1. Sub-mm Spectroscopic Observations from the JCMT: Composition, Chemistry and Winds at km B. Sandor, T. Clancy, G. Moriarty-Schieven, & F.P. Mills
Ground-based coordination
Experience gained from past coordination
Science case for coordinated measurements
Strategy for next MTP/semesters
Science Questions raised at Aussois:
Discrepancies:
Between ground-based (sub-mm) and SpicaV measurements of SO2 above 85 km
Between ground-based (submm) and SpicaV Temperatures at km
Between submm and 10 micron zonal winds
Atmospheric Dynamics Measurements: Extreme time variation of wind fields
Highly variable SO2
SO2 + SO by Factor > 10
SO2/SO by Factor of 100

2. Sub-mm Methods & Capabilities
Observations near 345 and 690 GHz
Spectral resolution = 107
Horizontal spatial resolution = 14” (345 GHz) to 8” (690 GHz)
Parameters measured:
Winds: km; 6 km vertical resolution
CO abundance: km; 6-10 km vert. resolution
Temperature: km; 6-10 km vert. resolution
SO2 and SO abundances: km, 15 km vert. resolution
HDO: km. 30 km vert. resolution

3. Experience from Past Coordination
Wind measured simultaneously at km (submm) and cloud tops (CFHT; T. Widemann).
Science gain would be improved if km winds were also measured.
Wind measured simultaneously at km (submm) and 110 km (10 micron; G. Sonnabend + M. Sornig).
Winds at coincident points agree.
Zonal wind strengths do not. Most probable explanation derives from difference in techniques applied to submm and 10 micron data

4. Future Coordination
CO and temperature at km (submm) will be measured simultaneously with 95 km O2(1Δg) (1.27 microns; S. Ohtsuki) in Sept 2010.
Temperatures will be compared directly.
Locally enhanced CO and O2(1Δg) are each associated with downward transport. Comparison will illuminate dynamics.
Winds at km (submm, JCMT) and similar altitude (mm, CARMA; H. Sagawa) will be measured simultaneously.
Larger altitude range (JCMT) and better horizontal resolution (CARMA) imply that JCMT and CARMA give more information in coordination than alone.

5. Science Case for Coordination
Examples discussed on previous 2 slides
make the case.

6. Sub-mm Observations => Wind Field Time- Variation is Large
Zonal (below left) and SSAS (below right) winds each show large variations.
Rapid change is common, and can be as fast as a 2x change in 4 hours (figure to right).

7. 110 km Zonal Wind Discrepancy between sub-mm & 10 μm analyses
Wind measurements at coincident points agree (M. Sornig + G. Sonnabend).
Zonal wind speeds over the visible disc do not.
Submm zonal wind varies 0 to 150 m/s.
10μm zonal wind is near 0 m/s.
Possible reasons include:
Submm data are night vs 10 μm are dayside
Data volume: 12 sub-mm, vs 2(?) ten μm determinations.
Temporal variation: Sub-mm wind maps are obtained in 1 hour. 10 μm wind maps involve observations separated by 2 weeks or more.

8. 95 km Nightside Temperature Discrepancy between sub-mm & SPICAV
SPICAV measures a warm layer not seen in sub-mm data.
SPICAV inconsistent with sub-mm [Clancy et al.], mm [eg Lellouch et al.], PV Orbiter, PV descent probes, and O2(1Δg) 1.27 μm [eg. Ohtsuki et al.] data.

9. Sub-mm Observations => Extreme Time Variations of [SO2+SO] & [SO2/SO]
[SO2 + SO] varies more than 10x, with no diurnal dependence (below left).
[SO2/SO] varies 5x during the day, 5x at night, and 100x between night and day (below right).

10. 85-110 km SO2 discrepancy between sub-mm & SPICAV
Sub-mm ground-based measurements find:
km SO2 abundance varies 0 ±2 to 74 ±9 ppbv.
km SO2 abundance upper limit is 100 ppbv.
SPICAV finds 10x more SO2 than do submm data, with no reported time variation.

