Projected Changes of Precipitation at the Fresnillo Mining Sites in Mexico: A Hybrid RCMs and a Weather Generator Approach

Climate change impacts on the precipitation regime in Mexico are yet uncertain and of great concern for the mining industry. In this study, we assess projected precipitation changes at the Fresnillo mining sites in Mexico, employing a comparative analysis of Regional Climate Models (RCMs) in conjunction with a Weather Generator (WG) that produces ensemble of likely-to-occur daily precipitation scenarios. An ensemble of sufficient likely-to-occur sequences of precipitation time series represents the natural variability of the historical precipitation records and their associated uncertainties. This precipitation ensemble can be analyzed probabilistically to conduct risk assessment studies for water resources management and planning tasks. The future projected change in daily precipitation is based on an analysis of six dynamically downscaled projections available from the NA-CORDEX. The six projections are from three RCP8.5 CMIP5 Global Climate Models (GCMs) (i.e., MPI-ESM-LR, HadGEM2-ES, GFDL-ESM2M), each GCM was dynamically downscaled to about 25 km² by two RCMs (i.e., WRF and RegCM4). We modified the WG, which was initially developed to represent the statistical features of the historical observed records by identifying changes in the RCMs projections and comparing the historic simulations (1986-2005) to simulate two future periods (2020-2039 and 2040-2059). The modifications of the WG that reflect the RCMs’ historic-future differences yielded ensembles of projected likely-to-occur precipitation scenarios, providing a probabilistic perspective for precipitation scenarios to perform key decisions at the mining site.