Evolution of the dry-wet variations since 1834 CE in the Liiliang Mountains, north China and its relationship with the Asian summer monsoon

Under the background of global climate change, arid to semi-humid areas are more vulnerable to extreme climate, such as floods and droughts. To better predict and cope with future climate change, more local and regional long-term high-resolution climate reconstructions, hydroclimate in particular, are required. Based on a 174-year regional tree-ring-width chronology, we reconstructed the February-June Standardized Precipitation Evapotranspiration Index (SPEI26) history in the Luliang Mountains, North China (NC). Reconstructed SPEI26 is expected to reflect the dry-wet variation from spring to early summer (STES) of NC with an explained variance of 43.8% for the instrumental record (1951-2007 CE). The reconstruction reveals three comparatively dry (1857-1878, 1919-1929 and 1995-2001 CE) and four comparatively wet (1883-1895, 1934-1944, 1952-1961 and 1980-1984 CE) periods during 1834-2007 CE. Although a drying trend is seen since the 1950s, an advent of wetting since the end of the 1990s is expected. As the driest period in the reconstruction, 1919-1929 CE records the widespread catastrophic 1920s drought in northern China. In addition to the local hydroclimatic signal, the reconstruction also reflects hydroclimatic variation over a large portion of northern China, which is evidented by the comparison with other hydroclimatic records and regional dry-wet index. Strength of the Indian summer monsoon and the East Asian summer monsoon in the previous year play vital roles in the STES dry-wet variations. Moreover, Atlantic Multi-decadal Oscillation index influents the hydroclimate in NC by influencing the Asian summer monsoon system