wind speed vs height above water

Listmates: I was sailing my other boat on Sunday, enjoying a comfortable singlehanded sail on a beam reach with apparent wind speeds averaging 16-plus knots and peaking at 19-plus. Sails were my excellent new working jib and a slightly reefed main. The wind, an unusual NW direction, let me sail both down and later back up the river. The wind speeds are from my handheld Kestrel anemometer. I'd stand up in the cockpit and reach as high as possible. That made me wonder about what Wikipedia identifies as "wind gradient" or the variation in wind speed above the surface. Read about it here: > http://en.wikipedia.org/wiki/Wind_gradient The article cites a couple sailing sources indicating that the most pronounced variation is in the first meter or two above the water's surface in wind speeds over 6 knots. If we assume that the speed device is approximately 10 feet above the surface, then it's probably a pretty accurate reading? I also assume that if the masthead fly indicates a beam reach on apparent wind, the true wind is actually a bit behind the beam . I also assume that my apparent wind speed readings are probably pretty close to true wind speed on the beam reach. Is that accurate? This matters a bit because I've been keeping wind speed/boat performance records for that boat for a couple years--wind speed, sea state, sail complement, point of sail, boat speed, general performance. It matters for that boat because she's a shoal draft vessel (2.5 feet with board up) that depends on form stability and is tender when pressed too hard. The new jib made a very large difference in comfort when the wind pipes up. The boat goes forward instead of over. What I used to blame on hull or rig design was really a problem with old sails. On Sunday I had my usual momentary regrets about reefing while I was in the river, where the wind speeds were less than expected, but was gratified when I reached open water, where they were exactly what I expected. The reef made for a very comfortable sail with lots of boat speed, no excessive heeling, and a light helm. I was beating the hell out of a guy sailing an S2 of about 27 feet under main only (still can't figure out why people do that--he even had a crew). Properly sailed, that boat would walk past me. How nice to sail so well in conditions that would have had me working very hard before the new sail. Do not assume that it was a day of unalloyed brilliance in the skipper department. Entering the slip under power, with an unfavorable wind, I got distracted and turned into the slip too late; bumped a piling lightly with the bow pulpit; tried to recover with much thrashing and noise from the outboard motor, and required assistance from some powerboaters down the dock to sneak into my slip. OMG, the ultimate humiliation for a sailor!!!! Give me your advice on wind speed readings, please. Chris Campbell