MM5 SIMMULATIONS OF SFBA TO SAC/SJV TRANSPORT DURING 30 JULY- 2 AUG 2000 CCOS OZONE EPISODE
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MM5 SIMMULATIONS OF SFBA TO SAC/SJV TRANSPORT DURING 30 JULY- 2 AUG 2000 CCOS OZONE EPISODE by Robert D. Bornstein: SJSU [email protected] Tesfamichael B. Ghidey: LBNL, SJSU Robert Van Buskirk: LBNL Prepared for GMU Workshop July 2004. OUTLINE. SYNOPTIC SUMMARY

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MM5 SIMMULATIONS OF SFBA TO SAC/SJV TRANSPORT DURING 30 JULY- 2 AUG 2000 CCOS OZONE EPISODE

by

Robert D. Bornstein: SJSU

[email protected]

Tesfamichael B. Ghidey: LBNL, SJSU

Robert Van Buskirk: LBNL

Prepared for GMU Workshop

July 2004


Outline
OUTLINE JULY- 2 AUG 2000 CCOS OZONE EPISODE

  • SYNOPTIC SUMMARY

    • 700 MB (NO MESO INFLUENCES OVER CALIF)

    • SFC

  • MM5 CONFIGURATION

  • DOMAIN 1: SYNOPTIC WINDS

  • DOMAIN 3: MEOS WINDS

    • LIV, SAC, & SJV SEQUENTIAL OZONE EPISODE DAYS

  • STAT MESO-EVALUATION

    • TEMP

      • MESOSCALE: TEMP DRIVES WINDS

      • SYN SCALE: MASS/PRESSURE DRIVES WINDS

    • WINDS (MESO CONVENTION)

      • FULL BARB = 1 M/S

      • FLAG = 5 M/S

  • CONCLUSION


Forcings
FORCINGS JULY- 2 AUG 2000 CCOS OZONE EPISODE

  • EPISODES OCCUR ON GIVEN DAYS

    • NOT B/C TOPO, EMISSIONS, OR SFC MESO-FORCING (EXCEPT FOR FOG) CHANGES

    • BUT B/C UPPER LEVEL SYNOPTICS CHANGE, WHICH ALTERS MESO-FORCINGS (TOPO, LAND/SEA, URBAN) VIA T AND THUS V

  • MUST THUS EVAL ALL ABOVE FACTORS:

    SYN, TOPO (grid spacing), MESO T & V


700 hpa nws preview 1200 utc or 0500 pdt
700 hPa NWS PREVIEW: JULY- 2 AUG 2000 CCOS OZONE EPISODE1200 UTC OR 0500 PDT

Movement of inland H causes episodes

  • Pre-episode: over Nevada

  • Episode days: moves SW to over SJV

    and intensifies

  • Post-episode: dissipates


Before ozone episodes: offshore G. C. High; synoptic High in Nevada;

boundary-Low between Highs; SSW-flow over SFBA



Surface nws preview 1200 utc or 0500 pdt
Surface NWS PREVIEW: Nevada; 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 and intensifies

    • Post-episode: weakens


B/F ozone episodes: warm core “inverted thermal L” from Sea of Cortez to S-Nevada; 2nd open-L into northern CA; NW-flow over SFBA and S-flow over SAC


LIV episode day: trough moves NW, forms closed low, with N-S axis thru central CA; SE-flow over Sac


Mm5 configuration
MM5 configuration axis thru central CA; SE-flow over Sac

  • 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


Mm5 domain 1 700 hpa winds preview
MM5 Domain-1: axis thru central CA; SE-flow over Sac 700 hPa WINDS PREVIEW

  • NWS charts

    • give 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-E of SFBA over AZ


(B/F episodes) MM5 correct: offshore GC H; Syn H in SE Nev; boundary-L;

but S-flow over SFBA vs. SW NWS

L

H

H


SAC episode day: Syn H to Utah with max (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


Mm5 domain 1 sfc winds preview 12 utc or 05 pdt
MM5 Domain-1: SFC WINDS PREVIEW (12 UTC OR 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

  • Flow details: in Domain-3


B/F episodes: warm-core thermal-L to S-Nevada & 2 nd CA-L to N (both correct);

NW-flow over coast & SFBA (correct) and con-flow over SAC (vs NWS S-flow)

L

L


SAC episode: S-Low moved N & N-Low moved bit S (NWS showed only closed-L gone); now more W-flow to Sac

L

L


Mm5 sfc temp stats
MM5 SFC-TEMP STATS only closed-L gone); now more W-flow to Sac

  • DAY AND NIGHT SPATIAL-PATTERNS ARE REASONABLE (NOT SHOWN)

  • STATS SHOW SOME BIAS (SHOWN), WHICH CAN BE ELIMINATED BY

    • SELECTING TRUSTWORTHY SITES

    • ADJUSTING DEEP SOIL TEMP AND SOIL MOISTURE CONTENT


Domain 3 700 hpa preview 2100 utc or 0200 pdt
DOMAIN-3: 700 hPa PREVIEW (2100 UTC or 0200 PDT) only closed-L gone); now more W-flow to Sac

  • 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


Pre-episode: uniform S-flow only closed-L gone); now more W-flow to Sac


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


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


Domain 3 summary of sfc transport to livermore key hours
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 from E-side of hills E of LIV

  • For episode need

    • Strong confluence

    • Low speeds


Sfc winds obs at 0700 PST

(1500 UTC) on 31 July,

(LIV episode morning)

Note con flow into LIV


Sfc-wind Obs at 1400 PST

(2200 UTC) on 31 July

(LIV episode afternoon)

Note flow from N into LIV and

out to E




Domain 3 sfc transport to sac summary
DOMAIN 3: SFC TRANSPORT TO SAC SUMMARY into E-Liv

  • TRANSPORT FROM SFBA BLOCKED BY OPPOSING FLOW ON DAYS BEFORE AND AFTER SAC EPISODE

  • TRANSPORT FROM SFBA NOT BLOCKED ON DAY OF SAC EPISODE




Domain 3 sfc transport to sjv summary
DOMAIN 3: SFC TRANSPORT TO SJV SUMMARY not blocked

  • TRANSPORT FROM SFBA TO SJV MUST NOT BE BLOCKED BY OPPOSING FLOWS

  • FLOW INTO SJV MUST

    • NOT BE TOO FAST

    • SHOW CONFLUENCE




Conclusion
CONCLUSION not blocked

  • SMALL CHANGES IN 700 MB-H AND SFC-L POSITIONS CAUSED SEQUENTIAL DAILY OZONE MAX IN LIV, SAC, AND SJV

  • NWS CHARTS COULD NOT DISCERN DETAILS OF CHANGES, BUT MM5 COULD

  • MM5

    • MATCHED NWS PATTERNS AND MESO-OBS REASONABLY WELL

    • PROVIDED ADDITIONAL DETAILS

  • ADDITIONAL SIMULATIONS SHOULD CORRECT REMAINING DIFFERENCES


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