Spatiotemporal variations of extreme precipitation regimes during 1961-2010 and possible teleconnections with climate indices across China

摘要

Spatiotemporal variations of extreme precipitation regimes are both caused by the climate change and the natural climate variability. The trends of extreme precipitation indices as an issue of climate change and the possible teleconnection with the ocean-atmospheric modes as an issue of natural climatic variability have been analysed in China. Ten extreme precipitation indices have been used in this study, and the station-based extreme precipitation indices were gridded into 1 degrees latitude x 1 degrees longitude using the angular distance weighting method. For extreme precipitation, an index is more likely influenced by the local topography if it represents the more extreme precipitation and then the regional response of this index to climate changes is more complex. Results of the trends of extreme precipitation indices indicated that three zones can be generally identified in China, namely: (1) a significant drying tendency can be confirmed along the strip stretching in the northeast and southwest direction; (2) northwest China is dominated by a wetting tendency and slight increase of precipitation intensity; and (3) southeast China exhibits a slight wetting tendency but significant intensifying precipitation. The wetting tendency in northwest China may be caused by increasing precipitation during November, December, January, and February. Besides, the teleconnections between precipitation extremes and El Nino-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Indian Ocean Dipole (IOD), and Pacific Decadal Oscillation (PDO) were also analyzed, and results showed that the regional responses of precipitation extremes to ENSO, IOD, NAO, and PDO varied for the climate indices at different stages, such as the precipitation extremes generally tend to be decreasing in the central part of China at the same year of positive ENSO while increasing in the east part of China a year after the positive ENSO. This study provides insights into regional response of weather extremes to global climate indices in China, and these are valuable for developing measures to mitigate the hazards due to weather extremes.