slide1
Download
Skip this Video
Download Presentation
Southern Hemisphere Climate Change Professor Matthew England

Loading in 2 Seconds...

play fullscreen
1 / 47

Southern Hemisphere Climate Change Professor Matthew England - PowerPoint PPT Presentation


  • 134 Views
  • Uploaded on

Southern Hemisphere Climate Change Professor Matthew England Climate and Environmental Dynamics Laboratory School of Mathematics, Faculty of Science The University of New South Wales. Outline. Observed 20 th Century changes in the Southern Hemisphere climate system Temperature Rainfall

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Southern Hemisphere Climate Change Professor Matthew England' - gaye


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1
Southern Hemisphere Climate Change

Professor Matthew England

Climate and Environmental Dynamics Laboratory

School of Mathematics, Faculty of Science

The University of New South Wales

outline
Outline
  • Observed 20th Century changes in the Southern Hemisphere climate system
          • Temperature
          • Rainfall
          • Land ice, ice shelves, and sea-ice
          • Ocean properties
          • Winds and extratropical weather systems
  • Projected changes
co 2 concentration is rising
2004

1959

290

190

CO2 Concentration is Rising

2000

1000

1200

1600

1800

1400

is the southern ocean changing
Is the Southern Ocean changing?

… observations

Larsson-B Ice Shelf Collapse 31 January to 7 March 2002

http://nsidc.org/iceshelves/larsenb2002/animation.html

west antarctic ice sheet
West Antarctic Ice Sheet

Oppenheimer (Nature 1998)

twentieth century land ice changes
Twentieth Century Land-Ice Changes

Davis et al., Vaughan; Science, 2005

arctic sea ice melting
Arctic Sea-ice melting

~10% decrease in sea-ice per decade

1990

2000

slide14
Ice Age Climate

Today’s Climate

slide17
0.017 psu

Rintoul 2006

slide18
.015

.008

.009

Rintoul 2006

causes of fresher shelf water
Causes of fresher shelf water
  • Increased glacial ice melt?
  • More precipitation?
  • Less sea ice formation?
  • Change in winds and ocean circulation?

Davis et al., Vaughan; Science, 2005

slide20
Intermediate depth waters in both hemispheres

have become cooler and fresher in recent decades.

Wong et al., 1999

slide21
Figure 3 from Gille, S. T., 2002. Warming of the Southern Ocean since the 1950s. Science,295, 1275-1277.

Temperature trends between 700 and 1100 m depth from ALACE floats.

Observations of temperature at intermediate depths show a greater than expected warming at high latitudes and a cooling at mid-latitudes of the Southern Ocean over the last 50 years (Gille 2002).

slide25
Changing Southern Hemisphere climate:

the Southern Annular Mode

Sen Gupta & England 2006

southern annular mode2
Southern Annular Mode

… trend due to ozone delpletion & greenhouse gas increases

slide31
Regression of the Southern Annular Mode

onto rainfall

‘Observed’

Model

Sen Gupta & England 2006

slide32
July Zonal Wind (200 hPa)

1949-1968 1975-1994 difference

Pandora Hope IOCI

climate modelling
Climate Modelling

Governing equations

Forcing conditions

Initial conditions

Model output

models of the ocean and atmosphere
Models of the ocean and atmosphere
  • Solve governing equations over a discrete grid
  • Use (sparse) observations in forcing functions
  • Integrate solutions forward in time
  • Assess simulation vs. observed fields
slide40
5.8

IPCC high

and low

projection

1.4

Spörer

minimum

Maunder

minimum

Dalton

minimum

2100

The Past and the Future

  • Instrumental Data
  • Proxy Reconstructions
  • Model Simulations

∆T

0.4

0.2

0

-0.2

-0.4

-0.6

-0.8

Year

1500

2000

500

1000

slide41
Climate change appears to be buffered by the Southern Ocean THC

Annual-mean temperature change predicted for ~ the year 2050 in the GFDL coupled climate model experiment (Manabe et al. 1989).

slide42
Annual-mean temperature change predicted for 2070-2100

in IPCC Third Assessment Report models

Annual mean change in temperature (colour shading) and its range (isolines) (Unit: °C) for the SRES scenario A2, showing the period 2071 to 2100 relative to the period 1961 to 1990.

slide44
CONTROL

2050

Figure 1. Model Simulation of Trend in Hurricanes

(from Knutson et al, 2004)

slide46
CONCLUSIONS
  • The Southern Hemisphere, like the antipodes, have undergone substantial climate change in the past century
  • A manifestation of climate change can be easily found in Southern Hemisphere air temperatures, rainfall, ocean properties, land-ice, sea-level, winds, and storm tracks
  • Models suggest these changes will continue for centuries even with relatively aggressive response strategies
slide47
Southern Hemisphere Climate Change

Professor Matthew England

Climate and Environmental Dynamics Laboratory

School of Mathematics, Faculty of Science

The University of New South Wales

ad