jason-2 exploitation review- may 12-14, 2014- 1 - before going to the salient scientific results,...

Jason-2 exploitation review- May 12-14, 2014 - 1 -

Before going to the salient scientific results,

Let’s go to the backstage…


Building long-term time series using consistent data records from the T/P-Jason legacy.

(source Bruce Haines, Harvest platform)

Fully understood and corrected in GDR-DFully understood and corrected in GDR-D

Almost fully understood but not corrected in GDR-C

Almost fully understood but not corrected in GDR-C


Better consistency with other missions and with in situ data: Envisat MSL is now getting more relevant for long term studies… (Ollivier et al. Marine Geodesy 2012)

• The reprocessing exercice enables to homogenize the GDR data set. Essential step for MSL studies

GDR Before ReprocGDR After V2.1 Reproc and Updates

Also using other past satellites such as Envisat

Or new ones such as SARAL/AltiKa


2 main sources of differences (Masters et al., Marine Geodesy, 2012):2 main sources of differences (Masters et al., Marine Geodesy, 2012):

• Geophysical correctionsGeophysical corrections

• Averaging methodsAveraging methods

Averaging along-track dataAveraging along-track data ((CU methodCU method))

Data gridding (2°x2°) before averagingData gridding (2°x2°) before averaging((AVISO methodAVISO method))

But also improving methods, processing, and corrections


Why measure sea surface height?Why measure sea surface height?


“Dynamic topography” – tells us the surface currents!

MDT_CNES-CLS09


Global Warming and satellite altimetry

Globally Averaged Sea Level Rise

Cause Effect

Atmospheric CO2 from Mauna Loa

Sea Level rise is our clearest indicator of human-caused global warming, and altimetry is our best tool to measure it


Sea Level is rising faster now than anytime in the last 2000 years

Sea Level Change in North Carolina from salt marsh data


Satellite altimetry is our “canary in the coal mine”

for sea level rise

Projections of Future RiseWhich path are we on?

Jason-3 & Continuity

Jason-2 exploitation review- May 12-14, 2014 - 10 -Updated from Cummins et al., GRL, 2005

http://jisao.washington.edu/pdo/

mm

/yr

For the past 20 years, the Pacific Decadal Oscillation has been trending negative

Will the next 20 years bring the US West Coast faster sea level rise?.... Probably!


from Chelton et al. (2007)

Eddies with Lifetimes greater than 16 weeks Eddies with Lifetimes greater than 16 weeks


SSHSteric (density related) height

Eastern Pacific140°Wt

o120°W

Western Pacific160°E

to 180°E

Argo and SSHSH and SSH annual cycles are nearly symmetric about the equator in the western Pacific, but the northern hemisphere signal is much larger in the central and eastern Pacific.

Similar to Kessler and McCreary (1993).

From D. Roemmich


Global Sea Level and El NinoGlobal Sea Level and El NinoGlobal sea level rise

with the seasonal cycle removed

Sea Level & components with trend

removed

Sea levelOcean massThermal expan.

El Nino and La Nina events cause sea level “bumps and wiggles”

Accounting for these, the trend has been VERY stead over the last 20

years

Sea Level trend

Sea Level trend – ENSO corrected

From Cazenave et al. (2014), Nature Climate Change


Ocean Currents around AntarcticaOcean Currents around Antarctica

from Vivier et al. (2014), Deep Sea Research II

3 ocean mooring were deployed to estimate the transport of the Antarctic Circumpolar Current through a trough in the Kerguelen Plateau as part of the TRACK Experiment. A Jason track passes directly overhead

Agreement between moorings and altimeter data was excellent!


ConclusionsConclusions

• Satellite altimetry continues to provide scientific breakthroughs, even after 20 years• Eddies• Regional Decadal Variations• Global Sea Level fluctuations

• Satellite altimetry provides our most important measure of human caused climate change

jason-2 exploitation review- may 12-14, 2014- 1 - before going to the salient scientific results,...

Documents