NYC METEOROLOGY: MODELS by BOB BORNSTEIN Dept of Meteorology, SJSU [email protected] for DHS/UDS...
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Transcript of NYC METEOROLOGY: MODELS by BOB BORNSTEIN Dept of Meteorology, SJSU [email protected] for DHS/UDS...
NYC METEOROLOGY: NYC METEOROLOGY:
MODELSMODELSby
BOB BORNSTEIN Dept of Meteorology, SJSU
DHS/UDS MeetingEML, NYCJune 2004
OUTLINEOUTLINE
URBAN MESOMODEL PROBLEM AREAS CURRENT STATUS
– URBAN WEATHER/CLIMATE– MESOMODELS– MODEL URBANIZATION
PROBLEM AREAS– MESOMODELS– MODELURBANIZATION
OUTLOOK
SJSU STUDIESSJSU STUDIES
URBMET/TVM: – NYC, SFBA, PHOENIX, SAO PAULO, FOS
MM5: – SFBA, ATLANTA, LA, HOUSTON
WRF (PROPOSED): – HOUSTON
URBAN MESOMODEL URBAN MESOMODEL PROBLEMSPROBLEMS
LINKAGE OF URBAN MODELING SCALES – Canyon (microscale model)– Roughness sub-layer [u*(z)] vs SBL (neighborhood
model)– Urban BL (mesomodel)
BUILDING-HEIGHT VARIATION what is lower boundary?
INHOMOGENEOUS SFC TYPE thermal, rad, and, roughness param are f(x,y)
RAD FLUX DIV DUE TO AEROSOLS interactive met and air quality models elev urban inversions & actinic flux
LOWER MODELLOWER MODELBOUNDARY SURFACE?BOUNDARY SURFACE?
GROUND SURFACECOMBO OF GROUND, WALL, AND
ROOF SURFACESROUGHNESS HEIGHTROUGHNESS SUBLAYER TOP
MESO-MODEL URBANIZATIONMESO-MODEL URBANIZATIONSIMPLE (NON-POROUS FLOWS)
– no T & V within URBAN CANYONS– Taha: OHM model for heat storage term– Bornstein: building-barrier effects
COMPLEX (POROUS FLOWS): from
Yamada’s forest canopy formulation– Brown and Williams: roof-drag effects– Mason: TEB urban canyon-energy effects– Martilli: wall-drag effects– Dupont: Martilli + forests + GIS data
1. Subgrid Variability1. Subgrid Variability
A. Predominant
B. Average Parameters (Kimura 1991)
concretep cc
cTT
cccc CGW
00
5.03.02.0
WATER 20%GRASS 30%
CONCRETE 50%
Barrier EffectBarrier Effect
Building Block Approach
Add grid-averaged urban-building topography height to natural topography
(Bornstein et al. 1993; Panayiotou 1995)
Reproduces: diffluence around city; blocking; daytime upslope convergent and nighttime downslope divergent flows
Does not reproduce: street canyon flows, which requires building-scale model
Advanced Urbanization Advanced Urbanization TechniquesTechniques
General Idea: Modify surface and/or atmospheric momentum, thermodynamic, and turbulence equations to directly account for urban effects
Allows prediction within UCL
Based on vegetation canopy model of Yamada (1982)
Vegetation parameters replaced with urban terms: Brown and Williams ; Masson; Martilli; Sievers ; Dupont; LLNL
From Masson (2000)
From Masson (2000)
Rough, warm urban simulationRough, warm urban simulation
USES OF MESOMODELS IN USES OF MESOMODELS IN NYC/DHS/UDSNYC/DHS/UDS
DESIGN OF MESONET: SFC AND PBLDESIGN OF TRACER STUDIESFORECASTS FOR TRACER STUDIESPARAMETERIZATIONS FOR MASS
CONSISTENT MESOMODELSUPPER BC FOR
– CFD MODELS– CANYON WIND MODELS