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Master Location Identifier Database (MLID) thread
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Author:  Tim Vasquez [ Thu Sep 23, 2010 5:21 pm ]
Post subject:  Master Location Identifier Database (MLID) thread

As many of you may know, one of my current projects is the Master Location Identifier Database. I consider this a pretty serious undertaking as the global station network has grown and there is considerable emphasis on mesoscale meteorology these days. In an attempt to quality-control the database, one problem I have been seeing crop up is various non-official websites that attach all WMOs and ICAOs to the nearest airport, which I think is bad practice (though this is not really the fault of the website but the sources for the info).

For listings in the US, this is not a problem as the NWS and FAA are thorough about publishing location information. For example the Fort Worth WSFO, ICAO=KFWD WMO=72249, is in a business park in North Fort Worth.

However in places like Russia, we do have a problem. For example, Vladivostok is given as WMO=31960 ICAO=UHWW. It is obvious that UHWW is the aerodrome (Knievichi Airport) but WMO Pub 9 shows 31960 as somewhere in Vladivostok city downtown. Apparently this is (may be?) common practice as if you look at this page: it is clear that Roshydromet (Russian weather agency) runs its observatory about 15 miles from the airport.

This poses some questions.
1. Does the Russian weather agency (Roshydromet) have a weather observatory in the city?
2. Are the meteorological readings for METAR reports (UHWW, etc) really taken at the airport or are they taken in the city and presented as valid for the airport?
3. Does the Russian weather agency have a listing of its observatories so we can get a better idea how they are sited?

I am not necessarily interested in Vladivostok specifically, or even Russia, but what is standard pratice in various countries, especially outside of the US and West Europe. I even suspect that this has been done in Mexico (primary weather stations separate from airports). Can any of you comment on whether "weather observatories" exist in your country and whether their location can cause confusion amongst the ICAO (METAR) and WMO (SYNOP) codes?


Author:  LaurierWilliams [ Fri Sep 24, 2010 12:25 am ]
Post subject:  Re: Weather stations and identifiers

Tim, firstly congratulations on even attempting the herculean task of rationalising historical weather stations and identifiers.

I'm looking only at Australia. On a quick inspection, there are numerous entries that appear to be incorrect - I say "appear" because the information may be correct in the context of the database from which it came, but in the context of a database which lists both historical and current weather stations it is wrong. Some examples, based as I say on quick inspection:

--Some ICAO indicators are listed that do not have, and never have had, weather stations, e.g. Kayrunnera. These are possibly locations used for the purposes of navigation, or tiny country or homestead airstrips.
--Many weather stations are listed as airports that are not airports (the point of your post), e.g. Mangrove Mountain.
--For some locations where there are two weather stations, both are listed as airports and have IATA codes, but only one is an airport and has an ICAO code, e.g. Orange
--Many weather stations are listed that record only rainfall, e.g. Louth
--Some locations have erroneous data, e.g. Katoomba has two stations listed, one with an elevation of 1030m, the other 305m which could not possibly be correct.

I will need to spend more time on this, in particular looking at the databases from which the material was sourced which I hope will be evident from the table or the description at

Author:  Tim Vasquez [ Fri Oct 01, 2010 9:12 pm ]
Post subject:  Re: Weather stations and identifiers

Thanks Laurier,

Yeah, about the smaller stations, I'm starting to suspect that there is bogus information being fed into and that some of the people who contribute to that site may be inventing identifiers or getting them from questionable sources. This conclusion comes from some identifiers I saw for Russian stations that I found absolutely no source for, even in the Russian AIP documents. I sent a message to the site owner (David) and he confirmed that they don't really have any QC system in place.

Fortunately the MLID now has an ICAO quality control column. Effective with the October 1 release, ALL sites that are confirmed by ICAO Doc 7910 or an AIP document have been upgraded to Grade A (this is complete, there are about 16,000 Grade A identifiers, so you can trust those). All the rest which were listed solely at OurAirports are currently flagged as Grade C ICAOs until I either confirm them with a national source (the Australian AIP), downgrade them to Grade F, or remove them. A lot of this should be reflected in the November 1 update.

If you have any concerns over the WMO identifiers, let me know as I haven't looked at those yet.


Author:  SgtUSMCWX [ Wed Jan 12, 2011 12:23 pm ]
Post subject:  Re: Master Location Identifier Database (MLID) thread

Mr. Vasquez

I use this website to find reporting stations in and outside of the US. I hope this is of some use.


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