# Presentation: 322966

## Band Residual Difference algorithm for retrieval of  SO2 from the AURA OMI 

- N. Krotkov1, S. Carn2, A. Krueger2 , P. K. Bhartia3 , K. Yang3
- Goddard Earth Sciences and Technology (GEST) Center, UMBC, Baltimore, MD
- Joint Center for Earth Systems Technology (NASA/UMBC), UMBC
- Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, MD
- 				With thanks to all the OMI Science and Support Teams

**Notes:**
Collaboration with UMCP group on validation provisional OMI SO2 data

## Global Sulfur Sources

|  | Northern Hemisphere | Southern Hemisphere | Global |
| --- | --- | --- | --- |
| Marine and Terrestrial DMS | 7.5 | 11.0 | 18.5 |
| Volcanic SO2 | 10.0 | 4.0 | 14.0 |
| Explosive degassing | 0.5-4 |  |  |
| Passive degassing | 5-10 |  |  |
| Biomass Burning | 1.0 | 1.5 | 2.5 |
|  Fossil Fuel Use 
 and Industry | 60.5 | 6.3 | 66.8 |
| TOTAL (S, Tg) | 79.0 | 22.8 | 101.8 |

- [Bluth *et al.*, 1993; Pyle *et al.*, 1996; Graf *et al.*, 1997; Andres & Kasgnoc, 1998]

**Notes:**
Sulfur dioxide is now recognized as the primary volcanic agent of climate change. 
SO2 is converted to a sulfate aerosol that has a long lifetime in the stratosphere. 
3) Emission inventories indicate that fossil fuel use and industry are predominant SO2 sources in NH
4) Space base industrial SO2 detection was previously demonstrated with GOME and SCIAMACHY UV spectrometers on ESA satellites
However, these sensors need several days to acquire a contiguous global map and hence could miss short-lived pollution events. 

## Ozone Monitoring Instrument (OMI )

**July 15 2004**

**July 15 2004**

- The NASA EOS Aura platform, launched on July 15, 2004, carries the Ozone Monitoring Instrument (OMI),  a hyperspectral UV/Visible spectrometer with a 2600 km swath for daily, global contiguous mapping that was provided by the Netherlands's Agency for Aerospace Programs (NIVR) in collaboration with the KNMI and Finnish Meteorological Institute (FMI) to the EOS Aura mission for continued monitoring of ozone and other trace gases.

**Notes:**
1) The NASA EOS Aura platform, launched on July 15, 2004, carries the Ozone Monitoring Instrument (OMI),[18],  a hyperspectral UV/Visible spectrometer with a 2600 km swath for daily, global contiguous mapping that was provided by the Netherlands's Agency for Aerospace Programs (NIVR) in collaboration with the Royal Netherlands Meteorological Institute (KNMI- PI institute) and Finnish Meteorological Institute (FMI) to the EOS Aura mission for continued monitoring of ozone and other trace gases 

2) The Ozone Monitoring Instrument (OMI) on EOS/Aura offers unprecedented spatial and spectral resolution, coupled with global coverage, for space-based UV measurements of sulfur dioxide (SO2). 

## OMI SO2 algorithm

- An OMI SO2        Band Residual Difference ( BRD) algorithm uses calibrated residuals at SO2 absorption band centers produced by the NASA operational ozone algorithm (OMTO3)
- [Bhartia et al 2002]

**Notes:**
an  Operational OMI SO2 algorithm (the Band Residual Difference or BRD algorithm) uses calibrated residuals at SO2 absorption band centers produced by the NASA operational ozone algorithm (OMTO3). 

