Split westerlies over Europe in the early Little Ice Age.

The Little Ice Age (LIA; ca. 1450-1850 C.E.) is the best documented cold period of the past millennium, characterized by high-frequency volcanism, low solar activity, and high variability of Arctic sea-ice cover. Past studies of LIA Atlantic circulation changes have referenced the North Atlantic Oscillation (NAO), but recent studies have noted that LIA climate patterns appear to possess complexity not captured by an NAO analogue. Here, we present a new precipitation-sensitive stalagmite record from northern Italy that covers the past 800 years. We show that in the early LIA (1470-1610 C.E.), increased atmospheric ridging over northern Europe split the climatological westerlies away from central and northern Europe, possibly caused by concurrent Artic sea-ice reduction. With ongoing ice melting in the northern high latitudes and decreasing solar irradiance in the coming years, the early LIA may potentially serve as an analogue for European hydroclimatic conditions in the coming decades

Split westerlies over Europe in the early Little Ice Age

International audienceAbstract The Little Ice Age (LIA; ca. 1450–1850 C.E.) is the best documented cold period of the past millennium, characterized by high-frequency volcanism, low solar activity, and high variability of Arctic sea-ice cover. Past studies of LIA Atlantic circulation changes have referenced the North Atlantic Oscillation (NAO), but recent studies have noted that LIA climate patterns appear to possess complexity not captured by an NAO analogue. Here, we present a new precipitation-sensitive stalagmite record from northern Italy that covers the past 800 years. We show that in the early LIA (1470–1610 C.E.), increased atmospheric ridging over northern Europe split the climatological westerlies away from central and northern Europe, possibly caused by concurrent Artic sea-ice reduction. With ongoing ice melting in the northern high latitudes and decreasing solar irradiance in the coming years, the early LIA may potentially serve as an analogue for European hydroclimatic conditions in the coming decades

Stalagmite-inferred precipitation record from northern Italy for the past 800 years and split westerlies over Europe in the early Little Ice Age

International audienceDuring the well-known “Little Ice Age” (LIA, ca. 1450–1850 C.E.), Europe experienced the coldest winters over the last ten thousand years. This interval was suggested to have been caused by major volcanic eruptions and periods of low solar activity. However, the detailed climate pattern in Europe remains unclear. By conducting high-precision radiometric U-Th dating and trace element analyses on a stalagmite collected from Bàsura Cave, northern Italy, the evolution of the westerly winds over the past 800 years in Europe and the Mediterranean realm was reconstructed. A comparison of the Bàsura record with previous published precipitation data shows that during the early LIA (1470–1610 C.E.) the westerly winds not only migrated southward, but also split into two branches away from mainland Europe. This strong decrease of moisture-delivering warm westerlies resulted in dry and cold winters in Europe. The splitting of the westerly winds could have been triggered by frequent high-pressure anomalies in northern Europe