WAKE TURB ENCOUNTER AND OBSERVATION OF WAKE TURB EFFECTS ALONG GND TRACK.

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WE WERE FOLLOWING AN ACR 747. TCASII PLACED THE 747 ABOUT 5 1/2 - 6 MI IN FRONT OF US. WE APPEARED TO BE CO-EQUAL AIRSPD AT ABOUT 130-135 KIAS. WE DID ENCOUNTER SOME WAKE TURB AT ABOUT 10 MI OUT BECAUSE WE WERE INTERCEPTING THE GS FROM A LEVEL ALT WHICH PUT US BELOW THE 747'S INTERCEPT AND GLIDE PATH. WE EXPECTED THIS AND THEN ADJUSTED OUR GLIDE PATH TO STAY ABOVE THE WAKE TURB ZONE. APCHING THE 2.7 IDGU FIX WE NOTED A SERIES OF RIPPLES AND 2 ACCOMPANYING WATER SPOUTS OR WATER DEVILS (IN CONTRAST TO A DUST DEVIL). I WILL DIAGRAM THIS ON THE ATTACHMENT. I FEEL THE SIGNIFICANT OF THIS OBSERVATION IS TO HELP CONFIRM PREVIOUS RESEARCH. FROM POS; SPDS; ETC; I ESTIMATE THAT IT TOOK THE 747'S VORTICES ABOUT 1 1/2 MINS TO DSND 400 FT TO THE WATER SURFACE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR MAINLY WANTED TO STATE THE OBSERVATION HE HAD WITH THE WATER FUNNELS RISING ALONG THE B747 GND TRACK. THE FLC DID ENCOUNTER SOME WAKE TURB FROM THE PRECEDING ACFT BUT IT WAS NOT STRONG. THE SAME PATTERN IS HERE AS IN OTHER OBSERVATION HE ENCOUNTERED WITH WAKE; WHICH IS DSNDING A HVY ACFT DOWN TO HIS ALT. BECAUSE HE KNEW WHAT COULD HAPPEN IN SUCH A SIT; HE SLOWED FOR GREATER SEPARATION AND BRACED FOR A POSSIBLE UPSET. HOWEVER; THE ENCOUNTER THAT AFFECTED HIS ACFT WAS SMALL; PROBABLY BECAUSE OF A LIGHT XWIND.