P1.3 SIMULATING THE EFFECTS OF URBAN-SCALE LAND USE CHANGE ON SURFACE METEOROLOGY AND OZONE CONCENTRATIONS IN THE NEW YORK CITY METROPOLITAN REGION

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P1.3 SIMULATING THE EFFECTS OF URBAN-SCALE LAND USE CHANGE ON SURFACE METEOROLOGY
AND OZONE CONCENTRATIONS IN THE NEW YORK CITY METROPOLITAN REGION
Kevin Civerolo
1,*
, Christian Hogrefe
2
, Jia-Yeong Ku
1
, William Solecki
3
, Christopher Small
4
, Charles Oliveri
3
, Jennifer
Cox
3
, and Patrick Kinney
5
1
New York State Department of Environmental Conservation, Division of Air Resources, Albany, NY, USA
2
Atmospheric Sciences Research Center, University at Albany, Albany, NY, USA
3
Hunter College, City University of New York, Department of Geography, New York, NY, USA
4
Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, USA
5
Columbia University, Mailman School of Public Health, New York, NY, USA
1. INTRODUCTION
Large-scale urbanization can have a profound
impact on air quality, regional climate, and ecosystem
and human health. This is particularly true in a
metropolis such as New York City, whose consolidated
metropolitan area covers portions of four states and
whose population exceeds 21 million. One of the goals
of the New York Climate and Health Project (please see
http://www.mailman.hs.columbia.edu/ehs/NYCHP1.html
)
is to develop a modeling framework to examine the
effects of global climate and land use change on human
health now and in the future. Here we present our
preliminary findings on the effects of current and future
land cover scenarios on surface meteorological fields
and ozone (O
3
) concentrations in the New York City
region. Analysis of the model simulations is ongoing,
and more complete results will be presented at the
upcoming AMS Annual Meeting’s 7th Conference on
Atmospheric Chemistry.
2. MODELING SYSTEM
The nonhydrostatic, primitive equation MM5
(Dudhia 1993) was used to generate the three-
dimensional meteorological fields over much of the
eastern US from July 12-16, 1995 (Civerolo et al. 2000).
The model used 32 pressure-following vertical layers to
about 16 km AGL, with the lowest layer 20 m thick.
Simulations were performed at a horizontal grid
resolution of 4 km, with initial and hourly boundary
conditions provided by Seaman (1996). The planetary
boundary layer utilized was the Blackadar scheme
(Zhang and Anthes 1982), a simplified slab model that
does not explicitly predict soil moisture. Figure 1(A)
displays the modeling domain.
The New York City metropolitan area was the
region of interest for this study, and it was critical to
make use of land use/cover information specific to this
region. Briefly, high-resolution (~70 m) land use
information were obtained from recent SLEUTH model
estimates (Solecki and Oliveri 2004) of the conversion of
rural-to-urban land cover using the Urban Growth Model
(UGM) and Land Cover Deltatron Model (LCDM) across
the 31-county metropolitan region. SLEUTH includes
the following land use classes: wetlands, water, urban,
barren, forest, agriculture, and range. We further
subdivided the single urban land use class into three,
based upon the remotely sensed vegetative fraction:
“high” urban, vegetative fraction <22%; “medium” urban,
vegetative fraction 22-51%; and “low” urban, vegetative
fraction > 51%. The SLEUTH domain is smaller than
the MM5 4 km domain, and where there is overlapping
coverage the SLEUTH land use data were aggregated
into the appropriate MM5 grid cells. If the dominant land
use was an urban category based on the SLEUTH
results, the category was assigned to the MM5 grid;
otherwise, the default MM5 land use designation was
kept.
We generated two sets of MM5-ready land use
files, the first corresponding to a base case in which
urban growth from 1960-1990 was used to estimate a
“current” (ca. 1990) land use pattern. In the second
simulation, we used SLEUTH results based on the
Intergovernmental Panel on Climate Change (IPCC)
“A2” emissions scenario for the year 2050 (please see
http://www.ipcc.ch/pub/sres-e.pdf
). Briefly, the IPCC A2
scenario assumes large increases in greenhouse gas
emissions, relatively weak environmental concerns, and
high population growth. Both simulations were driven
with the same meteorological fields. See Figures 1(B)
and 1(C) for the base year (ca. 1990) and future year
(ca. 2050) urban land cover, respectively, in the New
York City metropolitan region. Evident in these figures
is the substantial increase in the “low” urban cover
across the entire metropolitan region as a result of this
fairly pessimistic scenario.
Figure 1. (A) The MM5 modeling domain. (B) Base year urban
land cover in the New York City region, where red denotes
“high” urban, yellow denotes “medium” urban, and orange
denotes “low” urban. (C) Same as (B), except for future year.
*Corresponding author address: Kevin L. Civerolo, New York
State DEC, Division of Air Resources, 625 Broadway, Albany,
NY 12233-3259; e-mail: kxcivero@gw.dec.state.ny.us.

3.2 Surface O
3
concentrations
After generating the meteorology for this episode,
we used the US EPA Community Multiscale Air Quality
(CMAQ) model (Byun and Ching 1999) to predict the O
3
concentrations across the domain. Simulation results
are available from July 13-15, 1995, and details of the
photochemical model configuration can be found in a
similar study by Hogrefe et al. (2004). The
anthropogenic and biogenic emissions specific to the
summer of 1995 were generated using the Sparse
Matrix Operator Kernal Emissions (SMOKE) processing
system (Houyoux et al. 2000).
Figures 3(A) and (B) display the episode maximum
O
3
concentrations in the New York City region at each
grid cell for the base and future years, respectively, and
the differences in episode maximum O
3
(“future” –
“base”) are shown in Figure 3(C). While Figures 3(A)
and (B) are qualitatively similar, a few differences are
apparent. First, O
3
concentrations in the A2 scenario
increased in New York City and parts of eastern New
Jersey. The largest increases in O
3
occurred over
southern Connecticut, downwind of the core urban area.
At the same time, maximum concentrations in central
and northern New Jersey were slightly lower in the A2
scenario, possibly due to higher rates of O
3
or peroxy
radical titration by nitrogen oxides (NOx). These initial
findings highlight the complex interactions between
meteorology, emissions, land surfaces, and O
3
fields,
and will be explored further.
3. PRELIMINARY RESULTS
3.1 Surface meteorology
Figures 2(A)-(C) display the average diurnal
variation in temperature, water vapor mixing ratio, and
planetary boundary layer (PBL) height from July 13-15
over the 57 non-water grid cells that define New York
City. On average, in the A2 scenario: the surface
temperatures increased by a few tenths ºC during the
afternoon and early evening hours; nighttime mixing
ratios generally decreased; and afternoon PBL heights
generally increased slightly. All of these effects are
small on average, but are consistent with increased
impervious surface cover and decreased moisture
availability. We are currently examining these
parameters – as well as wind speed/direction and cloud
cover – over a larger region.
Figure 3. Episode (July 13-15) maximum O
3
concentrations
for the (A) base year and (B) future year simulations, in ppm,
as well as (C) the difference in episode maximum O
3
.
5. ACKNOWLEDGMENTS AND DISCLAIMER
This research is ongoing, and has been supported
by the National Urban and Community Forestry
Advisory Council, the U.S. Environmental Protection
Agency and the New York State Department of
Environmental Conservation. The views expressed by
the authors do not necessarily reflect those of the
sponsoring agencies.
Figure 2. Diurnal variations of (A) surface temperature, (B)
water vapor mixing ratio, and (C) PBL heights across New York
City from July 13-15. The base year simulation is shown in
green, and the future year simulation is shown in red.

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