Coastal Stratocumulus-Topped Boundary Layers and the Role of Cloud-Top Entrainment

Coastal Stratocumulus-Topped Boundary Layers and the Role of Cloud-Top Entrainment

Author: Daniel P. Eleuterio

Publisher:

Published: 2004-06

Total Pages: 134

ISBN-13: 9781423518709

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The ability of the U.S. Navy's Coupled Ocean-Atmosphere Mesoscale Prediction System (COAMPS) (Trademark) to accurately forecast the height and structure of the Marine Boundary Layer (MBL) in the coastal zone is analyzed and compared to surface and aircraft observations from the Dynamics and Evolution of Coastal Stratus (DECS) field study conducted along the central coast of California from June 16 to July 22, 1999. The stratus field was found to have significant mesoscale variability within 100 km of the coast due to interaction between the mean flow and the coastal terrain. This structure is consistent with general hydraulic flow theory and the development of a low-level coastal jet. However, the specific characteristics on any given day were very sensitive to flow direction, inversion height, and synoptic conditions. With some modifications, the model predicted the general evolution of these events with qualitative fidelity, but was slow to dissipate the cloud and frequently produced surface fog versus stratus. A consistent tendency was found in the model's predictions of inversion heights 200-300 meters too low, weak inversion strengths, high integrated liquid water content, and weak buoyancy flux near the cloud top. These observed biases are consistent with underestimating the cloud top entrainment velocity and entrainment fluxes in the modeled boundary layer. An explicit entrainment parameterization was developed to better represent the sub-grid scale processes at cloud top and was tested in the single column and 3D versions of COAMPS. The entrainment parameterization was found to improve the boundary layer height and cloud liquid water content as compared to field observations, but the modeled boundary layer still exhibited a low bias, and the entrainment velocity was higher than is generally expected from field studies for this regime. (2 tables, 53 figures. 80 refs.) ANNOTATION: The Role of Cloud-Top Entrainment in Coastal Stratocumulus-Topped Boundary Layers


Book Synopsis Coastal Stratocumulus-Topped Boundary Layers and the Role of Cloud-Top Entrainment by : Daniel P. Eleuterio

Download or read book Coastal Stratocumulus-Topped Boundary Layers and the Role of Cloud-Top Entrainment written by Daniel P. Eleuterio and published by . This book was released on 2004-06 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability of the U.S. Navy's Coupled Ocean-Atmosphere Mesoscale Prediction System (COAMPS) (Trademark) to accurately forecast the height and structure of the Marine Boundary Layer (MBL) in the coastal zone is analyzed and compared to surface and aircraft observations from the Dynamics and Evolution of Coastal Stratus (DECS) field study conducted along the central coast of California from June 16 to July 22, 1999. The stratus field was found to have significant mesoscale variability within 100 km of the coast due to interaction between the mean flow and the coastal terrain. This structure is consistent with general hydraulic flow theory and the development of a low-level coastal jet. However, the specific characteristics on any given day were very sensitive to flow direction, inversion height, and synoptic conditions. With some modifications, the model predicted the general evolution of these events with qualitative fidelity, but was slow to dissipate the cloud and frequently produced surface fog versus stratus. A consistent tendency was found in the model's predictions of inversion heights 200-300 meters too low, weak inversion strengths, high integrated liquid water content, and weak buoyancy flux near the cloud top. These observed biases are consistent with underestimating the cloud top entrainment velocity and entrainment fluxes in the modeled boundary layer. An explicit entrainment parameterization was developed to better represent the sub-grid scale processes at cloud top and was tested in the single column and 3D versions of COAMPS. The entrainment parameterization was found to improve the boundary layer height and cloud liquid water content as compared to field observations, but the modeled boundary layer still exhibited a low bias, and the entrainment velocity was higher than is generally expected from field studies for this regime. (2 tables, 53 figures. 80 refs.) ANNOTATION: The Role of Cloud-Top Entrainment in Coastal Stratocumulus-Topped Boundary Layers

