Linkage Between the Northeast Mongolian Precipitation and the Northern Hemisphere Zonal Circulation

The long-term relationship between the tree-ring-reconstructed annual precipitation in northeastern Mongolia （PRM） and the Northern Hemisphere Zonal Circulation （NHZC）, defined as the normalized zonal mean sea-level pressure at 60°N in May-June-July, is examined in this study. A significant correlation coefficient （0.31） was found between the NHZC indices and PRM based on the dataset for the period of 1872-1995. The mechanisms responsible for the relationship are discussed through analyses of the atmospheric general circulation variability associated with NHZC. It follows that NHZC-related atmospheric circulation variability provides an anomalous southeast flow from the ocean to Northeast Mongolia （northwest flow from Northeast Mongolia to the ocean） in the middle and low troposphere in positive （negative） phase of NHZC, resulting in more （less） water vapor transport to the target region and more （less） precipitation in Northeast Mongolia.