RELEASE NOTES FOR CRU TS v4.07: 19 April 2023 The CRU TS dataset was developed and has been subsequently updated, improved and maintained with support from a number of funders, principally the UK's Natural Environment Research Council (NERC) and the US Department of Energy. Long-term support is currently provided by the UK National Centre for Atmospheric Science (NCAS), a NERC collaborative centre. The 4.07 release of the CRU TS dataset covers the period 1901-2022. The new interpolation algorithm is unchanged since v4.03. To understand this dataset, it is important to understand its construction and limitations. It is therefore recommended that all users read the relevant paper: Harris, I., Osborn, T.J., Jones, P. et al. Version 4 of the CRU TS monthly high-resolution gridded multivariate climate dataset. Sci Data 7, 109 (2020). https://doi.org/10.1038/s41597-020-0453-3 1. What's new in 4.07 1.1 Process changes The underlying climatology for cloud cover (CLD) was recalculated in 2022, along with climatologies for the other relevant variables, released as CRU CL v1.1. However, later anaylsis, after feedback from users, revealed that, for CLD, the recalculation had produced an inferior climatology. The CLD climatology has, then, been reverted to v1.0 (the original). This affects all CLD data and, by implication, all PET data. The comparison plots reflect this. Work elsewhere in CRU has improved temperature and precipitation data for Ascension Island and St Helena (https://crudata.uea.ac.uk/cru/data/ascension/), this is reflected in the TMP and PRE datasets and can be seen in the comparison plots. 1.2 Bug fixes To the CLD climatology (see above). 2. Output files For now, the approach of issuing NetCDF and ASCII files in parallel will remain, as will the publications of decadal files as well as full-length versions. However, decadal files may not be archived when superceded, in order to make best use of space. As always, please contact BADC in the first instance if you have any questions, observations or suggestions (and have acquired CRU TS from them). If, however, you wish to contact CRU directly about these datasets, please contact me at i.harris@uea.ac.uk, as mail to other members of the Unit will be passed through to me anyway. Ian Harris NCAS-Climate Climatic Research Unit School of Environmental Sciences University of East Anglia Norwich NR4 7TJ i.harris@uea.ac.uk