Today we launch a new fleet on oldWeather.org: the focus this time is on Arctic voyages, and the logbooks are from the collection of the US National Archives in Washington. We’ve ships from the Revenue and Coast Guard, the Navy, and the Coast Survey; and they include some famous names and some exciting voyages.
The Arctic is very sensitive to climate variability and change. This year (2012) was a record year for sea-ice: there was less sea-ice this September than for any other year for which we have good satellite records. But the satellite records only go back to 1979, and we need many more than 30 years of records to really understand how the Arctic climate behaves. This means we need to rescue the weather records of the people who travelled there – to read the logs of Arctic voyages.
If you joined in the original oldWeather, you’ll notice some differences in this new version: There are fewer ships (at least to start with, we’ll be adding more regularly), but the records for each ship usually cover many years, so we have just as many pages to read. These logbooks are also older (back to 1850 in some cases), and differently laid-out, so we’ve had to change the way you enter data: Basically it’s the same – select the location on the log page with an important record and then type the record into the pop-up box – but the details have changed. So whether you’re a new recruit or an old hand, please experiment until you get used to it – there is a tutorial to guide you, and help and encouragement on the project forum.
We’re still looking for all weather records, and anything else you read and think is interesting or notable. There will be plenty of notable historical events: the dangers of sailing through the ice add a lot of drama to the stories in the logs – whether you prefer the daring rescue by USRC Bear, ice and fire on the USS Rodgers, or the so-far-unknown adventures of less famous ships.
The weather in Exeter yesterday was best described as “ocr“, so I missed the transit this time. Fortunately, the skies were clear back in 2004, and I remember the experience of peering through a pair of binoculars equipped with a sun-filter and seeing the small black dot of Venus silhouetted against the sun.
The transit of Venus is a periodic event, and the big year was in 1769. I understand that the astronomers valued the transit as a way to get a handle on the size of the universe; but the real virtue was that it provided an excuse for the British Government to send an expedition down into the South Pacific. That expedition was commanded by James Cook, and it started the career of the greatest explorer of them all.
Of course, as a naval officer (Lieutenant, at the time), Cook kept a journal. If your eyesight is up to it, you can read his account of June 3rd 1769 in the original handwriting; but I admit that I looked up Project Gutenberg’s transcription:
Saturday, 3rd. This day proved as favourable to our purpose as we could wish. Not a Cloud was to be seen the whole day, and the Air was perfectly Clear, so that we had every advantage we could desire in observing the whole of the Passage of the planet Venus over the Sun’s Disk. We very distinctly saw an Atmosphere or Dusky shade round the body of the planet, which very much disturbed the times of the Contact, particularly the two internal ones. Dr. Solander observed as well as Mr. Green and myself, and we differ’d from one another in Observing the times of the Contact much more than could be expected. Mr. Green’s Telescope and mine where of the same Magnifying power, but that of the Doctor was greater than ours. It was nearly calm the whole day, and the Thermometer Exposed to the Sun about the Middle of the day rose to a degree of heat we have not before met with.
The ideal weather observer does not expose his thermometer to the sun (shade temperatures please), so perhaps it’s no great loss that Cook’s journal does not contain regular weather observations. For those, we must turn to the Master’s log of HM Bark Endeavour (the closest equivalent to the familiar modern-day logs). For the day of the transit, this records “Little wind and variable with fine pleasant clear weather”. I reckon that’s “Lt. Airs, Var., 1, b” in our notation. Sadly, none of the logs contain regular thermometer or barometer observations – Cook did better on his subsequent voyages – but we do get wind speed and direction reports for every day.
Edmond Halley is best known for his comet, but he was one of the great polymaths – as well as making astronomical discoveries he was also a notable meteorologist: he did important early work understanding the trade winds and monsoons. It’s less well known that that he was also a Naval Officer: in 1699 he was granted a commission as captain in the Royal Navy, and he commanded HMS Paramour (a pink) on an expedition into the South Atlantic to investigate the variation of the compass.
