Roles of Moist Static Energy Transport in the Changing Arctic System

湿静态能量传输在不断变化的北极系统中的作用

• 批准号: 0455262
• 负责人: Jennifer Francis
• 金额: $ 25.68万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-15 至 2009-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0455262&HistoricalAwards=false
• 关键词: Roles; Moist; Static; Energy; Transport

The Arctic system appears to be heading toward a new state that may be unprecedented, and there are no apparent feedbacks within the Arctic that can arrest the cohesive change. Can negative feedback mechanisms involving lower latitudes offset widespread reductions in permanent ice and corresponding changes in physical and biological components? Possible candidates are feedbacks related to horizontally transported moist static energy. The likely amplification of warming in the Arctic relative to lower latitudes implies that heat transport should decrease as the poleward temperature gradient relaxes, but how do the fluxes of moisture and potential energy respond? Can they offset the reduced heat transport? How is advection affected by large-scale climate features such as the El Nino Southern Oscillation and changes in tropical sea surface temperatures? In which regions and seasons are transports most affected? This activity will attempt to answer these questions using a new combination of data sources. The European Center for Medium-Range Weather Forecast Reanalysis (ERA-40) will be used in regions where radiosondes and other observations are plentiful south of 70?N. Over the Arctic, however, there is little information for the reanalyses to assimilate, which is responsible for large uncertainties in many parameters and observed discrepancies with independent measurements. To ameliorate this problem, new products derived from satellite retrievals will be merged with ERA-40 output to create a hybrid hemispheric data set. This effort will use this resource to investigate how horizontal energy fluxes have behaved during the past 23 years, a period during which the Arctic system underwent widespread change. The effort contributes to a system understanding by focusing on the primary energy source for the Arctic climate system, exploring its role as a possible mitigator of Arctic change, and investigating its relationships with the global climate system.The objectives and methods of this project are:1. Calculate daily mean fluxes of potential energy from satellite-derived temperature profiles for the Arctic region. Sensible heat and moisture fluxes have already been completed.2. Calculate daily mean energy and moisture fluxes from ERA-40 fields and merge them with satellite-derived fluxes for the region north of 70?N to create a hybrid data set for the entire Northern Hemisphere (NH).3. Investigate spatial and temporal patterns (annual and seasonal anomalies and trends, dominant modes of variability) in fluxes and convergences at several atmospheric levels throughout the NH using a variety of spatial statistical techniques and time series analysis.4. Relate observed changes in a variety of Arctic parameters to changes in horizontal fluxes and correlate energy advection with large-scale circulation patterns, such as the ENSO and NAO using multivariate correlation methods.

北极系统似乎正在走向一个可能是前所未有的新状态，北极内部没有明显的反馈可以阻止这种凝聚力的变化。涉及低纬度地区的负反馈机制能否抵消永久冰的广泛减少以及物理和生物成分的相应变化？可能的候选人是水平输送湿静态能量相关的反馈。北极相对于低纬度地区变暖可能会加剧，这意味着随着向极温度梯度的缓和，热量输送应该会减少，但水分和位能通量如何反应呢？它们能抵消热量传输的减少吗？平流如何受到大尺度气候特征的影响，如厄尔尼诺南方涛动和热带海面温度的变化？在哪些地区和季节运输受到的影响最大？本练习将尝试使用新的数据源组合来回答这些问题。欧洲中期天气预报再分析中心（ERA-40）将用于70？N.然而，在北极地区，几乎没有什么信息可供再分析同化，这是造成许多参数存在很大不确定性和观察到的与独立测量值的差异的原因。为了改善这一问题，将把从卫星检索中获得的新产品与ERA-40的产出合并，以建立一个混合半球数据集。这项工作将利用这一资源来调查在过去23年中水平能量通量的表现，在此期间，北极系统经历了广泛的变化。本项目的主要目的是通过研究北极气候系统的主要能源，探讨其作为北极变化减缓因子的作用，并研究其与全球气候系统的关系，从而加深对北极气候系统的认识。从卫星获得的北极地区温度廓线计算每日平均势能通量。感热通量和感湿通量已经完成。计算每日平均能量和水分通量从ERA-40领域，并合并它们与卫星派生的通量为70？N来创建整个北方半球（NH）的混合数据集。使用各种空间统计技术和时间序列分析，调查整个北半球几个大气层通量和会聚的空间和时间模式（年度和季节异常和趋势，主要的变率模式）。将观测到的各种北极参数的变化与水平通量的变化联系起来，并使用多变量相关方法将能量平流与大尺度环流模式（如ENSO和NAO）联系起来。