## OMI SO2 provisional products released for validation in July 2005:

**  ****Explosive Eruptions: ****	****	****	****15km                                **
**2.  Passive degassing:  ****	****	****	****5km**
**3.  Anthropogenic SO****2**** pollution : PBL (<700mb)**

- Validation scientists are welcome to collaborate

**Notes:**
 OMI SO2 data are provisionally released for validation PIs and science team collaborators.

 In OMI algorithm the SO2 vertical distribution is assumed a-priori. 
 Explosive eruption SO2 data assumed to occur near tropopause height ~15km  (not critical assumption, since in stratosphere dependence on SO2 height is weak)
 Passive degassing So2 product assumes 5km height 
 Anthropogenic product  assumes uniform SO2 mixing  in the boundary layer below 700mb.
This is most critical assumption and needs validation with aircraft in situ data!

## TOMS climatic SO2 record from Explosive eruptions

- The AURA OMI SO2 volcanic data set will continue the TOMS SO2 record, which covers a quarter-century: http://toms.umbc.edu

## Anatahan eruption plumes

- OMI SO2 image of the Anatahan (Mariana Islands) eruption cloud on April 7, 2005, produced by an explosive eruption on April 6.
- White regions are meteorological clouds.

**Notes:**
1) The high sensitivity and contiguous coverage of OMI allows such emissions to be tracked for several days, providing opportunities for trajectory model validation.

2) OMI’s high sensitivity to SO2 also permits one to conclude with more confidence whether an explosive eruption has produced SO2 or if it has not (i.e. if it is a phreatic, or steam-driven event). This is very important in an aviation hazards context, since production of SO2 indicates a magmatic eruption with the potential for buoyant upper tropospheric or stratospheric (i.e. aircraft cruising level) plumes.

## Anatahan plume in July  2005, including the passage of some typhoons. 

- Anatahan plume in July  2005, including the passage of some typhoons.

**Notes:**
1) The high sensitivity and contiguous coverage of OMI allows such emissions to be tracked for several days, providing opportunities for trajectory model validation.
2) The movie of the Anatahan (Mariana Islands) plume in July  2005, including the passage of some typhoons. 

## OMI has permitted the first routine, space-based measurements of passive volcanic SO2 degassing 

- OMI SO2 image of passive degassing from Ambrym volcano, Vanuatu (16.25oS, 168.12oE) on February 20, 2005.

**Notes:**
The OMI BRD algorithm has permitted the first routine, space-based measurements of passive volcanic SO2 degassing (e.g., [25], [26]) in the lower troposphere. 

 Strong SO2 sources can be tracked on a daily basis with OMI (in the absence of significant cloud cover), 

whilst for weaker sources a successful approach has been to generate weekly or monthly averages of OMI SO2 data to increase the signal to noise ratio.

## Anatahan

- Manam

**MODIS and AIRS are part of NASA A-train satellite constellation in sun-synchronous afternoon orbit**

**OMI-SO2 (color bar) superimposed over high-resolution true-color composite map from AQUA-MODIS**

**CALLIPSO (LIDAR) and CloudSat on A-train will soon  provide  vertical  profiling of volcanic clouds**

- Soputan

**Notes:**

The high sensitivity and contiguous coverage of OMI allows such emissions to be tracked for several days, providing opportunities for trajectory model validation.

2) Clouds are true-color composite from AQUA-MODIS instrument, which is also part of NASA A-train satellite constellation

3) New additions to A-train: Callipso (Lidar) and Cloudsat (Radar)  instruments to be launched this year will provide vertical profile in eruption clouds for the first time

## Tropospheric SO2

**Notes:**
an interim OMI SO2 algorithm (the Band Residual Difference or BRD algorithm) uses calibrated residuals at SO2 absorption band centers produced by the NASA operational ozone algorithm (OMTO3). 

The SO2 vertical distribution should be known (or assumed) a-priori. This is most critical for tropospheric SO2.
Currently uniform mixing in assumed in the planetary boundary layer below 700mb.
 Data are provisional: released for validation Pis and science team collaborators
This needs validation with aircraft data.

## SO2 emissions from lignite-burning power plants in the Balkan region

**SO****2**** emissions ****from lignite-burning power plants in the Balkan region**

- SO2 enhancements observed by GOME  in February 1998            [Eisinger  and Burrows, GRL 1998].

