1. Chapter 11: Remote sensing A: Acoustic remote sensing (was chapter 9)‏ B: Geostrophic transport estimates ∫ v dx = 1/fρ 0 [ p(x 2 ) – p(x 1 ) ] and with the thermal wind relation this becomes d/dz ∫ v dx = -g/fρ 0 [ ρ(x 2 ) – ρ(x 1 ) ] Thus density profiles at the end points allow to obtain transport ∫ v dxdz. Bottom pressure gives reference layer velocity fluctuations. Here: example from MOVE array

2. Total geostrophic NADW transport variability

3. C: Satellites (and aircraft)‏ (most figures from Summerhayes&Thorpe “Oceanography: an illustrated guide Spectrum used: visible to microwave, for microwaves have passive and active sensors

6. Non-scanning versus scanning

7. Geostationary versus orbiting

8. Space-time scales

10. SST observations

11. Ocean color observations

12. Synthetic aperture radar (SAR) observations

13. SAR example

15. Waves and winds (scatterometer)‏

16. Altimetry After the success of SEASAT, the new planned altimetry missions were adusted to best complement the in-situ observations. Topex/Poseidon (T/P) was essentially designed for WOCE. Rationale: cm-accuracy sea-surface height geostrophic surface flow relative to geoid heat storage from large-scale steric effect variability from 20-10000km, 20days-10years Challenges and limitations: geoid insufficient at <3000km aliasing of tides at 62, 173,... days aliasing of high-frequ. wind-forced variability extrapolation to ocean interior no coverage in polar (and ice-covered) regions land motion of tide gauges for SL rise

18. Example result: extremely active time-dependence of the circulation (barotropic, baroclinic current systems, eddy motions, etc)‏ Quantified SSH and slope variance on all space/time scales globally (C. Wunsch)‏ (D.Stammer)‏

19. Eddy contribution to meridional heat flux: Other results/achievements: open-ocean tides measured globally to 2-3cm surface heat-flux estimates on basin-scales from storage observation of interannual variability (ENSO, circumpolar wave, etc)‏ kinetic energy of geostrophic currents in agreement with moorings eddy energy helped to demonstrate that models need 0.1° resolution agreement of T/P currents and ADCP data to 3-5cm/s global test of Rossby wave speeds global SL rise (calibrated with tide gauges) accurate to 0.5mm/yr transports of baroclinic current systems (variability)‏ drove advances in earth´s gravity field drove most of the work in assimilation many more..... (D. Stammer)‏

20. Missions at: http://airsea-www.jpl.nasa.gov/mission/missions.html (OLD) now see seperate ppt file..... More about altimetry at: http://topex-www.jpl.nasa.gov/ www.aviso.oceanobs.com/en/altimetry/index.html More about scatterometer at http://winds.jpl.nasa.gov/ General satellite missions www.aviso.oceanobs.com/

21. Some sensor types/names: Scatterometers: NSCAT (on Japanese ADEOS), QuickScat, SeaWinds (on ADEOS-II), ASCAT. Deliver vector wind (stress), sea ice, iceberg drift. Radars: altimeter, SAR Radiometer: AVHRR (advanced very high resolution radiometer), has several IR bands, can be used to estimate absorption in atmosphere, gives SST; Also in microwave now – SMMR (scanning multi-channel microwave radiometer), passive, also yields ice cover and humidity SSM/I: special sensor microwave imager, gives only wind speed (not direction), 4 bands, precipitation CZCS: coastal zone color scanner (on Nimbus satellite), many visible channels

22. More neat stuff, e.g. “Iridium flares” at www.heavens-above.com/ GRACE gravity mission

23. See also: www.eohandbook.com And www.esa.int/esaEO/index.html

24. Overview over some satellite-derived products: http://podaac.jpl.nasa.gov/http://podaac.jpl.nasa.gov/ http://coastwatch.pfeg.noaa.gov/coastwatch/CWBrowser.jsp Altimetry: AVISO: http://www.aviso.oceanobs.com/http://www.aviso.oceanobs.com/ http://las.aviso.oceanobs.com/las/servlets/dataset/ ftp://ftp.cls.fr/pub/oceano/AVISO/SSH/duacs/ Ocean color and SST (MODIS, SeaWIFS,...) http://oceancolor.gsfc.nasa.gov/http://oceancolor.gsfc.nasa.gov/ Ocean surface currents (using wind, altimetry:) http://www.oscar.noaa.gov/http://www.oscar.noaa.gov/ (from sequential satellite imagery:) http://ccar.colorado.edu/research/cali/http://ccar.colorado.edu/research/cali/ GRACE gravimetry http://op.gfz-potsdam.de/grace/ http://podaac.jpl.nasa.gov/DATA_CATALOG/graceinfo.html Satellite Data Websites:

25. altimetry Altimetry and ARGO Sea surface height (SSH) consists of - the steric (dynamic height H dyn ) contribution of T and S - a barotropic flow component (reference level pressure P ref )‏ Symbolically SSH = P ref + H dyn = SSH’ + SSH Altimetry has good spatial and temporal coverage but cannot determine - steric and non-steric components - mean SSH field (relative to geoid)‏ - T and S contributions (spiciness)‏ - interior structure (vertical distribution) of H dyn ARGO data can help resolve these issues

26. altimetry Float profiles Symbolically SSH = P ref + H dyn = SSH’ + SSH scatter is a measure for non-steric contributions (plus errors)‏ altimetric SSH‘ vs in-situ H‘ dyn Compare SSH‘ and float H‘ dyn : large barotropic contributions at high latitudes Correlation vs latitude (from P.-Y. Le Traon)‏

27. altimetry Float profiles deep trajectories residual Symbolically SSH = P ref + H dyn = SSH’ + SSH Deep mean flow (p ref ) from float trajectories : (from R.Davis)‏