Tuesday, 12 February 2013

Message from NCDC ISD team

There is a message from the ISD team at NCDC on the ISD FTP server about a problem with their merging process:

NCDC has identified a problem with merged ISD data. Under certain circumstances station merging is not taking place when it should, resulting in unsorted, non-merged output. This problem may be found in files on this FTP server from 2005-present. 

We are working to correct this issue and we apologize for any inconvenience this may cause.

This may have affected v1.0.1.2012p and we are investigating.  We will wait until this issue is resolved before finalising this update and creating v1.0.1.2012f.

Please let us know if you find anything untoward in the data.

Monday, 11 February 2013

2 Stations with the Wrong Latitudes

Thanks to Tim McVicar (CSIRO) we've found two stations that have been listed with the wrong latitude in our station listing files:

917650 61705 PAGO PAGO       +14332 -170711 +00030  (should be -14.3, -170.7)
    (American Samoa)
619670 70701 DIEGO GARCIA +07300 +072400 +00027  (should be -7.3, 72.4)

Both of these stations have the wrong latitudes in both v1.0.0.2011f and currently v1.0.1.2012p.  The listing files will be updated and synchronised with the ISD listing files before running the final v1.0.1.2012f quality control run.

Please do let us know if you find any other quirks in the data.
See also comment here regarding affect on HadISDH.

Wednesday, 6 February 2013


print "hello world"

This blog will hopefully act as a repository for ongoing developments with the HadISD dataset.  As this is a new dataset, all kinds of quirks or short interesting results are likely to come up, which might be of interest to users, and we can try and highlight these here. 

The current stable version of HadISD is, however, a preliminary version has just been released (  Although these versions are just a mass of numbers, hopefully the following will make them clear.

  • The final letter indicates whether the dataset is f-final or p-preliminary.  A final dataset is stable, and will not change, whereas this preliminary dataset will be updated and overwritten at some point in the future.  This is because the source data for HadISD, the Integrated Surface Database (ISD), is still being updated for the 2012 data.  Once ISD is stable, we'll re-run our scripts and update the data
  • The year stamp indicates the final complete year in the dataset (the first year is 1973, and for the moment is unlikely to move to earlier years)
  • The remaining three numbers indicate major-moderate-minor changes. Major changes (e.g. a complete re-write of our scripts) would require an accompanying publication in a peer-reviewed journal.  Moderate changes (e.g. an update to one of the QC tests) would have a technical note to explain the change and the resulting differences available on the website.  Minor changes include update to past years (not just the most recent) and will be noted on the download page.
Now it should be nice and clear - the dataset is a preliminary version of the one which includes data up to the end of 2012.  There has been a minor change in one of the QC tests (the global and African record high temperatures have changed, see paper and WMO press release) and the ISD maintainers updated data in the years 2004-9 and 2011.

We have checked through some of the summary and diagnostic plots (all available on the website too) and found no major unexpected changes in the flagging rates, however it is still a preliminary dataset.  If you find anything untoward or have problems please contact the maintainers through the HadISD website.