Comparing model and measured ice crystal concentrations in orographic clouds during the INUPIAQ campaign
This paper assesses the reasons for high ice number concentrations observed in orographic clouds by comparing in situ measurements from the Ice NUcleation Process Investigation And Quantification field campaign (INUPIAQ) at Jungfraujoch, Switzerland (3570 m a.s.l.) with the Weather Research and...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-04-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/4945/2016/acp-16-4945-2016.pdf |
| _version_ | 1818390447791276032 |
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| author | R. J. Farrington P. J. Connolly G. Lloyd K. N. Bower M. J. Flynn M. W. Gallagher P. R. Field C. Dearden T. W. Choularton |
| author_facet | R. J. Farrington P. J. Connolly G. Lloyd K. N. Bower M. J. Flynn M. W. Gallagher P. R. Field C. Dearden T. W. Choularton |
| author_sort | R. J. Farrington |
| collection | DOAJ |
| description | This paper assesses the reasons for high ice number
concentrations observed in orographic clouds by comparing in situ
measurements from the Ice NUcleation Process Investigation And Quantification
field campaign (INUPIAQ) at Jungfraujoch, Switzerland
(3570 m a.s.l.) with the Weather Research and Forecasting model
(WRF) simulations over real terrain surrounding Jungfraujoch. During the 2014
winter field campaign, between 20 January and 28 February, the model
simulations regularly underpredicted the observed ice number concentration by
10<sup>3</sup> L<sup>−1</sup>. Previous literature has proposed several processes for
the high ice number concentrations in orographic clouds, including an
increased ice nucleating particle
(INP) concentration, secondary ice multiplication and the advection of
surface ice crystals into orographic clouds. We find that increasing INP
concentrations in the model prevents the simulation of the mixed-phase clouds
that were witnessed during the INUPIAQ campaign at Jungfraujoch.
Additionally, the inclusion of secondary ice production upwind of
Jungfraujoch into the WRF simulations cannot consistently produce enough ice
splinters to match the observed concentrations. A flux of surface hoar crystals
was included in the WRF model, which simulated ice concentrations
comparable to the measured ice number concentrations, without depleting the
liquid water content (LWC) simulated
in the model. Our simulations therefore suggest that high ice concentrations
observed in mixed-phase clouds at Jungfraujoch are caused by a flux of
surface hoar crystals into the orographic clouds. |
| first_indexed | 2024-12-14T04:57:47Z |
| format | Article |
| id | doaj.art-58bf3b19985f404cb83c3aef4fce38d2 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-14T04:57:47Z |
| publishDate | 2016-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-58bf3b19985f404cb83c3aef4fce38d22022-12-21T23:16:18ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242016-04-01164945496610.5194/acp-16-4945-2016Comparing model and measured ice crystal concentrations in orographic clouds during the INUPIAQ campaignR. J. Farrington0P. J. Connolly1G. Lloyd2K. N. Bower3M. J. Flynn4M. W. Gallagher5P. R. Field6C. Dearden7T. W. Choularton8School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UKSchool of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UKSchool of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UKSchool of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UKSchool of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UKSchool of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UKMet Office, Exeter, UKSchool of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UKSchool of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UKThis paper assesses the reasons for high ice number concentrations observed in orographic clouds by comparing in situ measurements from the Ice NUcleation Process Investigation And Quantification field campaign (INUPIAQ) at Jungfraujoch, Switzerland (3570 m a.s.l.) with the Weather Research and Forecasting model (WRF) simulations over real terrain surrounding Jungfraujoch. During the 2014 winter field campaign, between 20 January and 28 February, the model simulations regularly underpredicted the observed ice number concentration by 10<sup>3</sup> L<sup>−1</sup>. Previous literature has proposed several processes for the high ice number concentrations in orographic clouds, including an increased ice nucleating particle (INP) concentration, secondary ice multiplication and the advection of surface ice crystals into orographic clouds. We find that increasing INP concentrations in the model prevents the simulation of the mixed-phase clouds that were witnessed during the INUPIAQ campaign at Jungfraujoch. Additionally, the inclusion of secondary ice production upwind of Jungfraujoch into the WRF simulations cannot consistently produce enough ice splinters to match the observed concentrations. A flux of surface hoar crystals was included in the WRF model, which simulated ice concentrations comparable to the measured ice number concentrations, without depleting the liquid water content (LWC) simulated in the model. Our simulations therefore suggest that high ice concentrations observed in mixed-phase clouds at Jungfraujoch are caused by a flux of surface hoar crystals into the orographic clouds.https://www.atmos-chem-phys.net/16/4945/2016/acp-16-4945-2016.pdf |
| spellingShingle | R. J. Farrington P. J. Connolly G. Lloyd K. N. Bower M. J. Flynn M. W. Gallagher P. R. Field C. Dearden T. W. Choularton Comparing model and measured ice crystal concentrations in orographic clouds during the INUPIAQ campaign Atmospheric Chemistry and Physics |
| title | Comparing model and measured ice crystal concentrations in orographic clouds during the INUPIAQ campaign |
| title_full | Comparing model and measured ice crystal concentrations in orographic clouds during the INUPIAQ campaign |
| title_fullStr | Comparing model and measured ice crystal concentrations in orographic clouds during the INUPIAQ campaign |
| title_full_unstemmed | Comparing model and measured ice crystal concentrations in orographic clouds during the INUPIAQ campaign |
| title_short | Comparing model and measured ice crystal concentrations in orographic clouds during the INUPIAQ campaign |
| title_sort | comparing model and measured ice crystal concentrations in orographic clouds during the inupiaq campaign |
| url | https://www.atmos-chem-phys.net/16/4945/2016/acp-16-4945-2016.pdf |
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