MM5%20SIMMULATIONS%20OF%20SFBA%20TO%20SAC/SJV%20TRANSPORT%20DURING%2030%20JULY-%202%20AUG%202000%20CCOS%20OZONE%20EPISODE

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MM5 SIMMULATIONS OF SFBA TO SAC/SJV TRANSPORT
DURING 30 JULY- 2 AUG 2000 CCOS OZONE
EPISODE by Tesfamichael B. Ghidey LBNL,
SJSU, DRI
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OUTLINE

• SYNOPTIC SUMMARY
• 700 MB
• SFC
• MM5 CONFIGURATION
• WINDS MESO CONVENTION
• FULL BARB 1 M/S
• FLAG 5 M/S
• RESULTS
• DOMAIN 1 SYNOPTIC WINDS
• DOMAIN 3 MEOS WINDS
• LIV, SAC, SJV SEQUENTIAL OZONE EPISODE DAYS
• CONCLUSION

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NWS 700 hPa PREVIEW1200 UTC ( 0500 PDT)

• Movement of inland-H causes episodes
• Pre-episode over Nevada
• Episode days
• moves SW to SJV
• intensifies
• Post-episode dissipates

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Before ozone episodes offshore G. C. High
synoptic High in Nevada boundary-Low between
Highs SSW-flow over SFBA
H
H
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SAC ozone day SJV-H at max intensity SW flow
over SFBA
H
H
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NWS Surface PREVIEW 1200 UTC or 0500 PDT

• Warm-core upper-H projects down to a
• Sfc inverted thermal-L
• Pre-episode over Nevada
• Episode days moves over SJV intensifies
• Post-episode weakens

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B/F ozone episodes warm core inverted thermal
L from Sea of Cortez to S-Nevada secondary
open-L into northern CA NW-flow over SFBA
S-flow over SAC
L
L
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LIV episode day trough moves NW, forms closed
low, with N-S axis thru central CA SE-flow over
Sac
L
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MM5 configuration

• Version 3.6.0
• Three domains
• 36, 12, 4 km
• 55 x 55, 91 x 91, 190 x 190 grid points
• 32 sigma levels
• up to 100 mb
• first full sigma level at 19 m
• GDAS IC and BC
• Analysis nudging only for V and T for
• 36 km domain
• above PBL
• No obs nudging
• Five layer soil model, Gayno-Seaman PBL
• Start 1200 UTC on 28 July and went for 7.5 days
• LBNL LINUX single processor 15 days

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D01
D03
D02
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(No Transcript)
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(No Transcript)
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Validation of 10-m dd
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MM5 Domain-1 700 hPa WINDS PREVIEW

• NWS charts
• gave only approx p-center locations
• cannot give flow details in SFBA, Carquinez
  Straits, SJV
• Thus need MM5 to show
• Pre-episode H E of SFBA over NEV
• Episode days bulge from H extends westward over
  SFBA
• Post-episode H back to E of SFBA over AZ

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(B/F episodes) MM5 correct offshore H H in SE
Nev boundary-L but S-flow over SFBA vs. NWS SW
L
H
H
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SAC episode day Syn H to Utah with (now NE-SW)
bulge (vs. NWS-H over SJV) L now S in Cal (vs.
NWS E over CA/AZ border) correct SW flow over
SFBA to Sac
H
H
L
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MM5 Domain-1 SFC WINDS PREVIEW AT 12 UTC ( 05
PDT)

• Movement to N of thermal L from S-CA sequentially
  cause episodes
• Convergence into LIV
• Increased flow to Sac from SFBA
• Increased flow into SJV from SFBA
• Moves offshore
• Domain-3 Flow details

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B/F episodes warm-core thermal-L to S-Nevada
2nd CA-L to N (both correct) NW-flow over coast
SFBA (correct) and con-flow over SAC (vs NWS
S-flow)
L
L
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SAC episode S-Low moved N N-Low moved bit S
(NWS showed only closed-L as gone) now more
W-flow to Sac
L
L
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DOMAIN-3 700 hPa PREVIEW (2100 UTC or 0400 PDT)

• Offshore-H formation Fresno-eddy movement cause
  episodes
• Initial flow from S does not produce SFBA to Sac
  transport
• Syn-H formation directs SFBA flow to Sac
  con-current Fresno-eddy blocks SFBA flow into SJV
• When eddy moves to N
• SFBA flow into Sac is blocked
• SFBA flow into SJV is allowed

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Pre-episode uniform S-flow
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SAC episode H moved to W at coast (vs bulge from
CV to coast in D-1) Fresno eddy N of D-1
position (blocks flow into SJV from SFBA W flow
over SFBA (vs. NWS S-flow) directly to SAC
H
L
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SJV episode Fresno eddy moved N H moves inland
(both better defined than in D-1) flow around
eddy blocks SFBA flow to SAC, but forces it S
into SJV
L
H
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DOMAIN-3 SUMMARY OF SFC TRANSPORT TO LIVERMORE
(KEY HOURS)

• Daytime confluence of 3-flows E of LIV (on Mt
  peak) causes episode
• Flow from N from Carquinez Straits
• Flow from W thru GGG
• Upslope flow on E-side of hills E of LIV
• For episode need
• Strong confluence
• Low speeds
• Obs first and then MM5

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Sfc winds-obs at 0700 PST (1500 UTC) on 31 July
(LIV episode morning) Note con flow into LIV
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• Sfc wind-obs at 1400 PST
• (2100 UTC) on 31 July
• (LIV episode afternoon)
• Note flow from N into LIV and
• out to E

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Pre-episode afternoon (1400 PDT) W flow thru GGG
weak con E of Liv
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Episode afternoon (1400 PDT) W flow thru GGG
strong con E of Liv
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DOMAIN 3 SFC TRANSPORT TO SAC SUMMARY

• TRANSPORT FROM SFBA BLOCKED BY OPPOSING FLOW ON
  DAYS BEFORE AND AFTER SAC EPISODE
• TRANSPORT FROM SFBA NOT BLOCKED ON DAY OF SAC
  EPISODE

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LIV-episode late-afternoon (1800 PDT) flow to
SAC from SFBA blocked
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SAC-episode late-afternoon (1800 PDT) flow to
SAC from SFBA not blocked
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DOMAIN 3 SFC TRANSPORT TO SJV SUMMARY

• TRANSPORT FROM SFBA TO SJV MUST NOT BE BLOCKED BY
  OPPOSING FLOWS
• FLOW INTO SJV MUST
• NOT BE TOO FAST
• SHOW CONFLUENCE

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SAC EPISODE NIGHT TRANSPORT TO SJV FROM SFBA IS
BLOCKED
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SJV EPISODE NIGHT TRANSPORT TO SJV FROM SFBA
CON WINDS
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CONCLUSION

• SMALL CHANGES IN 700 hPa-H SFC-L POSITIONS
  CAUSED SEQUENTIAL DAILY OZONE MAX IN LIV, SAC,
  SJV
• NWS CHARTS COULD NOT DISCERN DETAILS OF CHANGES,
  BUT MM5 COULD
• MM5
• MATCHED NWS PATTERNS MESO-OBS REASONABLY WELL
• PROVIDED ADDITIONAL DETAILS