Spatial distribution and temporal trends of extreme temperature and precipitation events on the Loess Plateau of China during 1961–2007

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Extreme climate events often cause catastrophic damage to nature and human society. Therefore, regional assessments in various climates and geographic regions are needed for understanding the uncertainties of the change trends for extreme climate events. The objective of this study was to assess the spatial distribution and temporal trends of extreme precipitation and temperature events on the Loess Plateau of China during 1961–2007. Nine indicators ( pq90, px5d, pint, pxcdd, pnl9, txq90, tnq10, tnfd, txhw90) were chosen to quantify extreme climate events, the Mann-Kendall method and linear trend analysis were used to test the change in trend and the magnitude, and inverse distance weighted interpolation was used to interpolate the spatial patterns. Results showed that most extreme climate indicators were spatially distributed with obvious gradients from the southeast to the northwest. Heavy rainfall threshold ( pq90), greatest 5-day total rainfall ( px5d), heavy rainfall days ( pnl9) and cold-night threshold ( tnq10) decreased from the southeast to the northwest, while simple daily rainfall intensity ( pint), longest dry period ( pxcdd) and number of frost days ( tnfd) increased from the southeast to the northwest. Most stations had monotonic trends in extreme indicators during 1961–2007. However, the number of stations with significant trends varied greatly. Precipitation-based indicators showed more mixed patterns of change and few stations had significant trends. However, temperature-based indicators had more uniform changes and most stations had significant trends. Hot-day threshold ( txq90) and cold-night threshold ( tnq10), and the longest heatwave ( txhw90) tended to increase while the number of frost days decreased since the 1960s on the Loess Plateau. Overall, extreme precipitation events did not change significantly; however, extreme temperature events became more severe and frequent. The results implied that extreme climate events on the Loess Plateau will continue to have adverse impacts, and adaptive measures should be considered for future ecological construction and agriculturally sustainable development.