After the episode about the shape of the Davis VP2 rain cone, and subsequent release of the Aerocone, I was musing on why my CoCoRaHS gauge seems to come out on the low side sometimes. It seems to be connected with southerly and easterly winds. With calm winds my NovaLynx 8" TBR agrees very well with the CoCoRaHS, as does the Davis.
I took a fresh look at my CoCoRaHS gauge installation, and I notice that my beveled board top end is very close to where the outer cylinder rim is. With the funnel installed, this will obviously be a bit better. I have been holding off on putting the funnel and inner cylinder in until the last snowflake has flown...
What I am beginning to wonder, is whether this bevel might be exacerbating wind lift also, just like the original non-Aerocone Davis. Even the "level and bevel" instructions on the CoCoRaHS site raises the possibility of this happening. I am fully aware of the reason for the bevel to prevent rain splashing into the gauge. I believe that this bevel might be causing an under-catch due to wind lift. I will try to raise the gauge up a bit, maybe add a baffle at the bottom of the bevel slope to hamper wind lift.
Greg H.