[Pete Roberts]

River Weaver, Frodsham, 9-8-10: 21C

Pete

[Pete Roberts]

River Weaver, Frodsham, 10-8-10: 21C

Pete

[Pete Roberts]

Not inland but briny, but I thought I'd put it in anyway ;)

Irish Sea (Cardigan Bay), Pwellhi, 12-8-10: 18C

A little on the low side for the time of year - should be 20C. Mind you if the rest of their summer was like today, I'm not surprised. Air temp a wretched 13.5C at lunchtime on what is supposed to be a high summer's day [n]

Pete

[Pete Roberts]

River Weaver, Frodsham, Cheshire, 14-8-10: 20.5C

Fairly stiff current so a fair amount of rain must have fallen on the Cheshire plain.

Pete

[Chris Alder]

Pete I still don't understand how the water temperature is 5c above the mean air temperature especially in a extended dull spell?

[Pete Roberts]

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Chris Alder - 14/8/2010 21:24 Pete I still don't understand how the water temperature is 5c above the mean air temperature especially in a extended dull spell?

The water temp reached 26C in June and the Weaver is a deep, slow flowing river so there's a lot of water to cool.  Not only that, brine pumping at Northwich results in hot brine seeping into the river through its bed. The river valley is also a sun-trap and even small amounts of summer sunshine can raise the water temp. by a surprising amount.

It's not thermometer error as regularly I check my instruments at 0C using a slush of ice and water.

 Pete

[rosskesava]

Brine? I understand brine to be basically a mixture of fresh and salt water?

I've looked on a map and Northwich is a far bit inland. Sorry to sound a bit dim (again) but I'm curious about the 'hot brine'?

Also, just out of curiosity and in bewtween working and on different days, I measured the temperature at the river Adur in West Sussex, which is tidal. Near the harbour at Shoreham, it was 17C but further up at Arundel, where the tidal effect was less, it was 21C. Both times the tide was on it's way out.

The thermometer I used was hardly 'state of the art' and disregarding the error possible from using a cheap thermometer as I assume it would be the same for both locations, was the difference due to the influence of the sun or the tide?

I think I've just posted another daft question.

Cheers

[Pete Roberts]

Quote

rosskesava - 15/8/2010 01:12 Brine? I understand brine to be basically a mixture of fresh and salt water? I've looked on a map and Northwich is a far bit inland. Sorry to sound a bit dim (again) but I'm curious about the 'hot brine'?

No - brine is a strong salt solution. In Cheshire salt is extracted using two methods.  It's mined as rock salt in Winsford, and this is where most of the UK's road grit is sourced.  The other method is by pumping hot water down into the salt beds which then returns as brine. This is done at Lostock Gralam just outside Northwich. Brine tends to be used where the salt is a chemical feedstock although table salt is also made from it.

Quote

rosskesava - 15/8/2010 01:12 Also, just out of curiosity and in bewtween working and on different days, I measured the temperature at the river Adur in West Sussex, which is tidal. Near the harbour at Shoreham, it was 17C but further up at Arundel, where the tidal effect was less, it was 21C. Both times the tide was on it's way out. The thermometer I used was hardly 'state of the art' and disregarding the error possible from using a cheap thermometer as I assume it would be the same for both locations, was the difference due to the influence of the sun or the tide? I think I've just posted another daft question. Cheers

I use a standard swimming pool thermometer.  The tidal part of a river receives colder sea water whereas the upper reaches don't.  In winter the reverse occurs: tidal estuaries are warmer than the freshwater upstream.

Pete

[Pete Roberts]

Hatchmere (lake), Delamere, Cheshire, 15-8-10: 20.5C

Pete

[Pete Roberts]

River Weaver, Frodsham, Cheshire, 16-8-10: 20C

Definite cooling trend.

Pete

[Pete Roberts]

River Weaver, Frodsham, 22-8-10: 22C

Pete

[Pete Roberts]

River Weaver, Frodsham, 25-8-10: 20C

Pete

[PK2]

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Pete Roberts - 5/8/2010 09:12

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PK2 - 5/8/2010 06:30  Thanks. IF they've got their figures correct (e.g. are not measuring temps much lower down the water column) it seems Loch Ness is only 5-7C. Does that seems likely?

