Trends and variability of precipitation extremes in the Peruvian Altiplano (1971–2013)

Abstract

Precipitation extremes have been investigated throughout the last decades in different regions of the Andes. However, little attention has been paid to the Altiplano region (Central Andes), especially to the Peruvian Altiplano (PA) that represents a complex area and is highly vulnerable to extreme events, such as floods and droughts, driven by the strong variability of precipitation. This study focuses on the analysis of 11 extreme precipitation indices (EPIs) in the period 1971-2013. In this context, commonly used statistical trend and break analyses were applied and a false discovery procedure was used in order to reduce the number of artificial significant tests. Additionally, the relative dominance of precipitation frequency and intensity in interannual precipitation datasets was determined. Finally, the correlation between EPIs and six oceanic-atmospheric indices were analysed. The results indicate that there is no significant global trend towards wet or dry conditions in the PA, although a signal of a more slightly decrease of precipitation is presented in the Southern PA. Additionally, interannual variability of total precipitation is mainly dominated by precipitation frequency. The Central Tropical Pacific sea surface temperature plays a major role for the maximum and average length of wet periods as well as for total precipitation. This finding is particularly relevant for the southwestern PA. Our results have important implications for risk management and adaptation planning related to extreme hydrological events in the PA.

A combined view on precipitation and temperature climatology and trends in the southern Andes of Peru

“…In contrast, during the wet summer season (DJF), the contribution of maximum 5-day precipitation to total precipitation is much lower (around 20%). In summer, precipitation is dominated by frequency rather than intensity (Huerta and Lavado-Casimiro, 2020), which is also confirmed by the high correlations of dry days and total precipitation observed in this study (Figure 8a). In austral spring (SON), precipitation is higher in northeastern than in southwestern areas as also shown by Andrade (2018), which may be related to the later start of the rainy season in the southwestern areas.…”

“…For total precipitation, recent studies focusing on similar areas found few significant trends and a high spatial variability for both annual and extended wet season time series (November–April) for slightly different periods within 1964 and 2013 (Haylock, 2006; Skansi et al ., 2013; Heidinger et al ., 2018; Huerta and Lavado‐Casimiro, 2020). Neukom et al .…”

“…For total precipitation, recent studies focusing on similar areas found few significant trends and a high spatial variability for both annual and extended wet season time series (November-April) for slightly different periods within 1964 and 2013 (Haylock, 2006;Skansi et al, 2013;Heidinger et al, 2018;Huerta and Lavado-Casimiro, 2020). Neukom et al (2015) argued that the long-term decreasing precipitation trend they observed comparing pre-industrial and present-day conditions may be superimposed by the spatial variability on the short period between 1965 and 2012.…”

“…This signal is opposite and less pronounced in the southern Andes of Peru. During El Niño, precipitation is reduced in the southern Andes (Vuille, 1999;Lavado Casimiro et al, 2012) and dry spells are significantly more likely to occur (Sulca et al, 2015;Huerta and Lavado-Casimiro, 2020), though the effect is not very pronounced. Temperature variability is more strongly modulated by ENSO and follows the sea surface temperature variations of the equatorial central Pacific with a lag of 1-2 months (Vuille et al, 2000).…”

“…(2013) decreasing precipitation in all four seasons albeit low significance and considering only a single station in the study area and somewhat shorter periods. More recent studies based on a similar area find no spatially consistent trend pattern for annual data (Heidinger et al ., 2018) and the extended wet season (November–April) (Huerta and Lavado‐Casimiro, 2020).…”