157
9.3.1 Storm Forecasting Theories
Father Secchi was perhaps the first scientist to apply the dynamic meteorology that
he had learned from Maury, and from his own study of the physics of the atmosphere based on authoritative scientists’ contributions (Halley 1686; Hadley 1735;
Bernoulli 1738; Lagrange 1788; Redfield 1831; Clapeyron 1834; Espy 1841; Dove
1861; FitzRoy 1863), for a highly humanitarian purpose: storm forecast and warning service.
Two competing models on the genesis and development of cyclonic and noncyclonic storms were in vogue in his time. One conceived them as great atmospheric
waves, while the other as actual whirlwinds. Secchi considered both valid, although
with their limits, asserting that in storms the “mere wave structure” would dominate
on a synoptic scale (on the order of 1000 kilometers and beyond), “without a definite rotary motion,” while the “vortex motion” would need to be ascertained at a
mesoscale (from 30–40 to 300 kilometers, approximately). Atmospheric waves
would regularly propagate “over large tracts of the Earth’s surface,” especially on
free surfaces such as the sea, while they would not spread as fast on the continents,
particularly in Europe, because of obstacles such as mountain ranges. Due to the
formation of secondary undulations, they would assume a typically whirling rotary
movement (Secchi 1862b). Storms would therefore be violent and irregular disturbances of atmospheric motions, characterized by deep depressions or cyclones, with
spiraling and then ascending motions (in the central region).
In order to study and forecast the evolution of storms, Secchi not only monitored
regular and irregular variations of the barometric pressure but also measured the
extraordinary magnetic perturbations induced by electrical discharges in the atmosphere connected with distant storms (Secchi 1862c). In his experience, variations of
the barometer and of the magnetometer were two useful indicators for providing
advance warning of storms. Based on studies carried out by the American mathematician Elias Loomis (1811–1889) concerning storms that occurred in different parts of
the world and especially in light of the results of his personal observations and research,
Father Secchi stated that European storms should be independent from American ones,
which generally did not cross the Atlantic Ocean (Secchi 1862a, 1, 3: 24).
In addition, and very much in advance of his time, Angelo Secchi introduced a
new subject area that he called “solar meteorology,” known today as “space weather”
(Altamore et al., Ermolli and Ferrucci, Chaps. 1 and 7 in this volume). By theorizing
about the Sun’s influence on the atmospheric phenomena, among other things,
he wrote:
There are long-term phenomena on Earth that are dependent on changes observed on the
solar surface, such as the ten-year magnetic period, which agrees with the well-known
sunspot cycle. So, this new field of study is pertinent to physics of imponderable fluids, on
the one hand, to astronomy, on the other […] to atmospheric physics. (Secchi 1862,1,1: 1)
3
3 … vi sono realmente fenomeni a lungo periodo sulla terra che sono dipendenti da modificazioni
osservate sulla superficie solare, qual è per esempio il periodo magnetico decennale, che è
d’accordo col periodo delle macchie solari. Talché questo studio nella sua pienezza tocca alla fisica
degli imponderabili da un lato e alla astronomia dall’altro, e include quanto spetta a tutta la fisica
dell’atmosfera.
9 Angelo Secchi and Meteorology in Italy
9.3.1 Storm Forecasting Theories
Father Secchi was perhaps the first scientist to apply the dynamic meteorology that
he had learned from Maury, and from his own study of the physics of the atmosphere based on authoritative scientists’ contributions (Halley 1686; Hadley 1735;
Bernoulli 1738; Lagrange 1788; Redfield 1831; Clapeyron 1834; Espy 1841; Dove
1861; FitzRoy 1863), for a highly humanitarian purpose: storm forecast and warning service.
Two competing models on the genesis and development of cyclonic and noncyclonic storms were in vogue in his time. One conceived them as great atmospheric
waves, while the other as actual whirlwinds. Secchi considered both valid, although
with their limits, asserting that in storms the “mere wave structure” would dominate
on a synoptic scale (on the order of 1000 kilometers and beyond), “without a definite rotary motion,” while the “vortex motion” would need to be ascertained at a
mesoscale (from 30–40 to 300 kilometers, approximately). Atmospheric waves
would regularly propagate “over large tracts of the Earth’s surface,” especially on
free surfaces such as the sea, while they would not spread as fast on the continents,
particularly in Europe, because of obstacles such as mountain ranges. Due to the
formation of secondary undulations, they would assume a typically whirling rotary
movement (Secchi 1862b). Storms would therefore be violent and irregular disturbances of atmospheric motions, characterized by deep depressions or cyclones, with
spiraling and then ascending motions (in the central region).
In order to study and forecast the evolution of storms, Secchi not only monitored
regular and irregular variations of the barometric pressure but also measured the
extraordinary magnetic perturbations induced by electrical discharges in the atmosphere connected with distant storms (Secchi 1862c). In his experience, variations of
the barometer and of the magnetometer were two useful indicators for providing
advance warning of storms. Based on studies carried out by the American mathematician Elias Loomis (1811–1889) concerning storms that occurred in different parts of
the world and especially in light of the results of his personal observations and research,
Father Secchi stated that European storms should be independent from American ones,
which generally did not cross the Atlantic Ocean (Secchi 1862a, 1, 3: 24).
In addition, and very much in advance of his time, Angelo Secchi introduced a
new subject area that he called “solar meteorology,” known today as “space weather”
(Altamore et al., Ermolli and Ferrucci, Chaps. 1 and 7 in this volume). By theorizing
about the Sun’s influence on the atmospheric phenomena, among other things,
he wrote:
There are long-term phenomena on Earth that are dependent on changes observed on the
solar surface, such as the ten-year magnetic period, which agrees with the well-known
sunspot cycle. So, this new field of study is pertinent to physics of imponderable fluids, on
the one hand, to astronomy, on the other […] to atmospheric physics. (Secchi 1862,1,1: 1)
3
3 … vi sono realmente fenomeni a lungo periodo sulla terra che sono dipendenti da modificazioni
osservate sulla superficie solare, qual è per esempio il periodo magnetico decennale, che è
d’accordo col periodo delle macchie solari. Talché questo studio nella sua pienezza tocca alla fisica
degli imponderabili da un lato e alla astronomia dall’altro, e include quanto spetta a tutta la fisica
dell’atmosfera.
9 Angelo Secchi and Meteorology in Italy