Dave Cornwell wrote:
Norman wrote:
Scott W wrote:

Of interest to contributors in the Home Counties I have published a snow
survey / winter index on my blog for my area in east London. It is
inspired
by the old Snow Survey of Great Britain which ceased publication
after the
1991/92 season.

Further to Dave Cornwell's comment a few weeks back that people mostly
remember a winter through the amount of days with snow lying I
decided to use
the data I produced for my winter forecast and try to find out what snow
cover has been like in my area going back to 1946/47 - the first year
of the
original snow survey. I then divided the snow lying days by the
winter mean
to give the index. I realise there is the work of Bonacina to
consider but as
this is national I wanted to look more indepth

Not surprisingly the 62/63 season came out a long way ahead of the
rest -
mostly through the sheer sustained depth of the cold. There's also
one or two
surprises - strange how the memory can fool you.

It is a work in progress and I would welcome any input.

http://wp.me/p2VSmb-8M

Using the mean temp in deg C gives a highly non-linear index as the temp
approaches 0 deg C. For example, for the same snow depth the index
calculated
with a mean temp of +0.1 is double the index calculated with a mean
temp of
+0.2 deg C, which is certainly not the sort of result you are looking
for. A
mean temp of 0 deg C would give an index of infinity then as mean
temps dropped
below 0 deg C the index would be a decreasing negative value. Using a
mean temp
in deg K would be a much more valid approach.

---------------------------------
Hi Norman - indeed I have been helping Scott with this and have
suggested Fahrenheit or adding a constant to the means to get a more
proportional index and I think Scott will do that when time permits.
Most interesting though and a good approach I think as it takes away
some of those more subjective memories.
Dave
-----------------------------------------
In deg F, with (Snow Lying/Mean deg F) x 100 it comes out something like
this:-
1 1962-63 0.2 32.3 213
2 1946-47 1.3 34.3 168
3 1981-82 3.7 38.7 74
4 1954-55 4.4 39.9 68
5 1984-85 3.6 38.4 68
6 1978-79 2.9 37.2 64
7 1952-53 3.8 38.8 64
8 1985-86 4.1 39.4 55
9 1955-56 3.8 38.8 51
10 2009-10 3.3 37.9 50


Nevertheless I agree deg K would be better. I don't think Scott's
intention is to get an index that has quantitative meaning, more a
general ranking which it seems to do better than anything else I've seen.