I had never heard what an Hovmöller diagram was until I watched the Deep Dive video produced by the Met OfficeUKMO The Meteorological Office is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy and put out on their Youtube channel yesterday. The Hovmöller diagram was first introduced by Ernest Aabo Hovmöller (1912-2008), a Danish meteorologist, in a paper that he published in 1949. I had seen charts like it before used to display climate data, but hadn’t realised that they had a name. In reality they’re very similar to a heat map as far as I can see, but I decided to see if I could reproduce one in software that was as similar as possible to the one that Alex Deakin showed.
As you can see the X-axis displays values of longitude for a fixed line of latitude, in this case 55° north. The Y-axis displays dates over the last month. In the Hovmöller diagram above I’ve displaid MSLPMSLP Mean sea level pressure is the pressure at sea level, or, when measured at a given elevation on land, the station pressure reduced to sea level assuming an isothermal layer at the station temperature. values from six hourly reanalysis data. It clearly shows various anticyclonic spells in red and hot spots of cyclonicity in blue. I think it will come in very handy as another way of looking at global MSLP or temperature climate data over a longer period although I’ve still to write the code for that😉