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uk.sci.weather (UK Weather) (uk.sci.weather) For the discussion of daily weather events, chiefly affecting the UK and adjacent parts of Europe, both past and predicted. The discussion is open to all, but contributions on a practical scientific level are encouraged. |
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#1
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Someone mentioned recently that North Sea temperatures in winter are
today about 2 degrees higher than they were some 60 years ago. Currently, the North Sea is around 7 to 8 degrees. This would seem to suggest that cold easterly weather cannot be anything like as severe as it might have been in the middle of the last century. Does anyone have data for North Sea temperatures in the mid 20th century? Jack |
#2
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![]() wrote in message oups.com... Someone mentioned recently that North Sea temperatures in winter are today about 2 degrees higher than they were some 60 years ago. Currently, the North Sea is around 7 to 8 degrees. This would seem to suggest that cold easterly weather cannot be anything like as severe as it might have been in the middle of the last century. Does anyone have data for North Sea temperatures in the mid 20th century? We discussed this a couple of years ago, when I scanned a page as under ..... this is for *February* (the coldest of the series): January shows 6 to 7 degC central & western North Sea, but well below 5 for coastal waters near Denmark & NW Germany. Not quite the mid-20th century, but a mean for the period 1854-1958, taken from the "Weather in Home Waters" publication. http://homepage.ntlworld.com/booty.w...t_historic.gif If anyone is interested in other times of the year, let me know and I'll try and find time to put up a composite through the year. Martin. -- FAQ & Glossary for uk.sci.weather at:- http://homepage.ntlworld.com/booty.weather/uswfaqfr.htm and http://booty.org.uk/booty.weather/metindex.htm |
#3
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Thanks Martin. The current end January temperatures are 1 to 2 degrees
warmer than that "February" graphic providing some correlation with earlier thoughts. Jack |
#4
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![]() wrote in message oups.com... Thanks Martin. The current end January temperatures are 1 to 2 degrees warmer than that "February" graphic providing some correlation with earlier thoughts. .... I managed to locate my original post from a couple of years ago: I think the data are still pertinent. quote Following some comments regarding the changes in sea surface temperatures in recent years, I thought I would dig out the maps published in the 'Weather in Home Waters' series and compare with current values (actually 15th February ... roughly in the coldest point of the annual cycle). The averaging period used in that publication is based on period: 1854 to 1958 (punched card dataset: US Navy); There is always a problem doing this exercise in that the data are not homogenous, and with SST measurement in particular, arguments surround how accurate or otherwise the data are; indeed the publication I took the long-period averages from discuss the differences between the 'bucket' method (recommended) and the 'intake' method. These maps are apparently based primarily on *intake* temperatures, which the author states had (at this time) been found to be on average some 0.5degC *warmer* than 'real' surface SST values (intake water is taken some way below the waterline, but is subject to warming on being drawn through & past the ship's internal pipework, into the engine-room area). Taking the worst case scenario then, the 'historic' map might be regarded as a little too warm, and the differences found below perhaps greater. That of course assumes that current values are accurate! However, remembering these problems, the figures appear to confirm the warming - quite significantly so in some cases. Using some 'fixed' points: (change, degC) 60N10W: +1.5 60N00W: +1.5 50N10W: +1.0 50N00W: +2.0 Generally, across the 'Shipping Forecast' domain, +1 to +1.5degC, but some places around +2degC, for example, large areas in the North Sea (where data coverage should be pretty good both 'then' and 'now') & fairly generally offshore Norwegian coastal waters. This year (Feb.2004) in particular, the waters of the Skagerrak appear to be particularly warm (5 or 6degC from 5-day mean, as opposed to 1 to 3 degC from averages). Anomalies not quite so high Irish and Celtic Seas (circa +1) or the western English Channel. Strong patterns are there - albeit with higher values, so no sign of the North Atlantic Drift disappearing just yet! Even the little bulge of warmer water running southward across west Forties from the Northern Isles is still very pronounced; also the broad 'front' of warm water from 60N25W to north Hebrides. The maps can be found on my web site at:- http://homepage.ntlworld.com/booty.w...st_current.gif (ex. Met Office for 15th Feb, 5-day mean) http://homepage.ntlworld.com/booty.w...t_historic.gif (ex. Weather in Home Waters, Meteorological Office, 1975) /quote -- FAQ & Glossary for uk.sci.weather at:- http://homepage.ntlworld.com/booty.weather/uswfaqfr.htm and http://booty.org.uk/booty.weather/metindex.htm |
#5
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While the extra warmth of the North Sea might mean that rain rather
