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In Situ Validation of the Suppression of Rain by Smoke from Forest Fires in the Amazon D. Rosenfeld and A. Khain (1), A. A. Costa (2), J. C. P. de Oliveira.

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Presentation on theme: "In Situ Validation of the Suppression of Rain by Smoke from Forest Fires in the Amazon D. Rosenfeld and A. Khain (1), A. A. Costa (2), J. C. P. de Oliveira."— Presentation transcript:

1 In Situ Validation of the Suppression of Rain by Smoke from Forest Fires in the Amazon D. Rosenfeld and A. Khain (1), A. A. Costa (2), J. C. P. de Oliveira (3), M.O. Andreae (4), P. Artaxo (5) 1.Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel 2.Universidade Estadual do Ceará, Av. Paranjana, Campus do Itaperi - Fortaleza - CE / CEP , Brazil, 3.Universidade Federal do Ceará, Campus do Pici, Caixa Postal 6030 – Fortaleza-CE / CEP , Brazil 4.Biogeochemistry Department, Max Planck Institute for Chemistry, P.O. Box 3060, D Mainz, Germany 5.Instituto de Fisica, Universidade de Sao Paulo, Rua do Matao, Travessa R, 187, CEP , Sao Paulo, Brazil

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3 VIRS+PR, Amazon, SEP 14:15 VIRS T-Re TOMS Aerosol Index 13 September 1998 Note that clouds do not precipitate before reaching height of 6.5 km or –12 o C isotherm, while containing ample cloud water. The “Green Ocean” turns dry: Smoky clouds over the Amazon

4 Note the shallow precipitating clouds, extensive warm rainout, glaciation at T>-10 o C, and few lightning TRMM VIRS+PR, Amazon, :28 VIRS T-Re The “Green Ocean”: Maritime clouds over the Amazon

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7 North of Ji Parana, 4 October 2002, 16:03 GMT. Moderate smoke,

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9 MODIS AQUA, 7S-12S, 62W-66W, 4 October 2002, 17:50 GMT.

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12 Near Cruzeiro do Sul, 4 October 2002, 22:10 GMT. Warm Rain, 2.5 km

13 MODIS AQUA, 5S-10S, 64W-71W, 4 October 2002, 17:50 GMT.

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19 Many more droplets for the same supersaturation Summary of CCN Spectra

20 Smoky Clean Smoky Clean

21 Smoky Clean Smoky Clean

22 Smoky Clean Smoky Clean

23 Smoky Clean Smoky Clean

24 Smoky Clean Smoky Clean

25 Smoky Clean Smoky Clean

26 Smoky Clean Smoky Clean

27 Smoky Clean Smoky Clean

28 Smoky Clean Smoky Clean

29 Smoky Clean Smoky Clean

30 Smoky Clean Smoky Clean

31 Smoky Clean Smoky Clean

32 Smoky Clean Smoky Clean

33 Smoky Clean Smoky Clean

34 Smoky Clean Smoky Clean

35 Smoky Clean Smoky Clean

36 Smoky Clean Smoky Clean

37 Smoky Clean Smoky Clean

38 Smoky Clean Smoky Clean

39 Smoky Clean Smoky Clean

40 Smoky Clean Smoky Clean

41 Smoky Clean Smoky Clean

42 The smoke decreases the rainfall amounts.

43 The smoke increases the updrafts intensity.

44 Conclusions 1.The aircraft measurements in clean and smoky clouds, up to the 0 o C isotherm confirm and strengthen the previous satellite inferences of smoke suppressing warm precipitation in convective clouds. 2.Apparently the giant ash CCN are not significant in initiation of warm rain, even in pyro-cumulus. 3.Model simulations replicate the aircraft measurements and extrapolate them to greater heights in the clouds, supporting the observations that smoky clouds have to exceed the -10 o C isotherm level for start precipitating. 4.Simulations show that smoky cumulonimbus produce less precipitation than clean clouds under the same conditions. 5.However, the updrafts velocities in smoky clouds are stronger and supercooled water content is greater, providing better conditions for cloud electrification.

45 The classification scheme of convective clouds into microphysical zones according to the shape of the temperature – effective radius relations Note that in extremely continental clouds r e at cloud base is very small, the coalescence zone vanishes, mixed phase zone starts at T<-15 o C, and the glaciation can occur at the most extreme situation at the height of homogeneous freezing temperature of –39 o C. In contrast, maritime clouds start with large r e at their base, crossing the precipitation threshold of 14  m short distance above the base. The deep rainout zone is indicative of fully developed warm rain processes in the maritime clouds. The large droplets freeze at relatively high temperatures, resulting in a shallow mixed phase zone and a glaciation temperature reached near –10 o C


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