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