1. Role of aqueous aerosol in the build up of large upper tropospheric moisture Anatoli Bogdan Institute of Physical Chemistry, University of Innsbruck Austria and Department of Physics, University of Helsinki Finland

2. Contents Introduction - observational data of UT moisture - water activity criterion Approaches for explanation of large UT moisture - cubic ice hypothesis - organic coating around sulfuric acid aerosol - glassy organic (citric acid) aerosol - mixed-phase cirrus cloud particles

3. Observations of UT moisture

4. The warming is large at the upper troposphere in the tropics and the lower troposphere in the northern high latitude. http://www.mri-jma.go.jp/Dep/cl/cl4/yosoku/yosoku-en.htm

5. Water activity criterion

6. Maximum RH i of aqueous aerosol droplets which is allowed by a water activity criterion (WAC).

7. Equilibrium partial pressures of the components of ideal and non-ideal binary solution as a function of the mole fraction X A. When X A → 1, we have a dilute solution of B in A. In this region the Raoult’s law p A = X A p* A is applied for A. In the region where X A → 0, we have the Raoult’s law p B = X B p* B for B component.

8. , Water activity may be approximated as

9. Cubic ice hypothesis

10. Hexagonal ice

11. The arrangement of water molecules in hexagonal ice

13. Cubic ice Hexagonal ice lattice

14. Diffraction patterns from frozen emulsified droplets of 30 wt % HNO 3.

15. Ratio of vapor pressure of cubic and hexagonal ices

16. The hypotheses of organic coating around sulfuric acid aerosol

17. Organic coating of sulfuric acid aerosol

18. The hypotheses of concentrated glassy citric acid aerosol

20. Calorimetric thermograms of emulsified 17 wt% H 2 SO 4 and 17/3 wt% H 2 SO 4 /HNO 3.

21. Complete and truncated thermograms of 20wt% H 2 SO 4.

22. 16 Cooling Droplets are on hydrophobic surface. 50 μm

23. 17 Cooling

24. 18 Cooling

25. 19 Cooling

26. 20 Cooling

27. 21 Cooling

28. 22 Cooling

29. 23 Cooling

30. 39 Warming

31. 40 Warming

32. 41 Warming

33. 42 Warming

34. 43 Warming

35. 44 Warming

36. 45 Warming

37. 46 Warming

38. 47 Warming

39. 48 Warming

40. 49 Warming

41. 50 Warming

42. 51 Warming

43. 52 Warming

44. 54 Warming

45. 55 Warming

46. 56 Warming

47. 57 Warming

48. 58 Warming

49. 62 Warming

50. 65 Warming