The political agenda of the day may be preventing NASA from linking a big drop in solar activity with falling global average temperatures, but they do indicate the complexity of the issue in a recent Sun-Climate report: “Understanding the sun-climate connection requires a breadth of expertise in fields such as plasma physics, solar activity, atmospheric chemistry and fluid dynamics, energetic particle physics, and even terrestrial history. No single researcher has the full range of knowledge required to solve the problem.”
The sun’s complex “top down” effect on climate is, basically, due to its relatively variable output of UV spectrum photons. The dynamic equilibrium and the heat of the air in the ozone layer are affected by long term relative changes in the photon emissions of the sun across the UV spectrum and the proton and electron emissions that arrive via the solar wind. When relatively low emissions of EUV –compared to UVA and UVB– occur then less ozone is formed and the temperature of the stratosphere and upper troposphere reduces.
Over the weekend, Italy suffered a sudden and dramatic drop in temperature. The mercury plunged by between 10 and 15 degrees Celsius across the country, resulting in Italy’s coldest September temps since the early 1970s (since the ‘weak’ solar cycle 20).
The bone-chilling cold, originating from the Arctic, also delivered heavy early-season snow to the most unusual of places: September snow fell on the hills in the greater Rome area as well as in the Lazio region. According to Italian newspaper Corriere della Sera, snow rarely ever falls this early in Lazio.
Rare September flurries were also recorded at Monte Livata (near Subiaco), Cervara di Roma, Ciociaria, Campocatino and Forca d’Acero, as well as in the area of S. Donato Valcomino, where Lazio meets the Abruzzo region.
Even the big cities, with all that data-skewing Urban Heat, were still experiencing a “particularly intense” bout of cold. Milan and Turinregistered record-busting lows of 5C (41F) and 4C (39F), respectively, on the night of Sunday, September 27. For reference, Milan’s average low for the time of year is 16C (61F), with Turin’s standing at a balmy 17C (63F).
The weekend chill was brutal and wide-reaching, and looking forward, Italy is forecast to remain anomalously-cold for the remainder of the week (at least).
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