Actual evapotranspiration (ETa) was studied using lysimeters in Germany from 2015 to 2020. The researchers found that daily ETa measurements from lysimeters at different sites were highly correlated up to 50km apart. This means that lysimeters can provide accurate information about ETa for larger areas, like fields or catchments. The main factor influencing ETa correlations was potential evapotranspiration (ET0).