Winter Cloudy Days Will Diminish Over China Under Global Warming

Abstract

AbstractChanges in winter cloudy days (CDs) exert substantial impacts on agricultural production, public transport, and the solar photovoltaic (PV) power industry. However, the physical mechanism behind the variability of winter CDs over China remains largely unclear, making it challenging to predict the future dynamics of winter CDs. In this study, we explored the spatiotemporal features of winter CDs over China from 1961 to 2013 and identified two independent formation mechanisms associated with its leading mode. Then, we projected the future changes (2021–2099) in winter CDs under global warming constrained by the identified formation mechanisms. Results revealed that: (a) The leading mode of winter CDs from 1961 to 2013 presents a homogeneous pattern. The positive winter CDs anomaly is connected to the anomalous southerlies related to the Eurasian Rossby wave train triggered by the Barents Sea thermal forcing, as well as the Asia‐Pacific zonal geopotential height gradient induced by the convection over the Maritime Continent; (b) Selected state‐of‐the‐art climate models project a notable decrease in winter CDs in the Tibetan Plateau and southern China regions, and almost unchanged winter CDs over northern China, under global warming; (c) In contrast to present‐day mechanisms, in the future, the shift of the Eurasian mean flow will terminate the role of the Barents Sea thermal forcing. Instead, the enhanced convection over the Maritime Continent emerges as the primary contributor to the decline in winter CDs. Our findings provide valuable insights for policymakers in the solar PV industry, particularly in relation to the challenges faced under global warming.