Old School Data Mining, Maritime Style?

jason0000042 writes "The BBC is reporting on Cliwoc, the Climatological Database for the World's Oceans, which pulls data about climate change from 18th and 19th Century sailing ships' logbooks. It's like a window in time that could help us better understand global climate change, if they can decipher the olde timey language of the 1750's. Personally, I can't wait to know if we're going to melt down, or alternatively, have an ice age."

Comments

Warming AND Ice Age

[RabidChipmunk]

Actually, current models look like we're going to get both.

The basic gyst is that the warming melts Greenland. This diverts the gulf stream; plunging Europe into an Ice Age. [It also cools the NE of North America, but Europe really gets it.]

The average temperature is rising, that doesn't mean it's getting warmer everywhere.

Re:Warming AND Ice Age

[Aardpig]

So you'd better watch out...if you don't play nice, we'll take the Rockies down

Hah, if you do that, then we'll blow La Palma and watch the US east coast disappear under a tsunami over half a kilometre tall! In fact, we don't need to blow it; according to this article, the collapse of La Palma becomes more likely as global temperatures rise.

However, there's no cause for panic. I have a friend working at the Instituto de Astrofisica de Canarias, and he's promised to phone me if La Palma collapses. I'll post to Slashdot as soon as I get word...

Both

[Euphonious Coward]

There's no reason not to expect a meltdown followed hard upon by an ice age.

The weather has been demonstrated conclusively to be a chaotic system. One feature common in chaotic systems, easily seen in the Lorenz simulation (e.g. in your screen saver) is that when the system's oscillations get increasingly large (a little moreso each cycle), this is prelude to a change in mode to a different attractor, where all recent history has no predictive value at all.

Imagine what would happen if the Gulf Stream decided to flow on a different path, e.g. because of the massive salinity decrease around the north pole. The end of agriculture in northwestern Europe is just a beginning. Anybody who thinks that ocean currents can only flow the way they do now is very silly indeed.

Funny, lots of shipping company executives are excited about the prospect of driving across the north pole.

Oh puh-LEEZ!

[ackthpt]

Yeah, can't count on anything from back in those days. They wouldn't know a trend in weather if their lives depended upon it.

Actually, they kept very complete records, as was required to establish best times of year to sail and what to expect. 100+ years of that information can help indicate if there's a trend or we are simply seeing spikes.

El Nino has been considered as evidence of global warming, however, there are records of extreme rainfalls along the west coast of California back in the late 1800's over a period of years. Examine what was known about volcanic activity or anything else which might alter the general global climate and you get a better picture.

Interesting reading this morning was a study of the 1811-1812 New Madrid earthquakes. Based upon newspaper accounts the character of the three great quakes could be assumed to a fairly accurate degree.

Re:Acuracy

[gone.fishing]

I'm not an expert but...

The tools that they used were briliantly simple and delivered reasonable accuracy as long as they were well treated. Even today, the sextent is used to confirm the locations of bouys and etc because it can independantly confirm the GPS reading. Windspeed was guaged with a spinning cup or a paddle. The spinning cup method depends on the accuracy of the count and time, and the paddle method depends on the accuracy of the paddle's measurements and it's precise weight. Since the ships were moving too, the ship's speed had to be known (which was calculated by latitude and longitude and time).

By the 1700's all these measurements were reasonably accurate. Maps made back then were already quite accurate and mariners were able to sail to pretty small islands because they knew exactly where to look. Their Navigation was a real science and required accurate time keeping and accurate measurments.

Bucket correction factor

[photonic]

Some years ago I heard a talk by a researcher of our national meteorology bureau. These old ship logs are the oldest available data series that are used to study long scale climate changes. One of the biggest challenges seems to be to 'calibrate' all the measurements that were done over time with different methods. In the past, the temperature measurements were done by trowing a bucket in the water, hoisting it to the deck and sticking a thermometer in it. At some time, however, they changed from using leather buckets to using metal ones, which has an influence on the reading that is taken.

According to the guy this causes one of the biggest uncertainties in todays climate models! They try to compensate this by fudging with the so called bucket correction factor.

Re:I was a National Weather Service researcher

[barakn]

No, he wasn't. Amsterdam Vallon is a famous troll (is he ekrout or $$$$$exyGal?). Was he working for the NWS at the same time he was "a consultant for the Israelis"? And try clicking on the link he's got for Slauhgter College. There's no such server, no such college.