What Processes Drive Southern Ocean Sea Ice Variability and Trends? Insights from the Energy Budget of the Coupled Cryosphere-ocean-atmosphere System

哪些过程驱动南大洋海冰的变化和趋势？

基本信息

批准号：
1643436
负责人：
Aaron Donohoe
金额：
$ 38.77万
依托单位：
University of Washington
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-05-01 至 2022-04-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1643436&HistoricalAwards=false
关键词：
What Processes Drive Southern Ocean

项目摘要

This project will use observations and coupled climate model simulations to examine the causes of sea ice variability. Sea ice in the Southern Ocean has increased in area over the observational record but researchers have yet to agree on the cause. Researchers suggests that changes in surface winds, upper-ocean freshening, or internal ocean/atmosphere variability could be the main driver for the increase in sea ice area. This project will determine how much of the change in sea ice area from year to year is due to oceanic, atmospheric, and radiative processes. Reconciling the observation-based understanding with model representations of sea ice variability will improve confidence in projections of future changes in Southern Ocean sea ice.The goal of this proposal is to improve our understanding of the processes that drive Southern Ocean sea ice year-to-year variability and long term trends. This knowledge will provide insight into how Southern Ocean sea ice responded to greenhouse gas and ozone forcing in the past and how it will respond in the future. The energy budget of the coupled cryosphere/ocean/atmosphere climate system will be used as a framework to disentangle drivers and responses during sea ice loss events. The technique consists of: (i) calculating the coupled energy budget of the climate system at the monthly timescale, (ii) isolating the radiative impact of sea ice variability from the radiative impact of cloud variability in the observed satellite radiation record and (iii) analyzing the vertical structure of atmospheric energy transport to determine the vertical profile of energy transport into the atmospheric column. This framework will allow the investigators to distinguish whether ice loss events are triggered by oceanic processes, atmospheric dynamics, or radiative processes. Preliminary results show that a diversity of mechanisms can drive Southern Ocean sea ice variability in coupled climate models whereas observed sea ice variability appears to be dominated by atmospheric dynamics. The exploration of biases between models and observations in both the mean state and in specific processes will yield more accurate projections of the future of sea ice in the Southern Ocean.

该项目将使用观察结果和耦合气候模型模拟来检查海冰变异性的原因。在观测记录中，南大洋地区的海冰在地区增加了，但研究人员尚未就此事业达成共识。研究人员认为，表面风，上海洋鲜明或内部海洋/大气变异性的变化可能是海冰地区增加的主要驱动力。该项目将决定海冰地区每年的变化是由于海洋，大气和辐射过程所致。将基于观察的理解与海冰变异性的模型表示，将提高对南方海洋冰的未来变化的预测的信心。该提案的目的是提高我们对推动南部海洋冰的一年一度变异性和长期趋势的过程的理解。这些知识将洞悉南大洋海冰如何对过去的温室气体和臭氧强迫以及将来的反应。耦合的冰圈/海洋/大气气候系统的能量预算将被用作在海冰损失事件期间解散驱动因素和响应的框架。该技术包括：（i）在每月时间表上计算气候系统的耦合能量预算，（ii）将海冰变异性的辐射影响与观察到的卫星辐射记录的辐射影响辐射影响辐射影响，并（iii）分析大气能量运输的垂直能量传输，以确定能量运输的垂直能量曲线到能量运输的垂直曲线。该框架将使研究人员能够区分冰丢失事件是由海洋过程，大气动态或辐射过程触发的。初步结果表明，各种机制可以推动耦合气候模型的南洋海冰变异性，而观察到的海冰变异性似乎由大气动力学主导。在平均状态和特定过程中，模型和观察之间的偏见探索将产生更准确的对南海中海冰未来的预测。