Slow Manifolds and Multiple Equilibria in Stratocumulus-Capped Boundary Layers
In marine stratocumulus-capped boundary layers under strong inversions, the timescale for thermodynamic adjustment is roughly a day, much shorter than the multiday timescale for inversion height adjustment. Slow-manifold analysis is introduced to exploit this timescale separation when boundary layer...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Geophysical Union (AGU)
2010-12-01
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| Series: | Journal of Advances in Modeling Earth Systems |
| Subjects: | |
| Online Access: | http://james.agu.org/index.php/JAMES/article/view/v2n14 |
| _version_ | 1818196577795178496 |
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| author | Junya Uchida Christopher Bretherton Peter N Blossey |
| author_facet | Junya Uchida Christopher Bretherton Peter N Blossey |
| author_sort | Junya Uchida |
| collection | DOAJ |
| description | In marine stratocumulus-capped boundary layers under strong inversions, the timescale for thermodynamic adjustment is roughly a day, much shorter than the multiday timescale for inversion height adjustment. Slow-manifold analysis is introduced to exploit this timescale separation when boundary layer air columns experience only slow changes in their boundary conditions. Its essence is that the thermodynamic structure of the boundary layer remains approximately slaved to its inversion height and the instantaneous boundary conditions; this slaved structure determines the entrainment rate and hence the slow evolution of the inversion height. Slow-manifold analysis is shown to apply to mixed-layer model and large-eddy simulations of an idealized nocturnal stratocumulus- capped boundary layer; simulations with different initial inversion heights collapse onto single relationships of cloud properties with inversion height. Depending on the initial inversion height, the simulations evolve toward a shallow thin-cloud boundary layer or a deep, well-mixed thick cloud boundary layer. In the large-eddy simulations, these evolutions occur on two separate slow manifolds (one of which becomes unstable if cloud droplet concentration is reduced). Applications to analysis of stratocumulus observations and to pockets of open cells and ship tracks are proposed. |
| first_indexed | 2024-12-12T01:36:18Z |
| format | Article |
| id | doaj.art-2be0fea5fc1f40baaccb10dca12a200e |
| institution | Directory Open Access Journal |
| issn | 1942-2466 |
| language | English |
| last_indexed | 2024-12-12T01:36:18Z |
| publishDate | 2010-12-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Journal of Advances in Modeling Earth Systems |
| spelling | doaj.art-2be0fea5fc1f40baaccb10dca12a200e2022-12-22T00:42:50ZengAmerican Geophysical Union (AGU)Journal of Advances in Modeling Earth Systems1942-24662010-12-012Art. # 1420 pp.10.3894/JAMES.2010.2.14Slow Manifolds and Multiple Equilibria in Stratocumulus-Capped Boundary LayersJunya UchidaChristopher BrethertonPeter N BlosseyIn marine stratocumulus-capped boundary layers under strong inversions, the timescale for thermodynamic adjustment is roughly a day, much shorter than the multiday timescale for inversion height adjustment. Slow-manifold analysis is introduced to exploit this timescale separation when boundary layer air columns experience only slow changes in their boundary conditions. Its essence is that the thermodynamic structure of the boundary layer remains approximately slaved to its inversion height and the instantaneous boundary conditions; this slaved structure determines the entrainment rate and hence the slow evolution of the inversion height. Slow-manifold analysis is shown to apply to mixed-layer model and large-eddy simulations of an idealized nocturnal stratocumulus- capped boundary layer; simulations with different initial inversion heights collapse onto single relationships of cloud properties with inversion height. Depending on the initial inversion height, the simulations evolve toward a shallow thin-cloud boundary layer or a deep, well-mixed thick cloud boundary layer. In the large-eddy simulations, these evolutions occur on two separate slow manifolds (one of which becomes unstable if cloud droplet concentration is reduced). Applications to analysis of stratocumulus observations and to pockets of open cells and ship tracks are proposed.http://james.agu.org/index.php/JAMES/article/view/v2n14Cloud-Topped Boundary LayersAerosol-Cloud Interaction |
| spellingShingle | Junya Uchida Christopher Bretherton Peter N Blossey Slow Manifolds and Multiple Equilibria in Stratocumulus-Capped Boundary Layers Journal of Advances in Modeling Earth Systems Cloud-Topped Boundary Layers Aerosol-Cloud Interaction |
| title | Slow Manifolds and Multiple Equilibria in Stratocumulus-Capped Boundary Layers |
| title_full | Slow Manifolds and Multiple Equilibria in Stratocumulus-Capped Boundary Layers |
| title_fullStr | Slow Manifolds and Multiple Equilibria in Stratocumulus-Capped Boundary Layers |
| title_full_unstemmed | Slow Manifolds and Multiple Equilibria in Stratocumulus-Capped Boundary Layers |
| title_short | Slow Manifolds and Multiple Equilibria in Stratocumulus-Capped Boundary Layers |
| title_sort | slow manifolds and multiple equilibria in stratocumulus capped boundary layers |
| topic | Cloud-Topped Boundary Layers Aerosol-Cloud Interaction |
| url | http://james.agu.org/index.php/JAMES/article/view/v2n14 |
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