It has long been known that fluctuations in the solar wind result in
meteorological effects on Earth, but Mai Mai Lam and her colleagues
believe that these effects are presently poorly represented in weather and climate models.
"It has been assumed that the effect of the Sun’s magnetic field on
our weather is strongest at the poles and negligible at low- and
mid-latitudes," Lam told environmentalresearchweb.
"While it is true that the effects are strongest at the poles, we have
found effects as far down as North Africa and up to Uruguay."
Lam and colleagues discovered that changes in the surface pressure of
the Earth’s atmosphere correlated with changes in the Sun’s magnetic
field. While the changes at the poles were caused by a direct effect, an
indirect effect was felt at lower latitudes: the change in surface
pressure at the poles modulated weather patterns at mid-latitudes.
"The effects we saw were small, but not insignificant," said Lam. "If
the Earth’s atmospheric pressure varies naturally +/− 30 hPa, we noticed
an effect of around +/− 2 hPa, which is about the same size as the
initial errors in ensemble weather forecasting. So while the effect is
small, if it were incorporated into weather models, it could change
forecasts."
According to Lam, previous proposals to link solar wind variations to
significant weather or climate variability have been dismissed on the
grounds that the magnitude of the energy change in the atmosphere
associated with the solar wind variability is far too small to impact
the Earth’s system. However, this argument neglects the importance of
non-linear atmospheric dynamics. [i.e. solar amplification]
"We have shown that a relatively localized and small amplitude solar
influence on the upper polar atmosphere could have an significant
effect, via the nonlinear evolution of atmospheric dynamics, on critical
processes such as European climate and the breakup of Arctic sea ice,"
said Lam. "We would ultimately like to see this effect incorporated into
weather forecasting models, but first more research needs to be carried
out to explore this effect and also to understand the mechanism behind
it."
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