Cryospheric and Hydrologic Contributions to Global Sea Level Change M. Tamisiea Proudman Oceanographic Laboratory R. Steven Nerem University of Colorado.

Cryospheric and Hydrologic ContributionsCryospheric and Hydrologic Contributionsto Global Sea Level Changeto Global Sea Level Change

M. TamisieaProudman Oceanographic Laboratory

R. Steven NeremUniversity of Colorado

AGU Meeting of the Americas, August 8-11, 2010

GRAVITY

Measurements of Sea Level ChangeMeasurements of Sea Level Change

0

10

20

30

40

50

60

1994 1996 1998 2000 2002 2004 2006 2008 2010

10

20

0

TOPEX/Poseidon

Jason-1 & 2

Trend = 3.3 mm/year

Global Mean Sea LevelGlobal Mean Sea Level

Mean Sea LevelMean Sea Level

-40

-30

-20

-10

0

10

20

30

1996 2000 2004 2008

Global (3.3 mm/yr)

Tropics (3.3 mm/yr)

Northern (2.5 mm/yr)

Southern (3.5 mm/yr)

Year

Area-Weighted Contribution to GMSLArea-Weighted Contribution to GMSL

-40

-30

-20

-10

0

10

20

30

1996 2000 2004 2008

Global (3.3 mm/yr)

Tropics (1.6 mm/yr)

Northern (0.5 mm/yr)

Southern (1.2 mm/yr)

Year

MSL Rates in 10° Latitude BandsMSL Rates in 10° Latitude Bands

0

1

2

3

4

5

-60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60Latitude

Spatial Variations in Sea Level Rise 1993-Spatial Variations in Sea Level Rise 1993-20102010

Detrended GMSL and MEIDetrended GMSL and MEI

-8

-6

-4

-2

0

2

4

6

8

-3

-2

-1

0

1

2

3

1996 2000 2004 2008

Detrended GMSL

MEI

Year

Hydrology Model vs GRACEHydrology Model vs GRACE

[Llovel et al., 2010]

Hydrology Model vs Altimeter GMSLHydrology Model vs Altimeter GMSL

[Llovel et al., 2010]

Hydrology Model vs Tide Gauge GMSLHydrology Model vs Tide Gauge GMSL

[Llovel et al., 2010]

GRACE Secular Trends (2002-2009)GRACE Secular Trends (2002-2009)

[Wahr, 2009]

GIA ModelRemoved

Rate of Ice mass change:

All Greenland: -239 Gton/yr

South Greenland: -162 Gton/yr

North Greenland: -77 Gton/yr

Total Greenland ice volumeApril, 2002 – June, 2010

-239 Gton/yr = 0.66 mm/yr sea level rise

(1 Gton = 1 km3 of water)

Greenland Ice Mass Changes from Greenland Ice Mass Changes from GRACEGRACE

[Wahr, 2010]

Rate of ice mass change:

All Antarctica: -143 Gton/yr

West Antarctica: -155 Gton/yr

East Antarctica: +15 Gton/yr

Uncertainty of GIA correction:

All Antarctica: ± 80 Gton/yr

West Antarctica: ± 20 Gton/yr

East Antarctica: ± 55 Gton/yr

-143 Gton/yr = 0.40 mm/yr sea level rise

Total Antarctic ice mass

April, 2002 – June, 2010

(noisy because of atmospheric pressure errors)

Antarctica Ice Mass Variations from Antarctica Ice Mass Variations from GRACEGRACE

[Wahr, 2010]

Rate of mass change between April, 2002 and May, 2010

Rate of mass change: -55 Gton/yr = 0.15 mm/yr sea level rise

.

Alaskan Glaciers from GRACEAlaskan Glaciers from GRACE

[Wahr, 2010]

Summary of GRACE Ice GMSL Summary of GRACE Ice GMSL ContributionsContributions

GRACE provides mass loss estimates for entire ice sheets.GRACE provides mass loss estimates for entire ice sheets.Between April 2002 and May/June 2010:Between April 2002 and May/June 2010:

Greenland lost ice at a rate of 239 Gton/yr.Greenland lost ice at a rate of 239 Gton/yr. Antarctica lost ice at a rate of 143 Gton/yr.Antarctica lost ice at a rate of 143 Gton/yr. Alaskan glaciers lost ice at a rate of 55 Gton/yr.Alaskan glaciers lost ice at a rate of 55 Gton/yr.

Total: 437 Gt/yr, equivalent to 1.2 mm/yr sea level rise.Total: 437 Gt/yr, equivalent to 1.2 mm/yr sea level rise.

Global Ocean Mass from GRACEGlobal Ocean Mass from GRACE

-15

-10

-5

0

5

10

15

20

2002 2004 2006 2008 2010

CSR04

GFZ04

Year

Global Ocean Mass from GRACEGlobal Ocean Mass from GRACE

-8

-6

-4

-2

0

2

4

6

8

2002 2004 2006 2008 2010

CSR04 (1.0 mm/year)

GFZ04 (1.4 mm/year)

Year

GIA Correction to GRACE Ocean Mass GIA Correction to GRACE Ocean Mass RateRate

Current Sea Level BudgetCurrent Sea Level Budget

Thermal Expansion: ~ 1.1 mm/year

Mountain Glaciers: ~ 1.2 mm/year

Greenland Ice Melt: ~ 0.6 mm/year

Antarctic Ice Melt: ~ 0.4 mm/year

Land Water Storage: ?

Total: ~ 3.3 mm/year

+

+

+

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