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A First Look at Mid-Level Clouds Using CloudSat, CALIPSO, and MODIS Data

Study to improve mid-level cloud forecasts through CloudSat, CALIPSO, MODIS. Learnings on supercooled liquid, ice content, cloud structures. Analysis of mixed-phase cloud data and validation effort. Importance of increased vertical resolution in NWP models for reliable cloud prediction.

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A First Look at Mid-Level Clouds Using CloudSat, CALIPSO, and MODIS Data

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  1. A First Look at Mid-Level Clouds Using CloudSat, CALIPSO, and MODIS Data Stanley Q. Kidder, J. Adam Kankiewicz, Thomas H. Vonder Haar Cooperative Institute for Research in the Atmosphere Colorado State University Vincent E. Larson Department of Mathematical Sciences University of Wisconsin–Milwaukee Lawrence D. Carey Department of Atmospheric Sciences Texas A&M University Denise E. Hagan Northrop Grumman Space Technology Redondo Beach, CA

  2. Why We Care about Mid-Level Clouds • They obstruct visibility • Supercooled water clouds pose an icing hazard for aircraft, particularly unpiloted aircraft • They are poorly forecast by NWP models • They provide a simple laboratory with which to study the interaction of latent heating, microphysics, radiation, and turbulence

  3. Mid-level Cloud Modeling Studies Goal: To help identify (and improve) forecast model deficiencies that inhibit reliable mid-level cloud forecasts Motivation: Current NWP models do a poor job of mid-level cloud prediction Need increased vertical resolution in NWP models to resolve mid-level clouds

  4. Cloud Layer Experiments (CLEX)Ten experiments since 1995 Generating Cells ~ 1-1.5 km in Length Optically Opaque Mixed-Phase Region (~300-500 m deep) Precipitating Ice Region (~.2-2.5 km deep) What we have learned: Supercooled Liquid = Typical Particle Concentrations: 100-200 cm-3 (Liquid) 20-150 L-1 (Ice) = Ice

  5. o Temperature ( C) -3 (g m ) Water Content 12 -36 -28 -20 -12 -4 4 Reflectivity (dBZ) Typical Mixed-Phase Cloud Structure Liquid Water on Top Cloud Radar Reflectivity Profile (14 Oct 2001) 6 5 -20 5 LWC -15 IWC Height (km) 4 4 Height (km) -10 3 3 Ice Below -5 2 1440 1455 1510 0.00 0.05 0.10 0.15 0.20 0.25 Time (UTC) The vertical profile of LWC (red diamonds) and IWC (blue diamonds) during the 14 October 2001 straight-line ascent from 1440 to 1510 UTC.

  6. Canadian CloudSat/CALIPSO Validation Project (C3VP) NRC Convair−580 Funded by CSA, C3VP will strive to provide an intensive evaluation of the CloudSat standard data products. Validation will occur over four twelve-day IOPs (Nov-Mar 2006-07) and involve ~ 100 hours of aircraft flight time. This is the only cold-season CloudSatvalidation effort planned during the mission! CIRA’s CLEX-10 participation in C3VP will include: ~23 hours of Convair-580 flight time devoted exclusively to the study of mixed-phase clouds and icing conditions

  7. B 9 Nov 2006 18:00 UTC MODIS 12 um C3VP Target Region A A B

  8. Early Results from C3VP/CLEX (31 Oct 2006) Supercooled Liquid Layers Ice Virga 532 nm backscatter (up & down) minutes before the A-train overpass (Courtesy of Kevin Strawbridge/Environment Canada)

  9. Mixed-Phase Clouds Viewed By MODIS/CloudSat/CALIPSO −178 −176 −174 −172 −170 −168 −166 A −22 −24 −26 −28 7/21/06 22:55 UTC MODIS 11 µm B

  10. 10 10 10 5 5 5 Height (km) Height (km) Height (km) 0 0 0 CloudSat Radar Reflectivity (dBZ) A B CloudSat Cloud Mask -40 -30 -20 -10 0 CALIPSO 532 nm Backscatter

  11. CloudSat Reflectivity

  12. CALIPSO 532 nm Backscatter

  13. Mixed-Phase Clouds Viewed By MODIS/CloudSat/CALIPSO A VIIRS Cloud Phase Algorithm B

  14. Preliminary CloudSat Data AnalysisJuly 2006 Definitions: • Cloud — a range bin with Cloud_Mask >= 20 • Cloud Top— a cloudy range bin with a non-cloudy range bin immediately above it • Cloud-Top Temperature— the temperature in the ECMWF analysis at the same height as the cloud top

  15. Mixed-phase defined as cloud tops with temps between 0°C and -45°C from ECMWF fields Few mixed-phase clouds in tropics and subtropics; many in the mid- and high latitudes Latitudinal Distribution

  16. All latitudes Fairly uniform distribution in the troposphere Cloud-Top Height Distribution

  17. Quite a uniform distribution with perhaps a few more at very cold and very warm temperatures Cloud-Top Temperature

  18. Most mixed-phase clouds are thin The long tail is puzzling, perhaps an artifact of the analysis Cloud Thickness

  19. Slightly fewer mixed-phase clouds at night (0130 LT) than in the daytime (1330 LT) Day/Night Distribution

  20. Cloud = CloudSat Cloud Mask >= 20 Cloud-Top Temp between -5°C and -40°C All latitudes, day and night Probably shows ice crystal growth below cloud top Contoured Frequency by Altitude Diagram (CFAD)

  21. Conclusions and Future Plans • We should be able to get a near global picture of mid-level, mixed-phase clouds using CloudSat, CALIPSO, and MODIS data • We will be analyzing CALIPSO data soon (They were released on Monday, Dec. 11) • A detailed study of CLEX-10/C3VP cases will take place • We hope to use these data to improve modeling of mid-level, mixed-phase clouds

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