Estimation of Stratocumulus-Topped Boundary Layer Depth Using Sea Surface and Remotely Sensed Cloud-Top Temperatures

Estimation of Stratocumulus-Topped Boundary Layer Depth Using Sea Surface and Remotely Sensed Cloud-Top Temperatures

Author: Marvin B. McBride, III

Publisher:

Published: 2000-06-01

Total Pages: 94

ISBN-13: 9781423536123

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The depth of the marine atmospheric boundary layer (MABL) is an important parameter for both scientific and operational meteorological applications. The depth of the marine boundary layer has a significant influence on the atmospheric dynamics in the coastal zone. Knowledge of the depth of stratocumulus-topped boundary layers (STELs) will enable coastal operations to more accurately anticipate weather, and electromagnetic propagation conditions. This study develops a satellite remote sensing technique for determining the height of MABLs topped with stratocumulus clouds. Validation of the technique using coastal rawinsonde dataset from the Monterey Area Ship Track (MAST) experiment revealed that an assumption of 41% cloud with a moist lapse rate equal to -7.0 deg C/km had the best overall fit to the data. However, for shallow boundary layers with depths below 400m the most accurate assumption was 75% cloud with a moist lapse rate equal to -6.5 deg C/km. The application of this technique to sounding data returned an overall BL depth accuracy of 50m while the satellite application returned an overall accuracy of 65m. A sensitivity analysis of both surface and cloud-top temperature revealed that a 1/2 deg C change in either temperature resulted in an error of 60-70m in boundary layer depth.


Book Synopsis Estimation of Stratocumulus-Topped Boundary Layer Depth Using Sea Surface and Remotely Sensed Cloud-Top Temperatures by : Marvin B. McBride, III

Download or read book Estimation of Stratocumulus-Topped Boundary Layer Depth Using Sea Surface and Remotely Sensed Cloud-Top Temperatures written by Marvin B. McBride, III and published by . This book was released on 2000-06-01 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: The depth of the marine atmospheric boundary layer (MABL) is an important parameter for both scientific and operational meteorological applications. The depth of the marine boundary layer has a significant influence on the atmospheric dynamics in the coastal zone. Knowledge of the depth of stratocumulus-topped boundary layers (STELs) will enable coastal operations to more accurately anticipate weather, and electromagnetic propagation conditions. This study develops a satellite remote sensing technique for determining the height of MABLs topped with stratocumulus clouds. Validation of the technique using coastal rawinsonde dataset from the Monterey Area Ship Track (MAST) experiment revealed that an assumption of 41% cloud with a moist lapse rate equal to -7.0 deg C/km had the best overall fit to the data. However, for shallow boundary layers with depths below 400m the most accurate assumption was 75% cloud with a moist lapse rate equal to -6.5 deg C/km. The application of this technique to sounding data returned an overall BL depth accuracy of 50m while the satellite application returned an overall accuracy of 65m. A sensitivity analysis of both surface and cloud-top temperature revealed that a 1/2 deg C change in either temperature resulted in an error of 60-70m in boundary layer depth.

Convective Activities Within the Stratocumulus-Topped Boundary Layer

Convective Activities Within the Stratocumulus-Topped Boundary Layer

Author: Michelle K. Whisenhant

Publisher:

Published: 1999-12-01

Total Pages: 96

ISBN-13: 9781423540052

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This study utilizes aircraft measurements obtained off the California coast to analyze the geometric, thermodynamic, and micro physical characteristics of convective updrafts and down drafts in the stratocumulus- topped boundary layer (BL). The vertical structure of thermodynamic and micro physical properties is consistent. The difference in peak droplet concentration between updrafts, down drafts, and the defined environment increases near the cloud top. We observe larger mean droplet diameters in down drafts near the cloud top, as the number of small droplets in cloud top down drafts appears to decrease. The horizontal variability seen in the cloud droplet spectra and micro physics properties is likely due to aerosol activation and growth in updrafts, cloud top entrainment, and penetrating cumulus. We compute the mass flux, using a mass flux parameterization. Several measured variables produce consistent results and agree with mass flux calculations from other stratocumulus datasets.


