10:45 AM - 11:00 AM
[MIS10-07] Ice Cloud Formation Related to Oceanic Supply of Ice-Nucleating Particles: A Case Study in the Southern Ocean near an Atmospheric River in Late Summer
★Invited Papers
Keywords:Antarctica, Cloud particle sensor sonde, Ice cloud
Polar region clouds play a key role in Earth’s climate. Knowledge of the cloud phase (i.e., liquid water, ice, or mixed) is important for determining the surface heat budget because the reflection of solar radiation at the cloud top depends on cloud phase. Although the development of numerical climate models allows the investigation of clouds globally, there still is a cloud phase (water or ice) bias in the models. Therefore, an observational study is required to investigate cloud formation environments.
This study investigated ice cloud formation associated with marine bioaerosols over the Southern Ocean using a combination of cloud particle sensor (CPS) sonde observations, satellite products, reanalysis data, and backward trajectory analysis. The CPS sonde detected ice clouds at temperatures higher than −10 °C in the mid-troposphere near an atmospheric river at high latitudes over the Southern Ocean. Backward trajectory analyses indicated that a mid-latitude air mass with a high concentration of atmospheric dimethylsulfide (DMS) in the atmospheric boundary layer (<1 km) arrived at the ice cloud formation layer over the high latitudes. The DMS in the boundary layer began to increase under high wave conditions, coincident with the highest chlorophyll-a concentrations in the ocean. These results suggest that bioaerosols emitted from the ocean over the mid-latitudes acted as ice-nucleating particles for ice cloud formation over high latitudes.
This study investigated ice cloud formation associated with marine bioaerosols over the Southern Ocean using a combination of cloud particle sensor (CPS) sonde observations, satellite products, reanalysis data, and backward trajectory analysis. The CPS sonde detected ice clouds at temperatures higher than −10 °C in the mid-troposphere near an atmospheric river at high latitudes over the Southern Ocean. Backward trajectory analyses indicated that a mid-latitude air mass with a high concentration of atmospheric dimethylsulfide (DMS) in the atmospheric boundary layer (<1 km) arrived at the ice cloud formation layer over the high latitudes. The DMS in the boundary layer began to increase under high wave conditions, coincident with the highest chlorophyll-a concentrations in the ocean. These results suggest that bioaerosols emitted from the ocean over the mid-latitudes acted as ice-nucleating particles for ice cloud formation over high latitudes.