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The main objective:

Microphysical properties of clouds Flight AS0725 14/07/07 12:11-13:52 UTC Krakovska Svitlana, Jarecka Dorota, Drzewiecki Piotr, Freud Eyal, Oprea Carolina, Ivanov Vladimir Petrov. The main objective:

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The main objective:

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  1. Microphysical properties of cloudsFlight AS0725 14/07/07 12:11-13:52 UTCKrakovska Svitlana, Jarecka Dorota, Drzewiecki Piotr,Freud Eyal, Oprea Carolina, Ivanov Vladimir Petrov

  2. The main objective: To obtain vertical profiles of droplet size distributions (DSD) in warm convective clouds and relate them to aerosol measurements below cloud base To achieve the main objective we intended: To make a vertical sounding in cloudless sky for reference; To document microphysical properties of the existing clouds at different levels to be able to produce in-cloud vertical profiles; To measure aerosol properties below cloud base; Optional: To identify different aerosol properties in the PBL in our research area, and penetrate clouds which are believed to form downwind from these different areas; To measure radiation over and below the cloud (horizontal flight) We developed different working methods for 3 scenarios: Stratocumulus cover Patches of small cumulus clouds More or less isolated well-developed Cumuli

  3. Flight plansampling method for preferred scenario ` • Visual criteria for choosing the “right” cloud (a developing young convective cloud) • 4-5 horizontal penetrations into the cloud at different levels (ΔZ depends on the cloud depth) • Aerosol measurements below cloud base • Choosing the next cloud

  4. Flight plan – Area of interest

  5. Just before takeoff… To help us choose the most suitable scenario Satellite image in visible wave length 14/7/07 11:30 UTC Picture taken from Iasi airport towards the north @ 14/7/07, 11:45 UTC

  6. In the air… Scenario 3 chosen Who wants to be our victim ..? Pictures taken ATR-42 cruising at 15,000 ft on 12:37 UTC, 14/7/07 Some of the suitable clouds were outside our domain

  7. Our pilots didn’t drink – they took us where we told them to Flight from our child dreams (or nightmares ????)

  8. Preliminary Results(or what have we done thus far…) Sounding during ascend Vertical Sounding during ascend 12:11-12:35 UTC

  9. Preliminary Results (cont.) Sounding during ascend • Some “noise” in data due to periodic opening of the aerosol inlet • Generally decreasing concentrations with H. PBL height

  10. Preliminary Results (cont.) Zoom on Flight track. Colors show elevation in feet. Black rectangles represent LWC Examples: Cloud 3 Cloud 2 & 2b

  11. Preliminary Results (cont.) Organization and summary of cloud penetration data:

  12. Preliminary Results (cont.) LWC measurements vs. Altitude: Offset: Gerber: +0.27 g/m-3 King: -0.18 g/m-3 • King seems to underestimate LWC • Gerber seems to overestimate LWC since readings are larger than possible Adiabatic water • We will integrate LWC mass from FSSP distribution for verification • King and Gerber correlate fairly nice (different measuring technique) • King seems to saturate because of breaking of larger droplets

  13. Preliminary Results (cont.) • Highest vertical velocities in clouds (both positive and negative) • Hint for the collapse of cloud 1

  14. Preliminary Results (cont.) • During flight at a constant height (5 kft) the aerosol mass and number concentration (calculated from GRIMM recorded size distribution) don’t vary much throughout the region Concentration and mass are derived from the size distributions Larger variations in small sizes show the importance of measuring smaller particles that can serve as CCN • Mass is ~5 µg m-3 • Number concentration is 150-200 cm-3

  15. Preliminary Results (cont.) Apparently there’s a problem with CCN counter. Concentration should increase with Supersaturation!!!

  16. Further Work • Receive FSSP data • Derive from FSSP data parameters such as: cloud droplet concentration (Nd), effective radius (Re) and LWC, to compare with other LWC measurements and relate to aerosol concentrations • Try to find a relation between the rate of Re increase with cloud depth and Nd • Compare Droplet Size Distributions (DSD) in different altitudes and LWC • Compare our findings with similar measurements from other places and with a cloud resolving 1-D model • Have some sleep…

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