Simulation of the atmospheric response to soil moisture anomalies over Europe

Abstract

Positive and negative anomalies in the initial soil moisture over central Europe were introduced in turn into integrations of a global model of the July atmosphere. The results show that by modifying the partitioning of the turbulent fluxes such anomalies can have major effects on the modelled rainfall, humidity and temperature during the following 50 days over the anomaly area and that the anomalies can propagate into adjacent land areas. Similar results were obtained with a lower‐resolution version of the model. The effects on rainfall were already important on day 3 of the integration over the anomaly area and on day 6 over parts of Scandinavia outside the anomaly area. The experiment was repeated with a version of the model in which the prevailing flow over Europe was less weak with increased moist westerly flow from the Atlantic. In this case the dry anomaly persisted for only about 20 days before it became too weak to affect the evaporation significantly.