SEARCH Open Science mtg., October 03
description
Transcript of SEARCH Open Science mtg., October 03
![Page 1: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/1.jpg)
![Page 2: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/2.jpg)
10/24/03 search_osm_10_03 2
Abrupt Change in Deep Water Formation in the Greenland Sea: Results from
Hydrographic and Tracer Time Series
SEARCH Open Science mtg., October 03
P. Schlosser, J. Karstensen, D. Wallace, J. Bullister, and J. Blindheim
CU/L-DEO, IfM Kiel, NOAA PMEL, IMR Bergen
![Page 3: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/3.jpg)
10/24/03 search_osm_10_03 3
Outline
Background
Early hydrography tracer observations
Tracer and hydrographic data from the 1990s
Evolution of deep waters
Evolution of intermediate waters
Connection to outflow waters
Summary
![Page 4: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/4.jpg)
10/24/03 search_osm_10_03 4
Greenland Sea in the context of Atlantic THC
Levitus salinity map
AMAP
![Page 5: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/5.jpg)
10/24/03 search_osm_10_03 5
Greenland Sea in the context of Nordic seas
Red: warm, salty Atlantic Water; Blue: cold, fresh Arctic outflowBlack: deep circulation
Inflow (Sv): NA: ca. 8 Sv; Bering Strait: ca. 1 SvOutflow (Sv): Near surface: ca. 3 Sv; Overflows: ca. 6 Sv
![Page 6: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/6.jpg)
10/24/03 search_osm_10_03 6
Mean surface conditions
![Page 7: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/7.jpg)
10/24/03 search_osm_10_03 7
Sections across the central
Greenland Sea (75N; 6/99)
1. Cyclonic circulation2. Doming of isopycnals3. Polar/Arctic front4. Relatively homogeneous
deep water
![Page 8: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/8.jpg)
10/24/03 search_osm_10_03 8
Evolution of tracer concentrations in surface waters
![Page 9: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/9.jpg)
10/24/03 search_osm_10_03 9
Early Hydrography/tracer time series
Boenisch et al., 1997
![Page 10: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/10.jpg)
10/24/03 search_osm_10_03 10
2000 m to bottom2000 m to bottom 200 to 2000 m
Evolution of T/S and tracer properties
Boenisch et al., 1997
![Page 11: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/11.jpg)
10/24/03 search_osm_10_03 11
Surveys during the 1990s
Cruises: Johan Hjort; IMR Norway, Johan Blindheim
10 cruises1991 to 2000
![Page 12: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/12.jpg)
10/24/03 search_osm_10_03 12
Hydrography/tracer time series during the 1990s
![Page 13: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/13.jpg)
10/24/03 search_osm_10_03 13
Evolution of deep water T/S properties
![Page 14: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/14.jpg)
10/24/03 search_osm_10_03 14
Evolution of deep water tracer properties
![Page 15: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/15.jpg)
10/24/03 search_osm_10_03 15
Background stratification versus features in convective cells. Conv. cells are characterized by temp. max. at the bottom of the feature.
Imprints from deep convection
![Page 16: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/16.jpg)
10/24/03 search_osm_10_03 16
Evolution of tracer inventories
Tracer inventories indicate formation of intermediate waters in 1994, 1999, and possibly 1992.
![Page 17: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/17.jpg)
10/24/03 search_osm_10_03 17
Evolution of T and S anomalies
![Page 18: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/18.jpg)
10/24/03 search_osm_10_03 18
During convection:
Re-distribution of tracersNo net mass transport
After convection:
Mass transport by eddies andmeridional circulation
Greenland Sea
Sea ice may be important
Convection and tracer profiles
![Page 19: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/19.jpg)
10/24/03 search_osm_10_03 19
Properties on overflow water isopycnals
![Page 20: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/20.jpg)
10/24/03 search_osm_10_03 20
Heat fluxes required to restore 1970’s conditions
![Page 21: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/21.jpg)
21
Summary
Change in deep water formation rates1. Abrupt change in DWF rate occurred around 19802. Reduction in DWF rate: ca. 80%; more or less constant
since 19803. Greenland Sea gyre still on trend away from properties
known from instrumental records. ‘Recovery’ needs significant forcing.
Deep waters1. Quasi-linear trends in T (10 mK yr-1) and S (1 ppm yr-1)2. Advection of water from Arctic Ocean3. Little influence of atmosphere (isolated from atm. Forcing
on short time scales)
Intermediate waters1. Variability in formation2. Warmer and fresher (sea ice plays little role)3. Events: 94/95 and 99/00 (possibly 92/93)4. Transport: 0.1 to 0.2 Sv (0.5 during conv. events)
![Page 22: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/22.jpg)
10/24/03 search_osm_10_03 22
Hydrography/tracer time series during the 1990s
![Page 23: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/23.jpg)
10/24/03 search_osm_10_03 23
Background stratification versus features in convective cells. Conv. cells are characterized by temp. max. and its depth.
![Page 24: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/24.jpg)
10/24/03 search_osm_10_03 24
GS variability
Local Regional
![Page 25: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/25.jpg)
10/24/03 search_osm_10_03 25
GS variability
Local Regional
![Page 26: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/26.jpg)
10/24/03 search_osm_10_03 26
Factors controlling GSDW
Arctic outflow (quasi constant)Deep convection (sporadic)Connection to surface temperature?
![Page 27: SEARCH Open Science mtg., October 03](https://reader034.fdocuments.in/reader034/viewer/2022051316/56815847550346895dc59ca5/html5/thumbnails/27.jpg)