On the Multi-Intensity Changes of Hurricane Earl (2010) Daniel Nelson, Jung Hoon Shin, and Da-Lin Zhang Department of Atmospheric and Oceanic Science University.

On the Multi-Intensity Changes of Hurricane Earl (2010)

Daniel Nelson, Jung Hoon Shin, and Da-Lin Zhang

Department of Atmospheric and Oceanic ScienceUniversity of Maryland, College Park

Our studies of NASA’s “old” Storms• Cecelski, S., and D.-L. Zhang, 2013: Genesis of Hurricane Julia (2010) within an African

Easterly wave: Low-level vortices and upper-level warming. J. Atmos. Sci., 70, 3799-3817.

• Cecelski, S., D.-L. Zhang, and T. Miyoshi, 2014: Genesis of Hurricane Julia (2010) within an African Easterly wave: Developing and non-developing members from WRF-LETKF ensemble forecasts. J. Atmos. Sci., 71, 2763-2781.

• Cecelski, S., and D.-L. Zhang, 2014: Genesis of Hurricane Julia (2010) within an African easterly wave: Sensitivity analysis of WRF-LETKF ensemble forecasts. J. Atmos. Sci., 71, 3180-3201.

• Cecelski, S., and D.-L. Zhang, 2015: Genesis of Hurricane Julia (2010) within an African easterly wave: Sensitivity to ice microphysics. Submitted to J. Appl. Meteor. Climatol.

• Zhu, L., D.-L. Zhang, S. F. Cecelski, and X. Shen, 2015: Genesis of Tropical Storm Debby (2006) within an African Easterly wave: Roles of the bottom-up and midlevel pouch processes. J. Atmos. Sci., in press.

NASA - HS3 Workshop

NASA - HS3 Workshop

From Cangialosi (2011)

NASA - HS3 WorkshopFrom Cangialosi (2011)

Previous studies of Hurricane Earl (2010)• Rogers et al. (2015) studied multiscale structure and evolution

during RI using data from aircraft missions flown into the storm;

• Chen and Gopalakrishan (2015) modeled the asymmetric RI using the HWRF system with the finest resolution of 3 km;

• Stevenson et al. (2015) examined the relationship between an inner-core lightning outbreak and the subsequent RI;

• Shay and Uhlhorn (2015) calculated enthalpy and momentum fluxes in relation to intensity change and underlying upper-ocean thermal structure during Earl’s RI stage.

NASA - HS3 Workshop

The purposes of this study

• Examine the multiple intensity and structural changes, including RI and an eyewall replacement cycle;

• Explore the mechanisms by which SEF occurred and the modeling sensitivity to SEF; and

• Study the structural changes of upper outflows during RI of Earl and their roles.

This work will be conducted using the WRF-ARW with the finest grid size of 1.333 km.

NASA - HS3 Workshop

Nested-grid domains 45/15/5/1.667-km resolutions 45-km domain: 210 x 15015-km domain: 319 x 3195-km domain: 301 x 301

1.667-km domain: 271 x 271Vertical grids 50 levels with higher resolution in the lowest 300 hPa

and the model top at 30-hPaPlanetary Boundary layer The YSU scheme

Cumulus parameterization The Betts-Miller scheme for 45/15/5-km domains.No Cumulus scheme for 1.667-km domain.

Cloud microphysics The Thompson scheme

Radiation parameterization: The RRTM longwave scheme, and the Dudhia shortwave schemeInitialization time: 0000 UTC 28 August 2010 with the NCEP re-analysis

Model configuration

NASA - HS3 Workshop

NASA - HS3 Workshop

. Model domain configuration and track comparison

NASA - HS3 Workshop

Time series of the model-simulated (PWRF, VWRF) and the observed (POBS, VOBS) maximum surface wind (m s-1) and minimum sea-level pressure (hPa)

Time series of the 1000 by 1000 km area-averaged 200-850 hPa vertical wind shear and shear direction.

NASA - HS3 Workshop

NASA - HS3 Workshop

NASA - HS3 Workshop

NASA - HS3 Workshop

Tangential winds as a function of time and radius (every 5 m s-1), superimposed with the radar reflectivity (dBZ), at z = 3 km

NASA - HS3 Workshop

NASA - HS3 Workshop

NASA - HS3 Workshop

Z = 14 km

NASA - HS3 Workshop

Summary and conclusions

• The WRF-ARW reproduces reasonably well the multiple intensity and structural changes, especially the eyewall replacement cycle, but with a large track error.

• Results show changes in SSTs, VWS, upper-level flows and environmental moistures during the multiple intensity and structural change period, indicating possible roles of these parameters in affecting the storm intensity and structural changes.

NASA - HS3 Workshop

NASA - HS3 Workshop