A new method for retrieval of the extinction coefficient of water clouds by using the tail of the CALIOP signal

Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Li J.; Hu Y.; Huang J.; et al. - Copernicus GmbH, 2011

A method is developed based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) level 1 attenuated backscatter profile data for deriving the mean extinction coefficient of water droplets close to cloud top. The method is applicable to low level (cloud top <2 km), opaque water clouds in which the lidar signal is completely attenuated beyond about 100 m of penetration into the cloud. The photo multiplier tubes (PMTs) of the 532 nm detectors (parallel and perpendicular polarizations) of the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) both exhibit a non-id ...

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[article] 

A new method for retrieval of the extinction coefficient of water clouds by using the tail of the CALIOP signal

  Available online: http://dx.doi.org/10.5194/acp-11-2903-2011

J. Li ; Y. Hu ; J. Huang ; K. Stamnes ; Y. Yi ; S. Stamnes

in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 3 [03/01/2011] . - p.2903-2916

A method is developed based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) level 1 attenuated backscatter profile data for deriving the mean extinction coefficient of water droplets close to cloud top. The method is applicable to low level (cloud top <2 km), opaque water clouds in which the lidar signal is completely attenuated beyond about 100 m of penetration into the cloud. The photo multiplier tubes (PMTs) of the 532 nm detectors (parallel and perpendicular polarizations) of the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) both exhibit a non-ideal recovery of the lidar signal after striking a strongly backscattering target (such as water cloud or surface). Therefore, the effects of any transient responses of CALIOP on the attenuated backscatter profile of the water cloud must first be removed in order to obtain a reliable (validated) attenuated backscatter profile. Then, the slope of the exponential decay of the validated water cloud attenuated backscatter profile, and the multiple scattering factor are used for deriving the mean extinction coefficient of low-level water cloud droplets close to cloud top. This novel method was evaluated and compared with the previous method which combined the cloud effective radius (3.7-μm) reported by MODIS with the lidar depolarization ratios measured by CALIPSO to estimate the mean extinction coefficient. Statistical results show that the extinction coefficients derived by the new method based on CALIOP alone agree reasonbably well with those obtained in the previous study using combined CALIOP and MODIS data. The mean absolute relative difference in extinction coefficient is about 13.4%. An important advantage of the new method is that it can be used to derive the extinction coefficient also during night time, and it is also applicable when multi-layered clouds are present. Overall, the stratocumulus dominated regions experience larger day-night differences which are all negative and seasonal. However, a contrary tendency consisted in the global mean values. The global mean cloud water extinction coefficients during different seasons range from 26 to 30 km−1, and the differences between day and night time are all positive and small (about 1–2 km−1). In addition, the global mean layer-integrated depolarization ratios of liquid water clouds during different seasons range from 0.2 to 0.23, and the differences between day and night also are small, about 0.01.

Language(s): English

Format: Digital (Free)

Tags: Water ; Methodology ; Water cloud ; Research Add tag

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Satellite Meteorology: GOES Channel Selection V2

The University Corporation for Atmospheric Research, 2011

This module is an update to the previous Satellite Meteorology: GOES Channel Selection module. It reviews the five GOES imager channels and their use, incorporating conceptual visualizations and numerous imagery examples. The module also includes updated information on improvements for the GOES-13, -14 and -15 satellites. Highlights include a higher resolution 13.3 micrometer CO2 channel (GOES-14 & -15), modified spectral response of the visible channel, improved radiometric performance and pixel geolocation, and shortened data outages during the fall and spring satellite eclipse periods.

English

 Satellite Meteorology: GOES Channel Selection V2

 Available online: https://www.meted.ucar.edu/training_module.php?id=784

Published by: The University Corporation for Atmospheric Research ; 2011

This module is an update to the previous Satellite Meteorology: GOES Channel Selection module. It reviews the five GOES imager channels and their use, incorporating conceptual visualizations and numerous imagery examples. The module also includes updated information on improvements for the GOES-13, -14 and -15 satellites. Highlights include a higher resolution 13.3 micrometer CO2 channel (GOES-14 & -15), modified spectral response of the visible channel, improved radiometric performance and pixel geolocation, and shortened data outages during the fall and spring satellite eclipse periods.

