Spatial Patterns of Precipitation Anomalies in Eastern China During Centennial Cold and Warm Periods of the Past 2000 Years

Abstract:

The spatial patterns of precipitation anomalies in eastern China during both warm and cold periods over the past 2000 years were studied. Four warm periods (ad 650–750, ad 1000–1100, ad 1190–1290, and ad 1900–2000) and five cold periods (ad 440–540, ad 780–920, ad 1390–1460, ad 1600–1700, and ad 1800–1900) were selected on a centennial timescale, referring to the synthesized temperature changes over China and Northern Hemisphere. The regional differences in precipitation were analyzed and compared using a data set consisting of the grades in severity of floods and droughts as derived from Chinese historical documents. The results showed that there has been no fixed spatial pattern of precipitation anomalies during either cold or warm periods in eastern China over the past 2000 years. For the most of warm periods, there existed coherence of spatial pattern with dry condition only occurred over north of the Yangtze River, and the consistent spatial patterns were found between the periods 650-750 and 1190-1290, 650-750 and 1000-1100. For the cold periods, the precipitation showed various spatial patterns, and similarities were only presented in the two periods of 1600-1700 and 1800-1900 featured by meridional distribution. Comparing the spatial patterns between cold and warm periods, inverse pattern of 440-540 and 1900-2000 over the most study area can be detected, but similar pattern was also found between the periods 1800-1900 and 1900-2000, and 1600-1700 and 1900-2000. Our results implicated that the relationship between temperature and spatial pattern of precipitation anomaly has high complexity, which would be of significance to understanding the spatial pattern of precipitation in the future climate change study.