There are waves piling on waves in the weather.
A new press release tells us that there have been an “exceptional” number of weather extremes in summer.
Weather extremes in the summer — such as the record heat wave in the United States that hit corn farmers and worsened wildfires in 2012 — have reached an exceptional number in the last ten years. Human-made global warming can explain a gradual increase in periods of severe heat, but the observed change in the magnitude and duration of some events is not so easily explained.
Heatwaves lend themselves to headlines. Not only are they scary, but for climate researchers at a loose end, there are 1,000 flavors of wave to comb through. Is that a 3 day, 4 day or 7 day wave you are interested in? Is the cut-off 40C, 38C, 35C or a flexible percentile anomaly above the monthly average? Is it a statewide average, a national record, or a hot week in Houston? Shall we analyze that in seasons, by months, years, or part thereof? The combinations and permutations can keep a supercomputer up late at night. There’s a whole field of cherry trees ripe for the plucking.
“…the role of the Sun is one of the largest unknowns in the climate system”
Meteorologists are already aware that changes in the interplanetary magnetic field (IMF) can affect the polar regions of Earth. Now, for the first time Lam et al report the magnetic field appears to influence atmospheric pressure in the mid latitudes. Lam compared the average surface pressure at times when the magnetic field is either very strong or very weak and found a statistically significant wave structure similar to an atmospheric Rossby wave. They claim to show that this works through a mechanism that is a conventional meteorological process, and that the effect is large enough to influence weather patterns in the mid-latitudes. The size of the effect is similar to “initial analysis uncertainties” in “ensemble numerical weather prediction” (which I take to mean “climate models”).
They are suggesting that small changes in this solar influence on the upper atmosphere could produce important changes through “non-linear evolution of atmospheric dynamics”.
Jo suggests that IPCC-favoured climate models don’t include any solar magnetic effect at all, which is just one of many reasons why they don’t work.
The large scale wandering convolutions of the jet stream [...]