Case Studies of Atmospheric River-Induced Surface Changes in the Arctic

• Main Author: Huang, Yonghuai
• Format: Text
• Language: unknown
• Published: Purdue University 2021
• Subjects: Arctic; Merra
• Online Access: https://docs.lib.purdue.edu/gdstr/5; https://docs.lib.purdue.edu/context/gdstr/article/1004/viewcontent/GDSTechReportAcc.pdf; https://docs.lib.purdue.edu/context/gdstr/article/1004/filename/0/type/additional/viewcontent/GDSTechSup01.pdf; https://docs.lib.purdue.edu/context/gdstr/article/1004/filename/1/type/additional/viewcontent/GDSTechSup02.pdf; https://docs.lib.purdue.edu/context/gdstr/article/1004/filename/2/type/additional/viewcontent/GDSTechSup03.pdf

Atmospheric river (AR) takes a significant role in transporting warm moisture into the Arctic, which could further enhance the Arctic Amplification. This project aims to examine the surface conditions during selected cases of AR events that are detected by climate time series of Arctic AR index. Mono-level variables related to temperature, pressure, heat fluxes and wind speed of fourteen AR events were analyzed using the MERRA-2 derived Arctic AR index, and results were compared with the detected AR basins. Results of MERRA-2 data show that AR basins detected by both Integrated Water Vapor (IWV) and Integrated water Vapor Transport (IVT) indices were able to capture changes on the surface conditions caused by Arctic AR intrusions. Evolution of AR was characterized best by surface temperature, when the location of an AR basin was tracked by the low-pressure field. Latent and sensible heat fluxes showed that evaporation dominated when ARs moved over ocean, but the mechanism and effect of it remained in questions. Also, the combination of longwave fluxes at the surface and atmosphere proved the fact that AR intrusion did enhance the Greenhouse Effect in the Arctic region. The IVT-based AR index had better performance in capturing the movement of ARs than the IWV-based index did, and the overall performance of AR indices was impacted by factors such as seasonal effect and extreme background value over continents, which should be considered for future research.