Yesterday saw a lot of debate about wind farms, numbers and windyness.
Ive mapped the national windspeed database for 45m, and imported it using some python. There is also mapped data for 25m and 10m but these show very similar maps with greatest differences being lower windyness at lower levels for lowland areas. I believe the scale is M/S average over a year but the technical documentation puzzlingly does not confirm this.
- The database was originally developed the Department of Trade and Industry (DTI) at some point before 2001, and as far as is known, the data that was used to build up the database was drawn from the mid-1970s to mid-1980s.
- The data uses an air flow model to estimate the effect of topography on wind speed.
- There is no allowance for the effect of local winds such as sea, mountain or valley breezes.
- The model uses a 1 kilometre square resolution and does not take account of topography on a small scale, or local surface roughness (such as tall crops, stone walls or trees), which may have a considerable effect on the wind speed.
- The data should be used as a guide only and should be followed by on-site measurements for a proper assessment.
- Each value stored in the database is the estimated average for a 1 kilometre square area, at either 10 metres, 25 metres or 45 metres above ground level (agl).
- The database uses the Ordnance Survey grid system for Great Britain and the grid system of the Ordnance Survey of Northern Ireland.
I have overlaid this boundaries of English LPAs for Plan Making Purposes. I can provide (on the clock) detailed maps and analysis for any LPA through interpolating down to the 1Ha grid I have for the whole of England and all national designations (part from flood risk) applying to each 1 ha grid square. From this it is easy to produce statistics for any geographical area, such as area within or outside AONB by LPA, within 10km of AONB etc. etc.
From the map you can see the windiest areas, North York Moors NP top, The South West is also very windy, the least windy areas being those areas in wind shadow of major upland areas. Most of SE England, the Midlands and East Anglia are fairly evenly windy with higher areas relatively (such as Northamptonshire, Downs, Chilterns, Charnwoord Forest etc.) being relatively more windy/