HadISD: interesting features of sub-daily climate data: December 2013

While homogenising HadISD (v.1.0.1.2012p) we have come across a number of stations which are bad mergers or station moves. These are the stations where the PHA algorithm of Menne & Williams (2009) found breaks of larger than 5 degrees in temperature.

026720-99999 KALMAR               +56.733 +016.300 +16m   Sweden
157250-99999 SNEJANKA /TOP/SOMME       +41.667 +024.683 +193m Bulgaria
700638-99999 FALSE PASS +54.850 -163.417 +6m US/Alaska
710620-99999 VIOLET GROVE +53.000 -115.117 +903m Canada
710730-99999 QUEENTOWN     +50.600 -112.800 +941m Canada
715500-99999 DAUPHIN CS +51.100 -100.050 +305m Canada
718260-99999 PANGNIRTUNG +66.150 -065.717 +23m Canada
718360-99999 MOOSONEE        +51.283 -080.600 +9m Canada
719040-99999 WIMBORBE    +51.933 -113.583 +940m Canada
726626-99999 LANGLADE         +45.150 -089.117 +464m US/Wisconsin
729595-99999 TUKTOYAKTUK +69.433 -133.033 +1m Canada

For station 719040, we suspect a typographical error in the ISD listing file as Wimborne is the name in the Environment Canada listing

In some cases we can determine the likely cause of the inhomogeneity.

Kalmar, False Pass, Dauphin, Moosonee, Tuktoyaktuk are all likely to have been erroneous merges carried out when creating HadISD.

The station number of Violet Grove (Alberta) has been reused by Environment Canada. The station number used to belong to Bernard Harbour (Nunavut, 68.8, -114.8).

The station number of Queenstown (Alberta) has also been reused by Environment Canada. The station number used to belong to Cluff Lake (Saskatchewan between 1999 and 2005 and Fort Reliance (Northwest Territories) until 1994.

The station number of Pangnirtung (Nunavut) has also been reused by Environment Canada. The station number used to belong to Nitchequon (Quebec) until 1985.

The station number of Wimborne (Alberta) has also been reused by Environment Canada. The station number used to belong to Quaqtaq (Quebec) until 1989.

For Snejanka and Langlade have not been merged when creating HadISD, and therefore we are not sure why the large inhomogeneities have occurred.

Please be careful when using these stations.

The merging process of HadISD will be addressed and updated in the near future, and include all information on station moves that we have available.