Mechanical Engineering EAS PhD Proposal Defense (Comprehensive Exam) by Mr. Jared M. Buckley
When: Thursday,
February 16, 2017
10:00 AM
-
12:00 PM
Where: Textiles Building 105
Description: Mechanical Engineering EAS PhD Proposal Defense (Comprehensive Exam) by Mr. Jared M. Buckley
February 16, 2017
10:00 a.m. 12:00 p.m.
Textile Building, Room 105A (CSCVR Room)
TOPIC:
Ocean Currents from Satellites, Inter-comparison of Air-Sea Fluxes, and the Ocean Response to Atmospheric Cold Pools in the Indian Ocean
ABSTRACT:
The current intra-seasonal predictability of the monsoons by models is poor due to insufficient representation of physical processes at sub-grid scales. This proposal will consist of three studies of physical processes related to air-sea interaction in the Bay of Bengal:
(1) Estimating near-surface currents is important for understanding the influence of advection on observed changes in the upper-ocean. Simultaneous in-situ mesoscale observations of the ocean sufficient to cover entire ocean basins are logistically and practically impossible with current technologies. In order to circumvent these limitations, previous studies have developed algorithms to estimate near-surface currents in the global oceans using satellite observations. In this proposal, I will present a modification of these global algorithms designed specifically for the Bay of Bengal. The Bay of Bengal is one of the freshest parts of the world ocean, and this algorithm accounts for the influence of strong salinity stratification in setting the magnitude of wind-driven currents. This modification results in improvements in both qualitative and quantitative assessments of near-surface current errors in the Bay of Bengal.
(2) Climate studies require knowledge of air-sea fluxes globally and over long time scales. Atmospheric reanalysis models provide long-term global estimates of air-sea fluxes, and previous studies have shown that errors in these estimates can be significant. In this proposal, I will present the results of an inter-comparison of atmospheric reanalysis air-sea fluxes and in-situ data in the Bay of Bengal. The reanalysis models have significant air-sea flux errors in the Bay of Bengal. In particular, the reanalysis models miss dramatic transient changes in air-sea fluxes due to atmospheric convective downdrafts. Although reanalysis models represent a spatial and temporal average of fluxes and are not generally expected to capture these small-scale downdrafts, idealized 1-dimensional ocean simulations and observations show that their presence is potentially important for understanding the evolution of upper-ocean structure at larger scales.
(3) In the tropical atmosphere, transient convective downdrafts, also known as cold pool events, significantly influence air-sea fluxes at small spatial (order 1-10 km) and time scales (minutes to hours). During cold pool events, the interaction between the cloud layer, atmospheric boundary layer (ABL), and sea surface temperature (SST) is well-studied, but little is known about the influence of upper-ocean structure on air-sea fluxes, ABL structure, and subsequent upper-ocean changes. In this proposal, I will present a series of numerical experiments, motivated and supplemented by observations, to explore the impact of cold pool events on air-sea fluxes, coupled boundary layer evolution, and persistent upper-ocean changes. The data and numerical experiments will primarily consist of observations and idealizations from the Bay of Bengal, where strong salinity stratification and horizontal gradients dramatically change the SST response to air-sea fluxes.
All three studies are potentially important for improving the intra-seasonal predictability of the monsoons.
ADVISOR:
Dr. Amit Tandon, Department of Mechanical Engineering
COMMITTEE MEMBERS:
Dr. Sanjiv Ramachandran, Research Assistant Professor, Mechanical Engineering Department
Dr. Daniel MacDonald, Associate Professor, Civil and Environmental Engineering Department
Dr. Hyodae Seo, Associate Scientist, Woods Hole Oceanographic Institution
Open to the public. All MNE students are encouraged to attend.
For more information, please contact Dr. Amit Tandon (atandon@umassd.edu, 508-999-8357).
Thank you,
Sue Cunha, Administrative Assistant
Department of Mechanical Engineering
508-999-8492/Telephone
scunha@umassd.edu
February 16, 2017
10:00 a.m. 12:00 p.m.
Textile Building, Room 105A (CSCVR Room)
TOPIC:
Ocean Currents from Satellites, Inter-comparison of Air-Sea Fluxes, and the Ocean Response to Atmospheric Cold Pools in the Indian Ocean
ABSTRACT:
The current intra-seasonal predictability of the monsoons by models is poor due to insufficient representation of physical processes at sub-grid scales. This proposal will consist of three studies of physical processes related to air-sea interaction in the Bay of Bengal:
(1) Estimating near-surface currents is important for understanding the influence of advection on observed changes in the upper-ocean. Simultaneous in-situ mesoscale observations of the ocean sufficient to cover entire ocean basins are logistically and practically impossible with current technologies. In order to circumvent these limitations, previous studies have developed algorithms to estimate near-surface currents in the global oceans using satellite observations. In this proposal, I will present a modification of these global algorithms designed specifically for the Bay of Bengal. The Bay of Bengal is one of the freshest parts of the world ocean, and this algorithm accounts for the influence of strong salinity stratification in setting the magnitude of wind-driven currents. This modification results in improvements in both qualitative and quantitative assessments of near-surface current errors in the Bay of Bengal.
(2) Climate studies require knowledge of air-sea fluxes globally and over long time scales. Atmospheric reanalysis models provide long-term global estimates of air-sea fluxes, and previous studies have shown that errors in these estimates can be significant. In this proposal, I will present the results of an inter-comparison of atmospheric reanalysis air-sea fluxes and in-situ data in the Bay of Bengal. The reanalysis models have significant air-sea flux errors in the Bay of Bengal. In particular, the reanalysis models miss dramatic transient changes in air-sea fluxes due to atmospheric convective downdrafts. Although reanalysis models represent a spatial and temporal average of fluxes and are not generally expected to capture these small-scale downdrafts, idealized 1-dimensional ocean simulations and observations show that their presence is potentially important for understanding the evolution of upper-ocean structure at larger scales.
(3) In the tropical atmosphere, transient convective downdrafts, also known as cold pool events, significantly influence air-sea fluxes at small spatial (order 1-10 km) and time scales (minutes to hours). During cold pool events, the interaction between the cloud layer, atmospheric boundary layer (ABL), and sea surface temperature (SST) is well-studied, but little is known about the influence of upper-ocean structure on air-sea fluxes, ABL structure, and subsequent upper-ocean changes. In this proposal, I will present a series of numerical experiments, motivated and supplemented by observations, to explore the impact of cold pool events on air-sea fluxes, coupled boundary layer evolution, and persistent upper-ocean changes. The data and numerical experiments will primarily consist of observations and idealizations from the Bay of Bengal, where strong salinity stratification and horizontal gradients dramatically change the SST response to air-sea fluxes.
All three studies are potentially important for improving the intra-seasonal predictability of the monsoons.
ADVISOR:
Dr. Amit Tandon, Department of Mechanical Engineering
COMMITTEE MEMBERS:
Dr. Sanjiv Ramachandran, Research Assistant Professor, Mechanical Engineering Department
Dr. Daniel MacDonald, Associate Professor, Civil and Environmental Engineering Department
Dr. Hyodae Seo, Associate Scientist, Woods Hole Oceanographic Institution
Open to the public. All MNE students are encouraged to attend.
For more information, please contact Dr. Amit Tandon (atandon@umassd.edu, 508-999-8357).
Thank you,
Sue Cunha, Administrative Assistant
Department of Mechanical Engineering
508-999-8492/Telephone
scunha@umassd.edu
Topical Areas: Faculty, General Public, Students, Students, Graduate, Students, Undergraduate, University Community, College of Engineering, Mechanical Engineering