Discussion forum (En)

Dear all, 

I am still puzzling with what to do if you move (relocate) a station. I searched the basic WMO regulatory material, but didn't find an answer or guidelines although I thought we solved it already. So, we have to propose some guidance to WMO to be inserted in e.g. the Man. WIGOS. (WMO-No. 1160) or Guide to the WIGOS (WMO-No. 1165). This Manual gives clear statements on issuing stations identifiers and the WSI format (will be discussed during next WMO Congress (see Cg-18/Doc. 6.1(1) on http://meetings.wmo.int/cg-18/English/Forms/AllItems.aspx)

We (in the NL) had comparable issues starting in the '90s. Because of urbanization we sometimes have to move a station. (I recommend not to simply move a station to a nearby location, but to do research first on how to improve your whole network design by finding a new and better location). Therefore we have developed a policy on when to change an Id, or not, in case of a movement.

The first and major criterion is 'representativety' in the sense that if you expect a 'break' in the climate records you should always change Id and name. Relevant is that Station Id and Station Name is coupled. In principle, if you change the name, then should change the number too, and vice versa, but that's not always easy to realize (think to large cities or large airports, > 10 km). The problem however is that you should first perform parallel measurements (as required by WMO, for 2 years) to know if a significant break may be expected (so start with a 'test' Id and Name).

Then we follow 4 rules:

[1] if the new station is in the same community (or township) [the smallest political community with its own local council] than Id and Name are unchanged

[2] if the new station is in the same community (or township), but has a significant different representativity than change Id only (so name is unchanged; to be avoided, but not always possible)

[3] if the new station is a neighboring community (or township) but there will not be a change in representativity (or a break in the climate records) than Id and Name are unchanged (to be avoided, but not always possible and recommended by the climate community).

[4] if the new station is in a another community (or township) and there will be a change in represenativity (or a break in the climate records expected) than Id and Name are changed (i.e. all other cases).

I experienced that in fact only rule [4] was used, so we always changed Id and Name.

In fact I am in principle only happy with rule [1] and [4], i.e. to maintain the link ID-Name, or change both.

Apart from this, two issues remain:

[a] what to do with e.g. windmasts, located relatively far from an AWS, but representative for the area in which the AWS is located (far from AWS because at the AWS the wind is disturbed, or in case you like to do measurements on two wind locations to get a better idea about the wind at that area like in mountainous areas).

[b] what to do with 'twin stations'. E.g. Upper air station De Bilt and nearby Upper Air Station Cabauw are 'twin stations' for GRUAN (De Bilt provides Radio Sonde data, Cabauw the rest, like Windprofiler data).

Kin dregards,

-Jitze van der Meulen

Dear colleagues

The issue has been discussed recently also in the OSCAR project team. The motivation for requiring uniqueness of names originated from the impracticality of choosing the right entry from a drop-down if there are several identical names. The requirement to display unique entries in a drop/down makes sense. This could be guaranteed by displaying a combination of name and either WIGOS station identifier or country. The combination with WIGOS station identifier is guaranteed to create unique entries, the combination with country is probably more human-readable, and therefore preferred. 

Dear all,

interesting issues have emerged during this multilingual discussion of station names and WIGOSIDs.

With respect to station names, we will indeed remove the restriction on uniqueness of the name. For convenience we will show additional information (country name, WIGOS ID) in dropdowns whenever there are multiple stations with the same name. 

Concerning the practice of documenting changes to a station, such as a change of location. The general practice in OSCAR is that most elements in OSCAR are "historized", meaning that old values as well as the date when they changed, can be recorded. This reflects the desire to be able to track the evolution of a station and the network as a whole.
In this context the question is often asked how significant a change must be for a station to be a "new" station. Examples of this are a change in location or a change in instrumentation. WMO does not prescribe any criteria here. Whether a station is indeed new or not is up to the Member to decide. However, we recommend not to create a new station in the case of "minor" changes, such as when the station after the change is still representative of the station as it was before. 

If the station history is kept differently in a national database, it should nevertheless be possible to record the changes that ocurred to the station as one single station with changes in OSCAR, as long as there is a means in the national DB to know that the series of stations is related to one single station.

best regard
Timo