If you think it's cold this winter...

If you think it's cold this winter...

Post by Phil » Wed, 27 Mar 2013 20:19:49


Haven't had a frost fair on the Thames for a while:
http://www.netweather.tv/index.cgi?action=winter-history
 
 
 

If you think it's cold this winter...

Post by Sarah Harbou » Wed, 27 Mar 2013 22:32:37

Quote:

> Haven't had a frost fair on the Thames for a while:

> http://www.netweather.tv/index.cgi?action=winter-history

True, but the frost fairs were held near the old London Bridge as the many buttresses slowed the flow down enough that ice would form, so it isn't just because of the temperature being colder.

Sarah

 
 
 

If you think it's cold this winter...

Post by Carl » Thu, 28 Mar 2013 00:18:41


Quote:

>> Haven't had a frost fair on the Thames for a while:

>> http://www.netweather.tv/index.cgi?action=winter-history

> True, but the frost fairs were held near the old London Bridge as the many buttresses slowed the flow down enough that ice would form, so it isn't just because of the temperature being colder.

> Sarah

The last century's warming climatic trend, although bringing increased
variability (more extremes of hot & cold, wet & dry), is going to
further reduce the likelihood of future frost fairs.  This doesn't mean
they can't happen, but it seems to reduce the probability of having
sufficiently intense cold and low flows for long enough for the Thames
to ice up solid.

In the UK, rowing has been particularly hit over the last decade or so
by exceptional extremes of weather, ranging from drought through
increasingly severe flooding.  You could almost call it the Olympic
curse: after our most successful rowing Games in many years, back in
2000, & just after a large resulting influx of keen rowers, the heavens
opened and stayed open for months such that many upriver clubs were
unable to boat.  This time, for much of the last 4 months the upper
reaches of many UK rivers have suffered nearly continuous high levels,
floods and extreme flows.  And in recent weeks we've also had unseasonal
cold, just as we had exceptional heat a year ago.

It's all becoming a bit of a mess!

Carl
--
Carl Douglas Racing Shells        -
     Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write:   Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find:    tinyurl.com/2tqujf



 
 
 

If you think it's cold this winter...

Post by Alistai » Thu, 28 Mar 2013 01:08:09

Quote:


>> Haven't had a frost fair on the Thames for a while:

>> http://www.netweather.tv/index.cgi?action=winter-history

> True, but the frost fairs were held near the old London Bridge as the many buttresses slowed the flow down enough that ice would form, so it isn't just because of the temperature being colder.

> Sarah

This is true, but equally important was the lack of embankments (Albert,
Victoria, etc.) Wider river = slower peak flow; also the embankments'
sheer sides give the ice a vastly poorer chance to form compared with a
normal shore.
 
 
 

If you think it's cold this winter...

Post by andymckenzi.. » Thu, 28 Mar 2013 02:21:00

Quote:



> >> Haven't had a frost fair on the Thames for a while:

> >> http://www.netweather.tv/index.cgi?action=winter-history

> > True, but the frost fairs were held near the old London Bridge as the many buttresses slowed the flow down enough that ice would form, so it isn't just because of the temperature being colder.

> > Sarah

> The last century's warming climatic trend, although bringing increased

> variability (more extremes of hot & cold, wet & dry), is going to

> further reduce the likelihood of future frost fairs.  This doesn't mean

> they can't happen, but it seems to reduce the probability of having

> sufficiently intense cold and low flows for long enough for the Thames

> to ice up solid.

> In the UK, rowing has been particularly hit over the last decade or so

> by exceptional extremes of weather, ranging from drought through

> increasingly severe flooding.  You could almost call it the Olympic

> curse: after our most successful rowing Games in many years, back in

> 2000, & just after a large resulting influx of keen rowers, the heavens

> opened and stayed open for months such that many upriver clubs were

> unable to boat.  This time, for much of the last 4 months the upper

> reaches of many UK rivers have suffered nearly continuous high levels,

> floods and extreme flows.  And in recent weeks we've also had unseasonal

> cold, just as we had exceptional heat a year ago.

> It's all becoming a bit of a mess!

> Carl

> --

> Carl Douglas Racing Shells        -

>      Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories

> Write:   Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK

> Find:    tinyurl.com/2tqujf




Ah - a topic where I can, if not speak with authority, at least leverage data.

I took gauged daily flow data on the Thames at Kingston, for which records stretch back to the 1880s. Rather as I expected, given other hydrological data in the UK, the record suggests that rather than the last 15 years being particularly 'bad' for high flows, it's that the period 1960 - 1990 or so had very few. Before that the pattern is similar to today (Climate colleagues will nod wisely and mutter about North Atlantic oscillations and atmospheric aerosols).

I took a flow of 200 m3/sec as representing a red board - no idea if that is in any way realistic, but seems about right calibrated to the last few months.

In an average year there are 25 days above 200 m3/sec.

The 'best' year - assuming that there was any water left to actually row on was 1948, with 1 day of high flow.

Best decade for low flows probably the 1890s, worst was the 1920s. 2000s were second worst.

'Worst' was 1951 where 200 m3/sec was exceeded on 87 days, with 1915 and 1916 also being above 80.

Over the 130 years its hard to pick a trend out that is in any way significant.

2000 was a 'bad' year for high flows, but then again so was 1960 when we won no medals at all, and 1948 was the really low flow year, and our medal haul, relative to the regatta size was fairly good.

My conclusion - no Olympic curse (sorry Carl), and that while we live in times of interesting weather, so did our grandparents. It's just that the sunny day you did row is more memorable than the rainy one when you didn't.

Andy McKenzie

 
 
 

If you think it's cold this winter...

Post by Henry La » Thu, 28 Mar 2013 04:03:50


Quote:
> leverage data

Oooh ... evidence-based analysis; just what we need.  Any chance you
could give messrs Gove, Hunt, etc a tutorial?

--

Henry Law            Manchester, England

 
 
 

If you think it's cold this winter...

Post by R.. » Thu, 28 Mar 2013 23:28:32

But why?  Policy-based evidence-making is so much more productive.
R
 
 
 

If you think it's cold this winter...

Post by andymckenzi.. » Fri, 29 Mar 2013 01:32:28

Quote:

> But why?  Policy-based evidence-making is so much more productive.

> R

And anecdote/bar chatter policy making is both more productive and fun!