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Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1 , Dong Huang 2 , Eugene Clothiaux 1 , Johannes Verlinde 1 , Kultegin Aydin 1 1 The Pennsylvania State University 2 Brookhaven National Laboratory
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Page 1: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual-

frequency Cloud RadarsCourtney Laughlin1, Dong Huang2, Eugene Clothiaux1,

Johannes Verlinde1, Kultegin Aydin1

1The Pennsylvania State University2Brookhaven National Laboratory

Page 2: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Objectives

• Retrieve accurate cloud LWCs of boundary-layer stratus and stratocumulus via an improved dual-frequency attenuation approach

• Analyze and quantify possible sources of error and assess any means to correct for them

Page 3: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Brief History of Dual-frequency Retrieval

• Atlas 1954

• Sekelsky 2000

• Hogan et al. 2005

• Huang et al. 2009

Page 4: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Liquid water cloud

Instruments

Page 5: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Liquid water cloud

Instruments

Page 6: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Liquid water cloud

Instruments

Page 7: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Possible Retrieval Sources of Error• Precision of reflectivity measurements• Overlap of sample volumes– Radar separation– Radar pointing differences– Radar range gate offsets

• Accuracy of radiosonde measurements• Temperature dependent absorption

coefficients of oxygen, water vapor, and liquid water

• Cloud drop size assumption

Page 8: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Possible Assessment Sources of Error

• Precision of LWP measurements• Beam-filling effects• Accuracy of radiosonde measurements• Temperature dependent absorption

coefficients of oxygen, water vapor, and liquid water

Page 9: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

November 26, 2012 14:00 – 15:00 UTC

Page 10: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

November 26, 2012 14:00 – 15:00 UTC

Page 11: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

November 26, 2012 14:00 – 15:00 UTC

Page 12: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

November 26, 2012 14:00 – 15:00 UTC

Page 13: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

July 08, 2013 16:00-17:00 UTC

Page 14: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

July 08, 2013 16:00-17:00 UTC

Page 15: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

July 08, 2013 16:00-17:00 UTC

Page 16: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Results

Page 17: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

ResultsMean = -0.0065(-0.0015) MAGICStandard Dev. = 0.14(0.10)

Mean = 0.09(0.09) NSAStandard Dev. = 0.09(0.09)

Mean = 0.54 (0.052) TCAPStandard Dev. = 0.12(0.12)

Mean = -0.17(-0.037) SGPStandard Dev. = 0.64(0.23)

Page 18: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Also…

•Assess satellite retrievals of cloud properties in the vicinity of the MAGIC ship tracks

Page 19: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Coincident MWACR and KAZR Data

Page 20: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

What about the next MAGIC period?

• July 07, 2013 ~ 21 UTC

• August 18, 2013 ~ 21 UTC

• August 19, 2013 ~ 21 UTC

There were 3!

Page 21: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

What about the next MAGIC period?

• July 07, 2013 Leg 14A – Just left Los Angeles

No MWACR Data

Page 22: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Coincident MWACR and KAZR Data

Page 23: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

A Closer Look..

Page 24: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Ceilometer Data

Page 25: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Conclusions• Multiple errors arise using this dual-frequency

retrieval approach • More work and analysis will be done to fully

understand reasons for these errors to correct for them

• Once accurate LWC measurements are achieved and corresponding retrieved LWPs are comparable to radiometer LWPs, we will extend approach to retrieve LWCs from all directions

Page 26: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Future Work

• Evaluate retrieval response to beam offsets from KAZR

• Study beamwidth differences between MWR3C and radars in more detail - especially in broken cloud periods

• Start analysis on the coincident time with CALIPSO/CloudSat soon

Page 27: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Acknowledgements

• Eugene Clothiaux • Dong Huang• Johannes Verlinde• Ernie Lewis• Maria Caddedu• Karen Johnson• Kultegin Aydin• Seiji Kato

Page 28: Retrieving Liquid Water Contents of Boundary-layer Clouds Using Dual- frequency Cloud Radars Courtney Laughlin 1, Dong Huang 2, Eugene Clothiaux 1, Johannes.

Thank You!

Questions?Comments?


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