Book Synopsis Convective Activities Within the Stratocumulus-Topped Boundary Layer by : Michelle K. Whisenhant

Download or read book Convective Activities Within the Stratocumulus-Topped Boundary Layer written by Michelle K. Whisenhant and published by . This book was released on 1999-12-01 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study utilizes aircraft measurements obtained off the California coast to analyze the geometric, thermodynamic, and micro physical characteristics of convective updrafts and down drafts in the stratocumulus- topped boundary layer (BL). The vertical structure of thermodynamic and micro physical properties is consistent. The difference in peak droplet concentration between updrafts, down drafts, and the defined environment increases near the cloud top. We observe larger mean droplet diameters in down drafts near the cloud top, as the number of small droplets in cloud top down drafts appears to decrease. The horizontal variability seen in the cloud droplet spectra and micro physics properties is likely due to aerosol activation and growth in updrafts, cloud top entrainment, and penetrating cumulus. We compute the mass flux, using a mass flux parameterization. Several measured variables produce consistent results and agree with mass flux calculations from other stratocumulus datasets.

Advances in Geophysics

Advances in Geophysics

Author:

Publisher: Academic Press

Published: 1996-02-29

Total Pages: 289

ISBN-13: 0080568688

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From the Foreword: "This series has provided workers in many fields with invaluable reference material and criticism." --Science Progress "Should be on the bookshelf of every geophysicist." --Physics Today "The entire series should be in the library of every group working in geophysics." --American Scientist


Book Synopsis Advances in Geophysics by :

Download or read book Advances in Geophysics written by and published by Academic Press. This book was released on 1996-02-29 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the Foreword: "This series has provided workers in many fields with invaluable reference material and criticism." --Science Progress "Should be on the bookshelf of every geophysicist." --Physics Today "The entire series should be in the library of every group working in geophysics." --American Scientist

Storm and Cloud Dynamics

Storm and Cloud Dynamics

Author: William R. Cotton

Publisher: Elsevier

Published: 2013-10-22

Total Pages: 896

ISBN-13: 1483288382

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This book focuses on the dynamics of clouds and of precipitating mesoscale meteorological systems. Clouds and precipitating mesoscale systems represent some of the most important and scientifically exciting weather systems in the world. These are the systems that produce torrential rains, severe winds including downburst and tornadoes, hail, thunder and lightning, and major snow storms. Forecasting such storms represents a major challenge since they are too small to be adequately resolved by conventional observing networks and numerical prediction models.


Book Synopsis Storm and Cloud Dynamics by : William R. Cotton

Download or read book Storm and Cloud Dynamics written by William R. Cotton and published by Elsevier. This book was released on 2013-10-22 with total page 896 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the dynamics of clouds and of precipitating mesoscale meteorological systems. Clouds and precipitating mesoscale systems represent some of the most important and scientifically exciting weather systems in the world. These are the systems that produce torrential rains, severe winds including downburst and tornadoes, hail, thunder and lightning, and major snow storms. Forecasting such storms represents a major challenge since they are too small to be adequately resolved by conventional observing networks and numerical prediction models.

Monthly Weather Review

Monthly Weather Review

Author:

Publisher:

Published: 2007

Total Pages: 1652

ISBN-13:

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Book Synopsis Monthly Weather Review by :

Download or read book Monthly Weather Review written by and published by . This book was released on 2007 with total page 1652 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Estimation of Stratocumulus-topped Boundary Layer Depth Using Sea Surface and Remotely Sensed Cloud-top Temperatures

Estimation of Stratocumulus-topped Boundary Layer Depth Using Sea Surface and Remotely Sensed Cloud-top Temperatures

Author: Marvin B. McBride

Publisher:

Published: 2000

Total Pages: 82

ISBN-13:

