On 29/10/2015 11:25, Eskimo Will wrote:


Hi Len, interesting stuff, but I have some questions about the graphs?

1. How consistent was the raingauge site over the years.

My experience of looking at Dartmoor gauges has revealed that just a
small change in location (even a few hundred metres) can make a
statistically sig. difference to rainfall. Cowsic is a case in question,
due to changes in aspect from one side of a valley to another.

2. In the 19th Century rainguage height was not consistent, in fact a
lot of gauges were elevated. Scientifically this was proven to produce
lower rainfalls than rainguages on the ground due to turbulence effects.

In my Dartmoor study I have been very careful to only use data where the
raingauge location has been consistent over the decades and where the
height of the gauge above ground has been consistent. I think that is
important.

3. Have you done a statistical Student's T test to measure significance
of the changes, I suspect that they are very sig (esp. winter). but with
the provisos of my points one and two above.

Jim, you need to look at your local area rainfall over the decades too,
if you can of course?

Will


Will. I've not been able to find anything from before 2000 anywhere.
Seems all the local weather stations in the county suddenly woke up
then, and records are pretty comprehensive after that date. All I can
say is that we never had any weather here in Northamptonshire before 2000!!!

jim