Annual precipitation variation for the southern edge of the Gobi Desert (China) inferred from tree rings: linkages to climatic warming of twentieth century

We developed a new reconstruction of annual precipitation (August–July) for the Helan Mountains near the southern edge of the Gobi Desert, using a regional tree-ring width chronology. The reconstruction explained 52.1 % of the observed precipitation variance during the period 1953–2008. In addition to the new precipitation reconstruction for the Helan Mountains, two previously published annual precipitation reconstructions from the same region were also used to infer the large-scale precipitation signal of the southern edge of the Gobi Desert. Spatial correlation analyses with gridded precipitation data showed that the tree-ring records were indeed able to capture much of the regional interannual precipitation variability. Using principal component analyses on the precipitation reconstructions and documentary records, 29 large-scale dry events were found during the period AD 1760–2006. Many of these dry events have had profound impacts on the people of the study area over the past several centuries. A notably good agreement with a temperature reconstruction for Zhangye suggests that the precipitation of the Gobi Desert has the characteristics of monsoon rainfall variability (wet–warm and cold–dry). Our precipitation reconstruction exhibited a downward trend during the last two decades, a trend also found in northern and eastern China. It might be caused by a weakening of the Asian summer monsoon induced by global warming (especially increased sea surface temperature).