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An Evaluation of the UWNMS Treatment of Water Vapor Transport and Cirrus Formation in the UT/LS

An Evaluation of the UWNMS Treatment of Water Vapor Transport and Cirrus Formation in the UT/LS. Monica Harkey, UW-Madison Matthew Hitchman, Marcus Buker. Hypothesis and method.

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An Evaluation of the UWNMS Treatment of Water Vapor Transport and Cirrus Formation in the UT/LS

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  1. An Evaluation of the UWNMS Treatment of Water Vapor Transport and Cirrus Formation in the UT/LS Monica Harkey, UW-Madison Matthew Hitchman, Marcus Buker

  2. Hypothesis and method • Changes in tropical cirrus microphysics caused by emissions from biomass burning may (partly) explain moistening of the lower stratosphere • UWNMS model runs with control and perturbed ice microphysics will show first-order effects on the distribution of water vapor in the UT/LS

  3. The volumes of interest … … in the vertical

  4. The volumes of interest … … in the horizontal Jensen et al., 2001

  5. Where the cirrus are—SAGE Wang et al., 1996

  6. Where the cirrus are—LITE Winker and Trepte, 1998

  7. How tropical cirrus form • wave motions • from convective influences (anvils, pileus) • large-scale, slow uplifting

  8. How clouds affect water vapor in the UT/LS Rosenfield et al. (1998)

  9. ? The “knowns:” • Water vapor in the lower stratosphere is increasing (Rosenlof et al., 2001) • Cirrus near the tropopause affect water vapor transport into the lower stratosphere • Cirrus occur near tropical tropopause frequently

  10. Tropical biomass burning—Africa Image taken by Bob Yokelson during SAFARI campaign, southern Africa in 2000

  11. Tropical biomass burning—South America MODIS image from 22 July 2003, showing fires surrounding Xingu National Park (and indigenous peoples reserve), Brazil

  12. Where biomass burning products were measured:

  13. How do we know biomass burning was really the source?

  14. Where did the material go?

  15. What are some properties of biomass-burning plumes?

  16. What are some properties of biomass-burning plumes? Kojima et al., 2004

  17. How can combustion materials affect ice clouds? • Kojima et al. (2004) found organics abundant in upper troposphere, many sulfate aerosols embedded with organics • Measurement techniques can destroy molecules (Cziczo et al., 2004) • Cziczo et al. also noted organics appear to be inefficient IN

  18. biomass burning emissions? The “knowns:” • Water vapor in the lower stratosphere seems to be increasing • Cirrus near the tropopause affect water vapor transport into the lower stratosphere • Cirrus occur near tropical tropopause frequently

  19. the UWNMS … • Arbitrary resolution—used 400 m in the vertical, 30 km in the horizontal • Non-hydrostatic model especially needed in region of study For more information on this model, written by Prof.Greg Tripoli, visit: http://mocha.meteor.wisc.edu/

  20. … the UWNMS … • ECMWF 12-hour, 2.5 x 2.5 degree winds, temperature, and moisture up to 200 hPa • HALOE latitude-binned and pressure-averaged water vapor at and above 200 hPa • Explicit microphysics predict concentration of pristine crystals, aggregates • convective parameterization using Kuo scheme

  21. … the UWNMS and idealized IN … • Control run: pristine crystals initialized at 1 μm (6.4 x 10-12 grams for hexagonal plate) • Perturbed run: crystals initialized at 0.45 μm (9.1 x 10-13 grams)

  22. Pristine crystal concentration at 13.5 km 24 hours into run Control run Perturbed run

  23. Pristine crystal concentration at 13.5 km 30 hours into run Control run Perturbed run

  24. Pristine crystal concentration at 13.5 km 36 hours into run Control run Perturbed run

  25. Pristine crystal concentration at 13.5 km 42 hours into run Control run Perturbed run

  26. Pristine crystal concentration at 13.5 km 48 hours into run Control run Perturbed run

  27. Pristine crystal concentration at 14.5 km24 hours into run Control run Perturbed run

  28. Pristine crystal concentration at 14.5 km30 hours into run Control run Perturbed run

  29. Pristine crystal concentration at 14.5 km36 hours into run Control run Perturbed run

  30. Pristine crystal concentration at 14.5 km42 hours into run Control run Perturbed run

  31. Pristine crystal concentration at 14.5 km48 hours into run Control run Perturbed run

  32. Pristine crystal concentration at 15.5 km24 hours into run Control run Perturbed run

  33. Pristine crystal concentration at 15.5 km30 hours into run Control run Perturbed run

  34. Pristine crystal concentration at 15.5 km36 hours into run Control run Perturbed run

  35. Pristine crystal concentration at 15.5 km42 hours into run Control run Perturbed run

  36. Pristine crystal concentration at 15.5 km48 hours into run Control run Perturbed run

  37. What does this mean, in bulk?

  38. Water vapor difference at 13.5 km

  39. Water vapor difference at 14.5 km

  40. Water vapor difference at 15.5 km

  41. The difference in water vapor between control and perturbed runs

  42. Summary As expected, • crystal mixing ratios higher in perturbed run, with smaller (0.45 micron) initial size • “cloud” extent between control, perturbed runs varies • ice initialized with a smaller crystal size results in an increase of water vapor mixing ratio within and above clouds

  43. Direction for the future • Fashion idealized “gunk”—biomass burning derived IN—to be activated at a specific T, q and interact with water vapor in the UWNMS • Conduct sensitivity studies with varying concentrations—how do cloud properties, water vapor distribution change?

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