The dataset contains 1km gridded estimates of hourly rainfall for Great-Britain for the period 1990-2014. The estimates are derived by applying the nearest neighbour interpolation method to a national database of hourly raingauge observations collated by Newcastle University and the Centre for Ecology & Hydrology (CEH). These interpolated hourly estimates were then used to temporally disaggregate the CEH-GEAR daily rainfall dataset. The estimated rainfall on a given hour refers to the rainfall amount accumulated in the previous hour.
The dataset also contains data indicating the distance between the grid point and the closest recording raingauge used in its interpolation. When this distance is greater than 50km, or there is zero rainfall recorded in the closest gauge, the daily value is disaggregated using a design storm. The dataset therefore also contains a flag indicating if the design storm was used. These data are provided as an indicator of the quality of the estimates.
Publication date: 2019-04-18
The hourly rainfall estimates are derived from the temporal disaggregation of the CEH-GEAR daily data using hourly gauge data. This methodology ensures that the daily totals of the CEH_GEAR daily and 1hr datasets are consistent. The hourly gauge data is from the Met Office, the England Environment Agency (EA), Natural Resources Wales (NRW) and the Scottish Environmental Protection Agency (SEPA). The CEH-GEAR daily data is derived from the Met Office national database of observed precipitation. The nearest neighbour interpolation methodology was used to generate the gridded hourly estimates which were subsequently used to disaggregate the daily data.
A quality control protocol was established in order to identify and reject erroneous hourly values in the gauge rainfall input dataset. The quality control procedure is a three step process:
1) The gauge data is compared to the gridded CEH-GEAR daily dataset to identify suspect gauges
2) A series of quality control tests are applied to identify suspect values at all gauges which are marked with a quality control flag
3) Combinations of quality control flags for a given hourly accumulation are used to determine which flagged data are treated as erroneous values and thus excluded from the gauge records.