Assessing the Impacts of Arctic Amplification on the Midlatitude Circulation with a Hierarchy of Atmospheric General Circulation Models

用大气环流模型层次评估北极放大对中纬度环流的影响

基本信息

批准号：
1815138
负责人：
Yutian Wu
金额：
$ 20.63万
依托单位：
Columbia University
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：
2017-09-01 至 2019-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1815138&HistoricalAwards=false
关键词：
Assessing Impacts Arctic Amplification Midlatitude

项目摘要

Arctic amplification refers to the tendency of the high latitudes of the Northern Hemisphere to warm faster than the rest of the globe. This effect has been documented both in the warming trends of recent decades and in climate model simulations of greenhouse gas-induced climate change, and is closely related to the decline of Arctic sea ice and reductions in Fall snow cover over northern Eurasia. This project addresses the potential for Arctic amplification to influence the weather and atmospheric circulation of the middle latitudes of the Northern Hemisphere. Motivation for the work comes from recent simulations which suggest that reductions in Arctic sea ice in late Summer and early Fall promotes the negative phase of the Northern Annular Mode, in which sea level pressure is high over the Arctic and the Northern Hemisphere jet streams and storm tracks are shifted southward. Further motivation comes from recent claims that Arctic amplification has resulted in an increase in the frequency of atmospheric blocking events, which are associated with extreme weather events including the cold air outbreaks over the US during the winter of 2013/2014 as well as recent summer heat waves over Europe.The research examines the effect of Arctic amplification on atmospheric circulation, including jet streams, storm tracks, and blocking events, using a hierarchy of models of varying levels of complexity. In this modeling approach, the simplest models are used to isolate and study the fundamental dynamical mechanisms responsible for the behaviors found in more complex and realistic simulations. A key concern of the research is that Arctic amplification will act in concert with other consequences of global warming, including the warming of tropical upper troposphere, and previous work suggests that the warming of the tropical upper troposphere leads to a poleward shift of jets and storm tracks which will somewhat offset the impact of Arctic amplification. A second concern is the possible role of the stratosphere in mediating connections between the Arctic and the midlatitude circulation. Previous work shows that circulation changes at stratospheric levels over the polar cap can influence midlatitude weather, and that these influences can propagate slowly downward, resulting in time lags up to a few months between high-latitude forcing and midlatitude response.As noted above, the topic of this research has societal broader impacts due to the potential for Arctic amplification to produce changes in the weather patterns of the Northern Hemisphere midlatitudes, in particular over the populous regions of the US and Europe. Even subtle shifts of jet streams and storm tracks can yield significant changes in rainfall and available water resources, and blocking events are an important source of extreme winter cold and summer heat waves. The research conducted here may be of value for both long-term climate projections and near-term weather forecasting.

北极扩增是指北半球高纬度的趋势比全球其他地方更快。在最近几十年的变暖趋势和温室气体引起的气候变化的气候模型模拟中，这种效果已被记录在趋势中，并且与北极海冰的下降和北欧亚大陆秋季雪覆盖的减少密切相关。该项目解决了北极扩增的潜力，以影响北半球中纬度的天气和大气循环。这项工作的动机来自最近的模拟，该模拟表明夏末和初秋的北极海冰减少促进了北方环形模式的负阶段，在北极，海平面压力高于北极，北半球喷气流和风暴轨道向南移动。最近的动机来自最近的说法，即北极扩增导致大气阻塞事件的频率增加，这些事件与极端天气事件有关，包括在2013/2014年冬季在美国的冷空气爆发以及欧洲最近的夏季热浪，研究研究了北极循环对大气循环的效果，包括射流事件，包括射流事件，以及隔离式的，隔离式播放的事件。复杂性。在这种建模方法中，最简单的模型用于隔离和研究负责在更复杂和现实的模拟中发现的行为的基本动力学机制。这项研究的一个关键问题是，北极扩增将与全球变暖的其他后果一致，包括热带对流层的变暖，先前的工作表明，热带上流对流层的变暖会导致喷气机和雨轨道的极点转移，这将抵消弧度扩增的影响。第二个问题是平流层在北极和中纬度循环之间介导连接中的可能作用。先前的工作表明，平流层高度盖上平流层水平的循环变化会影响中纬度的天气，并且这些影响可以缓慢地向下传播，从而导致时间在高纬度强迫和中纬度响应之间长达几个月，如上所述，这项研究的主题具有更广泛的影响，因为社会对北方的范围造成了北方的影响，从而在北方的范围内产生了北方的范围，从而在北方的情况下，在北方人的中间，北部的范围越来越多。美国和欧洲人口众多的地区。即使是喷气流和风暴轨迹的微妙变化也可以导致降雨和可用水资源的重大变化，而阻止事件是极端冬季寒冷和夏季热浪的重要来源。在这里进行的研究对于长期气候预测和近期天气预报都可能具有价值。