The Climate of Cuatro Ciénegas Basin: Drivers and Temporal Patterns

Abstract

The Cuatro Cienegas Basin (CCB) is considered an important biodiversity hot spot despite its arid climate conditions. The valley is located in the southern part of the Chihuahuan desert at 26 degrees 50' 41 `' N and is strongly affected by a divergent wind zone with high pressure at 30 degrees N. The average annual solar radiation is 5.28 kWh m(-2) day(-1), exhibiting a seasonal pattern with the highest values occurring in the summer months. The annual mean temperature is 21.9 degrees C. The average temperatures of the coldest month (January) is 12.9 degrees C while the hottest month (July) is 28.8 degrees C, resulting in a seasonal monthly pattern similar to that of solar radiation. The temperatures show a variation over the years with an apparent increase in the frequency of extreme cold events during the winter and extreme hot events during the summer. These results suggest that the winters are becoming colder while the summer months are becoming warmer. This annual variability is associated with the North Atlantic Oscillation (NAO). The annual averages of potential evapotranspiration and annual precipitation are 2602 mm year(-1) and 211 mm year(-1), respectively, suggesting that the average annual rainfall only represents only 8% of the annual water for evapotranspiration demand. The annual precipitation also shows high variability over the years as a consequence of El Nino, NAO, and tropical cyclones. The models under global climate change predict that the climate of CCB has a trend of becoming drier and warmer with a high frequency of extreme climatic events, resulting in a more extreme climate.