UPPER LEVEL WINDS (700 mb)

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Application of the urbanized MM5 to the
Houston-Galveston region by R. Bornstein, H.
Taha, R. Balmori, SJSU S. Dupont, J. Ching,
RTP/EPA/NOAA A. Martilli, UBC S. Stetson, SWS,
Inc. D. Byun, U of Houston S. Burian, U of
Utah pblmodel_at_hotmail.com 27th NATO/CCMS/ITM
Meeting Banff, Alberta, Canada October 2004
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OUTLINE

• PROJECT GOALS
• uMM5 CONFIGURATION
• SYNOPTIC SUMMARY 700 MB SFC
• DOMAIN 1 MM5 WINDS VS NWS
• MM5 WINDS (MESO CONVENTION)
• FULL BARB 1 M/S
• FLAG 5 M/S
• DOMAINS 2-4 MM5 WINDs
• DOMAIN 5 uMM5 TEMPs UHIs
• CONCLUSION

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Project Summary

• Overall Evaluate impacts of de- re-forestation
  on Houston O3 levels (Byun, USFS)
• SIP Episode Aug-Sept Texas2000 in Houston
• MetModel EPA uMM5 (Martilli, Dupont, Ching)
• Improved uMM5 input (Burian, Stetson)
• Machine SJSU 96 CPU cluster (Balmori)
• Evaluate (Taha)
• uMM5 vs. MM5 performance
• uMM5 sensitivity to LU/LC changes

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5-domain configuration, D5 is urbanized
Resolution 108, 36, 12, 4, 1 km Grid dimensions
(excluding surface) 435328, 555528,
10010028, 13615128, 13314148.
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Urbanization Techniques

• Urbanize surface, SBL, PBL momentum,
• thermo, TKE Eqs
• Allows prediction within UCL
• From vegetation canopy-model of Yamada (1982)
• Veg parameters replaced with urban (GIS/RS) terms
  
• Brown and Williams 1998
• Masson 2000
• Sievers 2001
• Martilli et al. 2001 (in TVM)
• Dupont et al. 2003 (in MM5)
• LLNL 2004

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? From Masson (2000)
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uMM5 input as f (x, y) in D-05 (from Burian,
Stetson, USFS)

• land use (38 categories)
• roughness elements
• anthropogenic heat as f (t)
• vegetation and building heights
• paved surface fractions
• drag-force coefficients for buildings vegy
• building height-to-width, wall-to-plan,
• impervious-area ratios
• building frontal, building plan, and rooftop
• area-densities
• vegetation top- and area-densities
• e, c?, a, etc. of walls and roofs

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From Stetson high- resolution Houston zo data
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Base-case (current) vegetation cover (urban min)
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Modeled increases in vegetation cover (urban
max) Values are 0.1 of those in previous chart
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MM5 vs. uMM5 Preview of Results

• uMM5 takes longer than MM5
• with 1-CPU 8 times longer
• with 96-CPU only 3 times longer
• each-day of our uMM5 simulation took
• 16.0 days with 1-CPU
• 4.5 hours with 96-CPU
• uMM5 gives better
• TKE, UHIs, winds

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Synoptic Preview

• Pre-episode day
• 700 hPa flow NE of Houston was from SE
• Sfc Sea-breeze frontal formation
• Episode day
• 700 hPa flow now from NE ?
• opposition to onshore sea-breeze flow
• Sfc offshore cold-core low forms ?
• along-shore (NE to SW) coastal-flow ?
• ozone episode
• NWS vs. MM5
• NWS charts show only subtle changes
• MM5 provides the details

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1200 UTC (0700 DST) 24 AUG

• 700 mb
• Pre-episode AM
• SE flow NE of Houston

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1200 UTC (0700 DST) 25 AUG

• 700 mb
• Episode AM
• Opposing NE flow NE of Houston
• Will cause con with sfc SB V

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1200 UTC (0700 DST) 25 AUG

• Sfc chart
• Episode AM
• Not much detail
• Similar to day b/f after

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MM5 results Preview

• Domain 1
• Captures NWS synoptic features (change in 700 hPa
  flow-direction NE of Houston)
• Indicates off-shore feature (cold-core L) not on
  NWS charts
• Domains 2-4 shows details of off-shore L
• Domain 5 shows UHI effects

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Coastal Cold-Core L Episode day 3 PM Domains
1-3
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Domain 4 (3 PM) Note cold-core L off of Houston
on O3 day (25th)
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Domain 4 weak sea breeze meets inland NE-flow

4th (MM5) 5th (uMM5) Domains Non-episode day
at 2 PM
Domain 5 Finer details of sea breeze and NE-flow
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Domain 3 (12 km) 4 PM cold-core L (from where?)
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1 km uMM5 11 PM nocturnal UHI
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1 km uMM5 3 PM daytime UHI
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1 km Domain end of daytime UHI (8 PM 21 Aug)

• Upper L MM5
• Upper R uMM5
• Lower L uMM5-MM5
• uMM5? 1.5 K warmer (stronger UHI)
• Blob is LU/LC error

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1km Domain end of night UHI 9 AM 22 Aug

• Upper L MM5
• Upper R uMM5
• Lower L MM5-uMM5
• uMM5? 1.5 K cooler (weaker UHI)

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Explanation of uMM5 UHI UCI

• Wet soil TI gt urban TI gt dry soil TI
• Urban an area surrounded by wet soil thus has
• Daytime UHI (as urban area warms faster than
  soil)
• Nighttime UCI (as urban area cools faster than
  soil)
• Reverse true with dry rural soil
• Current results thus consistent with wet rural
  soil (as expected) around Houston, as uMM5
  produced daytime warming nighttime cooling over
  urban Houston

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Ongoing future efforts

• Additional analysis of current simulation results
• Additional simulations on new 106 CPU cluster
• Use planned 2005-6 Houston field-study (?) data
  to determine atm and (GIS/RS) urban parameters

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THE END
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Domain 1 7 AM 24 AUG

• 700 mb
• Pre-episode
• Weak off- shore L (not in NWS)
• Weak NE flow NE of city

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Domain 1 0700 DST 25 AUG

• 700 mb
• Episode AM
• Stronger off-shore L
• Stronger NE ff NE of city
• Will cause con with SB ff

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Domain 1 1800 DST 23 AUG

• Sfc chart
• Pre-episode
• On-shore SB
• Not much difference at same time on next 2 days
• Need to see inner domains