Mark Hunt weather corner; 117
2024 as a weather year so far has served up plenty of surprises, not least the amount of rainfall over the winter, spring, summer and autumn.
In my books at the start of the year with EL Ninō firmly in position over The Pacific, I was expecting the U.K, Ireland and Europe to continue the trend for record temperatures and heat.
What we received was very different with many areas reporting record rainfall for the year and a distinct ‘lack of summer’. Only the east of England could be labelled as on the dry side this summer, but even here they have been playing catch up recently. Here in Market Harborough, with our average rainfall usually around 660mm, we are currently on 900mm y.t.d, so nearly 50% up on the 30-year average with 10 weeks still to go.
So just what is going on with the weather?
20+ years ago, I remember looking at some Met Office projections for our future climate (now our current climate) and it talked about wetter, warmer winters and drier, hotter summers. Well, the present-day reality is very different. The departure from predicted appears to be closely related to the fact that warmer air has the potential to hold more moisture. Indeed, for every 1°C increase in air temperature, it can hold 7% more moisture, as I reported in a recent Pitchcare article.
In a year with more rain, one would expect light levels to be lower as well, as more cloud reduces the amount of sunshine, so I looked into the amount of PAR (Photosynthetically Active Radiation) light that we received y.t.d vs. the same time period in 2023 & 2022 (arguably the last year we had a decent summer) using a Central England location.
Incidentally, PAR light is the part of the light spectrum that plants utilise for photosynthesis and we use an Apogee SQ 212 PAR light sensor fitted to a Davis Vantage Pro2 Weather Station to measure it (shown above and below left).
Here are the results;
Now, I thought it would be less, but not that much of a drop year-on-year vs. 2022, a year when we had more sunshine. That’s a 37.5% reduction for 2023 and 2024 vs. 2022 and remarkably the last 2 years are running within 1% of each other.
The decrease in PAR light availability has significant implications for the grass plant because, for example, Agrostis as a species needs much more light than Poa annua for example, whether that be Creeping or Browntop Bent (the exact amount is still not discerned), so we can assume that from a light perspective the last two years have been less beneficial for the high PAR requirement plant species, and more for Poa annua if we talk purely about fine turf.
Coping with wet years is a difficult task in itself to maintain a playing surface, but that lack of PAR light will be exerting a hidden selection pressure on the grass species you maintain.