recently launched CALIPSO mission, and compared to results from the regular CPL algorithm. These lidar ratios are used to retrieve extinction coefficient profiles, which are compared to actual observations from the CIN in-situ probe, putting the emphasis on their vertical variability. When observations coincide, retrievals from both instruments are very similar, in the limits of colocation. Differences are generally variations around the average profiles, and general trends on larger spatial scales are well reproduced. The two instruments agree well, with an average difference of less than 11% on optical depth retrievals. Results suggest the CALIPSO Deep Convection algorithm can be trusted to deliver realistic estimates of the lidar ratio, leading to good retrievals of extinction coefficients.

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Growth of monoatomic layer terraces on a (111) lead crystal face: In situ observations in dark field by UHV-TEM

Surface Science ◽

10.1016/0039-6028(85)90404-2 ◽

1985 ◽

Vol 155 (1) ◽

pp. 53-64 ◽

Cited By ~ 5

Author(s):

J.J. Métois ◽

K. Takayanagi ◽

Y. Tanishiro

Keyword(s):

Dark Field ◽

Lead Crystal ◽

Crystal Face ◽

In Situ Observations

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In situ observations of electromigration induced void behavior

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100137598 ◽

1995 ◽

Vol 53 ◽

pp. 244-245

Author(s):

T. Marieb ◽

J. C. Bravman ◽

P. Flinn ◽

D. Gardner ◽

M. Madden

Keyword(s):

Electron Microscopy ◽

Void Nucleation ◽

Plan View ◽

Transmission Electron ◽

Nucleation Sites ◽

Microelectronics Industry ◽

In Situ Observations ◽

Backscatter Electron Detector ◽

Voltage Scanning

Electromigration and stress voiding have been active areas of research in the microelectronics industry for many years. While accelerated testing of these phenomena has been performed for the last 25 years[1-2], only recently has the introduction of high voltage scanning electron microscopy (HVSEM) made possible in situ testing of realistic, passivated, full thickness samples at high resolution.With a combination of in situ HVSEM and post-testing transmission electron microscopy (TEM) , electromigration void nucleation sites in both normal polycrystalline and near-bamboo pure Al were investigated. The effect of the microstructure of the lines on the void motion was also studied.The HVSEM used was a slightly modified JEOL 1200 EX II scanning TEM with a backscatter electron detector placed above the sample[3]. To observe electromigration in situ the sample was heated and the line had current supplied to it to accelerate the voiding process. After testing lines were prepared for TEM by employing the plan-view wedge technique [6].

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