Environment Canada Data Errors

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Glacier
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Environment Canada Data Errors

Postby Glacier » Fri Mar 14, 2014 11:40 am

I don't know about you folks, but I see a lot of errors in the EC database. It seems to me that the number of errors were really high a long time ago (100-ish years ago) as well as more recently (the past 20 years).

Here are a few reasons I've seen for errors:
1) mixed up weather stations.
    For example: The "Kamloops" data from Jan/Feb 1895 is clearly not Kamloops, both in terms of the mild temperatures and the excessive rainfall. I suspect that this data is actually for Chilliwack, but somehow got mixed up when the guy was entering the data into the database.

2) Missed negative signs.
    We see these all the time. Just last couple months I can find several +28 readings in the middle of some god forsaken frozen hinterland.

3) Weather stations that moved around without documentation.
    Many weather stations, especially 100+ years ago moved around, but they did not have different station ID numbers. One example would be Big Creek, BC. It started in the 1800s, stopped for a few years, and then restarted until it ended in the 1990s. The earlier data was much warmer than the latter. I suspect that this is because it was moved up in elevation, perhaps from 500m to 1100m.

4) Glitches due to human or instrument error.
    Examples would be a +25 in December in Grand Forks, or a +41 in Labrador that is sandwiched between +16 days. I have seen the actual paper copies of these two stations, and they do indeed say 77F and 106F respectively.

5) Faulty readings due to station automation.
    This is an extremely common error these days as many stations are now automated, especially on the precipitation side of things. Automated stations can go months without getting checked while debris skews the measurements. Other stations record precipitation everyday even when there is none. Global Warming theories predicted that precipitation would increase, but we've seen a 30 year drop in precipitation. One has to wonder if instrument error has anything to do with this.

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stuffradio
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Re: Environment Canada Data Errors

Postby stuffradio » Mon Mar 17, 2014 11:17 am

What is with the difference between TWN and EC for precipitation amounts? TWN has 168mm in Pitt Meadows, and 190 mm at Abbotsford airport. Environment Canada has 218mm at Abbotsford airport for the same time period.

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Glacier
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Re: Environment Canada Data Errors

Postby Glacier » Tue Mar 18, 2014 9:24 am

I don't know why TWN says less. I'm assuming they missed a day or two. Personally, I find their site full of fluff with little substance. They give a lot of forecasts like the "bug report" that seems like a shot in the dark most of the time.

Anyway, some of you think that Abbotsford didn't get much snow this month, but I'm please to announce that they had 996 cm of snow on the ground on March 2nd. Glad to see you guys all survived!

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Abby_wx
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Re: Environment Canada Data Errors

Postby Abby_wx » Tue Mar 18, 2014 10:56 am

The code for a trace of snow is 997. I have no idea what 996 is supposed to indicate, but probably a typo. Either that or something is being lost in translation.
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stuffradio
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Re: Environment Canada Data Errors

Postby stuffradio » Tue Mar 18, 2014 12:10 pm

Glacier wrote:I don't know why TWN says less. I'm assuming they missed a day or two. Personally, I find their site full of fluff with little substance. They give a lot of forecasts like the "bug report" that seems like a shot in the dark most of the time.

Anyway, some of you think that Abbotsford didn't get much snow this month, but I'm please to announce that they had 996 cm of snow on the ground on March 2nd. Glad to see you guys all survived!

I saw that. Maybe we should add a Like button so I can like your post. Haha

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Glacier
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Re: Environment Canada Data Errors

Postby Glacier » Tue Mar 18, 2014 1:03 pm

stuffradio wrote:I saw that. Maybe we should add a Like button so I can like your post. Haha

There is another web forum I've visited that uses the exact same software as this one, and they added a "like" button, so it can't be that difficult to do.

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Glacier
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Re: Environment Canada Data Errors

Postby Glacier » Sat May 10, 2014 9:40 pm

Here's a good one:

April
May


Totally the same.

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Glacier
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Re: Environment Canada Data Errors

Postby Glacier » Thu Aug 07, 2014 3:40 pm

The deepest snow depth in Canada history was in Montreal. 999 cm on March 31, 2004. This is impressive, not only because there was only 1 cm on the ground the day before, but also because this number passed quality checking. Unbelievable!


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