Microphysical properties of Arctic mixed-phase clouds and their influence on radiation balance: Observation vs. modeling

• Main Author: 남지현
• Other Authors: 김상우, Jihyun Nam, 자연과학대학 지구환경과학부
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 서울대학교 대학원 2023
• Subjects: Arctic cloud; Mixed-phase cloud; ACLOUD; Cloudnet; PWRF; Cloud microphysics scheme; 550; Arctic; Svalbard; Ny-Ålesund; Morrison; Climate change; Ny Ålesund; Sea ice
• Online Access: https://hdl.handle.net/10371/197327; https://dcollection.snu.ac.kr/common/orgView/000000178662

학위논문(박사) -- 서울대학교대학원 : 자연과학대학 지구환경과학부, 2023. 8. 김상우. Clouds have a major impact on the Earth's radiative budget and climate change, yet little microphysical data has been collected on clouds in the polar regions. This lack of microphysics data is related to the challenges of deploying and operating instruments in some of the world's most challenging and remote atmospheric environments. This thesis investigates the macro- and microphysical properties of clouds based on observations over Ny-Ålesund, Svalbard, in order to better understand the role of clouds in the Arctic. The total cloud occurrence was found to be ~77.6% from February 2017 to February 2023. The most predominant cloud type is multilayer clouds with a frequency of occurrence of 39.1%, and single-layer clouds with ~37.2%. The total occurrences of single-layer ice, liquid, and mixed-phase clouds are 19%, 4.4%, and 14.9%, respectively. In addition, surface measurements of upward and downward shortwave and longwave radiation from the Baseline Surface Radiation Network (BSRN) at Ny-Ålesund station were examined. Relatively lower values of upward and downward longwave fluxes for ice and mixed-phase clouds were highly correlated with cloud top temperature by phase. The database of cloud properties and the classification method obtained in this work are used to evaluate weather prediction models. We evaluated the microphysical properties of Arctic low-level clouds simulated by four cloud microphysics parameterization schemes (Morrison, WDM6, NSSL, and P3) implemented in the Polar-optimized Weather Research and Forecasting (PWRF) model. The evaluation is based on a comparison with data from the Arctic Cloud Observations Using Airborne Measurements during the Polar Day (ACLOUD) experiment, which took place near Svalbard in May-June 2017. A significant number of clouds were observed during the campaign, mainly due to adiabatic motions and sensible/latent heat fluxes that caused air masses to warm (by 4°C) as they were transported over the sea ice and ocean ...