- SO2 enhancements detected by OMI in February 2005

**Notes:**
1) SO2 enhancements detected by OMI in Eastern Europe in February 2005 correspond in both location and approximate column amount to GOME observations from February 1998 reported in Eisinger and Burrows [1998]. These SO2 emissions are sourced from lignite-burning power plants in the Balkan region.

2) Left: Enhanced SO  observed by GOME over the Balkans on 8 February 1998. The small dots indicate the locations of the largest thermal power plants burning lignite in Romania (Turceni, Rovinari, and Craiova, total 5065 MWe) and Bulgaria (Gulubovo and Radnevo, forming the Maritsa-Iztok complex, total 3485 MWe). Together, these plants represent 27 % of the electric power capacity installed in these countries [US Department of Energy].
Figure 4. Eisinger and Burrows [1998]

## SO2 burdens over China

** ****70% of China’s energy is derived from coal burning**
** ****SO2 emissions increased at a rate 35%/decade in 1979-2000**
** ****China’s sulfate aerosol loading has increased by 17%/decade in 1979-2000 [Massie, Torres and Smith  2004]**
** ****65,000 SO****2**** tons/day emitted in 1995 [Streets & Waldhof, 2000]**

**Notes:**
1) We have also achieved very promising measurements of anthropogenic SO2 emissions using the BRD algorithm.
 2) SO2 emissions have been measured by OMI over known sources of air pollution, such as the Ohio valley in the USA, eastern China, and Eastern Europe

Emission inventories indicate that:
 Largest increases in tropospheric SO2 emissions have occurred in Asia during the last 20 years 
(35% per decade over China between 1979-2000 [Massie et al 2004] )
2) This result in positive trends (17% per decade) in sulfate aerosol loading over China  in winter between 1979 and 2000.
3) This example shows that OMI can observe SO2 emissions in the planetary boundary layer (PBL) over China on a daily basis, thereby improving on GOME and SCIAMACHY, which need several days to acquire a contiguous global map and hence could miss short-lived pollution events. 

4) However, for quantitative burdens estimation, SO2 vertical profiles used in OMI algorithm need validation.

## Anthropogenic SO2 burdens in Asia 

** ****Norislk Nickel is one of Russia’s heaviest industrial polluters**
** ****World’s biggest producer of nickel and palladium**
** ****Plans to reduce SO****2**** emissions by 80-90% by 2015**

**Notes:**
1) for weaker SO2 sources a successful approach has been to generate weekly to  monthly to yearly averages of OMI SO2 data to increase the signal to noise ratio.

## Persian Gulf region 

** ****SO****2**** emissions associated with oil and gas refining in the Persian Gulf (Kuwait, Saudi Arabia, Iran, UAE)**
** ****Outgassing flares from oil fields in the Gulf produce detectable SO****2**

**Notes:**
1) for weaker SO2 sources a successful approach has been to generate weekly to  monthly to yearly averages of OMI SO2 data to increase the signal to noise ratio.

## Major SO2 sources in Africa:

**Major SO****2**** sources in Africa:**

**GOME observation of the time evolution of the SO2  plume over Nyamuragira volcano during its December 1996 eruption. **

- OMI: South African power plants (e.g., near Johannesburg); copper smelting

- Nyiragongo
- (DR Congo)

- More than 90% of South Africa's electricity is generated by the combustion of coal
-  Coal-fired power plants not required to use scrubbers to remove sulfur from emissions

**Notes:**
for weaker SO2 sources a successful approach has been to generate weekly to  monthly to yearly averages of OMI SO2 data to increase the signal to noise ratio.

