Air Quality from a Quasi-Geostationary Orbit

PCW/PHEOS UV-VIS Spectrometer: Air 

Quality from a Quasi-Geostationary Orbit 

A geosynchronous-like view of the 

pole from a highly elliptical orbit 

C.T.McElroy, P. Rahnama, J.C. McConnell, C. Sioris, 

and the PHEOS Science Team* 

* PHEOS Science Team Members: 

CSA: M. Bergeron; York U.: B.H. Solheim, K. Semeniuk, 

Y.Chen, A. Lupu, I.C. McDade, J.J. Shan, W.F.J. Evans; 

U.Toronto: D. Jones, K. Strong, K. Walker, P.F. Fogal; 

Environment Canada: L. Garand, R. Nassar, Y. Rochon, 

C.`McLinden, R. Menard, D.S. Turner, A. Trichtchenko; 

Dalhousie U.: J. Drummond, R. Martin, T. Duck; 

U. Saskatchewan: D. Degenstein, A. Bourassa; U. Sherbrooke: 

N. O'Neill, A. Royer; HCO/SAO: K. Chance; ISPL, ULB: 

C. Clerbau; Carleton U.: A. Hakam; U. Waterloo: C. Boone; 

Xprime Consultants: J. Kaminski; Old Dominion U.: P. Bernath; 

RAL, UK: B. Kerridge; FMI: J. Tamminen; Yonsei U.: J. Kim; 

ECWMF: V.-H. Peuch; ABB H. Buijs.

Topics for Today 

• Proposed PCW Mission 

• Introduction to UV-Visible measurements 

• Rationale for highly elliptical orbit 

• Properties of the orbit 

• Observing strategy 

• Instrument synergy 

• Observation goals 

• Conclusion 

June 20, 2012 ESA ATMOS2012 

2

© ABB Remote Sensing – Space Activities 

2012-06-21 | Slide 3 

PHEOS team and authors 

Principal investigators 

–J.C. McConnell, York U. (science PI) 

–C.T. McElroy, York U. (UVS PI) 

–K.A. Walker, U. of Toronto (FTS PI) 

Responsibilities 

–ABB: Prime, IFTS 

–Science Team: Science 

–COM DEV: UVS 

ABB Team 

–Henry Buijs, Stéphane Lantagne, Louis Moreau, Michel 

Roux, Richard L. Lachance…. 


3


PCW 

• Polar communication satellite 

• Meteorological Imager (~21 channels) 

– Similar to ABI or MTG imagers 

• PHEOS Science package 

– Wide band imaging FTS 

– UV-Visible imager 

4


PHEOS 

• Polar, Highly Elliptical Orbit Science 

• A science package for PCW, the Polar 

Communications and Weather satellite 

• ABB Imaging Fourier Transform 

Spectrometer 

• UV-Visible imaging array detector 

spectrometer 

5

Primary Meteorological Products 

Data Product 

Horizontal 

Res. [km 2 ] 

Water vapor profile 10 × 10 (G) 

20 × 20 (T) 

Temperature profile 10 × 10 (G) 

20 × 20 (T) 


Vertical 

Res. [km] 

2 km (G) 

3 km (T) 

2 km (G) 

3 km (T) 

Precision Instrument 

10% FTS 

1°C FTS 

6

Instrument Spectral Range 

FTS 

(IR-NIR) 

UVS 

(UV-Vis) 

Spectral Regions 


Spectral 

Resolution 

Spatial 

Resolution 

Selected 

Species 

700 – 1500 cm –1 

1800 – 2700 cm –1 

5990 – 6450 cm –1 

13060 – 13168 

cm –1 

0.25 cm –1 

0.25 cm –1 

0.25 cm –1 

0.5 cm –1 

10 × 10 km2 H2O, T, CO, O3 , 

HNO3 , NH3 , 

CH4 , CO2 , CH4 , 

… 

Aerosols, Ps22 280 – 650 nm 1 nm 10 × 10 km2 O3, NO2, HCHO, 

BrO, SO2, … 

7

UVS 

Target 

Species 

O3 NO2 BrO 

OClO 

O4 H2O HCHO 

CHOCHO 

Aerosol 

optical 

depth 

Cross-sections [cm 2 ] 

