USAP-DC

Ice supersaturation plays a key role in cloud formation and evolution, and it determines the partitioning among ice, liquid and vapor phases. Over the Southern Ocean and Antarctica, the transition between mixed-phase and ice clouds significantly impacts the radiative effects of clouds. Remote regions such as the Antarctica and Southern Ocean historically have been under-sampled by in-situ observations, especially by airborne observations. Even though more attention has been given to the cloud microphysical properties over these regions, the distribution and characteristics of ice supersaturation and its role in the current and future climate have not been fully investigated at the higher latitudes in the Southern Hemisphere. One of the main objectives of this study is to analyze observations from three recent major field campaigns sponsored by NSF and DOE, which provide intensive in-situ, airborne measurements over the Southern Ocean and ground-based observations at McMurdo station in Antarctica. This project will analyze aircraft-based and ground-based observations over the Southern Ocean and Antarctica, and compare the observations with the Community Earth System Model Version 2 (CESM2) simulations. The focus will be on the observations of ice supersaturation and the relative humidity distribution in mixed-phase and ice clouds, as well as their relationship with cloud micro- and macrophysical properties. Observations will be compared to CESM2 simulations to elucidate model biases. Surface radiation and the precipitation budget at the McMurdo station will be quantified and compared against the CESM2 simulations to improve the fidelity of the representation of Antarctic climate (and climate prediction over Antarctica). Results from our research will be released to the community for improving the understanding of cloud radiative effects and the mass transport of water in the high southern latitudes. Comparisons between the simulations and observations will provide valuable information for improving the next generation CESM model. Two education/outreach projects will be carried out by PI Diao at San Jose State University (SJSU), including a unique undergraduate student research project with hands-on laboratory work on an airborne instrument, and an outreach program that uses social media to broadcast news on polar research to the public. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Person	Role
Diao, Minghui	Investigator and contact
Gettelman, Andrew	Co-Investigator

Antarctic Ocean and Atmospheric Sciences	Award # 1744965
Antarctic Ocean and Atmospheric Sciences	Award # 1744946

USAP-1744965_1

None in the Database

Repository	Title (link)	Format(s)	Status
Publication	AWARE_Campaign_Data	None	exists
UCAR	Diao, M. (2020). VCSEL 1 Hz Water Vapor Data Version 1.0 for NSF SOCRATES Campaign	None	exist
UCAR	Diao, M. (2020). VCSEL 25 Hz Water Vapor Data Version 1.0 for NSF SOCRATES Campaign	None	exist

