HadISD v2.0.1.2016p

We have just released HadISD version 2.0.1.2016p.  All plots and files should be on the website.  Between the release of v2.0.0.2015p in September, there have been no updates to years in the past.  The ISD raw data were downloaded on 19th January 2017 and processed over the following days.  

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).

Wind Direction Streak Check

Resolution (degrees)	Repeated Streak (h)	Repeated Streak (d)	Repeated Hours	Repeated Days
90	120	28	28	10
45	96	28	28	10
22	72	21	21	7
10	48	14	14	7
1	24	7	14	5

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.