1 / 18

Envisat: Near Real Time Processing and Oceanography

Envisat: Near Real Time Processing and Oceanography. Envisat CCVT Meeting. Kirk Whitmer Gregg Jacobs JE Sverdrup/NRL Stennis Space Center, MS, USA. ALPS and ODDITIES. ALPS : Near real time data processing system Data is quality checked at each step and suspect data is flagged

leann
Télécharger la présentation

Envisat: Near Real Time Processing and Oceanography

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Envisat: Near Real Time Processing and Oceanography Envisat CCVT Meeting Kirk Whitmer Gregg Jacobs JE Sverdrup/NRL Stennis Space Center, MS, USA

  2. ALPS and ODDITIES • ALPS: Near real time data processing system • Data is quality checked at each step • and suspect data is flagged • Must err on the side of caution because of • subsequent subsystems • Run daily at NRL and NAVO • ODDITIES: Graphical data analysis system • Results displayed on The Real Time Ocean Environment website • www.ocean.nrlssc.navy.mil/altimetry • Run daily at NRL Envisat imar data fed into the systems…

  3. read: data is read from gdrs into ALPS format • Smooth electromagnetic bias and • wet troposphere along track • Apply correction terms to height: • Wet troposphere, Dry troposphere • Inverse barometer, Solid tide • Ionosphere, Electromagnetic bias • Check for minimum number of high rate values (>15) • Check flag for water (sea ice?)

  4. Ionosphere drop plot Ku band correction only Doris Ku band correction only All ionosphere corrections applied: Ku band correction Doris Ku band correction Model Ku band correction

  5. interp: data is interpolated to reference ground tracks • Minimum number of points needed to interpolate • Interpolation incorporates the geoid gradient • Along track smoothing

  6. Data too sparse to interpolate to ground tracks • Single largest contributor to “dropped” data points

  7. aptide:tides are removed • got00.2 tide model applied • No points are dropped

  8. orbgem:orbit correction calculated and applied • Long term mean and climactic mean removed • Iterative sinusoidal fit calculation • Return means • Apply correction based on fit

  9. Orbit correction magnitude Mean: 60.7 cm RMS: 74.0 cm

  10. Even after orbit correction, still considerable noise.

  11. apply: mean removed • Along track “box car” filter • Sanity checks

  12. Sea ice issue? High latitude makes ice more important Detection algorithm or flag desireable SSH anomaly plot suggests many sea ice points remaining

  13. ERS-2 GFO

  14. Jason-1 • Multiple causes for ice point drops • Lower latitude reduces importance

  15. Percent data utilized Jason (osdr) 84.73/85.20 % Jason (igdr) 90.17/90.17 % Ers-2 84.22/90.26 % GFO (doppler) 87.49/87.49 % GFO (laser) 90.30/90.30 %

  16. Sea Surface Height Anomaly 14 October 2002

  17. Altimeter cross track intercomparisons • High latitude values sea ice influenced

More Related