The Convective-To-Total Precipitation Ratio and the “Drizzling” Bias in Climate Models

Details

• Journal Title:
  JGR Atmospheres
• Personal Author:
  Chen, Di ; Dai, Aiguo ; Hall, Alex
• NOAA Program & Office:
  OAR (Oceanic and Atmospheric Research) ; CPO (Climate Program Office)
• Description:
  Overestimation of precipitation frequency and duration while underestimating intensity, that is, the “drizzling” bias, has been a long-standing problem of global climate models. Here we explore this issue from the perspective of precipitation partitioning. We found that most models in the Climate Model Intercomparison Project Phase 5 (CMIP5) have high convective-to-total precipitation (PC/PR) ratios in low latitudes. Convective precipitation has higher frequency and longer duration but lower intensity than non-convective precipitation in many models. As a result, the high PC/PR ratio contributes to the “drizzling” bias over low latitudes. The PC/PR ratio and associated “drizzling” bias increase as model resolution coarsens from 0.5° to 2.0°, but the resolution's effect weakens as the grid spacing increases from 2.0° to 3.0°. Some of the CMIP6 models show reduced “drizzling” bias associated with decreased PC/PR ratio. Thus, more reasonable precipitation partitioning, along with finer model resolution should alleviate the “drizzling” bias within current climate models.
• Keywords:
  Climatology Mathematical Models Precipitation (Meteorology) Mathematical Models
• Source:
  JGR Atmospheres 126(16): e2020JD034198
• DOI:
  https://doi.org/10.1029/2020JD034198
• Document Type:
  Journal Article
• Funding:
  Grant no. NA18OAR4310425
• Rights Information:
  Other
• Compliance:
  Submitted
• Main Document Checksum:
  urn:sha256:8219872586e999455ed18c9d7f1bb887bb41bcfc8e954dd97766fd7eb745ce3a
• Download URL:
  https://repository.library.noaa.gov/view/noaa/44718/noaa_44718_DS1.pdf
• File Type:
  [PDF - 5.25 MB ]