1. Scatterometer wind use cases Ad.Stoffelen@KNMI.nl Manager NWP SAF at KNMI Manager OSI SAF at KNMI PI European OSCAT Cal/Val project Leader KNMI Satellite Winds Group www.knmi.nl/scatterometer

2. www.howtoons.com/ toon/the-beaufort-scale/

4. MetOp-B’s ASCAT will fill this gap at 60N

6. OceanSat-2 experimental at 50 km => 25-km plan

7. => Winds close to the coast

11. ASCAT storm winds

13. OceanSat-2 storm winds A little too high !

14. Very strong off-shore winds next to the coast

19.  Golvend front met gesloten laagje links (ASCAT pass om 00:18 GMT  HiRLAM positie (00 GMT) te NW-elijk (run 18Z+6h)  ASCAT ambiguity removal foutief  Alle vectoren ten N van de lijn moeten 180 graden gedraaid

20.  Golvend front meer ten oosten (OSCAT pass om 01:52 GMT  HiRLAM (00 GMT) verschillen klein maar wel 2 uur eerder  OSCAT ambiguity removal goed  OSCAT heeft last van regen

21. Storm and high water Delfzijl (NL) 1/11/’06 6:14  Underpredicted surge by HiRLAM (blue) and ECMWF winds (green)  OSI SAF QuikScat winds (red) are stronger and/or more directed into the harbour  R&D mesoscale needed 1/11/’06 4:03

22. Example of ASCAT Use Used as justification to initiate advisories on TD Four-E (later TS Douglas) and set initial intensity TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042008 800 PM PDT TUE JUL 01 2008 ASCAT DATA AT AROUND 16Z SHOWED THAT THE LOW PRESSURE AREA SOUTHWEST OF MANZANILLO MEXICO HAD A BROAD CENTER ELONGATED NORTH-NORTHWEST TO SOUTH-SOUTHEAST. SINCE THAT TIME...SATELLITE IMAGERY INDICATES THAT THE CIRCULATION AND ASSOCIATED SHOWER ACTIVITY HAS SOMEWHAT CONSOLIDATED AT THE SOUTHERN END OF THE ELONGATION. BASED ON THIS...ADVISORIES ARE INITIATED ON TROPICAL DEPRESSION FOUR-E. THE INITIAL INTENSITY IS 30 KT IN AGREEMENT WITH SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB...AS WELL AS THE OBSERVED WINDS IN THE EARLIER ASCAT DATA.... THE ASCAT DATA SHOWED 25-30 KT WINDS IN A BAND THAT IS CURRENTLY ABOUT 200 N MI FROM THE CENTER IN THE NORTHEASTERN QUADRANT. WHILE THE CENTER OF THE CYCLONE IS EXPECTED TO REMAIN WELL OFFSHORE...

23. ASCAT Use in TC Intensity Analysis ASCAT pass over Tropical Storm Philippe at 1410 UTC 4 October 2011 revealed the cyclone to be stronger (50-55 kt) than suggested by Dvorak satellite intensity estimates (45 kt) It is difficult to assess the peak intensity with ASCAT however due to spatial sampling considerations, especially in stronger TCs

24. ASCAT Use in TC Wind Field Analysis New ASCAT GMF has compared favorably to 34 and 50 kt wind radii estimates from aircraft data in some cases Old GMF New GMF Hurricane Irene 0152 UTC 26 August 2011 Analyzed wind radii from all sources (including aircraft) 50 KT.......110NE 100SE 50SW 75NW. 34 KT.......250NE 200SE 125SW 160NW ASCAT wind radii (new GMF) 50 KT.......90NE 105SE 60SW 70NW. 34 KT.......170NE 205SE 135SW 175NW.

25. ASCAT Use in TC Center Fixing Reduced rain contamination and prevalence of 3 rd and 4 th ambiguities in areas of low winds makes center fixing with ASCAT somewhat easier than with QuikSCAT if the pass samples the center location Tropical Storm Philippe 0024 UTC 3 October 2011

26. Thanks !