When it was developed, HadEX3 contained the usual set of ETCCDI (WMO Expert Team for Climate Change Detection and Indices) indices that were also part of HadEX2. The intention with the creating HadEX3 was to improve the spatial coverage and also extend the temporal coverage to more recent times (from ending in 2010 for HadEX2 to 2018 in HadEX3). We also moved to a new reference period, and found that there were non-linearities in how some indices behaved as a result.
However, the ETCCDI indices were developed from a climatological perspective, as the plan was to be able to both monitor changes in extremes and also perform detection and attribution studies. Over recent years, assessing the impact of our changing climate on sectors relevant to human society and infrastructure have become more important. After all, we know the climate is clearly warming, and have a much better understanding of how the tails of the temperature distribution are changing.
The approach used by the ETCCDI of developing indices, running workshops and providing standardized software was adopted by the WMO Expert Team on Climate Risk and Sector-specific Climate Indices (ET-CRSCI) and subsequently the Expert Team for Sector-specific Climate Indices (ET-SCI) to develop indices to monitor changes in climate conditions relevant to a number of societal sectors. These “ET-SCI indices” extend the ETCCDI indices and enable those working in sectors such as agriculture, health and water resources to more directly determine how relevant climate extremes are affecting them. The combined set of indices developed by both the ETCCDI and ET-SCI are termed the “Climpact indices,” and for a full list see https://www.climdex.org/learn/indices/. Indices defined by both Expert Teams are applicable across different sectors, and currently fall under the WMO Expert Team on Climate Information for Decision-Making (ET-CID).
We have recently released an extension to HadEX3 which incorporates the additional indices defined by the ET-SCI. We have where possible used the same input data and approach as for the original HadEX3 (for the ETCCDI indices), and so the additional indices have been released with the version number of 3.0.4 to tie into the current set.
Again, versions are available relative to 1961-90 and 1981-2010 for those indices where a reference period is used in their construction. For full details of the extension, see Dunn et al, (2024), and the data are available at https://www.metoffice.gov.uk/hadobs/hadex3.
Please do get in touch if you find this dataset useful, have comments or suggestions, or have found issues with any of the data files.