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The depth of the marine atmospheric boundary layer (MABL) is an important parameter for both scientific and operational meteorological applications. The depth of the marine boundary layer has a significant influence on the atmospheric dynamics in the coastal zone. Knowledge of the depth of stratocumulus-topped boundary layers (STELs) will enable coastal operations to more accurately anticipate weather, and electromagnetic propagation conditions. This study develops a satellite remote sensing technique for determining the height of MABLs topped with stratocumulus clouds. Validation of the technique using coastal rawinsonde dataset from the Monterey Area Ship Track (MAST) experiment revealed that an assumption of 41% cloud with a moist lapse rate equal to -7.0 deg C/km had the best overall fit to the data. However, for shallow boundary layers with depths below 400m the most accurate assumption was 75% cloud with a moist lapse rate equal to -6.5 deg C/km. The application of this technique to sounding data returned an overall BL depth accuracy of 50m while the satellite application returned an overall accuracy of 65m. A sensitivity analysis of both surface and cloud-top temperature revealed that a 1/2 deg C change in either temperature resulted in an error of 60-70m in boundary layer depth.


Book Synopsis Estimation of Stratocumulus-topped Boundary Layer Depth Using Sea Surface and Remotely Sensed Cloud-top Temperatures by : Marvin B. McBride

Download or read book Estimation of Stratocumulus-topped Boundary Layer Depth Using Sea Surface and Remotely Sensed Cloud-top Temperatures written by Marvin B. McBride and published by . This book was released on 2000 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: The depth of the marine atmospheric boundary layer (MABL) is an important parameter for both scientific and operational meteorological applications. The depth of the marine boundary layer has a significant influence on the atmospheric dynamics in the coastal zone. Knowledge of the depth of stratocumulus-topped boundary layers (STELs) will enable coastal operations to more accurately anticipate weather, and electromagnetic propagation conditions. This study develops a satellite remote sensing technique for determining the height of MABLs topped with stratocumulus clouds. Validation of the technique using coastal rawinsonde dataset from the Monterey Area Ship Track (MAST) experiment revealed that an assumption of 41% cloud with a moist lapse rate equal to -7.0 deg C/km had the best overall fit to the data. However, for shallow boundary layers with depths below 400m the most accurate assumption was 75% cloud with a moist lapse rate equal to -6.5 deg C/km. The application of this technique to sounding data returned an overall BL depth accuracy of 50m while the satellite application returned an overall accuracy of 65m. A sensitivity analysis of both surface and cloud-top temperature revealed that a 1/2 deg C change in either temperature resulted in an error of 60-70m in boundary layer depth.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports

Author:

Publisher:

Published: 1995

Total Pages: 456

ISBN-13:

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Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.


Book Synopsis Scientific and Technical Aerospace Reports by :

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Storm and Cloud Dynamics

Storm and Cloud Dynamics

Author: William R. Cotton

Publisher: Academic Press

Published: 2010-12-21

Total Pages: 826

ISBN-13: 0080916651

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Storm and Cloud Dynamics focuses on the dynamics of clouds and of precipitating mesoscale meteorological systems. Clouds and precipitating mesoscale systems represent some of the most important and scientifically exciting weather systems in the world. These are the systems that produce torrential rains, severe winds including downburst and tornadoes, hail, thunder and lightning, and major snow storms. Forecasting such storms represents a major challenge since they are too small to be adequately resolved by conventional observing networks and numerical prediction models. Provides a complete treatment of clouds integrating the analysis of air motions with cloud structure, microphysics, and precipitation mechanics Describes and explains the basic types of clouds and cloud systems that occur in the atmosphere-fog, stratus, stratocumulus, altocumulus, altostratus, cirrus, thunderstorms, tornadoes, waterspouts, orographically induced clouds, mesoscale convection complexes, hurricanes, fronts, and extratropical cyclones Summarizes the fundamentals, both observational and theoretical, of atmospheric dynamics, thermodynamics, cloud microphysics, and radar meteorology, allowing each type of cloud to be examined in depth Integrates the latest field observations, numerical model simulations, and theory Supplies a theoretical treatment suitable for the advanced undergraduate or graduate level, as well as post-graduate


