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

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.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.

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.

Sorry, I meant "for the same number of snow-lying days" not the "same snow
depth".

To illustrate the non-validity of using temps in deg C, if you carry out an
identical exercise using temps in deg F instead, the relative severity of the
individual winters changes markedly. Neither method is valid. The only valid
way is to use deg K.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.

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

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.

Dave Cornwell wrote:

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.

I agree that the approach is interesting. As you say, the absolute index values
don't have any meaning. The indices enable winters to be compared but deg K is
certainly the way to go.

If snow depth could be incorporated into the calculation of the index that
would add another relevant factor. Currently there is the so-call Eden Winter
Snow Index (EWSI). The monthly (or seasonal) value is calculated as the sum of
the daily 0900 snow depths (cm). It would then be a matter of deciding what
were appropriate weighting factors to be applied to Scott's index and the EWSI
before adding them. All good stuff.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.

Norman wrote:
Dave Cornwell wrote:

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.

I agree that the approach is interesting. As you say, the absolute index values
don't have any meaning. The indices enable winters to be compared but deg K is
certainly the way to go.

If snow depth could be incorporated into the calculation of the index that
would add another relevant factor. Currently there is the so-call Eden Winter
Snow Index (EWSI). The monthly (or seasonal) value is calculated as the sum of
the daily 0900 snow depths (cm). It would then be a matter of deciding what
were appropriate weighting factors to be applied to Scott's index and the EWSI
before adding them. All good stuff.

---------------------------
Posted the link for EWSI on our FAQ's to Scott last night and suggested
if he was bored on a dark winter's night.......
Great minds and all that ;-). What I like is that it is self
compensating for, say, a shortish but severe snowy spell but during a
relatively mild winter. This offsets people's perception of how bad it
was due to the disruption.
Dave

On Tuesday, December 17, 2013 11:21:39 AM UTC, Norman 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. Sorry, I meant "for the same number of snow-lying days" not the "same snow depth". To illustrate the non-validity of using temps in deg C, if you carry out an identical exercise using temps in deg F instead, the relative severity of the individual winters changes markedly. Neither method is valid. The only valid way is to use deg K. -- Norman Lynagh Tideswell, Derbyshire 303m a.s.l.

Thanks, Norman. the degK approach makes complete sense - I'll address the necessary changes on the spreadsheet when I get a moment. As for the snow 'cm days' it is looking increasingly like I'll need a trip to Exeter to view daily data - apart from my own relatively limited stats I only have access to the monthly data in the Snow Survey. All fascinating stuff

On Tuesday, December 17, 2013 4:01:11 PM UTC, Scott W wrote:
On Tuesday, December 17, 2013 11:21:39 AM UTC, Norman 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. Sorry, I meant "for the same number of snow-lying days" not the "same snow depth". To illustrate the non-validity of using temps in deg C, if you carry out an identical exercise using temps in deg F instead, the relative severity of the individual winters changes markedly. Neither method is valid. The only valid way is to use deg K. -- Norman Lynagh Tideswell, Derbyshire 303m a.s.l.



Thanks, Norman. the degK approach makes complete sense - I'll address the necessary changes on the spreadsheet when I get a moment. As for the snow 'cm days' it is looking increasingly like I'll need a trip to Exeter to view daily data - apart from my own relatively limited stats I only have access to the monthly data in the Snow Survey. All fascinating stuff
--------------------------------------------------------------------
What chance of winter mean temp going below zero C in Wanstead?
-----------------------------------------------------------------
Zero if you ask me.
If you are worried I would use Fahrenheit rather than Kelvin.
The latter scale would make the index rather insensitive.
People in the past have always had to use multiplying/dividing factors to make their indices show what they are trying to show.
The length of the snow lying is important but makes the working out of an index rather sklushy.

Speshially over a glass of mulled wine.

Len
------------------------------------------------------------------




Len

In article ,
Scott W writes:
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

That's very interesting. Thanks for going to the trouble of producing
it.

If snow cover is the main interest, then why divide the number of days
with lying snow by the mean temperature? Because the mean for 1962-3 was
0.2C and that for 1946-7 was 1.3C, the division massively inflates the
index for 1962-3 compared to the earlier winter. (And what would you
have done if the mean for 1962-3 had come out negative, as it very
nearly did? [Added later: Having now read the follow-ups, I see that
Norman has made the same point, only rather better.]

There was snow lying through much of the first two weeks of March in
1946-7. It looks as though that is included in the number of days of
snow lying, but how is the winter mean value defined (and the winter
rainfall total)? Was that the mean for the "traditional" three months of
DJF? If so then it seems inconsistent.

I'm surprised that 2010-11 doesn't make the top 20, given how cold and
snowy December 2010 was over much of the country.
--
John Hall "He crams with cans of poisoned meat
The subjects of the King,
And when they die by thousands G.K.Chesterton:
Why, he laughs like anything." from "Song Against Grocers"