Water temperatures for the period 1984 to 2007 at 35 sites on 21 UK rivers

Stream water temperature (WT) is a key control for many river processes. WT data were collated from various completed or on-going projects, involving or ran by the Centre for Ecology & Hydrology (CEH), UK. The temporal resolution of the individual datasets therefore varies, as well as the way data are or were collected. These datasets totalled individually 35 sites. The Climate Hydrology and Ecology research Support System (CHESS) dataset features six climate variables (Air temperature (AT), Long wave radiation (LWR), Specific humidity (SH), Precipitation (P), Short wave radiation (SWR) and Wind speed (WS)). CHESS is the forcing dataset for the Joint UK Land Environment Simulator model (JULES; Best et al., 2011). CHESS is a UK-wide 1-km grid dataset derived by down scaling the UK Meteorological Office Rainfall and Evaporation Calculation System (MORECS) 40-km grids except for precipitation, which is based on rain gauge data. For each 1-km cell, modelled daily time series of all variables are available for the period 1971-2007. Firstly, sub-daily water temperature datasets were averaged at a daily time step while spot measurements were assumed representative of the day they were taken. Secondly, daily temperature data were matched by date to the daily climate data. Thirdly, seasonal averages were computed from the daily data for all seven variables. Common season definitions were applied: December-February (winter), March-May (spring), June-August (summer), and September-November (autumn). For winter, the seasonal data for year y are based on data from December of year y-1 to February of year y (e.g. for 1976, December 1975, January and February 1976). Lastly, five time series were compiled: one series per season at an annual time step (i.e. winter year y, winter year y+1, etc.), and one series with all seasons at a seasonal time step (i.e. autumn year y, winter year y, spring year y, etc). These series and their related models will be thereafter referred to as 'autumn', 'winter', 'spring', 'summer', and 'all seasons'.