Book Synopsis Storm and Cloud Dynamics by : William R. Cotton

Download or read book Storm and Cloud Dynamics written by William R. Cotton and published by Academic Press. This book was released on 2010-12-21 with total page 826 pages. Available in PDF, EPUB and Kindle. Book excerpt: Storm and Cloud Dynamics focuses on the dynamics of clouds and of precipitating mesoscale meteorological systems. Clouds and precipitating mesoscale systems represent some of the most important and scientifically exciting weather systems in the world. These are the systems that produce torrential rains, severe winds including downburst and tornadoes, hail, thunder and lightning, and major snow storms. Forecasting such storms represents a major challenge since they are too small to be adequately resolved by conventional observing networks and numerical prediction models. Provides a complete treatment of clouds integrating the analysis of air motions with cloud structure, microphysics, and precipitation mechanics Describes and explains the basic types of clouds and cloud systems that occur in the atmosphere-fog, stratus, stratocumulus, altocumulus, altostratus, cirrus, thunderstorms, tornadoes, waterspouts, orographically induced clouds, mesoscale convection complexes, hurricanes, fronts, and extratropical cyclones Summarizes the fundamentals, both observational and theoretical, of atmospheric dynamics, thermodynamics, cloud microphysics, and radar meteorology, allowing each type of cloud to be examined in depth Integrates the latest field observations, numerical model simulations, and theory Supplies a theoretical treatment suitable for the advanced undergraduate or graduate level, as well as post-graduate

Fast Processes in Large-Scale Atmospheric Models

Fast Processes in Large-Scale Atmospheric Models

Author: Yangang Liu

Publisher: John Wiley & Sons

Published: 2023-12-11

Total Pages: 483

ISBN-13: 1119528941

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Improving weather and climate prediction with better representation of fast processes in atmospheric models Many atmospheric processes that influence Earth’s weather and climate occur at spatiotemporal scales that are too small to be resolved in large scale models. They must be parameterized, which means approximately representing them by variables that can be resolved by model grids. Fast Processes in Large-Scale Atmospheric Models: Progress, Challenges and Opportunities explores ways to better investigate and represent multiple parameterized processes in models and thus improve their ability to make accurate climate and weather predictions. Volume highlights include: Historical development of the parameterization of fast processes in numerical models Different types of major sub-grid processes and their parameterizations Efforts to unify the treatment of individual processes and their interactions Top-down versus bottom-up approaches across multiple scales Measurement techniques, observational studies, and frameworks for model evaluation Emerging challenges, new opportunities, and future research directions The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.


Book Synopsis Fast Processes in Large-Scale Atmospheric Models by : Yangang Liu

Download or read book Fast Processes in Large-Scale Atmospheric Models written by Yangang Liu and published by John Wiley & Sons. This book was released on 2023-12-11 with total page 483 pages. Available in PDF, EPUB and Kindle. Book excerpt: Improving weather and climate prediction with better representation of fast processes in atmospheric models Many atmospheric processes that influence Earth’s weather and climate occur at spatiotemporal scales that are too small to be resolved in large scale models. They must be parameterized, which means approximately representing them by variables that can be resolved by model grids. Fast Processes in Large-Scale Atmospheric Models: Progress, Challenges and Opportunities explores ways to better investigate and represent multiple parameterized processes in models and thus improve their ability to make accurate climate and weather predictions. Volume highlights include: Historical development of the parameterization of fast processes in numerical models Different types of major sub-grid processes and their parameterizations Efforts to unify the treatment of individual processes and their interactions Top-down versus bottom-up approaches across multiple scales Measurement techniques, observational studies, and frameworks for model evaluation Emerging challenges, new opportunities, and future research directions The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.