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P. K. Bhartia, Omar Torres, Nickolay Krotkov, Richard McPeters, Joanna Joiner
NASA Goddard Space Flight Center
Greenbelt, Maryland, USA
Measurement of Atmospheric Constituents from Space: History & State-of-Art
Satellite Techniques
Nadir-Viewing Instruments•Back-scatter UV/VIS/SWIR•Thermal IR (TIR)
Limb-viewing Instruments•Occultation (solar, lunar, stellar)
– UV, VIS, TIR
•Limb Emission– TIR, Microwave
•Limb Scattering– UV, VIS, SWIR
Merged Total Ozone Time Series (Frith et al., JGR 2014)
60S-60N
30S-30N
Fit to Eqv. Effect. Strat. Cl (EESC)
Diurnal Variation of Ozone (MLO MWR)
3 hPa Ozone Time Series
60S-60N
30S-30N
SCIAMACHY
Profile Shape Error in TOMS Total O3
Nadir View, March (sza≈lat)
85˚ sza
75˚ sza
Estimated using ozonesonde climatology (mean & covariance)
Comparison of Tropospheric Column Ozone Derived by Combining MLS and OMI
2005-2012 JJA average
Data Assimilation Trajectory Method
Direct retrieval- no MLS Model
Assessment of Space-based O3 Measurements
• Total O3
– Quality of data from BUV instruments is now roughly comparable to that from Double Brewers, which are considered the “gold standard”.
• Strat O3 Profile– Limb/occultation instruments provide high quality data
above 20 km in tropics, 15 km elsewhere.
• Trop O3 Profile
– Good quality trop O3 column, but profile information is limited.
Volcanic SO2 Record
Operational Products
• O3 Vertical Profiles (cloud top to 60 km)– 7000/day, 84S-84N, daylight only
– ~1.8 km vert res, 1 km sampling
– Number density vs alt profiles are primary
– Mixing Ratio vs p produced using assimilated GPH and temp data from NASA GMAO, which compares well with Aura/MLS
– Aerosol scattering inde at 350, 510 & 650 nm
• Aerosol Profiles (cloud top to 35 km) – Extinction at 750 and 500 nm & size info
Decrease in SO2 over the Eastern US
The Ozone Monitoring Instrument (OMI) data confirm a substantial reduction in sulfur dioxide (SO 2) values around the largest US coal power plants as a result of the implementation of SO2 pollution control measures. The figure shows average SO2 values measured by OMI on the NASA Aura spacecraft for the periods 2005-2007 and 2008-2010 over the Eastern US where the majority of large SO2 sources are located. Scientists use this information to identify anthropogenic sources of SO 2 and to estimate their emission rates. The greatest values are in violet; the lowest in green. Yellow to violet colors correspond to statistically significant enhancements in SO2 pollution in the vicinity of largest SO2 emitting coal-burning power plants indicated by the black dots.
Previous use of space-based SO2 retrievals has been limited to monitoring plumes from volcanic eruptions and detecting anthropogenic emissions from large
source regions as in China. A new spatial filtration technique allows detection of individual pollution sources in Canada and US.
Mean SO2 values for 2005-2007 Mean SO2 values for 2008-2010
0 2.7 10 molecules/cmx 16 2
power plants
Fioletov, V., et al., (2011), Geophysical Research Letters,
Increase over India
Lu, Zifeng, David G. Streets, Benjamin de Foy, and Nickolay A. Krotkov, Ozone Monitoring Instrument Observations of Interannual Increases in SO2 Emissions from Indian Coal-Fired Power Plants during 2005−2012, Environmental Science and Technology, 2013
There has been a rapid decrease in NO2 pollution in the US.
Rate of decrease in the past decade is - 4%/year.
17
• Chinese NOx emissions and NO2 pollution is growing almost at a pace similar to the nation’s GDP: +7%/year
• NO2 pollution over India is also increasing +2%/year.
SNPP/Ozone Mapping & profiler Suite (OMPS)
nadir profiler
nadir mapper
limb profiler
Launched Oct 28, 2011 on Suomi NPP
Limb Scattering Technique
Line of sightTangent point
Tangent heightDiffuse upwelling radiation
Solar Radiation
Comparison with Aura MLS- Center slit
% difference (LP- MLS)
The current LP algorithm doesn’t have an explicit correction for strat aerosols
Comparison with ACE-FTS
__LP, __ACE
% Difference (LP-FTS) Diurnal effect: negative differences above ~45 km, positive near 40 km.
Std Dev of difference (%)
Comparison with High Trop Ozonesondes
35N, 87W21S, 56E
LP has ~ 1.8 km vertical and ~200 km horizontal res
Comparison with Payerne (47N, 7E) Ozonesondes
Comparison with Antarctic Ozonesondes
71S, 8W 69S, 40E
Aerosol Extinction Profiles- March 2013
Log Scale Linear Scale
Planned Instruments with BUV capability
• Deep Space Climate Observatory (DSCVR): Launch early 2015– Located at 1st Lagrange Point (1.5 million km from
Earth along the sun-earth line) to provide hourly global coverage- useful for erythemal UVB
• Sentinel 5P/TropOMI (~2016)– OMI-like products with 7 km horizontal resolution
• Geostationary Instruments (2018-2020)– TEMPO (US), GEMS (S. Korea), Sentinel 4 ( ESA)
Comparison of Satellite Total O3 Record (30S-30N)
OMI
GOME/SCIA
SBUV
GOME/SCIA-SBUV OMI-SBUV
OMI/SBUV Differences are due to use of different O3 abs x-section
High Latitude Comparison (55N-60N)
GOME/SCIA-SBUV OMI-SBUV
Key ConclusionQuality of total O3 record from satellite BUV sensors is becoming comparable
of that from best quality ground station
Altitude vs. Distance Along LOS
1.5 km
196 kmTangent Ht.
x
z
IFOV
x