Temperature-precipitation relationship of the Common Era in northern Europe
Due to the lack of knowledge on dynamics of the North Atlantic Oscillation (NAO) prior to the last millennium, synchronized records of air temperature and precipitation variability are needed to understand large-scale drivers of the hydroclimate. Here, we use completely synchronized paleolimnological proxy-based records of air temperature and effective precipitation from two Scandinavian lakes with ∼2000-year sediment profiles. We show that the relationship between air temperature and precipitation (T/P ratio) is synchronous in both study sites throughout the records suggesting warm and dry conditions at ∼300–1100 CE and cold and wet conditions at ∼1200–1900 CE. Owing to the significantly increased air temperatures, the most recent T/P ratio has again turned positive. During the first millennium of the Common Era, the T/P mimics patterns in Southern Oscillation index, whereas the second millennium shows response to the NAO index but is also concurrent with solar irradiance shifts. Since our T/P reconstruction is mostly linked with the NAO, we propose the T/P ratio as an indicator of the NAO. Our results from the coherent records provide first-time knowledge on the long-term temperature-precipitation relationship in Northern Europe that increase understanding of the comprehensive hydroclimate system in the region and the NAO dynamics also further back in time.
- D’Arrigo R, Wilson R, Jacoby G (2006) On the long-term context for late twentieth century warming. J Geophys Res 111:D03103Google Scholar
- Korhonen J (2007) Discharge and water level variations in lakes and rivers in Finland. Finnish Environ 45:1–120Google Scholar
- Nevalainen L, Luoto TP, Sarmaja-Korjonen K (2008) Late Holocene water-level changes in Lake Iso Lehmälampi, southern Finland, reflected in subfossil cladocerans and chironomids. Studia Quaternaria 25:33–42Google Scholar
- Zawiska I, Luoto TP, Nevalainen L, Tylmann W, Jensen TC, Obremska M, Słowiński M, Woszczyk M, Schartau AK, Walseng B (2017) Climate variability and lake ecosystem responses in western Scandinavia (Norway) during the last millennium. Palaeogeogr Palaeoclimatol Palaeoecol 466:231–239CrossRefGoogle Scholar