Clean Winter Air Drives Major Irradiance Surplus Across China and Taiwan in February

Why It Matters

The contrast underscores how atmospheric cleanliness can markedly boost solar output, shaping PV yield forecasts and investment decisions, while regional weather swings demand adaptive grid management.

Key Takeaways

• Southern China clearsky GHI >10% above long‑term average
• Taiwan total GHI up 15‑18% above 2007‑2025 average
• Maritime SE Asia irradiance 10‑20% below normal due to rain
• Reduced aerosols during Chinese New Year enhanced Chinese solar resource
• ENSO shift to neutral fuels convection, lowering tropical solar irradiance

Pulse Analysis

The February surge in solar irradiance across southern China highlights the growing influence of atmospheric cleanliness on photovoltaic performance. A temporary dip in industrial emissions during the Chinese New Year, combined with naturally low aerosol concentrations, lifted clearsky global horizontal irradiance (GHI) by more than 10% in provinces such as Sichuan and Yunnan. This clean‑air effect amplified total GHI beyond 20% in some locales, offering a tangible boost to solar farm output and sharpening the accuracy of AI‑driven forecasting models that rely on high‑resolution satellite inputs.

Taiwan’s solar landscape painted a different picture, where the primary driver was a dramatic reduction in cloud cover rather than aerosol changes. Total GHI in Taipei and Taichung surged to 15‑18% above the 2007‑2025 baseline, while clearsky GHI lagged at only 4‑5% above normal. This disparity underscores the importance of distinguishing between clearsky potential and actual generation, especially for asset managers overseeing portfolios in regions prone to rapid weather shifts. The pronounced irradiance boost translates into higher capacity factors for Taiwanese PV installations, improving revenue forecasts and reinforcing the island’s role as a solar‑rich hub in East Asia.

Conversely, maritime Southeast Asia faced a sharp irradiance deficit as enhanced tropical convection delivered 8‑12 mm /day above‑average rainfall, driving clearsky GHI 10‑20% below norms. The pattern aligns with a transition from La Niña toward ENSO‑neutral conditions, which typically intensifies convection over the western Pacific warm pool. For grid operators and developers in Indonesia, the Philippines, and surrounding islands, these deficits signal tighter supply margins and heightened reliance on weather‑responsive dispatch strategies. The episode illustrates the value of Solcast’s 1‑2 km resolution satellite‑derived data, which equips stakeholders with the granular insight needed to navigate such regional volatility.