100 likes | 115 Vues
Explore constraints in emission inventories of ozone precursors with GOME satellite data. Assess and enhance bottom-up inventories using top-down information from GOME for accurate mapping of NOx emissions.
E N D
TOP-DOWN CONSTRAINTS ON EMISSION INVENTORIES OF OZONE PRECURSORS Daniel Jacob Dorian Abbot Paul Palmer Kelly Chance Thomas Kurosu Randall Martin
HOW DO WE EVALUATE AND IMPROVE BOTTOM-UP INVENTORIES? Surface NOX • Global NOx Emissions (Tg N yr-1) • Fossil Fuel (20-33) • Biomass Burning (3-13) Soils (4-21) • Here in Tg N yr-1 (based on) • Fossil Fuel 24 (GEIA) • Biomass Burning 6 (Logan/Duncan) • Soils 5 (Yienger and Levy)
TOP-DOWN INFORMATION FROM THE GOME SATELLITE INSTRUMENT • Operational since 1995 • Nadir-viewing solar backscatter instrument (237-794 nm) • Low-elevation polar sun-synchronous orbit, 10:30 a.m. observation time • Spatial resolution 320x40 km2, three cross-track scenes • Complete global coverage in 3 days
USE GOME MEASUREMENTS TO RETRIEVE NO2 COLUMNS TO MAP NOx EMISSIONS Retrieval Summary Spectral Fit (423-451 nm) GOME Total Slant Column Remove Stratosphere Tropospheric Slant Column Tropospheric NO2 column ~ ENOx Calculate AMF Tropospheric Column BOUNDARY LAYER Martin et al., 2002 NO2 NO/NO2 W ALTITUDE NO lifetime ~hours HNO3 Emission NITROGEN OXIDES (NOx)
GOME Tropospheric NO2 GEOS-CHEM Tropospheric NO2 r=0.75 bias 5% Martin et al., 2003 1015 molecules cm-2
STRATEGY: OPTIMIZE SURFACE INVENTORY USING A PRIORI BOTTOM-UP AND GOME TOP-DOWN INFORMATION Top-down emissions A priori emissions A posteriori emissions Top-down errors A priori errors Martin et al., 2003
TOP-DOWN INFORMATION FROM GOME REDUCES ERROR IN NOX EMISSION INVENTORY Bottom-up error a Mean=2.0 Top-down error tMean=2.0 Mean=1.6 Martin et al., 2003
37.7 Tg N yr-1 36.4 Tg N yr-1 OPTIMIZED SURFACE NOX EMISSIONS Martin et al., 2003
A POSTERIORI MINUS A PRIORI EMISSIONS Martin et al., 2003
GOME HCHO COLUMNS SHOW SEASONAL VOC EMISSIONS GOME GEOS-CHEM (GEIA) GOME GEOS-CHEM (GEIA) MAR JUL APR AUG MAY SEP JUN OCT -0.5 0 1016 molec cm-2 2.0 2.5 Agreement in general pattern, regional discrepancies point to need for improving GEOS-CHEM isoprene emissions (in progress using GBEIS) Abbot et al., 2003