Weather and ground effect

I was wondering if someone can shed some light on a phenomon I keep
experiencing. I took a Mooney up to warm it up prior to an oil change.
There was 70 degree crosswind at 20 gusting 28. Needless to say, there was
moderate turbulance below 8K. As expected, I got beat up pretty good just
briefly flying out of the pattern to do a full systems check. The plane was
all over the place during the approach. I could keep the plane in an
imaginary box but inside that box, I was at the mercy of the elements. Once
I got the plane safely into ground effect, everything smooths out for the
touchdown and rollout. This is not the first time I have experienced this.
Nearly everytime where there is turbulance and gusting winds, it seems that
if I can safely make it into ground effect, the turbulance and gusts either
go away or have little effect. It makes for beautiful landings after an
uncomfortable approach. Why is this?

Thanks in advance,
Kevin Chandler