than snow would be the more frequent scenario today, given a REALLY cold blast, those higher SSTs would result in deeper and more impressive convection than in the past - and heavier snow perhaps....... Or am I talking rubbish? Jack |
#6
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#7
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In message , Martin Rowley
writes ... I managed to locate my original post from a couple of years ago: I think the data are still pertinent. quote Following some comments regarding the changes in sea surface temperatures in recent years, I thought I would dig out the maps published in the 'Weather in Home Waters' series and compare with current values (actually 15th February ... roughly in the coldest point of the annual cycle). The averaging period used in that publication is based on period: 1854 to 1958 (punched card dataset: US Navy); There is always a problem doing this exercise in that the data are not homogenous, and with SST measurement in particular, arguments surround how accurate or otherwise the data are; indeed the publication I took the long-period averages from discuss the differences between the 'bucket' method (recommended) and the 'intake' method. These maps are apparently based primarily on *intake* temperatures, which the author states had (at this time) been found to be on average some 0.5degC *warmer* than 'real' surface SST values (intake water is taken some way below the waterline, but is subject to warming on being drawn through & past the ship's internal pipework, into the engine-room area). Taking the worst case scenario then, the 'historic' map might be regarded as a little too warm, and the differences found below perhaps greater. That of course assumes that current values are accurate! On the Weather Ships there were 3 ways of measuring sea temperatu 1. The canvas bucket method. 2. A tap on a pipe in the engine room. You turned on the tap and held a thermometer bulb in the flow. 3. A thermistor somewhere in the intake pipework connected to a readout in the Met Office at the stern of the ship. They all gave different readings, with the bucket usually being the lowest. There was a theory that the water in the bucket was cooled by evaporation before the reading settled. I was never convinced by that. The "rule" was that the bucket method should be used whenever possible but stormy weather often precluded that. Also, some observers were less keen than others about using the bucket method every hour on a filthy wet night in December :-). What often happened, but not always, was that the bucket method was used at a main synoptic hour and a thermistor reading was taken at the same time. Thermistor readings, adjusted by the difference found at the main synoptic hour, were then used at the intervening hours until the bucket method was used again at the next main synoptic hour. In stormy weather, when it was not feasible to use the bucket method, the thermistor readings were used unadjusted. The manual readings using the tap in the engine room were logged once daily but were not normally used in the SYNOPs. Sea temperatures in the weather ship archive are therefore a random mix of bucket and intake figures. Norman. (delete "thisbit" twice to e-mail) -- Norman Lynagh Weather Consultancy Chalfont St Giles 85m a.s.l. England |
#8
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Felly sgrifennodd
Norman Lynagh : On the Weather Ships there were 3 ways of measuring sea temperatu 1. The canvas bucket method. 2. A tap on a pipe in the engine room. You turned on the tap and held a thermometer bulb in the flow. 3. A thermistor somewhere in the intake pipework connected to a readout in the Met Office at the stern of the ship. They all gave different readings, with the bucket usually being the lowest. There was a theory that the water in the bucket was cooled by evaporation before the reading settled. I was never convinced by that. Might the reason be that the bucket was filled by dangling it over the side into the very top of the surface of the sea, whereas the others came from pipework a little further below the surface? Adrian -- Adrian Shaw ais@ Adran Cyfrifiadureg, Prifysgol Cymru, aber. Aberystwyth, Ceredigion, Cymru ac. http://users.aber.ac.uk/ais uk |
#9
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In message , Adrian D. Shaw
writes Felly sgrifennodd Norman Lynagh : On the Weather Ships there were 3 ways of measuring sea temperatu 1. The canvas bucket method. 2. A tap on a pipe in the engine room. You turned on the tap and held a thermometer bulb in the flow. 3. A thermistor somewhere in the intake pipework connected to a readout in the Met Office at the stern of the ship. They all gave different readings, with the bucket usually being the lowest. There was a theory that the water in the bucket was cooled by evaporation before the reading settled. I was never convinced by that. Might the reason be that the bucket was filled by dangling it over the side into the very top of the surface of the sea, whereas the others came from pipework a little further below the surface? Adrian That could obviously explain why the readings were different but not why the bucket was almost always cooler. As Martin said earlier in the thread the intake water was probably warmed slightly before its temperature was read. Norman. (delete "thisbit" twice to e-mail) -- Norman Lynagh Weather Consultancy Chalfont St Giles 85m a.s.l. England |
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