Continental Geometrys Role in Shaping Regional Temperature Distributions

Central North America experiences the highest temperature variability on Earth, with twice as much variance in daily-mean and synoptic temperatures as Eurasia. There is growing recognition that changes in temperature variability are as important as changes in mean temperature. However, the present-day pattern of temperature variability is poorly understood. For example, A previous study found that orography explains about 25% of this difference in temperature variance, leaving the majority still unexplained. Temperature variability is largely determined by land-surface interactions. In this study, we conduct a set of simulations with an idealized GCM to explore how continental geometry affects the variance of near-surface temperature. These include experiments with a generic control mid-latitude continent, which acts as a kind of null-hypothesis of temperature variability, as well as modified continents which mimic some of the key geographic features of North America and Eurasia. These results provide insight into what determines the temperature variability of mid-latitude continents and, more specifically, how the geographies of North America and Eurasia shape the difference in temperature variability between the two continents.