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Detecting Supercooled Water Clouds Using Passive Radiometer Measurements

Zhou, Ganning and Wang, Jianjie and Yin, Yan and Hu, Xiuqing and Letu, Husi and Sohn, Byung-Ju and Yung, Yuk L. and Liu, Chao (2022) Detecting Supercooled Water Clouds Using Passive Radiometer Measurements. Geophysical Research Letters, 49 (4). Art. No. e2021GL096111. ISSN 0094-8276. doi:10.1029/2021gl096111.

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Supercooled water clouds (SWCs) have significant impacts on the Earth's radiation balance, aircraft ice accretion and precipitation augmentation. This study introduces an efficient algorithm to detect SWCs from passive radiometers, which combines information from the reflectance difference between 1.61 and 2.25 μm channels, the brightness temperature difference between the 8.5 and 11 μm channels, and the cloud top temperature. Validated by space radar and lidar measurements, our algorithm can correctly detect 91% of SWC pixels, better than current Visible Infrared Imager Radiometer Suite operational product. SWCs are found mostly over the mid- to high-latitude oceans and have a global occurrence frequency of ∼8% in cloudy skies. Since the channels used for the detection are available in most current operational polar and geostationary satellite radiometers, this SWC detection algorithm can be easily implemented for operations such as cloud monitoring, aviation safety, and SWC-related weather modification.

Item Type:Article
Related URLs:
URLURL TypeDescription of study
Yin, Yan0000-0002-8391-2712
Letu, Husi0000-0002-7336-8872
Sohn, Byung-Ju0000-0001-6134-3515
Yung, Yuk L.0000-0002-4263-2562
Liu, Chao0000-0001-7049-493X
Additional Information:© 2022. American Geophysical Union. Issue Online: 14 February 2022. Version of Record online: 14 February 2022. Accepted manuscript online: 18 January 2022. Manuscript accepted: 14 January 2022. Manuscript revised: 23 November 2021. Manuscript received: 14 September 2021. The authors acknowledge the funding supported by the National Natural Science Foundation of China (42122038 and 42105135). B. J. Sohn was supported by the National Research Foundation of Korea (NRF) under Grant NRF-2021R1A4A5032320. Data Availability Statement. All data related to this work are available online. The VIIRS and CloudSat-CALIPSO data can be obtained from the National Aeronautics and Space Administration (NASA) LAADS DAAC (, ICARE data and services center ( The results from this study can be downloaded from:
Funding AgencyGrant Number
National Natural Science Foundation of China42122038
National Natural Science Foundation of China42105135
National Research Foundation of KoreaNRF-2021R1A4A5032320
Subject Keywords:cloud properties; supercooled water clouds; passive radiometers
Issue or Number:4
Record Number:CaltechAUTHORS:20220317-377264000
Persistent URL:
Official Citation:Zhou, G., Wang, J., Yin, Y., Hu, X., Letu, H., Sohn, B.-J., et al. (2022). Detecting supercooled water clouds using passive radiometer measurements. Geophysical Research Letters, 49, e2021GL096111.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:113954
Deposited By: George Porter
Deposited On:17 Mar 2022 20:01
Last Modified:17 Mar 2022 20:01

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