Land‐atmosphere coupling and diurnal temperature range over the contiguous United States

Soil moisture influences on daily maximum ( T max ) and minimum ( T min ) temperatures, and thus the diurnal temperature range (DTR) in summer, are statistically quantified across the contiguous Unites States using soil moisture from the Global Land Data Assimilation System and observational temperatures. A soil moisture feedback parameter is computed based on lagged covariance ratios. Over the zone from California through the Midwest to the Southeast, the soil moisture exhibits a negative feedback on DTR mainly through its damping effect on T max . In contrast, a positive feedback on DTR dominates Arizona and New Mexico as the soil moisture exerts a stronger negative forcing on T min relative to T max . The feedback‐induced variability accounts for typically 10–20% of the total DTR variance over regions where strong feedbacks are identified. The results provide a useful benchmark for evaluating climate model simulations, although the employed data and method have limitations that should be recognized.