Publication Abstracts

Naud et al. 2019, in press

Naud, C.M., J. Jeyaratnam, J.F. Booth, M. Zhao, and A. Gettelman, 2019: Evaluation of modeled precipitation in oceanic extratropical cyclones using IMERG. J. Climate, in press, doi:10.1175/JCLI-D-19-0369.1.

Using the high spatial and temporal resolution precipitation dataset Integrated Multi-satellitE Retrievals for GPM (IMERG), extratropical cyclone precipitation is evaluated in two reanalyses and two climate models. Based on cyclone-centered composites, all four models overestimate precipitation in the western subsiding and dry side of the cyclones, and underestimate the precipitation in the eastern ascending and moist side. By decomposing the composites into frequency of occurrence and intensity (mean precipitation rate when precipitating), the analysis reveals a tendency for all four models to overestimate frequency and underestimate intensity, with the former issue dominating in the western half and the latter in the eastern half of the cyclones. Differences in frequency are strongly dependent on cyclone environmental moisture, while the differences in intensity are strongly impacted by the strength of ascent within the cyclone. There are some uncertainties associated with the observations: IMERG might under-report frozen precipitation and possibly exaggerate rates in vigorously ascending regions. Nevertheless, the analysis suggests that all models produce extratropical cyclone precipitation too often and too lightly. These biases have consequences when evaluating the changes in precipitation characteristics with changes in cyclone properties: the models disagree on the magnitude of the change in precipitation intensity with a change in environmental moisture and in precipitation frequency with a change in cyclone strength. This complicates accurate predictions of precipitation changes in a changing climate.

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BibTeX Citation

  author={Naud, C. M. and Jeyaratnam, J. and Booth, J. F. and Zhao, M. and Gettelman, A.},
  title={Evaluation of modeled precipitation in oceanic extratropical cyclones using IMERG},
  journal={J. Climate},
  note={Manuscript accepted for publication}

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RIS Citation

ID  - na04400s
AU  - Naud, C. M.
AU  - Jeyaratnam, J.
AU  - Booth, J. F.
AU  - Zhao, M.
AU  - Gettelman, A.
PY  - 2019
TI  - Evaluation of modeled precipitation in oceanic extratropical cyclones using IMERG
JA  - J. Climate
DO  - 10.1175/JCLI-D-19-0369.1
ER  -

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