Science Source
Last updated October 10, 2018

Observed changes in precipitation on the wettest days of the year in China, 1960–2000

  • States that previous studies have suggested that extreme precipitation events accounted for a disproportionate share of the nearly 2% increase in precipitation in China over the period of 1960–2000
  • Finds that:
    • (10 wettest days)
      • trends of precipitation on the 10 wettest days are generally proportional to changes in annual total precipitation
      • a disproportionate increase is observed in southwest China
      • while the greatest absolute increase in precipitation on the wettest 10 days is seen in east China, the trend as a percentage of the annual total is not statistically significant
      • in the other six climate regions, the annual total rainfall is increasing at a proportionally greater rate than the 10 wettest days
    • (5 wettest days)
      • the changes in precipitation on the five wettest days show increasing trends both nationally and for most of the climate regions
      • the greatest absolute increase in precipitation on the wettest five days is seen in east China in both summer and winter half-years
      • only in southwest China during the summer half-year do we see a significant, disproportional increase in the precipitation falling on the 5 wettest days
  • Finds that, nationally, there has been an increasing trend in the frequency of precipitation exceeding the long-term mean 97.5th percentile and 99th percentile values
  • Concludes that although the annual increasing precipitation on the 10 wettest days corresponds with a similar increase in water vapour pressure in China nationally, regional results suggest that change in humidity is not the only factor that influences the changes in heavy precipitation