Jason-2 exploitation review- May 12-14, Before going to the salient scientific results, Let’s go to the backstage…

Jason-2 exploitation review- May 12-14, 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-D Almost fully understood but not corrected in GDR-C

Jason-2 exploitation review- May 12-14,  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, main sources of differences (Masters et al., Marine Geodesy, 2012): Geophysical corrections Geophysical corrections Averaging methods Averaging methods Averaging along-track data (CU method) (CU method) Data gridding (2°x2°) before averaging (AVISO method) But also improving methods, processing, and corrections

Jason-2 exploitation review- May 12-14, Why measure sea surface height?

Jason-2 exploitation review- May 12-14, “Dynamic topography” – tells us the surface currents! MDT_CNES-CLS09

Jason-2 exploitation review- May 12-14, Global Warming and satellite altimetry Globally Averaged Sea Level Rise CauseEffect Atmospheric CO 2 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, 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, Satellite altimetry is our “canary in the coal mine” for sea level rise Projections of Future Rise Which path are we on? Jason-3 & Continuity

Jason-2 exploitation review- May 12-14, Updated from Cummins et al., GRL, 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, from Chelton et al. (2007) Eddies with Lifetimes greater than 16 weeks

Jason-2 exploitation review- May 12-14, SSHSteric (density related) height Eastern Pacific 140°Wt o 120°W Western Pacific 160°E to 180°E Argo and SSH SH 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, Global Sea Level and El Nino Global sea level rise with the seasonal cycle removed Sea Level & components with trend removed Sea level Ocean mass Thermal 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, Ocean 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, Conclusions 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