His main concern was with magnetism, but as a man of wide interests, Halley took with him examples of those two exciting modern scientific instruments: the thermometer and the barometer. I can’t find the logbook of the voyage, but Halley’s notes have survived: they were published by Alexander Dalyrmple, in 1775, as part of “A collection of voyages chiefly in the Southern Atlantick Ocean“. They date from 220 years before the logbooks we’re used to in OldWeather, but to anyone who’s looked at our logbooks they are oddly familiar: records of latitude, longitude, wind force and direction and, in the left-hand margin, thermometer and barometer readings.
In 1699 the barometer had been around for more than 50 years, and the barometer records in Halley’s account are clearly in the familiar inches of mercury. But the thermometer did not become a reliable, precision instrument until about 1725, when Fahrenheit invented the mercury thermometer with a standardized, calibrated scale. So when Halley says the temperature is ’33′ it’s not immediately obvious how this should be interpreted. Careful scholarship has established, however, that Halley was using a thermometer designed by Robert Hooke, and lavishly described in his book Micrographia:
The Stems I use for them are very thick, straight, and even Pipes of Glass [...] above four feet long [...] [filled] with the best rectified Spirit of Wine highly tinged with the lovely colour of Cocheneel, which I deepen the more by pouring some drops of common Spirit of Urine, which must not be too well rectified, [...]
From Hooke’s description we can convert Halley’s reported units into modern equivalents at least approximately – Halley’s ’33′ was about 8°C.
The diary entries are mostly routine accounts of the movements of the ship, but occasionally he puts in longer and more interesting reports: here’s an example from Thursday 1st February 1700, when they were close to South Georgia, in the cold waters of the Southern Ocean:
[...] between 4 and 5 we were fair by three Islands as they then appeared; being all flat on the top, and covered with Snow milk white, with perpendicular Cliffs all round them [...] The great height of them made us conclude them land, but there was no-appearance of any tree or green thing on them, but the Cliffs as well as the tops were very white, our people called A by the name of Beachy-Head, which it resembled in form and colour. And the Island B in all respects was very like the land of the North-foreland in Kent, and was at least as high and not less than 5 miles in front, [...]
The following day they were disconcerted to discover that these ‘islands’ had moved, and fled north to warmer waters. This is the first recorded sighting of a tabular iceberg.
Halley’s observations are probably not of great value to climate scientists: his instruments were state-of-the-art for 1699, but it took decades longer for such observations to became accurate and plentiful enough for climate reconstructions. He did set a precedent though – possibly as the first person to go to sea with a barometer and a thermometer – and we’re still following his example more than 300 years later.
When scientists talk about pressure, they measure it in Pascals (Pa: the SI unit for pressure). For atmospheric pressure, 1Pa is an inconveniently small number, so we lump them together in groups of 100 and talk about hectopascals (hPa: 1hPa=100Pa). The atmospheric pressure at sea level is usually given as 101325 Pa, which is approximately 1000 hPa; so 1 hectopascal is also referred to as 1 millibar – when you hear your weather forecaster talking about millibars, hectopascals are what he’s really using. The ships, however, don’t measure pressure in hectopascals or even millibars; they measure it in inches. This is an artefact of the way they measure the pressure – with a mercury barometer.
Back in the early 17th century there was much discussion among the scientists of the day about why it was impossible to pump water more than about 10m upwards. It was Evangelista Torricelli, in 1643, who realised not only that the height to which the water rose was determined by the weight of the surrounding air, but also that you could use this effect to measure changes in the air pressure. A 10m column of water is a nuisance to work with, so he switched to the much heavier mercury as his working medium, and made the first ever barometer measurement.
We’ve been measuring air pressure in the same way ever since – balance the weight of a column of mercury against the weight of the surrounding atmosphere, and the taller the column the higher the atmospheric pressure. At sea-level, the column will be about 76cm (29 inches) high, and the changes in atmospheric pressure as the weather changes cause fluctuations of up to a few inches. The pressure is proportional to the height, so we can get the pressure in hPa by multiplying the height in inches by 33.86389.
