Hydroclimatic trends in areas with high agricultural productivity in Northern Mexico

Global climate change affects not only temperature but also the hydrologic cycle and therefore the aridity index, with variations at the local level. A non-parametric analysis was carried out on time series data collected from temperature and precipitation records (1970 to 2011) from 38 CONAGUA (National Water Commission) weather stations located in the Mexican states of Sinaloa, Baja California Sur, Durango, Sonora, and Chihuahua. The magnitude of change trends of average, maximum, and minimum temperature and precipitation, potential evapotranspiration, and the aridity index were calculated. The data were aggregated, and the Mann-Kendall statistic calculated using the MOCLIC 1.0 program, to determine whether there was continuity in the data from each station and to define the magnitude of the statistically significant trend under the threshold α=0.05. The magnitude of the change trend was determined for significant trends using Sen’s method of slopes. Potential evapotranspiration and the aridity index were calculated by the Hargreaves and UNEP methods. The results show that the climate variables displayed positive and negative trends; mainly temperature, with a range of -0.13 to 0.16°C・yr^-1, which is above world averages. The values obtained for RMSE, bias, the Pearson correlation coefficient (r) and the coefficient of determination (R2) do not show significant differences between the control values and the calculated values. It was concluded that aggregating significant trends can provide information on the direction of local climate change in this environment in northern Mexico, and its important consequences and repercussions, as well as impacts on social and environmental systems.