The station selection was re-run, and so the station list has updated, with now 7877 stations present in this version. There have also been some minor changes to the quality control tests (affecting wind measurements) outlined below. A file indicating which stations are new to HadISD and which are no longer included compared to v2.0.0 is available.
As a result of requests from users, in this version we have passed the wind speed observations through the spike check, and also the wind direction observations through the repeated values (streak) check.
The threshold values used to activate flagging in the spike check are calculated from the properties of the data themselves, using the distribution of differences between one observation and the next.
For the streak check, although the parameters are calculated using the distribution of repeated values, these are only used to flag values if they are less than the defaults used in HadISD versions 1.0.x. We ensure that no calm periods are assessed when applying the streak check. The default values depend on the resolution of the wind direction and are in the table below (see Table 4 in Dunn et al, 2012 for more information).
|Repeated Streak (h)||Repeated Streak (d)||Repeated Hours||Repeated Days|
However if you find something strange, do let us know using the contact details on the HadISD website. Please note the stations which are known to have issues are documented on this blog and on the website.
The quality control code used in this version will be uploaded to the github repository in the coming days.