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Language(s): English

Format: Digital (Standard Copyright)

Tags: Weather forecasting ; Cloud type ; Lesson/ Tutorial ; Jet stream ; Fog ; Satellite Skills and Knowledge for Operational Meteorologists Add tag

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Kinematic and Thermodynamical Structures of Longitudinal-Mode Snow Bands over the Sea of Japan during Cold-Air Outbreaks Part I: Snow Bands in Large Vertical Shear Environment in the Band-Transverse Direction

Journal of the Meteorological Society of Japan, Vol. 88. No 4. Yamada Yoshinori; Murakami Masataka; Mizuno Hakaru - Meteorological Society of Japan, 2010

The kinematic and thermodynamical structures of two longitudinal-mode (termed “L-mode”) snow bands over the Sea of Japan occurring on February 8, 1991 and January 21, 1993 are analyzed mainly based on dual-Doppler radar data. The L-mode snow bands with multicellular structure in 1991 and 1993 formed, respectively, at the early onset of and toward the end of cold-air outbreaks, where the magnitude of the band-transverse vertical shear was roughly 2 × 10-3 s-1 approximately in the lower-half of the mixed layer. This magnitude was larger than that associated with L-mode snow bands characterized b ...

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[article] 

Kinematic and Thermodynamical Structures of Longitudinal-Mode Snow Bands over the Sea of Japan during Cold-Air Outbreaks Part I: Snow Bands in Large Vertical Shear Environment in the Band-Transverse Direction

  Available online: https://www.jstage.jst.go.jp/browse/jmsj/88/4/_contents

Yoshinori Yamada ; Masataka Murakami ; Hakaru Mizuno

in Journal of the Meteorological Society of Japan > Vol. 88. No 4 (2010) . - 45 p.

The kinematic and thermodynamical structures of two longitudinal-mode (termed “L-mode”) snow bands over the Sea of Japan occurring on February 8, 1991 and January 21, 1993 are analyzed mainly based on dual-Doppler radar data. The L-mode snow bands with multicellular structure in 1991 and 1993 formed, respectively, at the early onset of and toward the end of cold-air outbreaks, where the magnitude of the band-transverse vertical shear was roughly 2 × 10-3 s-1 approximately in the lower-half of the mixed layer. This magnitude was larger than that associated with L-mode snow bands characterized by axi-symmetric circulation, which will be described in Part II. Thermodynamical structures and the spatial distributions of water substances in the two snow bands were inferred from variational-based retrieval.
A pronounced feature of the airflow structures in both snow bands was upshear-tilting updrafts in the band-transverse vertical cross-section. At least two factors could account for their formation: the existence of a certain depth of the vertical layer of the environmental band-transverse system-relative wind components directing to the upshear, and the lower terminal fall velocities of snow and graupels. The retrieval results showed that both snow bands had a subsaturated cold pool beneath the band around the surface, whose collision with the unstable ambient air could have been responsible for overall upward motion in the bands. With regard to the energetics of the band circulation, energy production by buoyancy and the band-transverse shear was dominant.
The repeated formation of new cells was observed in the two snow bands in the downshear side, which may have been triggered by the low-level collision of the outflow from active cells or a cold pool with the unstable ambient air. As the new cell developed enough, the older cell significantly decayed. Consequently, the successive formation of cells did not change the overall echo pattern of the L-mode snow bands without producing elongated echoes branching o. into the downshear direction at large angles to the orientation of the L-mode snow bands.

Language(s): English; Other Languages: Japanese

Format: Digital (Free)

Tags: Cloud ; Sea ; Japan Add tag

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The Structure and Formation Mechanism of Transversal Cloud Bands Associated with the Japan-Sea Polar-Airmass Convergence Zone

Journal of the Meteorological Society of Japan, Vol. 88. No 4. Eito Hisaki; Murakami Masataka; Muroi Chiashi - Meteorological Society of Japan, 2010

During a cold-air outbreak, a broad cloud band is occasionally observed over the Japan-Sea Polar-Airmass Convergence Zone (JPCZ) that forms over the Sea of Japan from the base of the Korean Peninsula to the Japanese Islands. On 14 January 2001, a broad cloud band associated with the JPCZ (JPCZ cloud band) extended in a southeastward direction from the base of the Korean Peninsula to Wakasa Bay, and it stagnated for half a day. The JPCZ cloud band consisted of two cloud regions: one was a long cloud band extending along its southwestern edge (a developed convective cloud band), and the other wa ...

