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

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

Height (km) Typical Mixed-Phase Cloud Structure The vertical profile of LWC (red diamonds) and IWC (blue diamonds) during the 14 October 2001 straight- line ascent from 1440 to 1510 UTC. Liquid Water on Top Height (km) Temperature ( C) o Reflectivity (dBZ) (g m ) -3 Water Content Time (UTC) Cloud Radar Reflectivity Profile (14 Oct 2001) LWC IWC Ice Below

6 Canadian CloudSat/CALIPSO Validation Project (C3VP) 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 ) and involve ~ 100 hours of aircraft flight time. This is the only cold-season CloudSat validation 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 NRC Convair−580

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8 9 Nov :00 UTC MODIS 12 um A B A B C3VP Target Region

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

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

11 Height (km) CloudSat Radar Reflectivity (dBZ) CloudSat Cloud Mask BA Height (km) Height (km) CALIPSO 532 nm Backscatter

12 CloudSat Reflectivity

13 CALIPSO 532 nm Backscatter

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

15 Preliminary CloudSat Data Analysis July 2006 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 Definitions:

16 Latitudinal Distribution 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

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

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

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

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

21 Contoured Frequency by Altitude Diagram (CFAD) 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

22 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