Of course, making precise measurements requires great care (very pure mercury, no air in the tube, careful calibration, …) but by our period (1914) barometer manufacturers were making very good instruments. There are, unfortunately, still a few complicating factors which we need to be aware of:
- The weight of a column of mercury changes with temperature – the weight of 760mm of mercury is less when it’s hot than when it’s cold, so we need to adjust for this when calculating pressure from height. A further complication is that the column height is usually measured using brass measuring rods, and the length of brass rods also changes with temperature. So we apply a correction from a table or an empirical formula – these tables vary slightly depending on the barometer design, but in OldWeather we don’t usually know the make of barometer in use so we use a generic table. To make this temperature correction we need, of course, to know the temperature of the barometer: Almost all mercury barometers have a thermometer attached and it is usual to record the barometer height and attached thermometer temperature together – as is done in many of our logs. Moving from 0C to 35C (Arctic to the tropics or February to July in the UK) would introduce a change of about 0.5% (2 tenths of an inch).
- The weight of a column of mercury changes with latitude. We launch satellites from French Guiana, rather than Europe, because satellites weigh less in French Guiana than they do in Europe. Moving from Plymouth to Singapore would reduce your weight by about 0.2% (about 8 hundredths of an inch)
- We generally want the pressure at sea-level. We usually keep the barometer above sea-level, so we need to add a little to the pressure to adjust for this. Every 80 or 90 feet above sea-level reduces the pressure by 1 tenth of an inch.
- It’s usual to measure the position of the top of the mercury column. As the mercury rises in the tube, the level of the mercury in the cistern at the bottom of the tube will fall. Because the mercury column balancing the atmosphere runs from the top of the level in the tube to the level in the cistern, we need to add a little to measured height changes to allow for this.
- If the glass tube containing the mercury column is narrow (to reduce weight and to damp oscillations) the height of the mercury will be reduced by capillary action. We need to add a little to the measured height to allow for this.
We call these, respectively, the temperature correction, the gravity correction, the height correction, the capacity correction and the capillary correction. By 1914, with a good barometer, the last two should have been allowed for in the instrument’s calibration and operation, and the third is small for ships, but we still need to make the first two corrections. The changes involved are small compared with the changes associated with short term weather, but they are important for correctly representing the more subtle, longer-term changes.
Mercury barometers are great for fixed, stable, weather stations. They are however expensive, difficult to read accurately in a ship in motion, a terrible nuisance to carry around, and really too fragile for service in a warship. So much ingenuity has been spent on devising cheap, portable, alternatives. The aneroid barometer is essentially a sealed metal bellows that grows and shrinks as the air pressure rises and falls, coupled to machinery to amplify its movements and display them on a scale. These first appeared in 1843, but it took a long time to make them accurate and reliable enough for serious use. By 1914, however, they were coming into use, and it’s clear from the logs that our ships used both mercury and aneroid barometers. Aneroids don’t require gravity, capacity, or capillary correction – and are mostly deliberately designed to be insensitive to temperature changes, so they don’t need an attached thermometer measurement. Nowadays aneroid barometers report pressure in hPa, but back in 1914 most gave readings in inches of mercury. So far I’ve only seen one ship reporting pressures in hPa – HMS Glowworm.
Were the aneroids on our ships less accurate than mercury barometers? more accurate? different in some subtle way? I don’t know – but I look forward to finding out. So if you see any reference in the log to the type or make of barometer in use, please transcribe it. We don’t need to know what they were using, as we can guess with good accuracy, but it does help. A few ships record both mercury and aneroid barometer readings – if you see this, please transcribe both of them; the comparison between them helps us estimate the accuracy of the measurements.
As we said in our recent blog post, Old Weather has been churning through Royal Navy logbooks from World War 1 for long enough now that we can start to extract some interesting stats from the words transcribed by the community.
Social networks are all the rage now, but here at Zooniverse HQ we’ve been wondering what the 90-year-old social graph of Old Weather would look like. We’ll have more to say in the near future about the interactions of people on board the Royal Navy ships from our logs, but what about the ships themselves? When ships pass each other at sea, or meet to exchange supplies, officers and information, they make a note of this in their logs.
