Evaluation of satellite-based snowfall estimates: A comprehensive assessment of IMERG V07B across diverse monitoring networks

Snowfall significantly affects regional climate and water resources across mountainous and high-elevation regions, where it determines seasonal water availability and influences local hydrological processes. The high spatial and temporal heterogeneity of snowfall in complex terrain regions poses considerable challenges for conventional observation networks Satellite-based precipitation products provide an effective approach to monitor snowfall from regional to global scales. However, validating these products against ground observations remains essential for quantifying their uncertainties.

The Global Precipitation Measurement (GPM) mission's latest IMERG algorithm has been updated to improve its snowfall retrieval capabilities, incorporating enhanced detection methods and refined quantification procedures. However, comprehensive evaluation across different monitoring networks remains crucial for understanding its performance in various environmental conditions. This study examines IMERG V07B's snowfall estimation accuracy through systematic comparison with diverse ground-based monitoring networks over mainland China, including standard meteorological stations, automatic weather stations, and specialized snowfall observation sites.

By leveraging these multi-source observations, we investigate IMERG's performance not only in terms of snowfall amount but also in capturing the temporal characteristics of snowfall events, including intensity distribution and duration patterns. The evaluation is stratified by elevation zones and network density to assess the impact of topographic complexity and observation capability on validation results. Initial findings reveal varying degrees of estimation accuracy across different network types, with notable challenges in regions with complex terrain and sparse monitoring coverage. We also compare the differences in snowfall estimation between IMERG V06B and IMERG V07B.

Our comprehensive assessment provides valuable insights into the strengths and limitations of IMERG V07B's snowfall estimates across different monitoring environments, offering essential guidance for both algorithm refinement and product applications in various research and operational contexts.