CIMMSE TC Wind GroupConference Call

Wednesday, June 5th, 201311:00 AM

Agenda

• Improved modified Rankine vortex interpolated wind images

• Modeling Focus– Literature review– Goals of simulations– Initial WRF-LES setup

Improved Modified Rankine Vortex Interpolated Wind Images

• Jonathan had requested images of some of the storms with the improved error function be posted online/be made available for download– Select images have been posted to:

https://sites.google.com/a/ncsu.edu/modified-_rankine_improvements/

• Collaborators are encouraged to examine images and provide comments

• Where to go from here in terms of R2O?

Modeling Focus• Climatology aspect of the study has largely been

completed– Gust factors as a function of sustained wind speed, wind

direction, and distance from coastline using ASOS data– NDFD verification of recent storms impacting the region– Potential improvement to the wind interpolation method

used in the TCMWindTool

• Now can approach from more of a dynamical perspective with aid of WRF– WRF-LES option as of WRF V3

Large-Eddy Simulation (LES)

Resolved

Log(k)Lo

g(E k)

kc = /f

Subgrid iu iu

Subgrid

iu

iu

Resolved

Physical Space Fourier Space

(Courtesy: Dr. Sukanta Basu, NC State)

Literature Review

• WRF-LES has been used quite frequently in operational community for examining small scale turbulence in the boundary layer

• Very few studies have used WRF-LES for tropical cyclones

Modeling Goals/Focuses• Use Irene (2011) as a first case study

– Conducted 24 hour WRF-LES simulation near location of landfall beginning at 0000 UTC 27 August

– Examine large eddy circulations within the boundary layer– Conduct TKE budget to explore relative magnitude of

contributions of the various terms– Examine gust factors at various locations within inner domain

(compare to the climatology analysis we have conducted)• Sensitivity studies

– Lower level stability– Storm intensity– Other suggestions?

Modeling Setup

• 5 Domains, with innermost two domains having no PBL scheme

• Use of 1/16° daily SST analyses, 0.5° six hourly GFS analyses for boundary conditions

• Grid Spacing (consistent with Zhu et al. 2008):– D1: 8.1 km D3: 900 m D5: 100 m– D2: 2.7 km D4: 300 m

Discussion

Next Conference Call: Wednesday, July 10th, 2013 11 AM