This enormous chart shows all of the Old Weather ships in a big grid, highlighting in purple where ships connect to each other. You can look down the chart, or across it, to find the interactions for a given ship. You can see that the HMS Arlanza and the Alsation seem to meet up with quite a few of the other ships of the chart. Both are Armed Merchant Cruisers that cross the busy stretch between the UK and the USA. So is the HMS Motugua, and it too has a fair few interactions with other vessels.
Taking those ships that are often mentioned, we can delve further into their interactions and create arc plots for those vessels. The arc plot below, for the HMS Alsatian, shows that it has encountered 26 ships in the transcriptions made to date. The thickness of the lines connecting vessels indicates the relative number of times that the two ships reference each other. The HMS Moldavia and HMS Patia are fairly well-connected with the Alsatian.
What isn’t shown on the large network plot is that the most mentioned vessel in the Old Weather fleet is the HMS Bee, a river gunboat and a ship that is only 36% complete so far on Old Weather (maybe you could jump aboard and help to complete it?). This ship is not mentioned a great deal by every ship but rather features regularly in the logs of a few vessel in the fleet. The arc plot for the HMS Bee is shown below. The HMS Bee interacts a great deal with the HMS Scarab and the HMS Cricket. all three are gunboats, as is the HMS Gnat. The next step here is to examine the logs and find out when these vessels interacted so much, and why. A blog post of these at a later time.
Finally, for this post, let’s look at the arc plot for the top twenty most-connected vessels in Old Weather so far. These are the ships from the large network plot that connect with the most other ships. These plots can be made for the whole fleet – but they become very large and complex and thus difficult to take value from. This slimmed-down version showing just the top twenty gives you an idea of the ships that are linked to other ships.
This is the kind of simplistic data that can be extracted from your transcriptions of events. So far, only the development team have been looking at this, but the tools are being made available to the historians of Old Weather for further analysis. I’m excited by what they can uncover.
Many of the ships listed in these charts are available on our Old Weather Voyages page, so you can see for yourselves how they interact with each other. You can use that page to read the log entries and see where ships were when they encountered one another. We’re always trying to find new ways for everyone to explore the Old Weather data and if you have any suggestions we’d love to hear them, either here on the blog or via twitter @oldweather.
Can you believe that Old Weather is 44% complete‽ I can’t, but that’s what the site is currently telling me. It’s amazing how much care and effort has been poured into this project by people all over the world. 63 vessels are now complete and the task of processing and understanding everything is underway.
Yesterday we said we had a little thank you coming and here it is: Old Weather Voyages. Stuart Lynn, the principal developer for Old Weather, and myself have been toying with the idea of displaying your weather and event transcriptions in a fun and interesting way. Old Weather Voyages lets you see the data that you have all provided in a way that puts the voyages of these ships front and centre
The Old Weather Voyages site displays one ship’s log book at a time and lets you watch events unfold as they did nearly a centrury ago. you can either just sit back and watch the ship at it voyages around the globe, or you can grab the time slider and whiz back and forth, seeing what happens and when.
As the ship moves around the world, its track is coloured according the the sea temperatures that have been recorded. The events from the ship’s log are shown on the log page on the left hand side. The image below shows the voyage of the HMS Africa up to the afternoon of Saturday November 3rd 1917. The log on the left shows that there have been several sicknesses reported over the past week on the ship. The ship’s track shows that the water is warmer nearer the equator than it is in South Africa, for example.
We hope that this new way of exploring the Old Weather data shows not only that the information being transcribed is coherent and useful, but also that your data really does go somewhere! We are often asked, here at the Zooniverse, what happens to your clicks and transcriptions. Here is a great way to explore the early results of the project and explore the history behind the science.
[If you have a Mac, you can also grab Old Weather Voyages as a screensaver]
I wanted to say something about the results from our fifth finished ship HMS Inflexible, so I’ve proccessed all the measurements and made a full set of plots showing trends in the weather over the voyage. The results are excellent, but sometimes even I get a bit tired of barometric pressures and wet-bulb temperatures, so instead of posting them here I’ve sneaked over to the other side of the project to have a look at the history data – the log entries that we’ve selected for inclusion.
