HadUK‐Grid—A new UK dataset of gridded climate observations

Abstract

HadUK‐Grid is a new dataset of gridded climate observations for the UK produced by the Met Office Hadley Centre for Climate Science and Services. The dataset interpolates in situ observations to a regular grid using methods developed in a previous equivalent dataset that had been made available to users since 2002 through the UK Climate Projections project (UKCIP02, UKCP09). The new dataset differs from the existing one in a number of key respects: higher spatial resolution, longer time series for some variables, improved consistency with regard to the pre‐processing of station observations, the use of publicly‐accessible ancillary data sources, a revised calculation sequence for some variables and improved version control. This makes for a dataset that is more internally consistent, more traceable and more reproducible. The result is a dataset of key UK climate variables of up to 1 km resolution from 1862 for monthly rainfall, 1884 for monthly temperature, 1891 for daily rainfall, 1929 for monthly sunshine and a wider set of variables with start dates from the 1960s to support the need for national climate monitoring and climate research.

A new heatwave definition for the UK

“…The thresholds have been determined based on the 90th percentile of the July daily maximum temperature for a 1981–2010 climatological reference period using a dataset of gridded observations (Hollis et al ., ). Parts of the United Kingdom, particularly in northern Scotland and upland regions, rarely if ever exceed this threshold.…”

“…The resulting 90th percentile on a 1‐km resolution dataset (Hollis et al ., ) are shown in Figure . To achieve the thresholds presented in Figure , the percentiles were rounded to the nearest whole degree, and the median value was determined for each geographic county.…”

Glowing, glowing, gone? Monitoring long‐term trends in glow‐worm numbers in south‐east England

“…(a) Annual variation in climate (spring temperature on the left axis, spring rainfall on the right axis) across the 18 years of the study. Temperature and rainfall values were derived from the monthly mean values for the 1 × 1 km grid interpolation point nearest to each site (HadUK‐grid; Hollis et al ., ) for May and June in each year (averaged for temperature and summed for rainfall). Points/bars (± error bars) represent the median (± inter‐quartile range) of values across the 19 sites.…”

“…This allowed us to distinguish trends through time that might be explained solely by changing annual temperature or rainfall, versus trends that might be driven by additional factors over and above climate variation (Møller, ). We used spring temperature and rainfall derived from monthly mean values for the 1 × 1 km grid interpolation point nearest to each site (https://www.metoffice.gov.uk/research/climate/maps-and-data/data/haduk-grid/haduk-grid Hollis et al ., ) for 2 months preceding transect surveys, May and June, in each year (averaged for temperature and summed for rainfall), as we considered these most likely to influence seasonal phenology and variation in glow‐worm numbers across years.…”

Observed Emergence of the Climate Change Signal: From the Familiar to the Unknown

“…To demonstrate that this framework can be applied to a range of gridded data sets and spatial scales, we consider one small region in more detail. The United Kingdom has a gridded rainfall data set available, covering 1891–2017 (daily) and 1862–2017 (monthly), which is suitable for examining changes in mean and extreme rainfall (Hollis et al, 2019).…”