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HadISD is a global sub-daily dataset based on the ISD dataset from NOAA's NCDC. As well as station selection criteria, a suite of quality control tests has been run on the major climatological variables. The data span 1/1/1931 to end 2017 and each station is available individually. The current version of HadISD is 220.127.116.117f. For previous versions please contact the dataset maintainers.
Precipitation in HadISD: For users wishing to use the precipitation information available in HadISD, we ask them to take care and familiarise themselves with both the HadISD and the ISD documentation. The precip1_depth field derives from the first ISD precipitation field, and must be used with the precip1_period field, as the "1" in the name does not refer to hourly accumulations. Also, despite the time dimension being in hours, the precipitation accumulations may refer to longer time periods, detailed in precip1_period. Furthermore, we note here that the precipitation depths have not been quality controlled and users should confirm for themselves that the data are sufficiently free of erroneous measurements for their purposes (RJHD 26-February 2018).
A station listing with IDs and location information is here (also with names).
Individual stations within the ISD were composited when it was appropriate to do so. Then stations were selected on the basis of their length of record and reporting frequency. There are 8103 stations in HadISD.18.104.22.1687f, and these were passed through a suite of automated quality control tests designed to remove bad data while keeping the extremes. None of the ISD flags were used. The QC tests focussed on the temperature, dewpoint temperature and sea-level pressure variables, although some were applied to the wind speed and direction and cloud data. The data files also contain other variables which were pulled through from the raw ISD record, but have had no QC applied. Note: These data have not yet been homogenised and so trend fitting should be undertaken with caution. Results from the homogeneity assessment can be found here.
Keep in touch
Follow us on twitter: @metofficeHadOBS for updates, news and announcements.
For more detailed information, follow our HadISD blog. Here we describe bug fixes, routine updates and other exploratory analysis.
The python code used for the station selection and quality control can be
found on github.
We do not intend to provide in-depth support for this code. We emphasise that the choices we have made in the selection and QC one of a number of other equally reasonable choices, and encourage other interested parties to develop their own QC and filtering procedures to allow the structural uncertainties of this sub-daily dataset to be investigated.
We have assessed the homogeneity of four of the observed meteorological variables present in HadISD: temperature, dew point temperature, sea-level pressure and wind speed. This has been performed on monthly averages of the sub-daily data, and is fully described in Dunn et al, 2014, Climate of the Past, 10, 1501-1522. The homogeneity assessment results for v22.214.171.1247f are available for download here.
A number of summary and diagnostic outputs from the quality control code as well as station lists for a number of selection criteria are available here. Also available is the information from the homogeneity assessment of v126.96.36.1997f.
We have adapted our versioning system from CRUTEM4, and so the dataset numbering is of the form HadISD.X.Y.Z.1234i, and is outlined in more detail in the paper linked above. X is for a major change and would be accompanied by a peer-reviewed paper. Y is a more minor change, e.g. in one of the QC tests and would be described in a tech-note. Finally Z is a small change, for example addition or changes to data in the past. The last complete year of the dataset is given by 1234, and the final character shows if the dataset is f-final or p-preliminary. Therefore HadISD.188.8.131.522f is the final version of the dataset containing data up to the end of 2012, and there have been some changes to past data over HadISD.184.108.40.2061f.
NEW: A number of images and movies created from HadISD to show its capabilities are here.
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