Department of Estuarine and Ocean Sciences PhD Dissertation Defense by Adrienne Silver
When: Wednesday,
December 21, 2022
11:00 AM
-
12:00 PM
Where: > See description for location
Description: The School for Marine Science and Technology
Department of Estuarine and Ocean Sciences
PhD Dissertation Defense
“A Multiscale and Multidisciplinary Investigation of the Gulf Stream System, its Rings and their Impacts”
By
Adrienne Silver
Advisor
Avijit Gangopadhyay
Committee
Steven Lohrenz, School for Marine Science and Technology at the University of Massachusetts Dartmouth
Gavin Fay, School for Marine Science and Technology at the University of Massachusetts Dartmouth
Glen Gawarkiewicz, Woods Hole Oceanographic Institution
Magdalena Andres, Woods Hole Oceanographic Institution
Wednesday, December 21, 2022
11:00 am
SMAST East Rooms 101/102/103
and via Zoom
Abstract:
This work can be divided into three main research areas. The first study focused on the Gulf Stream system as a whole. A Gulf Stream North Wall forecasting model was created (Silver et al, 2021a) using wind and buoyancy forcing. An existing model with multiple parameters including the previous year's Gulf Stream North Wall index, location and amplitude of the Icelandic Low center, and the Southern Oscillation Index was augmented with basin-wide Ekman drift over the Azores High and validated over the last 40 years. Results indicate the possibility of better understanding and enhanced predictability of the dominant wind-driven variability of the Atlantic Meridional Overturning Circulation and of fisheries models that use the Gulf Stream path as a metric. A related work found that ring formation behavior has been asymmetric over both interannual and seasonal time-scales. Warm Core Ring formation underwent a regime shift in the year 2000 whereas Cold Core Ring formation rates remained consistent over the last forty years (Silver et al. 2021b). This increase in Warm Core Ring production leads to an excess heat transfer of 0.10 PW to the Slope Sea, amounting to 7.7–12.4% of the total Gulf Stream heat transport, or 5.4–7.3% of the global oceanic heat budget at 30°N. Seasonally, a higher (lower) number of cold rings formed in winter (summer) than warm ones. The second section of my dissertation follows a Warm Core Ring as it moves through the Slope Sea using a 10 year Ring trajectory dataset (Silver et al., 2022a,b). This analysis reveals a very narrow band between 66° and 71°W along which rings travel almost due west along ∼39°N across isobaths – the “Ring Corridor.” The rings generated to the west of the New England Seamount Chain by a process called an aneurysm tend to have shallower vertical extent than those formed by a pinch-off mechanism from Gulf Stream to the east of the New England Seamount Chain. The last section of my dissertation focuses on the impact of a Warm Core Ring hitting the shelfbreak via an shelfbreak exchange process called the mid-depth salinity maximum intrusion. This work found the first observational evidence of a regime-shift for Salinity Maximum intrusions in the northeast US shelf waters which corresponded to a regime shift in the occupancy of Warm Core Ring along the shelfbreak. This part also links changes in the Gulf Stream with the shifts in the shelf ecosystem through exchanges of water, nutrients and plankton.
