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Item type:Publication, Present variability and future change in onset and cessation of the rainy season over Peru(Wiley, 2024-12-03)Changes in patterns of accumulated rainfall, as well as the rainy season onset, cessation and duration, can impact the availability of water resources and sectors such as agriculture, affecting the livelihoods of the population. The knowledge of these changes is crucial for regions driven by strong precipitation variability such as the Andean countries. Therefore, the aim of this work is to determine the present and future spatio‐temporal patterns of the onset, cessation and duration of the rainy season in Peru. For this purpose, we analysed in a first step the present variability and trends in 11 homogeneous regions using data from 377 ground stations for the period 1981–2019. The results showed significant trends (1981–2019) of earlier onset and increased duration only in the Southern Peruvian Amazon (Madre de Dios River basin). Furthermore, the accumulated rainfall has significant trends of increases in North East Andes, Northern and Southern Amazon. In a second step, we assessed future changes of the rainy season from an ensemble of statistically downscaled CMIP6 climate scenarios. A two‐tailed Student t‐test was used to evaluate the significance of changes. Two future time slices (2031–2060 and 2071–2100) relative to the reference period (1981–2010) were analysed. Future changes of the rainy season showed significant delays in the onset for the Central East Andes, South West Andes and Amazon regions in the period 2071–2100. Likewise, the rainy season duration presents future significant reductions in regions of the central and southern Andes under the SSP2‐4.5 scenario. Moreover, the accumulated precipitation is projected to increase significantly in the Pacific slope and Andes regions, mainly under the SSP5‐8.5 scenario. These findings are particularly important for sectors like agriculture, energy and water resources management. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Long-term variability, extremes and changes in temperature and hydrometeorology in the Amazon region: A review(Instituto Nacional de Pesquisas da Amazonia, 2024-01-01)This review discusses observed hydroclimatic trends and future climate projections for the Amazon. Warming over this region is a fact, but the magnitude of the warming trend varies depending on the datasets and length of the analyzed period. The warming trend has been more evident since 1980 and has further enhanced since 2000. Long-term trends in climate and hydrology are assessed. Various studies have reported an intensification of the hydrological cycle and a lengthening of the dry season in the southern Amazon. Changes in floods and droughts, mainly due to natural climate variability and land use change, are also assessed. For instance, in the first half of the 20th century, extreme flood events occurred every 20 years. Since 2000, there has been one severe flood every four years. During the last four decades, the northern Amazon has experienced enhanced convective activity and rainfall, in contrast to decreases in convection and rainfall in the southern Amazon. Climate change in the Amazon will have impacts at regional and global scales. Significant reductions in rainfall are projected for the eastern Amazon. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Future projections of summer precipitation-driving mechanisms over the South American Altiplano(Springer Science+Business Media, 2025-03-01)The South American Altiplano, located in the central Andes between 15 and 22 ºS, stands out for its high altitude, reaching up to 3000 m above sea level (m.a.s.l.). Rainfall patterns in this area, with 70% occurring during the summer season (December to February), are vital for soil moisture recharge and sustaining life, vegetation, and agriculture during dry months. Therefore, projections of future precipitation changes are crucial for water management and related risks. However, General Circulation Models (GCMs) show unreliability in predicting precipitation over the region, with significant biases and uncertainty. This study aims to address this issue by analyzing projected changes in precipitation using mechanisms previously identified in the literature, like zonal winds at 200 hPa over the southern tropical Andes (U200 mechanism) and vertical motion at 500 hPa over the western Amazon (W500 mechanism). These mechanisms, derived from more reliable GCM variables such as winds, explain interannual precipitation variability over the Altiplano. By assessing 13 GCMs from the sixth phase of the Coupled Model Intercomparison Project (CMIP6), this study evaluates changes in precipitation over the mid-twenty-first century across historical (1980–2014) and future (2050–2084) periods under the SSP3-7.0 scenario. Results indicate successful models capture the relationship between U200, W500, and precipitation over the Altiplano, projecting a reduction of up to 35% when considering the U200 mechanism and 26% under the W500 mechanism. These reductions vary across the Altiplano, with the southern region experiencing the most significant projected decreases.2