vertical distribution of radar reflectivity in hurricanes in the presence of shear

Vertical Distribution of Radar Reflectivity in Hurricanes in the Presence of Shear

Image: NASA

Black et al., 2002 modified by Houze 2009

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UR DR

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Quantifying Vertical Structure

• Hence and Houze 2011, 2012 (a,b) analyzed data from TRMM PR– Snapshots of radar reflectivity– 10+ years of data– Contoured by Frequency Altitude Diagrams

(CFADs)• 200-850hPa shear from NCEP

Hence and Houze 2011 Reflectivity (dBZ)

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ht (k

m)

Hence and Houze 2011

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ht (k

m)

Reflectivity (dBZ)30 3040 40

2

2

6

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8

8DL DR

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Shea

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Courtesy of D. Hence

Field Campaigns• RAINEX (2005)– Katrina: 8/28– NOAA 43

• IFEX/GRIP (2010)– Earl: 8/29, 8/30, 9/1, 9/2– NOAA 42 & 43

Hurricane Katrina – 8/28/2005

Shea

r

Shea

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Hurricane Earl – 8/30/2010

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Hurricane Earl – 8/30/2010

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Conclusions

• Structures of Katrina and Earl at strong intensities share similarities with statistics– Intense low-level reflectivities

• Early sampling of Earl on 8/30 did not– Shear calculation issue?– Rapid Intensification?– Circulation pattern?

EndThis research was supported by NSF grant # ATM-0743180 and NASA grant #NNX09AM73G