Pollen-based quantitative reconstructions of Holocene climate at Gun Nuur in the northern Mongolian Plateau

This study quantitatively reconstructs Holocene climate based on a palynological analysis of a 745-cm lake core at Gun Nuur in the northern Mongolian Plateau. The core is precisely dated with 49 dates and the dataset comprises 372 pollen samples providing high temporal resolution. We obtained quantitative reconstructions of annual temperature (Tann) and precipitation (Pann) based on comparison with a modern pollen dataset comprising 604 data sites for which climate correlation coefficients are high (R2 = 0.76 for Tann and R2 = 0.70 for Pann) and the uncertainties are relatively small (RMSEP = 1.99 °C for Tann and RMSEP = 46.22 mm for Pann). Results show that the climate in the northern Mongolian Plateau experienced a warm-dry climate in the early Holocene (∼10,300 to ∼7900 cal. yr BP), a stable cool-wet climate in the middle and early-late Holocene (∼7900 to ∼2300 cal. yr BP), and an increasingly cool-wet climate in more recent times (last ∼2300 years). The high temperature in the northern Mongolian Plateau before ∼7900 cal. yr BP is attributable to the thermal sensitivity of the interior Asian continent to high summer insolation. The nearly constant and rather stable temperature during the past ∼7900 years is most likely the result of the thermal insensitivity of the well-developed and densely-covered Taiga forests in south Siberia to declining summer insolation. Increasing precipitation in the northern Mongolian Plateau in the period before ∼7900 cal. yr BP is similar to coeval records from the Altai Mountains, the Yinshan Mountains and the Lake Baikal basin, and most likely resulted from rising sea surface temperature both in the North Atlantic Ocean and in the Western Tropical Pacific Ocean. The stable and nearly constant precipitation during the past ∼7900 years most likely resulted from the combined effect of decreasing water vapor supply from the cooling Western Tropical Pacific Ocean and the increasing water vapor supply from the warming North Atlantic Ocean.