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INTERANNUAL VARIABILITY IN SOIL NITRIC OXIDE EMISSIONS OVER THE UNITED STATES AS VIEWED FROM SPACE Rynda Hudman, Ashley Russell, Luke Valin, Ron Cohen.

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Presentation on theme: "INTERANNUAL VARIABILITY IN SOIL NITRIC OXIDE EMISSIONS OVER THE UNITED STATES AS VIEWED FROM SPACE Rynda Hudman, Ashley Russell, Luke Valin, Ron Cohen."— Presentation transcript:

1 INTERANNUAL VARIABILITY IN SOIL NITRIC OXIDE EMISSIONS OVER THE UNITED STATES AS VIEWED FROM SPACE Rynda Hudman, Ashley Russell, Luke Valin, Ron Cohen College of Chemistry UC Berkeley OMI NASA Standard Product Version 1.0.5 December 14, 2009

2 ATMOSPHERE BIOSPHERE NO & N 2 O IS A HIGHLY VARIABLE PRODUCT OF MICROBIAL ACTIVITY IN SOILS N 2 O(g), N 2 (g), NO(g) [Meixner and Yang, 2006] Processes not well understood, HUGE spatial variability, but best correlation w/ wfps, T, N avail. [See Poster: Placella et al., B13C-0527]

3 LARGE SOIL NO x SOURCE INFERRED FROM SATELLITES GOME Constraints on Natural Soil and Agriculture [Jaeglé et al., PNAS, 2005] GLOBAL: 8.9 Tg N/yr MIDLATITUDES: 3.9 Tg N/yr ~22% of global NO x source ~Midlatitude soil source X2-3 current global model estimates

4 We examine interannual variability in soil NO emissions and our understanding of pulsing behavior over the Agricultural Great Plains OMI NO 2 Column Aug 4, 2004 2600 km swath width providing daily global coverage 1:45 pm equatorial overpass time 14 x 24 km pixel size at nadir OZONE MONITORING INSTRUMENT (OMI) HAS MUCH FINER SCALE RESOLUTION AND DAILY GLOBAL COVERAGE

5 [Bertram et al., GRL, 2005] SOIL NOx “EVENTS” pulsing over freshly fertilized Montana fields after rain event E NOx = f( T, biome, w/d) x Pulse (dryspell) x canopy uptake [Yienger and Levy, 1995] We extend this work to include U.S.: daily NARR Temp & Precip MODIS Landtype Fertilizer emissions [Ramankutty] ENO x 2005-2007

6 MONTHLY MEAN MODELED SOIL NO x EMISSIONS Dry, warm conditions  anomalously high June 2006 soil emissions Mean Yearly Total: 0.62 Tg N/yr (Fert: 0.12 Tg N/yr)

7 SOIL EMISSION CONTRIBUTION TO NO 2 COLUMN June 2006 SOIL COLUMN / TOTAL COLUMNSOIL S.D. / COLUMN S.D. SOIL COLUMN = TOTAL COLUMN – NO SOIL COLUMN GEOS-Chem global CTM (2x2.5)

8 OMI NO 2 JUNE INTERANNUAL VARIABILITY FOLLOWS SOIL NO x OMI June 2006 AnomalySoil NO model June 2006 June 2006 had lower than average lightning emissions, suggesting this was not a factor here

9 OMI NO 2 JUNE INTERANNUAL VARIABILITY FOLLOWS SOIL NO x 200520072006

10 LARGE PULSING EVENT SEEN IN OMI TIMESERIES OVER RURAL SOUTH DAKOTA Pulsing event reaches 4x10 15 molec cm 2, ~ 2 ppbv assuming 1km well mixed BL We can use OMI to test understanding pulsing triggers Future work: Test using Yan et al., [2005] & soil moisture based scheme developed at Dalhousie Univ.

11 OMI COLUMN NO 2 SCALED TO MODEL MEAN MODEL COLUMN NO 2 SOIL COLUMN NO 2 MODELED VARAIBILITY AND PULSING LIKELY UNDERESTIMATED Using updated retrievals should be able to compute magnitude of emission Column NO 2 MayJuneJuly

12 MEAN MAXIMUM 8-HR OZONE ENHANCEMENT DUE TO SOIL NO x Mean June maximum 8-hr ozone A lower bound, ozone enhancement due to soil NO x emission doubles from 3  6ppbv

13 Model Model No Soil NO 2 pulse in OMI SOIL NO x ENHANCEMENT IMPROVES LOW BIAS & CORRELATION WITH OBSERVED 8-HR MAX OZONE “SUBURBAN” SIOUX FALLS, SD

14 CONCLUSIONS Anomalously dry, warm conditions in June 2006 over the agricultural Great Plains increased observed tropospheric OMI NO 2 column by 30% likely due to a ~X2 increase in pulse driven soil NO x emissions. Daily OMI NO 2 columns can be used to refine our understanding of pulsing triggers Soil NO x emissions are predicted to enhanced mean surface 8- hr max ozone by 6 ppbv, compared with 3 ppbv for 2005 & 2007. A drier, warmer future climate is predicted over the Great Plains with implications for how efficiently soils retain nitrogen and ozone air quality.


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