Jason-2 exploitation review- May 12-14, 2014- 1 - Before going to the salient scientific results,...
-
Upload
louisa-norris -
Category
Documents
-
view
214 -
download
0
Transcript of 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…
Jason-2 exploitation review- May 12-14, 2014 - 2 -
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
Jason-2 exploitation review- May 12-14, 2014 - 3 -
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
Jason-2 exploitation review- May 12-14, 2014 - 4 -
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
Jason-2 exploitation review- May 12-14, 2014 - 5 -
Why measure sea surface height?Why measure sea surface height?
Jason-2 exploitation review- May 12-14, 2014 - 6 -
“Dynamic topography” – tells us the surface currents!
MDT_CNES-CLS09
Jason-2 exploitation review- May 12-14, 2014 - 7 -
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
Jason-2 exploitation review- May 12-14, 2014 - 8 -
Sea Level is rising faster now than anytime in the last 2000 years
Sea Level Change in North Carolina from salt marsh data
Jason-2 exploitation review- May 12-14, 2014 - 9 -
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!
Jason-2 exploitation review- May 12-14, 2014 - 11 -
from Chelton et al. (2007)
Eddies with Lifetimes greater than 16 weeks Eddies with Lifetimes greater than 16 weeks
Jason-2 exploitation review- May 12-14, 2014 - 12 -
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
Jason-2 exploitation review- May 12-14, 2014 - 13 -
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
Jason-2 exploitation review- May 12-14, 2014 - 14 -
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!
Jason-2 exploitation review- May 12-14, 2014 - 15 -
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