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Rynda C. Hudman ([email protected]), A.R. Russell, L.C. Valin, R.C. Cohen
Department of Chemistry
U.C. Berkeley
1. Background1. Background
(c)
REFERENCES REFERENCES
This work was supported by NASA (grant NNX08AE566)
INTERANNUAL VARIABILITY IN SOIL NITRIC OXIDE EMISSIONS OVER THE UNITED STATES AS VIEWED FROM SPACE
OMI NO2 Column Aug 4, 2004OZONE MONITORNING INSTRUMENT8
• 2600 km swath width providing daily global coverage
•1:45 pm equatorial overpass time
•14 x 24 km pixel size at nadir
I. Soil NOx Emissions (SNOx)
Nitric oxide (NO) is a highly variable product of microbial activity in soils.
Processes governing SNOx are not well understood, but correlate best
with water-filled pore space, temperature, and N availability, so that
emissions are highly dependent on local temperature, precipitation, as
well as fertilizer management practices1-6. Surface observations of soil
NOx emissions (SNOx) have sparse spatial coverage, so generalizing
these results to regional and global budgets has proven difficult, with
global above-canopy estimates ranging from 4.7 -13 Tg N yr-1.
II. Satellite Observations
Satellite observations of NO2 have advanced such that they can provide
global continuous coverage on fine spatio-temporal scales allowing a
bridge in the gap between previous satellite analysis at regional scales
(100s of km) and process-based observations at meter scales.7
We use tropospheric NO2 column densities from the Ozone Monitoring Instrument (OMI)8, interpreted with a model of SNOx
9, driven by daily soil temperature and precipitation from the North American Regional Reanalysis (NARR) for 2005-200810, to show that satellite observations can detect interannualvariability in SNOx over the United States. This interannualvariability is a function of climate and soil state variables. We then use GEOS-Chem, a chemical transport model, which represents the variability in N emissions to examine implications of this variability for ozone air quality.
III. Model Description
3. 3. InterannualInterannual variability in OMI NOvariability in OMI NO22 & & SSNOxNOx
ACKNOWLEDGEMENTS ACKNOWLEDGEMENTS
4. Soil 4. Soil NOxNOx impact on ozone air quality impact on ozone air quality
CONCLUSIONS CONCLUSIONS
Algorithm9: SNOx = f( T, biome, w/d)
x Pulse (dryspell)
x canopy uptake
Inputs (2005-2008):daily NARR Temp &
Precipitation10
MODIS Landtype
Fertilizer emissions11
Daily SNOx (0.25°x0.25°) for 2005-2008 Mean Yearly Total: 0.62 Tg N/yr (Fert: 0.12 Tg N/yr)
GEOS-Chem12-14 CTM to examine Ozone air quality
Dry, warm conditions ���� anomalously high June 2006 soil
emissions (Largest predicted month to month variability)
SNOx should be visible from
space. Soil column predicted to comprise 15-40% (mean) and 50-75% (std dev) of the tropospheric NO2 column.
OMI NO2 JUNE INTERANNUAL VARIABILITY FOLLOWS SOIL NOx
June mean OMI NO2 tropospheric column concentrations (top) are compared to mean anomaly for OMI NO2, SNOx, and lightning flashes calculated as difference between with June 2005-2008 mean.
Timeseries of soil NO pulsing event over rural South Dakota (43-45N, 98.75 - 96.25W). OMI NO2 (top) for Standard Product (black) and DOMINO Product (grey) are compared with SNOx (top, green) and ppt (bottom, red) for May - July 2006.
Pulsing event reaches 4x1015 molec cm-2, ~ 2 ppbv assuming 1km well mixed BL
Ozone enhancement due to SNOx increases from 3 ���� 5 ppbv in 2006 vs. 2005-2008 mean.
Mean 8-hr maximum June ozone
enhancement from SNOx for 2005 –2008 (top) are compared with 2006 (bottom) simulated using GEOS-Chem.
*SOIL COLUMN = TROPOSPHERIC
COLUMN – NO SOIL COLUMN
•The interannual variability in the OMI NO2 column over much of the
central United States in June is driven by fertilizer application.
•Dry, warm conditions followed by convective precipitation induced
pulsed SNOx over the agricultural Great Plains in June 2006 resulted in a
50% increase in SNOx and a 30% increase in the tropospheric NO2
column relative to June 2005-2008 mean.
• In a case-study of fertilized fields over SE South Dakota, we find an
associated pulsing event reaching up to 4.6x1015 molec cm-2, equivalent
to a surface concentration of 2 ppbv.
•Driving GEOS-Chem with predicted SNOx we find a mean maximum
surface 8-hr ozone enhancement due to SNOx of 5 ppbv in June 2006
compared with 3 ppbv for 2005-2008.
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S. M. et al. (2002), J. Geophys. Res., 107(D20), 8058, doi:10.1029/2001JD000358. 3Ludwig, J. et al. (2001), Biogeochemistry, 52, 225– 257. 4Stehfest, E. and L. Bouwman
(2006), Nutr. Cycl. Agroecosyst., 74, 207-228, doi 10.1007/s10705-006-9000-7. 5Schindlbacher, A. et al.(2004), J. Geophys. Res., 109, D17302,
doi:10.1029/2004JD004590.6Meixner, F.X. and W.X. Yang (2006), Dryland Ecohydrology,
Springer, pp. 233–255. 7Bertram, T.H. et al. (2005), Geophys. Res. Lett., 32, L24812, doi:10.1029/2005GL024640. 8Boersma, K.F. et al. (2002), OMI Trace Gas Algorithms,
ATBD-OMI-04 2002, (Version 2), 13-2. 9Yienger, J. J. and Levy II, H. (1995), J. Geophys.
Res., 100, 11447–11464. 10Mesinger, F. et al. (2006), Bulletin of the American
Meteorological Society, 87(3), 343. 11Potter, C.S. et al. (2010), Earth Interactions, in press. 12Bey, I. et al. (2001), J. Geophys. Res., 106, 23,073– 23,095. 13Park R.J. et al. (2004), J. Geophys. Res., 109, D15204, doi:10.1029/2003JD004473. 14Hudman R.C. et al. (2007), J. Geophys. Res., 112, D12S05, doi:10.1029/2006JD007912.
2. Simulated 2. Simulated SSNOxNOx contribution to NOcontribution to NO22 columncolumn
4. Case4. Case--study of fertilizer induced pulsing over South Dakotastudy of fertilizer induced pulsing over South Dakota