Influence of teleconnections on night-time minimum temperature variability in the Southwestern U.S.

Abstract

Night-time minimum temperatures are increasing, faster than day-time maximum temperatures. They are also strongly connected to key outcomes such as health, vegetation, and crop productivity, and therefore changes in the distributions of night-time minimum temperatures have strong impacts on living systems. Night-time minimum temperatures are also related to teleconnections, which are indices that capture climate phenomenon occurring on a large spatial and temporal scale. As autocorrelated sequences, teleconnections are predictable and therefore inform distributions of weather in the near future. In this paper, we link four well-known teleconnections to night-time minimum temperatures in the American Southwest. These teleconnections are covariates for the mean process, but also for the variance, which is modelled as an exponential generalized autoregressive conditional heteroskedastic process (AR-EGARCH). The resulting models are used to estimate the probability of a low temperature event across the phases of each teleconnection, demonstrating the impact each teleconnection has on variability of night-time minimum temperatures.