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Heidy Plata1, Ezinne Achinivu1, Szu-Ting Chou1, Sheryl Ehrman1, Dale Allen
2, Kenneth Pickering2♦, Thomas Pierce3, James Gleason 3
1Department of Chemical and Biomolecular Engineering2Department of Atmospheric and Oceanic Science
University of Maryland, College Park, Maryland♦Laboratory for Atmospheres, NASA Goddard Space Flight Center
3 Atmospheric Modeling and Analysis Division, NERL, US EPA, Research Triangle Park, North Carolina
Towards improved emissions inventories of soil NOx via model/satellite measurement
intercomparisons
UNIVERSITY OF MARYLAND
Outline
Current Problem Objectives Brief introduction to BEIS3 and satellite products
• Biogenic Emissions Inventory System• OMI-standard and OMI-DOMINO tropospheric
NO2 products Effect of precipitation on NO emissions Approach Discussion and Future Work
Current Problem
NOx contributes
Sources of NOx
Sources of Nitrogen Oxides
Biogenic
Anthropogenic
Modeling NOx emissions from biogenic sources poses a challenge as the frequency and magnitude of their emissions are uncertain.
Point Combustion Sources/Power Plants
Motor Vehicles
Lightning
Soil
Objectives
Develop a better understanding of soil based sources of nitrogen oxides
Evaluate whether satellite observations of NO2 can be used to improve emissions estimates for soil derived NOx
Use this understanding and satellite observations to improve model estimates of NOx emissions in BEIS3, which is the biogenic emission module used in CMAQ
Details about BEIS3
Soil NO emissions in BEIS3 are a function of:
• Land use and temperature
• Precipitation: Emissions can increase by up to a factor of 12 with heavy rain.
• Fertilizer: It doesn’t vary with region. Emissions are constant for first month of growing season (April) and then decrease
• Canopy: the canopy adjustment factor is 1 for the first 30 days of
the growing season then goes down linearly until it is 0.5 and then remains constant.
Details about BEIS3
Land use (crop) and temperature
Details about Ozone Monitoring Instrument (OMI) Tropospheric NO2 column
OMIOMI
NASA Standard Product
NASA Standard Product
KNMI DOMINO Product
KNMI DOMINO Product
Start with same slant column densities fromspectral fit of OMI observed radiances
Estimate stratospheric NO2 column using data from areas without significant tropospheric pollution. Interpolate globally using a wave-2pattern.
Use stratospheric Column NO2 from TM4 global chemical transport model.
AMF assumes annual mean vertical profiles from GEOS-Chem global model
AMF assumes daily vertical profiles from TM4 model
Effect of precipitation on NO emissions
If dry soil is wetted, a large burst, or pulse occurs and then decays rapidly over a period of time following the wetting event.
Wetting Drying
Nutrient Accumulation
NO
Effect of precipitation on NO emissions
<0.1 cm/day no pulse
0.1<rain<0.5 sprinkle (3 day pulse)
0.5<rain<1.5 shower (1-week pulse)
1.5<rain heavy rain (2 week pulse)
0
2
4
6
8
10
12
14
0 2 4 6 8 10 12 14 16
days following precipitation event
pre
cip
itati
on c
orr
ecti
on f
acto
r sprinkle
shower
heavy rains
Approach
Choose dates with likely
NOx soil emissions due to precipitation
Remove days with lightning or days
with aerosol index>1
Spring 2005(April6-May15)
Select regions in which Biogenic emissions are substantial compared to anthropogenic
North and South Dakota
Missouri and Arkansas
Approach
Evaluate response of BEIS3 emissions
and CMAQ tropospheric NO2
columns to precipitation events
Choose dates with likely
NOx soil emissions due to precipitation
Remove days with lightning or days
with aerosol index>1
Spring 2005(April6-May15)
Select regions in which Biogenic emissions are substantial compared to anthropogenic
Evaluate response of CMAQ
tropospheric NO2 columns using OMI-retrieved
columns
Time
Episode of April 11
Biog
enic(mol/s
)
Episode of April 11
Time
cm
/day
101
5 mo
lecules /cm2
Episode of April 11
Episode of April 12
Pre
cipi
tatio
n (
cm
/day
)
Biog
enic(mol/s
)
Time
Pre
cip
itatio
n (
cm
/da
y )
and
CM
AQ
(10^
15 m
olec
ules
/cm
^2)
Biog
enic(mol/s
)
Episode of April 12
Time
cm
/day
101
5 mo
lecules /cm2
Episode of April 12
Time
Episode of May 9
Biog
enic(mol/s
)
Time
Episode of May 9
Biog
enic(mol/s
)
Pre
cip
itatio
n (
cm
/da
y )
and
CM
AQ
(1015
mol
ecul
es /
cm2 )
Time
Episode of May 9
101
5 mo
lecules /cm2
cm
/day
Discussion
Analysis is hampered by lack of OMI data on days during and sometimes following rainfall events due to clouds.
For cases in which CMAQ tropospheric NO2 columns show the clearest response to increases in biogenic emissions:
• CMAQ high-bias relative to OMI increases after precipitation events implying that the sensitivity of BEIS3 soil emissions to precipitation events is overestimated at least for these cases
Firm conclusions must await analysis of additional cases.
Can additional cases be found in regions where the magnitudes of anthropogenic and biogenic emissions are comparable?
Episode of May 08
Biog
enic(mol/s)
Pre
cipi
tatio
n (
cm
/day
)
Biog
enic(mol/s)
Pre
cip
itatio
n (
cm
/da
y )
and
CM
AQ
(10^
15 m
olec
ules
/cm
^2)
Time
Episode of May 08
101
5 mo
lecules /cm2
cm
/day
Time
Episode of May 08
101
5 mo
lecules /cm2
cm
/day
Time
Discussion
For regions with a greater fraction of anthropogenic emissions, NO2 pulses reflected in BEIS3 output but response of CMAQ tropospheric NO2 columns is controlled by other factors
Suggests utility of our approach limited to rural regions
Future Work
Continue focus on Northern Great Plains and Upper Midwest Region
Expand analysis to include spring 2006 precipitation events
Re-run analysis with reprocessed OMI data Refine screening algorithms
Future Work
Refine method used to determine if tropospheric NO2 column response to changes in biogenic emissions is more than expected from normal day-to-day variations
Use satellite-derived adjustments to improve BEIS-3 emissions
Consider modifying BEIS3 to better resolve the magnitude and duration of soil NOx pulses associated with precipitation
Acknowledgments
Financial Support: NASA Applied Sciences Air Quality Decision Support System Program.
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