Status and plans for a Southern Ocean observing system for climate
description
Transcript of Status and plans for a Southern Ocean observing system for climate
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Status and plans for a Southern Ocean observing system for
climate
Steve Rintoul, Kevin Speer and
Eberhard FahrbachAlfred-Wegener-Institut für Polar- und Meeresforschung
Bremerhaven, Germany
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Schmitz (1996)
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Heat and freshwater budget
Gas exchange
Sea ice biota
Technical challenge
Sea ice
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Rintoul 2001
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Mean temperature in the Weddell gyre at the Greenwich Meridian Warm Deep Water
temperature increased until the mid 1990’s and isdecreasing since
Weddell Sea Bottom Water temperature is still increasing
pot.
Tem
pera
ture
[°
C]
pot.
Tem
pera
ture
[°C
] HOWEVER:
Cooling and freshening in the East Antarctic sector
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Time series of salinity in Winter Water
1985 1990 1995 2000 2005
34.16
34.2
34.24
34.28
34.32
34.36
Sal
inity
S(Tm in)S(Tm in) corrected
Salinity increase in the Winter Water
HOWEVER
Freshening of mode and intermediate waters
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Wide range of time scales:Aliasing!?
Increase of temperature and salinity in the bottom water of the Weddell Sea from moored instruments and CTD profiles
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Relevant time scales (ACW, SAM, ENSO, AADP) exceed duration research projects
Thompson and Solomon 2002
Recent trends in surface temperature and wind (Dec-May 1969-2000).
Total trends Congruent with SAM
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Carbon uptake
Sabine et al., 2004
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
IPABWCRP/SCAR International Programme for
Antarctic Buoys
Problems to maintain it due to seasonal sea ice
Committments are needed
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Sea ice
Altimeter
Scatterometer
Gravimeter
SST
SSS
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
CLIVAR/CliC/SCAR Southern Ocean Region Implementation Panel
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
CLIVAR/CliC/SCAR Southern Ocean Region Implementation Panel
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Calibration by means of
Climate of Antarctica and the Southern
Ocean
CASO – IPY
CLIVAR/CliC/SCAR Southern Ocean
Region Implementation
Panel
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Joint sponsorship of GOSS/GCOS (OOPC), research (CLIVAR OOP, JGOFS, …) and the DEOS
A Time Series Science Team for the development of sustained time series stations
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Recent ARGO float distribution
http://argo.ocean.fsu.edu/images/big-so-map.pdf
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Ice compatibility of ARGO floats: a 3 step process
Ice sensing algorithm (ISA)
Interim storage
(iStore)
RAFOS
Checks temperature in the upper 50 m, ascent
aborted if near freezing point
Provides delayed mode profile when surfacing
impossible
Provides subsurface profile position when surfacing impossible
Tested successfully
about 80% survival rate
additional modifications are planed
8 NEMO floats are
currently under test and delivered first results
Tested in 2003/4 with 5 RAFOS floats:
tracking range is at least 600 km
throughout season.
Now standard for all AWI float orders (APEX and
NEMO)
Ordered for all further NEMO floats
Ordered for further NEMO floats
(APEX and NEMO)
ISA/iSore/RAFOS – Float = fully ice compatible
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Range of RAFOS signals in the Weddell Sea
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Sound sources (red: to be deployed by Keith Nichols, BAS, black: in the water, blue: in plan) and floats (green: floats)in the Weddell Sea west of the Greenwich Meridian. The extension of the network will occur in cooperation with Svein Osterhus frorm the Bjerknes centre in Bergen (Norway)
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Forecasting Ocean Assimilation Model
Data from all Argo floats are assimilated in to the Forecasting Ocean Assimilation Model (FOAM) run at the Met Office. Images of potential temperature, salinity and velocity at five metres and 995.5 m supplied by the Met Office at monthly intervals are provided
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
Enhancements needed• Sea ice zone
– Sea ice thickness/volume– Ocean properties under sea ice– Expanded met buoy network– Coastal margin; onshore-offshore exchange
• Meteorology– High quality ship obs (IMET on supply vessels)– Air-sea flux reference stations
• Argo– Maintaining and re-seeding array– Under sea ice
• Repeat hydrography + tracers + time series stations– Good plans, but not all funded
• Satellite data streams must be maintained.– Altimeter; gravity; ice; SST; SSS, wind
Establishing a coordinated Southern Ocean Observing System (SOOS) Hobart, 15 July 2006
SCAR/SCOR Oceanography expert group