Westerlies Influenced Monsoonal Climate: Reconstructions of Summer/Winter Temperature and Precipitation Based on Japan Sea Shelf Late Holocene Sediments Geochemistry

Abstract For the first time, paleoclimate reconstructions for the East Asian Monsoon (EAM) region were performed by extending instrumental climate series with reconstructions based on submillimeter scanning of the chemical composition of shelf sediments using a synchrotron‐based quantitative X‐ray fluorescence analysis. This allowed the reconstruction of winter/summer temperature and precipitation variations over the last millennia on a single sediment sequence with decadal resolution. The results indicate the influence of solar irradiation and global atmospheric processes associated with westerlies and their latitudinal migration on climate variability in the zone of the northern end of the EAM. Precession‐driven solar insolation determines multidirectional trends in air temperature changes (increase in winter and decrease in summer), while total solar irradiation forms the periodicity of variations from the longest Hallstatt cycles (2,060–2,200 years) to short ones comparable to the Schwabe/Hale cycles (21–22 years). The influence of summer westerlies is more pronounced in precipitation variations. Its extreme northern position, typical of the last 800–1,000 years, creates conditions for the spread of southwest coastal winds that bring moisture from the Meiyu Zone to northeastern China and southeastern Russia. Short‐term precipitation variability is significantly determined by variations of the Arctic Oscillation. The overlap of the main cycles of its variability (1,270–1,365, 680–700, 280–300 years, etc.) determines the years (periods) of abnormally high precipitation with the possibility of catastrophic floods.