Mar 15, 2016

Spatial analysis and temporal trends of daily precipitation concentration in the Mantaro River basin: central Andes of Peru

Ricardo Zubieta, Miguel Saavedra, Yamina Silva, Lucy Giráldez
Stochastic Environmental Research and Risk Assessment
  • States that a high percentage of total annual precipitation can fall in just a few days, causing floods or landslides
  • States that large economic losses from these events are particularly common in Peru, where the daily precipitation has been poorly investigated
  • States that regions such as the Mantaro River basin (MRB) in the central Andes of Peru are highly vulnerable to extreme weather events associated with climate variability; this vulnerability will increase in coming years due to climate change
  • Presents a spatio-temporal analysis of concentration index over the Mantaro River basin in the central Peruvian Andes
  • Selects daily rainfall data recorded at 46 rainfall stations between 1974 and 2004
  • Finds that daily rainfall (in terms of average values) indicates that low-intensity events account for 36 % of rainy days but only approximately 9 % of the total rain amount
  • Finds, in contrast, high- and very high-intensity events account for 37 % of rainy days and approximately 72 % of the total rain amount
  • The results also indicate higher concentration and lower intensity over the Northern and Central regions, compared to Southern region of the basin
  • States that rainfall concentration gives evidence of why some of these places are more likely to be affected by extreme weather events; spatial distribution of event intensity can be partly explained by daily rainfall heterogeneity and orography
  • Finds a significant change toward a weaker seasonality of daily precipitation distribution over high-mountain regions
  • Estimates annual irregularity of daily precipitation (CI) to detect possible trends between 1974 and 2004
  • Finds that for the heavy precipitation period (January–March), the number of rain stations with positive CI trends is much higher than those with negative trends