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Meeting ID: 926 8486 2619
Passcode: 122022
***************************************************************************
For additional information, please contact Sue Silva at s1silva@umassd.edu
Department of Estuarine and Ocean Sciences
PhD Dissertation Defense
“A Multiscale and Multidisciplinary Investigation of the Gulf Stream System, its Rings and their Impacts”
By
Adrienne Silver
Advisor
Avijit Gangopadhyay
Committee
Steven Lohrenz, School for Marine Science and Technology at the University of Massachusetts Dartmouth
Gavin Fay, School for Marine Science and Technology at the University of Massachusetts Dartmouth
Glen Gawarkiewicz, Woods Hole Oceanographic Institution
Magdalena Andres, Woods Hole Oceanographic Institution
Wednesday, December 21, 2022
11:00 am
SMAST East Rooms 101/102/103
and via Zoom
Abstract:
This work can be divided into three main research areas. The first study focused on the Gulf Stream system as a whole. A Gulf Stream North Wall forecasting model was created (Silver et al, 2021a) using wind and buoyancy forcing. An existing model with multiple parameters including the previous year's Gulf Stream North Wall index, location and amplitude of the Icelandic Low center, and the Southern Oscillation Index was augmented with basin-wide Ekman drift over the Azores High and validated over the last 40 years. Results indicate the possibility of better understanding and enhanced predictability of the dominant wind-driven variability of the Atlantic Meridional Overturning Circulation and of fisheries models that use the Gulf Stream path as a metric. A related work found that ring formation behavior has been asymmetric over both interannual and seasonal time-scales. Warm Core Ring formation underwent a regime shift in the year 2000 whereas Cold Core Ring formation rates remained consistent over the last forty years (Silver et al. 2021b). This increase in Warm Core Ring production leads to an excess heat transfer of 0.10 PW to the Slope Sea, amounting to 7.7–12.4% of the total Gulf Stream heat transport, or 5.4–7.3% of the global oceanic heat budget at 30°N. Seasonally, a higher (lower) number of cold rings formed in winter (summer) than warm ones. The second section of my dissertation follows a Warm Core Ring as it moves through the Slope Sea using a 10 year Ring trajectory dataset (Silver et al., 2022a,b). This analysis reveals a very narrow band between 66° and 71°W along which rings travel almost due west along ∼39°N across isobaths – the “Ring Corridor.” The rings generated to the west of the New England Seamount Chain by a process called an aneurysm tend to have shallower vertical extent than those formed by a pinch-off mechanism from Gulf Stream to the east of the New England Seamount Chain. The last section of my dissertation focuses on the impact of a Warm Core Ring hitting the shelfbreak via an shelfbreak exchange process called the mid-depth salinity maximum intrusion. This work found the first observational evidence of a regime-shift for Salinity Maximum intrusions in the northeast US shelf waters which corresponded to a regime shift in the occupancy of Warm Core Ring along the shelfbreak. This part also links changes in the Gulf Stream with the shifts in the shelf ecosystem through exchanges of water, nutrients and plankton.
************************************************************************
Join Zoom Meeting
https://umassd.zoom.us/j/92684862619?pwd=WUd4dXpWeGNmVzZ2YmxteGdjTXgyUT09
Meeting ID: 926 8486 2619
Passcode: 122022
One tap mobile
+16469313860,,92684862619#,,,,*122022# US
+13017158592,,92684862619#,,,,*122022# US (Washington DC)
Dial by your location
+1 646 931 3860 US
+1 301 715 8592 US (Washington DC)
+1 305 224 1968 US
+1 309 205 3325 US
+1 312 626 6799 US (Chicago)
+1 646 876 9923 US (New York)
+1 360 209 5623 US
+1 386 347 5053 US
+1 507 473 4847 US
+1 564 217 2000 US
+1 669 444 9171 US
+1 669 900 6833 US (San Jose)
+1 689 278 1000 US
+1 719 359 4580 US
+1 253 205 0468 US
+1 253 215 8782 US (Tacoma)
+1 346 248 7799 US (Houston)
Meeting ID: 926 8486 2619
Passcode: 122022
Find your local number: https://umassd.zoom.us/u/abgUch3ySJ
Join by SIP
92684862619@zoomcrc.com
Join by H.323
162.255.37.11 (US West)
162.255.36.11 (US East)
115.114.131.7 (India Mumbai)
115.114.115.7 (India Hyderabad)
213.19.144.110 (Amsterdam Netherlands)
213.244.140.110 (Germany)
103.122.166.55 (Australia Sydney)
103.122.167.55 (Australia Melbourne)
149.137.40.110 (Singapore)
64.211.144.160 (Brazil)
149.137.68.253 (Mexico)
69.174.57.160 (Canada Toronto)
65.39.152.160 (Canada Vancouver)
207.226.132.110 (Japan Tokyo)
149.137.24.110 (Japan Osaka)
Meeting ID: 926 8486 2619
Passcode: 122022
***************************************************************************
For additional information, please contact Sue Silva at s1silva@umassd.edu
Contact: > See Description for contact information
Topical Areas: School for Marine Sciences and Technology, SMAST Seminar Series