Trends in Monthly Temperature and Precipitation Extremes in the Zhujiang River Basin, South China (1961-2007)

摘要

Monthly temperature and precipitation time-series for the Zhujiang River Basin are analyzed in order to identify changes in climate extremes.Daily temperature and precipitation data from 1961 to 2007 of 192 meteorological stations are used.Two temperature indicators(monthly mean and monthly maximum mean) and three precipitation indicators (monthly total,monthly maximum consecutive 5-day precipitation,and monthly dry days) are analyzed.Tendencies in all five indicators can be observed.Many stations show significant positive trends(above the 90%confidence level) for monthly mean temperatures and monthly maximum mean temperatures.For all months,a significant increase in temperature from 1961 to 2007 can be observed in the entire basin with the coastal area in particular.Positive trends of precipitation extremes can be observed from January to March.Negative trends are detected from September to November. The number of dry days in October increased significantly at 40%of all meteorological stations.Stations with changes of monthly precipitation extremes are scattered over the Zhujiang River Basin.An aggregation of heat waves and droughts can be detected which is accompanied by significant increases of temperature extremes and the negative tendencies in precipitation extremes.The detection of tendencies in climate extremes essentially relies on a good data quality and high station density.