OMI Tropospheric NO2 in China

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OMI Tropospheric NO2 in China

• Dasa Gu
• EAS 6410

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NO2 in Troposphere

• Nitrogen dioxide is an important chemical species
  in both the stratosphere, where it plays a key
  role in ozone chemistry, and in the troposphere,
  where it is a precursor to ozone production. In
  the troposphere, it is produced in various
  combustion processes and in lightning.

(From SHODOR)
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Motivation

• Normally, understanding of NOx sources has been
  developed largely using the bottom-up approach,
  meanwhile, the tropospheric NO2 distributions
  measured by several satellite instruments in last
  decade provide very important information to
  constrain the bottom-up inventories.
• Richter et al. 2005 presented the tropospheric
  column amounts of NO2 retrieved from two
  satellite instruments GOME and SCIAMACHY over the
  years 1996-2004. They found a highly significant
  increase of about 50 over east China.
• Zhang et al. 2007 estimated bottom-up NOx
  emissions and its trend. Compared with the
  satellite observations, the growth rate from the
  bottom-up inventory is lower.
• Therefore
• 1. China is a hot area being concerned.
• 2. There is a new satellite observation
  OMI, started from 2004 and havent been used for
  trop-NO2 analysis in papers.
• 3. There is inconsistence between
  bottom-up inventory and satellite observations.

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Aura OMI  NO2 Observation

• The OMI NO2 data product, OMNO2, contains the
  observed slant column NO2 (total amount along the
  optical path from the sun into the atmosphere,
  and then toward the satellite), the total
  vertical column NO2 (cm-2), and the estimated
  tropospheric portion of the total column NO2
  (cm-2).

(From NASA)
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Trop-OMI NO2 in China

• North China Plain (NCP)
• Yangtze River Delta (YRD)
• Pearl River Delta (PRD)

112E 120E, 34N 40N 118E 122E, 20N
32.5N 112.5E 114E, 22N - 23.5N
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Trop-NO2 Concentration Variations
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Concentration Trend
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Conclusions

• OMI Troposheric NO2 shows there are three
  significant high value areas in China North
  China Plain, Yangtze River Delta and Pearl River
  Delta.
• Compared between three areas, PRD NO2
  concentration was higher than both NCP and YRD.
• NO2 concentrations increased from Sep to Nov at
  each 3 areas in every individual years.
• In NCP and YRD, NO2 concentration increased from
  2004 to 2007, while the value had a decreasing
  trend in PRD.

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Future Plans

• More months, cover the whole years.
• Sensitivity analysis.
• Compared with bottom-up inventory.