Evaluation of Modeled Precipitation in Oceanic Extratropical Cyclones Using IMERG

Naud, Catherine M.; Jeyaratnam, Jeyavinoth; Booth, James F.; Zhao, Ming; Gettelman, Andrew

doi:10.1175/JCLI-D-19-0369.1

i

Evaluation of Modeled Precipitation in Oceanic Extratropical Cyclones Using IMERG

Supporting Files

2020
By Naud, Catherine M. ; Jeyaratnam, Jeyavinoth ; Booth, James F. ; ...

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Journal Title:

Journal of Climate
Personal Author:

Naud, Catherine M. ; Jeyaratnam, Jeyavinoth ; Booth, James F. ; Zhao, Ming ; Gettelman, Andrew
NOAA Program & Office:

OAR (Oceanic and Atmospheric Research) ; CPO (Climate Program Office) GFDL (Geophysical Fluid Dynamics Laboratory) ; CREST (Center for Earth System Sciences and Remote Sensing Technologies and Tech Center at City College of CUNY)
Description:

Using a high-spatial- and high-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 underreport 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.
Keywords:

Atmospheric Sciences Climate Cloud Properties Extratropical Cyclones Meteorology Midlatitude Model Evaluation Northern Performance Precipitation Sensitivity Cloud Properties Extratropical Cyclones Model Evaluation
Source:

Journal of Climate, 33(1), 95-113.
DOI:

https://doi.org/10.1175/JCLI-D-19-0369.1
Document Type:

Journal Article
Funding:

Grant no. NA15OAR4310094
Rights Information:

Other
Compliance:

Submitted
Main Document Checksum:

urn:sha256:1f2888c6ba514ea6bbc54cad01bba3bd9198b61532043ba223c79f8b7458127a
Download URL:

https://repository.library.noaa.gov/view/noaa/29933/noaa_29933_DS1.pdf
File Type:

[PDF - 1.86 MB ]

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