Mean 500 hPa geopotential heights
Here is a grid of charts for IONA for the last three months. I downloaded the NOAA Climate Forecast System [CFS] reanalysis charts from the Wetterzentrale site, the grid resolution of which is 0.5°x0.5°. The background colour filled contours are the 500 hPa geopotential heights. In my opinion it would be more useful if Wetterzentrale could produce a background colour fill of partial thickness, either for 1000-500 hPa or maybe 1000-850 hPa, which would then give a you a better idea of the air mass at the surface rather than the geopotential height.
I came up with some code that counts the individual number of pixels of each colour in these thumbnails across IONA. You could make this area larger , smaller or for anywhere in the chart and analyse heights from anywhere in Europe. The limiting factor is the 4 dam resolution of the colours used in the contouring. Obviously when you count the pixels you have to ignore the black and white ones which are used for surface isobars and text labels. It’s a bit of a crazy idea, and I still don’t know where this idea will lead me, if anywhere at all, but here are the results in graph form for each day since the 2nd of October for what it’s worth. If I don’t publish the work I’ve done so far I may forget about it, if you have any ideas let me know.
Its interesting to see just how dramatically geopotential heights at 500 hPa have increased across IONA since just before Christmas.