1.0E-16 

1.0E-17 

1.0E-18 

1.0E-19 

1.0E-20 

1.0E-21 

1.0E-22 

1.0E-23 

1.0E-24 

1.0E-25 

SO 2 


OClO 

BrO 

CHOCHO 

O 3 

HCHO 

O 4 

NO 2 

H 2 O 

300.0 400.0 500.0 600.0 

280 nm Wavelength [280 to 650 nm] 650 nm 

8

Instrument Proposal 

• UV-Visible imaging spectrometer 

• 280 to 680 nm 

• Complement imaging FTS 

• Target measurements: 

• Ozone 

• Nitrogen dioxide 

• Bromine monoxide 

• Chlorine dioxide 

• Formaldehyde 

• Glyoxal 

• Oxygen dimer 

• Water 

• Aerosol optical depth (index) 


9

Orbit 

Determination 

LEO (Terra) 

Apogee: 703 km 

Perigee: 702 km 

Inclination: 98.2° 

Swath: 300 km 


Low-Earth Orbit (LEO) 

v. High-Earth Orbit 

HEO 

Apogee: 39851 km 

Perigee: 500 km 

Inclination: 63.4° 

Sensor: 4.5°× 4.5° 

More than 20 satellites in LEO are 

needed to match PCW coverage. 

10

TAP orbit chosen 

16h orbit is very good alternative 

candidate for PCW 

2012-06-21 

Latitude 

-90 

-180 

1x10 4 

Suggested apogees: 95°W, 25°E, 145°E 


Longitude 

2x10 4 3x10 4 

[Kilometres] 

3x10 4 

180 

11

2-D Imaging 

Scanning 

Pattern 

3200 km 

< > 


1-D 

Scanning 

Mirror 

3200 km 

The Imager provides a 2-D 

image with wavelength in 

one direction and a spatial 

dimension in the other. 

A mechanical scanner fills in 

the remaninig spatial dimension. 

12

Instrument 

Spectrometer Properties 

UVS 

Spectral Range 

[nm] 

280 - 650 

Resolution 

1 nm 


Pixel 

Size [km 2 ] 

10 x 10 

Target 

Species 

O 3 

NO 2 

SO 2 

BrO 

OClO 

HCHO 

CHOCHO 

Aerosol O.D. 

13

Target 

Species 

O 3 TC 

O 3 SC 

NO 2 TC 

NO 2 SC 


Performance 

Horizontal 

Resolution 

[km 2 ] 

10x10 G 

20x20 T 

10x10 G 

20x20 T 

10x10 G 

20x20 T 

10x10 G 

20x20 T 

Typical 

Column 

[mol-cm -2 ] 

8x10 18 

to 3x10 19 

3x10 17 

to 2x10 18 

10 15 

to 10 16 

10 14 

to 10 16 

Precision 

TC – Tropospheric Column G – Goal 

SC – Stratospheric Column T – Threshold 

3% G 

5% T 

5% G 

15% T 

3% G 

5% T 

1x10 15 G 

2x10 15 T 

14

Optics 

Scan Mirror 

Telescope 

Entrance Slit 

Offner 

Spectrometer 

Figures courtesy COM DEV International 


Three 

Mirror 

Anastigmatic 

Telescope 

> 

> 

< 

< 

Scanning 

Mirror 

Entrance 

Slit 

Array 

Detector 

Offner 

Spectrometer 

15

2012-06-21 

Optimal concept 

Address all science objectives 

Exceeds allocation 

PHEOS Instrument 

Satisfies goal sensitivity requirements 


All Band concept 

Address all science objectives 

Slightly exceed allocations 

Satisfies threshold sensitivity requirements 

Compliant concept 

Address priority science objectives 

Satisfies allocations 

Satisfies threshold sensitivity 

requirements 

16

This work was supported by the Canadian Space Agency, 

ABB, COM DEV International and York University 

Thank You for Your Attention 


17

Air Quality from a Quasi-Geostationary Orbit

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