A case study of the life cycle of a stratus‐lowering coastal‐fog event in Newfoundland, Canada
Abstract We present a case study of a coastal‐fog stratus‐cloud‐lowering event on September 13–14, 2018, during the C‐FOG field campaign conducted along the east coast of Newfoundland, Canada. The goal of this work is to understand the mechanisms governing the life cycle of a 4‐hr‐long coastal‐fog e...
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crwiley:10.1002/qj.4615 2024-06-02T08:10:43+00:00 A case study of the life cycle of a stratus‐lowering coastal‐fog event in Newfoundland, Canada Singh, Dhiraj K. Hoch, Sebastian W. Gultepe, Ismail Pardyjak, Eric R. Office of Naval Research 2023 http://dx.doi.org/10.1002/qj.4615 https://rmets.onlinelibrary.wiley.com/doi/am-pdf/10.1002/qj.4615 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.4615 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Quarterly Journal of the Royal Meteorological Society volume 150, issue 759, page 641-662 ISSN 0035-9009 1477-870X journal-article 2023 crwiley https://doi.org/10.1002/qj.4615 2024-05-03T12:05:10Z Abstract We present a case study of a coastal‐fog stratus‐cloud‐lowering event on September 13–14, 2018, during the C‐FOG field campaign conducted along the east coast of Newfoundland, Canada. The goal of this work is to understand the mechanisms governing the life cycle of a 4‐hr‐long coastal‐fog event that resulted from the complex interplay of dynamic, thermodynamic, and microphysical processes. In addition to standard meteorological measurements, turbulence, irradiance, droplet‐size spectra, tethered‐balloon wind and thermodynamic profiles, visibility, precipitation, and spatial heterogeneity of microphysics measurements are presented to discriminate and interpret the fog formation, development, and dissipation. After sunset, strong radiative cloud‐top cooling induced top‐down convection length scales that can be characterised with the Thorpe scale. Top‐down mixing and turbulence kinetic energy generated due to buoyant/shear mixing are characterised using the flux and bulk Richardson number near the surface. Use of these parameters is unique in the analysis of fog events and helped describe mixing processes. Downward mixing led to fog droplet formation that precipitated from the cloud base, which in turn cooled the sub‐cloud layers via droplet evaporation and moistened the air beneath the cloud. Once fog formed, it was affected by dry‐air entrainment from its top. As a result, the fog thinned, creating patchy fog that was characterised by remarkable oscillations in visibility near the surface. Dissipation of the fog was driven by strong turbulence above the fog layer and horizontal thermal advection demonstrated using the temperature tendency equation. This work provides novel measurements and analysis techniques that have previously not been used to understand the mechanisms governing stratus‐lowering events. These observations and analyses help highlight processes and explain mechanisms related to the fog life cycle that are inherently challenging to predict in mesoscale models. Article in Journal/Newspaper Newfoundland Wiley Online Library Canada Quarterly Journal of the Royal Meteorological Society 150 759 641 662 |
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Wiley Online Library |
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crwiley |
language |
English |
description |
Abstract We present a case study of a coastal‐fog stratus‐cloud‐lowering event on September 13–14, 2018, during the C‐FOG field campaign conducted along the east coast of Newfoundland, Canada. The goal of this work is to understand the mechanisms governing the life cycle of a 4‐hr‐long coastal‐fog event that resulted from the complex interplay of dynamic, thermodynamic, and microphysical processes. In addition to standard meteorological measurements, turbulence, irradiance, droplet‐size spectra, tethered‐balloon wind and thermodynamic profiles, visibility, precipitation, and spatial heterogeneity of microphysics measurements are presented to discriminate and interpret the fog formation, development, and dissipation. After sunset, strong radiative cloud‐top cooling induced top‐down convection length scales that can be characterised with the Thorpe scale. Top‐down mixing and turbulence kinetic energy generated due to buoyant/shear mixing are characterised using the flux and bulk Richardson number near the surface. Use of these parameters is unique in the analysis of fog events and helped describe mixing processes. Downward mixing led to fog droplet formation that precipitated from the cloud base, which in turn cooled the sub‐cloud layers via droplet evaporation and moistened the air beneath the cloud. Once fog formed, it was affected by dry‐air entrainment from its top. As a result, the fog thinned, creating patchy fog that was characterised by remarkable oscillations in visibility near the surface. Dissipation of the fog was driven by strong turbulence above the fog layer and horizontal thermal advection demonstrated using the temperature tendency equation. This work provides novel measurements and analysis techniques that have previously not been used to understand the mechanisms governing stratus‐lowering events. These observations and analyses help highlight processes and explain mechanisms related to the fog life cycle that are inherently challenging to predict in mesoscale models. |
author2 |
Office of Naval Research |
format |
Article in Journal/Newspaper |
author |
Singh, Dhiraj K. Hoch, Sebastian W. Gultepe, Ismail Pardyjak, Eric R. |
spellingShingle |
Singh, Dhiraj K. Hoch, Sebastian W. Gultepe, Ismail Pardyjak, Eric R. A case study of the life cycle of a stratus‐lowering coastal‐fog event in Newfoundland, Canada |
author_facet |
Singh, Dhiraj K. Hoch, Sebastian W. Gultepe, Ismail Pardyjak, Eric R. |
author_sort |
Singh, Dhiraj K. |
title |
A case study of the life cycle of a stratus‐lowering coastal‐fog event in Newfoundland, Canada |
title_short |
A case study of the life cycle of a stratus‐lowering coastal‐fog event in Newfoundland, Canada |
title_full |
A case study of the life cycle of a stratus‐lowering coastal‐fog event in Newfoundland, Canada |
title_fullStr |
A case study of the life cycle of a stratus‐lowering coastal‐fog event in Newfoundland, Canada |
title_full_unstemmed |
A case study of the life cycle of a stratus‐lowering coastal‐fog event in Newfoundland, Canada |
title_sort |
case study of the life cycle of a stratus‐lowering coastal‐fog event in newfoundland, canada |
publisher |
Wiley |
publishDate |
2023 |
url |
http://dx.doi.org/10.1002/qj.4615 https://rmets.onlinelibrary.wiley.com/doi/am-pdf/10.1002/qj.4615 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.4615 |
geographic |
Canada |
geographic_facet |
Canada |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
Quarterly Journal of the Royal Meteorological Society volume 150, issue 759, page 641-662 ISSN 0035-9009 1477-870X |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/qj.4615 |
container_title |
Quarterly Journal of the Royal Meteorological Society |
container_volume |
150 |
container_issue |
759 |
container_start_page |
641 |
op_container_end_page |
662 |
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1800756619049435136 |