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[article] 

The Structure and Formation Mechanism of Transversal Cloud Bands Associated with the Japan-Sea Polar-Airmass Convergence Zone

  Available online: https://www.jstage.jst.go.jp/browse/jmsj/88/4/_contents

Hisaki Eito ; Masataka Murakami ; Chiashi Muroi

in Journal of the Meteorological Society of Japan > Vol. 88. No 4 (2010) . - 23 p.

During a cold-air outbreak, a broad cloud band is occasionally observed over the Japan-Sea Polar-Airmass Convergence Zone (JPCZ) that forms over the Sea of Japan from the base of the Korean Peninsula to the Japanese Islands. On 14 January 2001, a broad cloud band associated with the JPCZ (JPCZ cloud band) extended in a southeastward direction from the base of the Korean Peninsula to Wakasa Bay, and it stagnated for half a day. The JPCZ cloud band consisted of two cloud regions: one was a long cloud band extending along its southwestern edge (a developed convective cloud band), and the other was the region consisting of cloud bands normal to a wind direction of winter monsoon (transversal cloud bands). The structure and formation mechanism of the transversal cloud bands were examined on the basis of observations (e.g., satellite images, in situ measurement and cloud-pro.ling radar data from an instrumented aircraft and upper-air soundings from observation vessels) and simulation results of a cloud-resolving model with a horizontal resolution of 1 km.
The transversal cloud bands had the following characteristic structures; they extended along a northeast-southwest direction, which was parallel to the direction pointed by the vertical shear vector of horizontal wind in the mixed layer, they mainly consisted of convective clouds, which slanted with height toward the down-shear side, and they widened and deepened toward southwest, as the depth of the mixed layer increased. An examination of simulation results presented that the transversal cloud bands were accompanied by roll circulations. The axes of rolls were oriented nearly parallel to the direction of the vertical shear vector in the mixed layer. An analysis of the eddy kinetic energy budget indicated that the roll circulations derived most of its energy from the mean vertical shear and the buoyancy.

Language(s): English; Other Languages: Japanese

Format: Digital (Free)

Tags: Cloud ; Sea ; Japan Add tag

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Regime Behavior in the Sea Surface Temperature-Cloud Radiative Forcing Relationships over the Pacific Cold Tongue Region

Atmospheric and Oceanic Science Letters, Volume 3 Number 5. Wu Chun-Qiang; Zhou Tian-Jun; De-Zheng Xiao-Li - Science Press, 2010

Previous analyses on the estimates of water vapor and cloud-related feedbacks in the tropics usually use observations over the Earth Radiation Budget Experiment (ERBE) period (1985–89). To examine the sample dependence of previous estimates, the authors extend the analysis to two additional periods: 1990–94 and 1995–99. The results confirm our hypothesis, i.e., the values of the feedbacks depend on the period of data coverage. The differences in the feedbacks from cloud radiative forcings (CRFs) estimated from the three periods are particularly significant. Two possible causes for these differ ...

English

[article] 

Regime Behavior in the Sea Surface Temperature-Cloud Radiative Forcing Relationships over the Pacific Cold Tongue Region

  Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10042

Chun-Qiang Wu ; Tian-Jun Zhou ; Xiao-Li De-Zheng

in Atmospheric and Oceanic Science Letters > Volume 3 Number 5 (16 September 2010) . - p.271-276

Previous analyses on the estimates of water vapor and cloud-related feedbacks in the tropics usually use observations over the Earth Radiation Budget Experiment (ERBE) period (1985–89). To examine the sample dependence of previous estimates, the authors extend the analysis to two additional periods: 1990–94 and 1995–99. The results confirm our hypothesis, i.e., the values of the feedbacks depend on the period of data coverage. The differences in the feedbacks from cloud radiative forcings (CRFs) estimated from the three periods are particularly significant. Two possible causes for these differences are proposed. First, a regime behavior in the CRFs-Sea Surface Temperature Anomaly (SSTA) relationship over the cold tongue region is revealed: when SSTA is below –0.5oC, the CRFs anomalies are insensitive to the SSTA; when the SSTA is between –0.5oC and 2.0oC, the CRF anomalies are positively correlated with the SSTA; however, when the SSTA exceeds 2.0oC, the CRF anomalies decrease with the SSTA. This regime behavior is due to the regime behavior of cirrostratus and deep convective clouds. Second, the CRFs-SSTA relationship is regulated by remote forcings. Warming of the far eastern equatorial Pacific would reduce the water vapor convergence over the central Pacific by weakening the trade wind over the southeastern Pacific, thereby reducing the feeding of moisture to the convective flow. The results suggest that CRFs-SSTA relationships during ENSO events are nonlinear and strongly depend on the magnitude and the spatial distribution of the SSTA.

