RELEASE NOTES FOR CRU TS v4.09: 19 March 2025

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 4.09 release of the CRU TS dataset covers the period 1901-2024.

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 4.09

1.1 Process changes

As planned, the new 'cohort' selection procedure (see the v4.08 Release
Notes) has been extended to DTR. At the same time, for PRE, the process
has been discontinued: it created anomalous patterns in sparsely-supported
regions.

CLIMAT observations were drawn from MCDW (as usual), and BoM (for Australia
Tmin and Tmax). However, gaps in the December 2024 cover from MCDW necessitated
the use of DWD CLIMAT observations (raw, not QC'd). These were then all passed
through the CRU TS QC processes.

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 However, decadal files may not be archived when superceded, in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 t.osborn@uea.ac.uk in the first instance.

Ian Harris (ret'd)
NCAS-Climate
Climatic Research Unit
School of Environmental Sciences
University of East Anglia
Norwich
NR4 7TJ

All enquiries: t.osborn@uea.ac.uk