权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

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.

该项目将使用观测和耦合气候模型模拟来研究海冰变化的原因。与观测记录相比，南大洋的海冰面积有所增加，但研究人员尚未就原因达成一致。研究人员提出，海面风、上层海洋淡水或内部海洋/大气变化的变化可能是海冰面积增加的主要驱动因素。该项目将确定每年海冰面积的变化有多少是由海洋、大气和辐射过程造成的。将基于观测的理解与海冰可变性的模型表示相结合，将提高对南大洋海冰未来变化预测的信心。这项提议的目标是增进我们对驱动南大洋海冰年际变化和长期趋势的过程的理解。这一知识将有助于洞察南大洋海冰过去如何应对温室气体和臭氧强迫，以及未来将如何应对。冰冻圈/海洋/大气耦合气候系统的能量收支将被用作一个框架，以区分海冰丧失事件期间的驱动因素和应对措施。这项技术包括：(1)在每月时间尺度上计算气候系统的耦合能量收支；(2)在观测的卫星辐射记录中将海冰变化的辐射影响与云变化的辐射影响分开；(3)分析大气能量传输的垂直结构，以确定进入大气层柱的能量传输的垂直剖面。这一框架将使研究人员能够区分冰流失事件是由海洋过程、大气动力学还是辐射过程触发的。初步结果表明，在耦合气候模式中，多种机制可以驱动南大洋海冰的可变性，而观测到的海冰可变性似乎是由大气动力学主导的。对平均状态和具体过程中的模型和观测之间的偏差进行探索，将对南大洋海冰的未来作出更准确的预测。