Hawkdancer....Your pic looks like a rainbow to me.A very nice picture of one though.Ice crystals are needed for sun dogs so don't appear unless it is in the winter.The ice in the atmosphere acts as prisms.Most times showing though at a low angle to the horizon.The reason we don't see as many rainbows in the winter has a lot to do with the type of rain we see in a season.Rain in the winter is in stratiform.The reason they are called sundogs is because they appear beside or around the sun most times in pairs as a dog does following it's master or as a halo.Rainbows don't.A greek origin word [parhelia] which means beside the sun.A circle completely around the sun in winter is called a halo sometimes called a 22 degree halo and also needs ice crystals in the atmosphere to appear.
As JW said it is a phenomena that just means it's pretty cold outside.
bjrogg....I've always wanted to own my own plane in some ways myself.Cool that you have.My neighbor here does and still to this day flies his most evenings a short while as a person does pleasure riding his horse.In fact he took me for a short flight over my farm to take pics after I trapped out coons harrassing his cats and dog feed pans.Cool experience of a circular rainbow that you saw on the lake I'm sure.Colors of both rainbows and sundogs and halos will be the same as sunlight through ice is the same as water.Difference is sundogs and halos are beside or around the sun and rainbows are'nt.
I have seen double rainbows after rains before and think that was just because there was more moisture in the atmosphere.
