Publications

Svensmark, J (2025). Reduced ERA-I Forecasting Skill During Forbush Decreases. GEOPHYSICAL RESEARCH LETTERS, 52(10), e2024GL109210.

Abstract
Correlations between week-long cosmic ray flux perturbations and terrestrial cloud cover have previously been identified. Still, uncertainty persists on whether the cloud response is due to a physical link involving cosmic rays or caused by random weather fluctuations. To investigate this further, we compare a time series of daily assimilated weather observations from the ERA-INTERIM system with its forecasts. This probes whether the presumed cloud signal originates from weather fluctuations consistent with the ERA-INTERIM model. We find that the ERA-INTERIM forecasting system performed significantly worse during rapid cosmic ray suppressions over the last 20 years, supporting the hypothesis that cosmic rays influence terrestrial cloud formation.

DOI:
10.1029/2024GL109210

ISSN:
1944-8007