NYU/NYC STUDYNYU/NYC STUDY 10 IOPs

– FIVE DAYS EACH (DAY AND NIGHT)– ALL SEASONS

80 SFC WIND SITES HOURLY FLOW CHARTS PIBALS:

– 1- 4 THEODOLITES FOLLOWING 1OR 2 BALLOONS– 15 SEC OBS 37.5 m z-RESOLUTION

HELICOPTER SOUNDINGS (ABOUT 1000)– T, Q, & SO2

NOAA TETROONS: ABOUT 200 EMISSIONS

– 1 KM X 1 KM– SO2, HEAT, & MOISTURE

Sea-breeze frontal (S to N) passage over NYC:Sea-breeze frontal (S to N) passage over NYC:9 March 19669 March 1966

a. hourly positions a. hourly positions (left)(left)b. 1800 EST b. 1800 EST (right): note urban-induced retardation area(right): note urban-induced retardation area

NYC daytime sea-breeze sfc div-field during sea NYC daytime sea-breeze sfc div-field during sea breeze frontal (SBF) passagebreeze frontal (SBF) passage

Note: Note: (a) conv area strongest at front(a) conv area strongest at front(b) div areas over Ocean and Long Island Sound (LIS)(b) div areas over Ocean and Long Island Sound (LIS)

D = ∂u/∂x +D = ∂u/∂x + ∂ ∂v/∂yv/∂y

OceanOcean

LISLIS

SBFSBF

URBAN TURBULENCE DURING A URBAN TURBULENCE DURING A NYC SEA BREEZE FRONTAL PASSAGE:NYC SEA BREEZE FRONTAL PASSAGE:•VALUES HIGH ALONG FRONT (LEFT)VALUES HIGH ALONG FRONT (LEFT)•AIR STABLE BEHIND FRONT (RIGHT) AIR STABLE BEHIND FRONT (RIGHT)

R (deg)R (deg)

Tetroons in sea-breeze flows Tetroons in sea-breeze flows produce produce interesting (x, y) and (x, z) trajectoriesinteresting (x, y) and (x, z) trajectories

that returns balloon (left) and raises it (right)that returns balloon (left) and raises it (right)

SEA-BREEZE (SB) EFFECTS ON SEA-BREEZE (SB) EFFECTS ON χχ•AM syn-V pushes AM syn-V pushes χχ offhore (right) offhore (right) • PM sea breeze flow pushes it onshorePM sea breeze flow pushes it onshore & concentrates it in narrow conv & concentrates it in narrow conv zone (lower L)zone (lower L)• The SB thus raises The SB thus raises χχ at coastal JFK & at coastal JFK & lowers it at inland LGA (lower R)lowers it at inland LGA (lower R)

KEY IDEA: IDEAL MESO-MET ATM-MODEL KEY IDEA: IDEAL MESO-MET ATM-MODEL CAPTURES ALL BC FORCINGS CAPTURES ALL BC FORCINGS IN CORRECT IN CORRECT

ORDERORDER O3 EPISODES OCCUR ON A GIVEN DAY:

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

– BUT DUE TO CHANGES IN UPPER-LEVEL SYNOPTIC WX PATTERNS, WHICH

COME FROM AN EXTERNAL MODEL & WHICH ALTER MESO SFC-FORCINGS (i.e., TOPO, LAND/SEA, URBAN)

VIA MESO-TEMP AND THUS WIND MUST THUS EVALUATE ABOVE FACTORS:

– UPPER LEVEL SYN WX Patterns: pressure & then winds– TOPOGRAPHY (via grid spacing): channeling of wind– MESO SFC: temperature & then winds

NYC Sea breeze:NYC Sea breeze: obs (upper)obs (upper)TVM/URMET TVM/URMET (lower) (lower)

NYC OBS REFERENCESNYC OBS REFERENCES

Bornstein, 1968: J. Appl. Met.., 7., 575-82.Born. & Johnson, 1977: At. Env., 11, 597-04Loose & Born., 1977: MWR, 105, 567-71.Born. & Thompson, 1981: JAM, 20, 843-58Born., 1987: Modeling the Urban BL, AMS, 53‑93. Gaffen & Born., 1988: Met. & Atmos. Phys, 38,

185‑94