Language(s): English

Format: Digital (Free), Hard copy

Tags: Ocean-atmosphere interaction ; Cloud ; Observations ; Sea-surface temperature ; Pacific Ocean ; Region V - South-West Pacific Add tag

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Special issue - Atmospheric brown cloud in the Himalayas

is an issue of Atmospheric Chemistry and Physics (ACP). Copernicus GmbH, 2010

English

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Aerosol Indirect Effects on Warm Clouds in the Grid-Point Atmospheric Model of IAP LASG (GAMIL)

Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Shi Xiang-Jun; Wang Bin; Liu Xiao-Hong; et al. - Science Press, 2010

Aerosol indirect effects on warm clouds are estimated in the Grid-point Atmospheric Model of IAP LASG (GAMIL) with a new two-moment cloud microphysics scheme using two different physically-based aerosol activation parameterizations: Abdul-Razzak and Ghan, and Nenes and Seinfeld. The annual global mean changes in shortwave cloud forcing from preindustrial times to present day (a measure of the aerosol indirect effects) estimated from these two parameterizations are remarkably similar: 0.76 W m-2 with the Abdul-Razzak and Ghan parameterization, and 0.78 W m-2 with the Nenes and Seinfeld paramete ...

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Volume 3 Number 4 - 16 July 2010

is an issue of Atmospheric and Oceanic Science Letters. Science Press, 2010

English

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Cloud effects on erythemal UV radiation in a complex topography

Walker Daniel - Confédération Suisse, 2010

UV radiation is part of the solar spectrum with wavelengths between 100 and 400 nm. In this study, erythemal UV is investigated; a measure directly related to the harmfulness of
solar radiation to our skin. UV radiation has important impacts on di?fferent ecosystems, life and also on public health. Therefore, detailed information about the spatial distribution of UV radiation and its temporal evolution is required. Since observations are spatially and temporally sparse, these issues are often approached by radiative transfer modeling. These models perform well for simulating UV radiatio ...

English; German

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S-290 Unit 4: Basic Weather Processes

The University Corporation for Atmospheric Research, 2008

The “S-290 Unit 4: Basic Weather Processes” distance learning module summarizes atmospheric structure and composition, the Sun-Earth radiation budget, weather elements used to describe the atmosphere, the greenhouse effect, and temperature lags observed both daily and seasonally. The content introduces the concepts of pressure, atmospheric heating, and temperature and provides a basis for understanding weather topics that are explored in more detail in other modules of the Intermediate Wildland Fire Behavior Course.

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WCRP, 122. GCSS-ARM Workshop on the Representation of Cloud Systems in Large-Scale Models

World Meteorological Organization (WMO) - WMO, 2005 (WMO/TD-No. 1290)

1 CD-ROM

English

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WMP Report Series, 42. Regional Seminar on Cloud Physics and Weather Modification

Bojkov Rumen D.; World Meteorological Organization (WMO) - WMO, 2004 (WMO/TD-No. 1227)

1 CD-ROM

English

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Feature Identification Exercises: Clouds, Snow, and Ice Using MODIS

The University Corporation for Atmospheric Research, 2002

This module consists of four exercises where users identify surface features, distinguish clouds from snow on the ground, and determine cloud phase using multispectral analysis. The module also includes an overview of multispectral techniques available on many operational and research polar-orbiting satellites. A page with links to real-time polar-orbiting data and information is also included.

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WCRP Informal/Series Report, 19/2001. Report of the ninth session of the GEWEX Cloud system study (GCSS)

World Meteorological Organization (WMO) ; Intergovernmental Oceanographic Commission (IOC); International Council for Science (ICSU) - WMO, 2001

English

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WMP Report Series, 33. Report of the WMO Workshop for the Planning of Precipitation Enhancement Project in the Mediterranean, SE Europe and Middle East Countries (MEDSEEME-PEP)

World Meteorological Organization (WMO) - WMO, 2000 (WMO/TD-No. 998)

English

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