No - that's journalistic licence tending to utter nonsense.  I swam in Loch Ness in early September and the surface water temp was 18C - a long way from 6-7C which is what I'd expect in winter.

Bear in mind that Ness is situated at the bottom of the Great Glen at virtually sea level.

Pete

It seems the answer was "non of the above"

Quote

Water temperature was recorded at 11.5ºC but varied between 9ºC and 12ºC throughout.

[Pete Roberts]

Quote

PK2 - 25/8/2010 14:35  It seems the answer was "non of the above"

Quote

Water temperature was recorded at 11.5ºC but varied between 9ºC and 12ºC throughout.

I wonder whether they used a properly calibrated thermometer and made the measurement at 400mm depth?  Some boats are fitted with water temp. readouts but from what I've seen of them are pretty inaccurate.  I'm very wary of newspaper quotes given how I've been misquoted in the past.

Even give Scotland's more appalling than usual summer I can't see a body of water at sea level being that cold.  I'm also suspicious of the mention of a "current".  Ness is a huge enclosed, very deep lake with a comparatively miniscule inlet and outlet -  there can't be any current unless Nessie was flapping her wings. [hehe]  More likely be the wind.

Pete

[PK2]

Quote

Pete Roberts - 25/8/2010 15:17

Quote

PK2 - 25/8/2010 14:35  It seems the answer was "non of the above"

Quote

Water temperature was recorded at 11.5ºC but varied between 9ºC and 12ºC throughout.

I wonder whether they used a properly calibrated thermometer and made the measurement at 400mm depth?  Some boats are fitted with water temp. readouts but from what I've seen of them are pretty inaccurate.  I'm very wary of newspaper quotes given how I've been misquoted in the past.

Even give Scotland's more appalling than usual summer I can't see a body of water at sea level being that cold.  I'm also suspicious of the mention of a "current".  Ness is a huge enclosed, very deep lake with a comparatively miniscule inlet and outlet -  there can't be any current unless Nessie was flapping her wings. [hehe]  More likely be the wind.

Pete

Yeah the current reference is odd [dunno] . I can imagine there'd be a current near the end (IIRC there's a weir not far along the canal at that end which would give an non lock-based flow) but I wouldn't have thought it noticeable until VERY close to the end. The wind on the other hand...
As to the temp, I dunno, I'd have assumed they'd know how the check the temp properly (and it's their own website so less chance of a misquote) but maybe they did just use one on the boat [dunno] .

[Pete Roberts]

River Weaver, Frodsham, 27-8-10: 19C

Definite cooling trend now.

Pete

[Pete Roberts]

Hatchmere (lake), Delamere Forest, Cheshire, 29-8-10: 18.5C

Definitely on the way down now. Should be around 20-21C this time of the year after a "normal" summer.

Edit: Despite being a lake I was definitely being pushed around by a strong "current" - an air current! It was down to the 25kt near gale howling down from the NW. [tn]

Pete

[PK2]

Quote

Pete Roberts - 29/8/2010 22:06

Hatchmere (lake), Delamere Forest, Cheshire, 29-8-10: 18.5C

Definitely on the way down now. Should be around 20-21C this time of the year after a "normal" summer.

Edit: Despite being a lake I was definitely being pushed around by a strong "current" - an air current! It was down to the 25kt near gale howling down from the NW. [tn]

Pete

Yeah, I decided it was a bit windy yesterday and stayed on land. Looks like the conditions kept the lifeboat busy with having to rescue a yacht and search for kayaker (they haven't found her ATM :( ). I did have a look at high tide and marvelled at the people parking their cars on the prom where the waves broke over their cars. If they'd have looked inland for a second they'd have seen where a similar, although slightly stronger, wind had smashed the wall that was inland of where they'd parked their car.

[Pete Roberts]

River Weaver, Frodsham, 30-8-10: 17.5C

Down nearly 5C in just over seven days - not a good sign.

Pete

[Pete Roberts]

River Weaver, Frodsham, 31-8-10: 20C

Looks as though I was being overly pessimistic and the Monday's low of 17.5C was down to Thursday's cold rain making its way downstream. Anyway the water temp has now recovered to what I'd describe to be about right for the time of year despite last night's cold. Temp measured at same location using same thermometer.

Pete