Winds are changing: An explanation for the warming of the Netherlands

Abstract

Western Europe is warming rapidly, much faster than the world average. To explain this phenomenon for the Netherlands, we look at the region where the airflow comes from instead of looking at the wind on the ground. Thereto, we consider 24 so-called weather patterns, which describe the origin of the airflow (north, northeast, etc.) and whether the airflow comes straight at us, or with bending of isobars (cyclonal or anticyclonal). For each day from January 1, 1836 onwards, we have determined the corresponding weather pattern on basis of the weather maps from Reanalysis archives at wettercentrale.de. Using a statistical test, we can see that a shift has occurred in the weather patterns, which has resulted in a significant increase in airflow coming from warmer directions. We further have applied linear regression to explain the daily average temperatures on basis of the weather patterns for the period 1961-2020. In this way, we find for the daily model an R-2 value of 0.60 and for the yearly model, based on the aggregated average daily values, we find an R-2 of 0.81, which is increased to 0.85 when we take the influence of the Atlantic Multidecadal Oscillation (AMO) and the Total Solar Irradiance (TSI) into account. These values strongly suggest that the warming in the Netherlands is caused by a shift in the origin of the airflow to warmer directions.