11. Interpreting JCMT vs SPICAV SO2
Temperature: Temperature uncertainties are not relevant to JCMT vs SPICAV SO2 disagreement. To make SPICAV consistent with submm SO2, nightside temperatures ~260 K at km would be required.
Time: SPICAV and JCMT data are not simultaneous, but in >30 measurements since 2004, we never see SPICAV-like km SO2. Temporal variability can not explain JCMT vs SPICAV SO2 inconsistency.
Spatial scale: JCMT’s smallest beam width is 4000 km, much larger than SPICAV’s spatial scale. If large km SO2 abundances are spatially small, infrequent phenomenon, then JCMT would not see them. However, if SPICAV’s very large km SO2 abundances are common, then differing spatial resolutions cannot explain our SO2 disagreement.
Time of Day: SPICAV solar occultation data measurements are of the twilight atmosphere. JCMT data have insufficient spatial resolution to isolate the terminator. If thermospheric SO2 abundance has strong, brief increase at the day-night transition, SPICAV would see it and JCMT would not.

12. -->In 2006 and 2007 (bottom figures), large (>300%) AM increases in northern (2006) and southern (2007) CO mixing ratios were observed. -->In 2002 and 2004 (top figures), CO variations in the lower thermosphere were much reduced (~50%) and peak abundances are centered on the anti-solar point. -->Remarkably, the large diurnal, north-south variations in [CO] in 2006, 2007 extend deep into the mesosphere to below the 1 mbar pressure level (85 km altitudes).

14. Conclusions
Since 2004, we have observed Venus sub-mm SO and SO2 lines from the James Clerk Maxwell Telescope (JCMT). These lines exhibit remarkable global variations in mesospheric SO2, SO, SOx (SO2+SO), and SO2/SO, both diurnally and on a timescale ≤ 1 week.
SPICAV km SO2 is not consistent with JCMT SO2.
Discoveries include:
Diurnal behavior: There is more SO2’ and less SO, in night than day.
Secular behavior includes 2x variation of both SO2 and SO.
Total SOx [SO2+SO] varies more than 10x.
The ratio [SO2]/[SO] varies almost 100x.
Both SO2 and SO are altitude increasing, with more at km than at km. This requires an unanticipated in-situ upper mesospheric source for SOx.

15. REFERENCES
Sandor and Clancy. Water variations in the Venus Mesosphere from Microwave Spectra. Icarus v
Sandor et al.. SO and SO2 in the Venus mesosphere: Observations of extreme and rapid variation. Bull. Am. Astron. Soc. 39, 503. Abstract
Sandor et al. Diurnal and altitude behavior of SO and SO2 in the Venus mesosphere. Bull. Am. Astron. Soc. 40, 514. Abstract
Sandor, Clancy, Moriarty-Schieven, and Mills. Sulfur Chemistry in the Venus Mesosphere from SO2 and SO Microwave Spectra. Icarus, 208. pp
Belyaev et al.. First observations of SO2 above Venus clouds by means of Solar Occultation in the Infrared. J. Geophys. Res E00B25. doi: /2008JE
Bertaux et al. A warm layer in Venus cryosphere and high- altitude measurements of HF, HCl, H2O and HDO. Nature 450, 646–
Wilquet, et al. Preliminary characterization of the upper haze by SPICAV/SOIR solar occultation in UV to mid-IR onboard Venus Express. J. Geophys. Res E00B42. doi: /2008JE
Yung, Y.L., DeMore, W.B. Photochemistry of the atmosphere of Venus: Implications for atmospheric evolution. Icarus 51, 199–

16. Author Affiliations:
Sandor and Clancy at: Space Science Institute, Boulder, CO.
Moriarty-Schieven at: National Research Council of Canada, Joint Astronomy Centre, Hilo, HI.
Mills at: Research School of Physics and Engineering, and Fenner School of Environment and Society,Australian National University, Canberra, ACT, Australia.
Observatories:
The Kitt Peak 12m Telescope is a facility of the National Science Foundation currently operated by the University of Arizona Steward Observatory under loan agreement with the National Radio Astronomy Observatory.
JCMT: The James Clerk Maxwell Telescope is operated by the Joint Astronomy Centre, Hilo, HI. Operations supported by PPARC-United Kingdom, NRC-Canada, and NOW-Netherlands.