The decline trends of the observed winds over China mostly attributed to urbanization-induced wind blocking from the anemometers

Abstract

The observed winds over China have experienced decline trends over several decades before 2000s and a recovery in the recent two decades. The urbanization-enhanced surface roughness has been paid more attention on the decline trends. However, we believe the urbanization around the weather stations blocking wind from the anemometers is a dominant driver of the decline trends. Here, we attempted to quantitatively measure this influence by analyzing the observed wind speed trends during the period 1971–2020, using data from 625 and 1056 weather stations with and without relocation records, respectively. The results indicate that this driver should be account for the decline trends by 70% at the nation-averaged basis, with ranging from 55% to 80% across eight administrative divisions over China. In addition, the upward trends of the observed winds in the recent two decades are caused by data bias, which are directly attributed to relocation of weather stations rather than changes of the meteorological conditions.