1. D’Alessandro, John J. and Diao, Minghui and Wu, Chenglai and Liu, Xiaohong and Jensen, Jorgen B. and Stephens, Britton B. "Cloud Phase and Relative Humidity Distributions over the Southern Ocean in Austral Summer Based on In Situ Observations and CAM5 Simulations" Journal of Climate , v.32 , 2019 (doi:10.1175/JCLI-D-18-0232.1)
2. D'Alessandro, John "Cloud Microphysical Properties based on Airborne In Situ Observations and Evaluation of a Weather Forecasting Model and a Global Climate Model" Master?s theses directories , v.4935 , 2018 (doi:10.31979/etd.7855-fqvh)
3. Zhang, Meng and Liu, Xiaohong and Diao, Minghui and D'Alessandro, John J. and Wang, Yong and Wu, Chenglai and Zhang, Damao and Wang, Zhien and Xie, Shaocheng "Impacts of Representing Heterogeneous Distribution of Cloud Liquid and Ice on Phase Partitioning of Arctic Mixed‐Phase Clouds with NCAR CAM5" Journal of Geophysical Research: Atmospheres , v.124 , 2019 (doi:10.1029/2019JD030502)
4. Patnaude, Ryan and Diao, Minghui "Aerosol indirect effects on cirrus clouds based on global aircraft observations" Geophysical Research Letters , 2020 (doi:10.1029/2019GL086550)
5. Patnaude, Ryan and Diao, Minghui and Liu, Xiaohong and Chu, Suqian "Effects of Thermodynamics, Dynamics and Aerosols on Cirrus Clouds Based on In Situ Observations and NCAR CAM6 Model" Atmospheric chemistry and physics discussion , 2020 (doi:10.5194/acp-2020-497)
6. Sanchez, K. J. and Roberts, G. C. and Diao, M. and Russell, L. M. "Measured Constraints on Cloud Top Entrainment to Reduce Uncertainty of Nonprecipitating Stratocumulus Shortwave Radiative Forcing in the Southern Ocean" Geophysical Research Letters , v.47 , 2020 (doi:10.1029/2020GL090513)
7. Patnaude, Ryan and Diao, Minghui and Liu, Xiaohong and Chu, Suqian "Effects of thermodynamics, dynamics and aerosols on cirrus clouds based on in situ observations and NCAR CAM6" Atmospheric Chemistry and Physics , v.21 , 2021 (doi:10.5194/acp-21-1835-2021)
8. Gettelman, A., Bardeen, C. G., McCluskey, C. S., Järvinen, E., Stith, J., Bretherton, C., et al. (2020). Simulating observations of Southern Ocean clouds and implications for climate. Journal of Geographical Research: Atmospheres, 125, e2020JD032619 (doi:10.1029/2020JD032619)
9. Zhang, M., Liu, X., Diao, M., D’Alessandro, J. J., Wang, Y., Wu, C., … Xie, S. (2019). Impacts of Representing Heterogeneous Distribution of Cloud Liquid and Ice on Phase Partitioning of Arctic Mixed‐Phase Clouds with NCAR CAM5. Journal of Geophysical Research: Atmospheres, 124(23), 13071–13090. (doi:10.1029/2019jd030502)
10. Yip, J., Diao, M., Barone, T., Silber, I., & Gettelman, A. (2021). Evaluation of the CAM6 Climate Model Using Cloud Observations at McMurdo Station, Antarctica. Journal of Geophysical Research: Atmospheres, 126(16). (doi:10.1029/2021jd034653)
11. Yang, C. A., Diao, M., Gettelman, A., Zhang, K., & Sun, J. (2020). Ice and Supercooled Liquid Water Distributions over the Southern Ocean based on In Situ Observations and Climate Model Simulations. (doi:10.1002/essoar.10504450.1)
12. D’Alessandro, J. J., Diao, M., Wu, C., Liu, X., Jensen, J. B., & Stephens, B. B. (2019). Cloud Phase and Relative Humidity Distributions over the Southern Ocean in Austral Summer Based on In Situ Observations and CAM5 Simulations. Journal of Climate, 32(10), 2781–2805. (doi:10.1175/jcli-d-18-0232.1)
13. Atlas, R., Mohrmann, J., Finlon, J., Lu, J., Hsiao, I., Wood, R., & Diao, M. (2021). The University of Washington Ice-Liquid Discriminator (UWILD) improves single particle phase classifications of hydrometeors within Southern Ocean clouds using machine learning. (doi:10.5194/amt-2021-123)
14. Atlas, R., Mohrmann, J., Finlon, J., Lu, J., Hsiao, I., Wood, R., & Diao, M. (2021). The University of Washington Ice–Liquid Discriminator (UWILD) improves single-particle phase classifications of hydrometeors within Southern Ocean clouds using machine learning. Atmospheric Measurement Techniques, 14(11), 7079–7101. (doi:10.5194/amt-14-7079-2021)
15. Sanchez, K., Roberts, G., Russell, L. M., & Diao, M. (2020). Measured Constraints on Cloud-Top Entrainment to Reduce Uncertainty of Non-Precipitating Stratocumulus Shortwave Radiative Forcing in the Southern Ocean. (doi:10.1002/essoar.10504264.1)
16. Yang, C. A., Diao, M., Gettelman, A., Zhang, K., Sun, J., McFarquhar, G., & Wu, W. (2021). Ice and Supercooled Liquid Water Distributions Over the Southern Ocean Based on In Situ Observations and Climate Model Simulations. Journal of Geophysical Research: Atmospheres, 126(24). (doi:10.1029/2021jd036045)
17. Barone, T., Diao, M., Shi, Y., Zhao, X., Liu, X., & Silber, I. (2024). Impacts of Synoptic‐Scale Dynamics on Clouds and Radiation in High Southern Latitudes. Journal of Geophysical Research: Atmospheres, 129(16). Portico. (doi:10.1029/2023jd040329)