Left: figure 2 from Eisinger and Burrows 1998: Time evolution of the SO  plume over Nyamuragira volcano (yellow triangle) during its December 1996 eruption. In order to visualize the extent of the volcanic SO  plume, three-day composites giving full ground coverage are shown. No background correction has been applied. GOME data are not available for 10 December. Before 1 Dec and after 18 Dec, no SO  above background levels could be observed. 
Nyamuragira and Nyiragongo are about 20 km apart. Nyamuragira erupts  sporadically (in 1996, 1998, 2000, 2001, 2002 and May 2004) but  Nyiragongo has been emitting SO2 constantly since late 2002. So only  the Nyiragongo emissions have been seen by OMI to date. 
More than 90% of South Africa's electricity is generated by the combustion of coal
 Coal-fired power plants not required to use scrubbers to remove sulfur from emissions

## South East Asia

- Anatahan (Mariana Is)

- Ambrym (Vanuatu)

- Manam (PNG)

**Notes:**
for weaker SO2 sources a successful approach has been to generate weekly to  monthly to yearly averages of OMI SO2 data to increase the signal to noise ratio.
This plot shows how OMI could directly compare degassing volcanoes vs anthropogenic emissions.

## Conclusions

- The OMI SO2 data set will continue the TOMS record but the improved sensitivity and smaller footprint of OMI will extend the range of detection to smaller eruptions and older clouds, and to degassing volcanoes.
- Anthropogenic SO2 emissions measured over China, Peru, USA (Ohio Valley), Europe, Central America, Uzbekistan.
- (Sources generally in agreement with 1985 GEIA database )
- Algorithm improvements are needed (realistic a-priori vertical SO2 and temperature profiles, bias, noise) before public release of anthropogenic SO2 data
- Validation collaborations are welcome

**Notes:**
1) These examples show that OMI can observe SO2 emissions in the planetary boundary layer (PBL) on a daily basis, thereby improving on GOME and SCIAMACHY, which need several days to acquire a contiguous global map and hence could miss short-lived pollution events. 

## backup

**Notes:**
an interim OMI SO2 algorithm (the Band Residual Difference or BRD algorithm) uses calibrated residuals at SO2 absorption band centers produced by the NASA operational ozone algorithm (OMTO3). 

The SO2 vertical distribution should be known (or assumed) a-priori. This is most critical for tropospheric SO2.
Currently uniform mixing in assumed in the planetary boundary layer below 700mb.
 Data are provisional: released for validation Pis and science team collaborators
This needs validation with aircraft data.

## Comparisons with GOCART model 

- GOCART model  monthly average SO2

- OMI cumulative SO2

- ( December 2001)

- ( December 2004 )

**Notes:**
 Left:  GOCART model monthly mean SO2 columns in December 2001 
 Right: OMI monthly cumulative SO2 burdens in December 2004
 OMI data will help improving SO2 sources characterization.

## Manam volcano eruption: January 27-28 2005

**Manam volcano eruption: January 27-28 2005**

- TOMS SO2

- OMI  SO2

- AIRS  SO2

**http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=16820**

## Sierra Negra eruption on October 23-25, 2005

**Notes:**
1) The high sensitivity and contiguous coverage of OMI allows such emissions to be tracked for several days, providing opportunities for trajectory model validation.

2) OMI’s high sensitivity to SO2 also permits one to conclude with more confidence whether an explosive eruption has produced SO2 or if it has not (i.e. if it is a phreatic, or steam-driven event). This is very important in an aviation hazards context, since production of SO2 indicates a magmatic eruption with the potential for buoyant upper tropospheric or stratospheric (i.e. aircraft cruising level) plumes.

## Africa 

**Nyiragongo**
**(DR Congo)**

** ****Major SO****2**** sources in Africa: Nyiragongo volcano (DR Congo); South African power plants (e.g., near Johannesburg); copper smelting **
** ****M****ore than 90% of South Africa's electricity is generated by the combustion of coal**
** ****Coal-fired power plants not required to use scrubbers to remove sulfur from emissions**

**Notes:**
1) for weaker SO2 sources a successful approach has been to generate weekly to  monthly to yearly averages of OMI SO2 data to increase the signal to noise ratio.