Algorithms

• 25.7.2003 AMSR-E data: ASI5 P0=47K P1=11.7K
• 26.2.2003 Changed back to P0=47K P1=7.5K (ASI-v4.1).
• 26.2.2003 Changed tie points to P0=47K P1=9.5K (ASI-v4.3).
• 19.2.2003 Changed method of merging the swaths from overlapping mosaic to averaging
• 18.10.2002 ARTIST Version 4.1 Draft Technical Report
  
• 6.5.2002 Sea ice drift algorithm.
• 24.4.2002 Lomax et al. multiyear ice algorithm. Tiepoints: PCTF=194.2, PCTM=248.6
  
• 25.10.2001 ARTIST Version 4.1
  Polarstern Observations ARK-17/2 were used for fine tuning of parameters. See ARK-17/2.
• 25.9.2001 Added operational statistical analysis. Choose "Evaluation" and hemisphere at the main page.
• 25.9.2001 ARTIST Version 4.1
  The difference between NTA and ASI ice concentrations is used to calculate adaptive tiepoints.
• 19.9.2001 ARTIST Algorithm Version 4.0
  This version uses R-factor in order to decide between ASI-v3.2 and NTA for cloudy regions. The bias in the ice concentration should be removed in future versions of ASI.
• 14.3.2001 Added diploma thesis (pdf):
  Klassifikation von ERS-SAR Bildern des Meereises durch Texturanalyse mit Neuronalen Netzen
• 24.1.2001 Added CJRS manuscript. Please email me if you find errors in this text.
• 17.1.2001 Included multiyear fraction maps
• 17.1.2001 Included NASA-Team weather filter
  Cavalieri et al., Journal of Glaciology, Vol. 41, No. 139, 1995, pp. 455-464
• 15.1.2001 Paper submitted: Canadian Journal of Remote Sensing - Focus Issue on Ice and Icebergs
  Sea Ice Concentration Retrieval from the SSM/I 85.5 GHz Channels: Validation and Applications
  Authors: Lars Kaleschke, Christof Lüpkes, Timo Vihma, Jörg Haarpaintner, Axel Bochert, Jörg Hartmann, Georg Heygster
  
• 14.9.2000 Sample images:state of the sea ice edge 30-Mar/6-Apr-1998
• 18.8.2000 ASI-v3.2 (tiepoints changed). Validation results.
• 26.7.2000 Algorithm cookbook added.
• 25.7.2000 R-Factor
  J. Miao, K. Johnsen, S. Kern, G. Heygster
  Signature of clouds over antarctic sea ice detected by the special sensor microwave/imager,
  IEEE Transactions on Geoscience and Remote Sensing, September 2000.
• 20.7.2000 New weather filter ("iterative relaxation method") implemented.
  Tested with days 175-188 (arctic).
  It removes more than 70% of the strong weather systems.
• 14.7.2000 Change in ARTIST weather filter threshhold.
  open_water=where(ct(nasa_team) lt 30%); it was 50% before
  recalculation of day 170-195
  Side effects
  • ARTIST algorithm gives more accurate values at low ice concentrations.
  • Stronger weather influence. Please take care!
    (Low pressure systems lead to false high ice concentrations over the ice free ocean.
    You can easily identify such errors by looking at maps of the previous days.)

Technical

• 5.11.2002 Switched to DMSP-F15 platform
• 29.7.2002 Changed the second colortable (ASIc, NTc, MY) for an easier comparison to the NIC ice maps.
• 17.6.2002 Changed to PNG image format. Added some more regions. More frequent calculations. Update GMT3.4.1.
• 17.6.2002 Harddisk broken due to the update of the operating system. Restored from backup
• 15.5.2001 Sorry, the reconstruction of our IT-infrastructure has caused some problems. Now it should work more reliable.
• 26.3.2001 Removed discussion forum due to lack of interest
• 9.2.2001 Flight planner demo (please email me for obtaining the password or the source code)
• 17.1.2001 Design cleaned up
• 9.12.2000 Maps for Polarstern (Weddell Sea area)
• 17.11.2000 Maps for the SEPOR campaign (Greenland Sea area).
• 13.9.2000 Server version changed: Apache/1.3.12 (Unix) (SuSE/Linux)
• 22.8.2000 Colortable should look like IDL 4 now (maps since day 230).
• 21.8.2000 Hole at the north pole fixed ;-)
• 7.8.2000 Ross Sea area added.
• 3.8. 2000 Recalculation after power failoff will take some time.
• 28.7.2000 Discussion Board added.
• 27.7.2000 Gallery added.
• 25.7.2000 Weddell Sea, R-Factor and Weather Filter added.
• 21.7.2000 Kara Sea, Laptev Sea and Hudson Bay area added.
• 21.7.2000 Frequent map updates cancelled due to lack of computational power :-(
  New update time: ~7:00 MEZ
• 19.7.2000 Sea ice map updates now every few hours.
• 19.7.2000 New 60GB disc drive installed which should serve as data archive ;-)
• 18.7.2000 Recalculation of day 170-199.
• 17.7.2000 Greenland Sea area added.
• 17.7.2000 Different colormap which should give useful results on black-and-white printers.
• Change of image format to progressive JPEG.
• 17.7.2000 Page for ice concentration data.
  If you don't like the data format, please email me.
• this updates page ;-)
• image size and colormap option cancelled.
• 14.7.2000 update to GMT 3.3.4.
• 13.7.2000 Server changes
  Seaice.de data manager has moved to a 400MHz Pentium II with 100Mb/s instead of 10Mb/s network link.