A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes
Observations of long-lived mixed-phase Arctic boundary layer clouds on 7 May 1998 during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE)Arctic Cloud Experiment (ACE)Surface Heat Budget of the Arctic Ocean (SHEBA) campaign provide a unique opportunity to...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20130014863 2023-05-15T14:52:57+02:00 A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes vanDiedenhoven, Bastiaan Morrison, Hugh Fridlin, Ann Ackerman, Andrew S. Shupe, Matthew D. Mrowiec, Agnieszka Avramov, Alexander Zuidema, Paquita Unclassified, Unlimited, Publicly available January 2012 application/pdf http://hdl.handle.net/2060/20130014863 unknown Document ID: 20130014863 http://hdl.handle.net/2060/20130014863 Copyright, Distribution as joint owner in the copyright CASI Meteorology and Climatology GSFC-E-DAA-TN8905 Journal of the Atmospheric Sciences; 69; 1; 365-389 2012 ftnasantrs 2019-07-21T00:35:32Z Observations of long-lived mixed-phase Arctic boundary layer clouds on 7 May 1998 during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE)Arctic Cloud Experiment (ACE)Surface Heat Budget of the Arctic Ocean (SHEBA) campaign provide a unique opportunity to test understanding of cloud ice formation. Under the microphysically simple conditions observed (apparently negligible ice aggregation, sublimation, and multiplication), the only expected source of new ice crystals is activation of heterogeneous ice nuclei (IN) and the only sink is sedimentation. Large-eddy simulations with size-resolved microphysics are initialized with IN number concentration N(sub IN) measured above cloud top, but details of IN activation behavior are unknown. If activated rapidly (in deposition, condensation, or immersion modes), as commonly assumed, IN are depleted from the well-mixed boundary layer within minutes. Quasi-equilibrium ice number concentration N(sub i) is then limited to a small fraction of overlying N(sub IN) that is determined by the cloud-top entrainment rate w(sub e) divided by the number-weighted ice fall speed at the surface v(sub f). Because w(sub c)< 1 cm/s and v(sub f)> 10 cm/s, N(sub i)/N(sub IN)<< 1. Such conditions may be common for this cloud type, which has implications for modeling IN diagnostically, interpreting measurements, and quantifying sensitivity to increasing N(sub IN) (when w(sub e)/v(sub f)< 1, entrainment rate limitations serve to buffer cloud system response). To reproduce observed ice crystal size distributions and cloud radar reflectivities with rapidly consumed IN in this case, the measured above-cloud N(sub IN) must be multiplied by approximately 30. However, results are sensitive to assumed ice crystal properties not constrained by measurements. In addition, simulations do not reproduce the pronounced mesoscale heterogeneity in radar reflectivity that is observed. Other/Unknown Material Arctic Arctic Ocean Surface Heat Budget of the Arctic Ocean NASA Technical Reports Server (NTRS) Arctic Arctic Ocean |
institution |
Open Polar |
collection |
NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Meteorology and Climatology |
spellingShingle |
Meteorology and Climatology vanDiedenhoven, Bastiaan Morrison, Hugh Fridlin, Ann Ackerman, Andrew S. Shupe, Matthew D. Mrowiec, Agnieszka Avramov, Alexander Zuidema, Paquita A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes |
topic_facet |
Meteorology and Climatology |
description |
Observations of long-lived mixed-phase Arctic boundary layer clouds on 7 May 1998 during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE)Arctic Cloud Experiment (ACE)Surface Heat Budget of the Arctic Ocean (SHEBA) campaign provide a unique opportunity to test understanding of cloud ice formation. Under the microphysically simple conditions observed (apparently negligible ice aggregation, sublimation, and multiplication), the only expected source of new ice crystals is activation of heterogeneous ice nuclei (IN) and the only sink is sedimentation. Large-eddy simulations with size-resolved microphysics are initialized with IN number concentration N(sub IN) measured above cloud top, but details of IN activation behavior are unknown. If activated rapidly (in deposition, condensation, or immersion modes), as commonly assumed, IN are depleted from the well-mixed boundary layer within minutes. Quasi-equilibrium ice number concentration N(sub i) is then limited to a small fraction of overlying N(sub IN) that is determined by the cloud-top entrainment rate w(sub e) divided by the number-weighted ice fall speed at the surface v(sub f). Because w(sub c)< 1 cm/s and v(sub f)> 10 cm/s, N(sub i)/N(sub IN)<< 1. Such conditions may be common for this cloud type, which has implications for modeling IN diagnostically, interpreting measurements, and quantifying sensitivity to increasing N(sub IN) (when w(sub e)/v(sub f)< 1, entrainment rate limitations serve to buffer cloud system response). To reproduce observed ice crystal size distributions and cloud radar reflectivities with rapidly consumed IN in this case, the measured above-cloud N(sub IN) must be multiplied by approximately 30. However, results are sensitive to assumed ice crystal properties not constrained by measurements. In addition, simulations do not reproduce the pronounced mesoscale heterogeneity in radar reflectivity that is observed. |
format |
Other/Unknown Material |
author |
vanDiedenhoven, Bastiaan Morrison, Hugh Fridlin, Ann Ackerman, Andrew S. Shupe, Matthew D. Mrowiec, Agnieszka Avramov, Alexander Zuidema, Paquita |
author_facet |
vanDiedenhoven, Bastiaan Morrison, Hugh Fridlin, Ann Ackerman, Andrew S. Shupe, Matthew D. Mrowiec, Agnieszka Avramov, Alexander Zuidema, Paquita |
author_sort |
vanDiedenhoven, Bastiaan |
title |
A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes |
title_short |
A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes |
title_full |
A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes |
title_fullStr |
A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes |
title_full_unstemmed |
A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes |
title_sort |
fire-ace/sheba case study of mixed-phase arctic boundary layer clouds: entrainment rate limitations on rapid primary ice nucleation processes |
publishDate |
2012 |
url |
http://hdl.handle.net/2060/20130014863 |
op_coverage |
Unclassified, Unlimited, Publicly available |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Surface Heat Budget of the Arctic Ocean |
genre_facet |
Arctic Arctic Ocean Surface Heat Budget of the Arctic Ocean |
op_source |
CASI |
op_relation |
Document ID: 20130014863 http://hdl.handle.net/2060/20130014863 |
op_rights |
Copyright, Distribution as joint owner in the copyright |
_version_ |
1766324365291421696 |