Title: Performance evaluation of isoprene in ozone modeling of Houston
1Performance evaluation of isoprene in ozone
modeling of Houston
- Mark Estes, Clint Harper, Jim Smith, Weining
Zhao, and Dick Karp - Texas Commission on Environmental Quality
- Presentation for the CMAS Conference, October
2008 - mestes_at_tceq.state.tx.us
2Acknowledgements
- TCEQ Air Modeling Team Doug Boyer, Pete
Breitenbach, Bright Dornblaser, Barry Exum,
Marvin Jones, Chris Kite, Jim MacKay, Jocelyn
Mellberg, Ron Thomas, Zarena Post, Steve Davis. - TCEQ Monitoring Operations
3Questions of interest
- At the isoprene monitors used to evaluate
performance, what is the long-term behavior? How
does the model behave during similar time
periods? - How much geographic variation is observed in
these patterns, and does the modeled variation
match observed variation?
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5Methods Biogenics modeling
- Emissions model GloBEIS v3.1 biogenic emissions
model (Yarwood et al., Guenther et al.) at 2km
maximum resolution. - Land cover data University of Texas Center for
Space Research (UT-CSR) land cover data (Feldman
et al., 2007), 30 meter native resolution. - Vegetation data Houston Green Urban Forest
Survey (Smith et al., 2005) - Met data interpolated temperature data for
local networks, and GOES-derived
photosynthetically active solar radiation data
(Byun et al., 2005)
6Methods Photochemical grid modeling
- CAMx v4.51, run at 4km and flexi-nested to 2km.
- MM5 v3.7.3, with ETA PBL scheme, UH GOES-derived
sea surface temperatures, UT-CSR land cover data,
NOAH LSM, 4km maximum resolution, analysis
nudging on outer grids, obs nudging with profiler
data in 4km grid, TKE Kv scheme. - Carbon Bond 05 chemical mechanism (Luecken et
al., 2008). - TCEQ emissions inventory, version
bcYYMMM.reg8_pscfv2
7Episodes of interest
- May 19 June 3, 2005
- June 17 June 30, 2005
- July 26 August 8, 2005
- May 31 June 15, 2006
- August 15 September 15, 2006 (TexAQS II field
study intensive) - September 16 October 11, 2006 (TexAQS II field
study intensive) - Total number of days of interest 96
8Example for Aug 16, 2006 Total isoprene
emissions, 1924 tons/day for whole domain 610
tons/day in Houston nonattainment area.
9Auto GC locations
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11Suburban/ex-urban monitoring site
12Rural monitoring site
13Industrial monitoring site
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22Finding
- Temporal patterns Modeled isoprene matches the
diurnal and seasonal patterns of the
measurements, but doesnt always match the
magnitude. - Spatial patterns Modeled isoprene appears to be
correlated with the measured spatial patterns,
but doesnt always match the magnitude.
23Geographic analyses
- Isoprene performance varies by site. Is the
geographic distribution of trees correct?
24Are the trees in the right places?
- Calculate the difference between the elevations
estimated by the Shuttle Radar Tomography Mission
(Feb 11-22, 2000) and the elevation of the ground
surface using the National Elevation Database
(USGS). The difference can represent the height
of the tree canopy. - Calculate the Normalized Difference Vegetation
Index (a vegetative greeness index) for a Landsat
image of approximately the same age (1999). This
tells where the vegetation is located. - Identify all areas with both high NDVI and height
of 4 to 80 meters. - Calculate the number of tree pixels within each
4km grid cell. - Contrast the locations of these areas to the
areas identified by the UT-CSR landcover data as
forested. - Plot isoprene emissions per grid cell vs. number
of tree pixels per grid cell.
25UT-CSR Land Coverall categories displayed
26UT-CSR Land Coveronly forested categories
displayed
27Areas with tree canopy NDVI between x and y,
and canopy height between 4m and 80m
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29Current state of these analyses
Photos by Bohne, U. Vermont
30Future work
- Further comparisons between modeled isoprene and
TexAQS II observations (aircraft data, RHB ship
data, Moody Tower data) - C. Warneke analysis comparing PTRMS data aboard
NOAA P3 aircraft to the biogenic emissions models
GloBEIS, MEGAN, and the latest version of BEIS. - Hyperspectral satellite data analysis to
distinguish tree species? Aerial photography to
assist in species identification?