The sort of history we’re doing in OldWeather: collecting and synthesising large quantities of diverse material, is an example of a new research trend sometimes called ‘digital humanities’. Because it’s new, the methods for making use of the events we’ve been collected are not yet well established (and anyway I’m no historian) so I’m not sure what the best way to use the events we’ve recorded is. But it’s always a good start to plot the data and see what you’ve got, so I’ve fed all the events recorded from the Inflexible into Wordle (www.wordle.net) and made this:
It’s a bit like the blob plots I’ve posted before – everything is in there (I’ve stripped out a few really common words like ‘the’ and ‘ship’), but more popular entries are bigger. Inflexible is most famous for being in the battle of the Falkland Islands (like her sister ship – HMS Invincible), but I think this image gives a more balanced indication of the real day-to-day story of the ship: Routine activities and references to other ships loom large, and only right down in the small print are the signs of drama: ‘Firing’, ‘Killed’, ‘Died’, and ‘Sunk’. I was baffed at first by the frequent reference to ‘Sabretache’ – a sort of cavalryman’s handbag, but it turns out that it is the name of another ship – a French destroyer.
So thanks and well done to captain clibby34, lieutenants sarek and instigator008, and all the crew. And just in case you’re interested in the wind direction, barometer height etc., I’ve put that on line here.
Every now and then, while working at the logbooks, we come across a page which has a particularly compelling story to tell. My favourite page, so far, is the log of the battlecruiser HMS Invincible, for Tuesday, December 8th, 1914. It’s appealing not just because of the dramatic course of the day, but because of the way history and the weather, the two halves of the Old Weather project, come together to shape events.
Invincible starts that day moored in Port William, in the Falkland Islands, and the first entry in the log is 4 am, with a weather
report: light airs from the SSE, broken cloud, air temperature of 40F – quite a nice day, by the standards of the South Atlantic. A 4am weather report is a standard feature of these logs, but on this page, it’s the last we hear of the weather for some time, as the sailors are distracted by other events.
At 5am it’s still a normal day, the log records the coaling of the ship, and work to remove a cable fouling Invincible’s propeller. At 8am we’d normally expect another weather observation, instead we see the start of a flurry of activity: ‘strange vessels sighted … on horizon to southward’, ‘Stopped coaling’, ‘Action stations’, ‘Enemy in sight of Port William’. At 9:22 the first shots are fired ‘Canopus opened fire’ (Canopus was an older British battleship moored permanently at Port Stanley), and at 10:00 Invincible ‘Weighed and proceeded at full speed … in chase of German Squadron now observed to consist of Scharnhorst (flagship of Admiral Count von Spee), Gneisenau, Nürnberg, Dresden and Leipzig’.
The afternoon records in the log provide a live, first-hand report of the Battle of the Falkland Islands
(Wikipedia entry; details from naval-history.net). It ends, like all the best epics, with tragedy: ’4.17 Scharnhorst sinks’, ’6.2 Gneisenau sinks … proceeded at full speed to pick up survivors.’ That’s the end of the battle for the Invincible, but it took a further 5 hours for the crew to calm down sufficiently to remember their wider duties – the second weather observation of the day does not appear until midnight: Wind from WNW, force 4, pressure 29.5/51.
So history understandably limits our records of the weather for that day, but the weather also had a role to play in the battle: The German sailors, fleeing from the faster, more heavily armed British fleet, must have prayed for storms, rainfall, fog, heavy seas – anything to help them make their escape. Their prayers went unanswered, 1881 sailors died in the battle; Scharnhorst, Gneisenau, Nürnberg, and Leipzig were all sunk – and their logbooks (and weather records) went down with them.
Sailors have been deeply concerned with the weather since ancient times: wind speed and direction, and estimates of ocean currents, were critical information for keeping track of the ship’s position. The Royal Navy records in the National Archives and the National Maritime Museum go back into the 17th century, and even the earliest logbooks contain descriptions of the weather of each day. Read More…
Old Weather is a revolutionary approach to naval, as well as family history research. More and more people are fascinated by their past, including the naval and military careers of their British forebears, especially in the two world wars. As so many families are now spread around the world, this is a global interest, especially in the United States and the Commonwealth. Read More…