Roles of Moist Static Energy Transport in the Changing Arctic System

北极系统似乎正在走向一个前所未有的新状态，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相应的物理和生物成分的变化？可能的候选是与水平输送的湿静态能有关的反馈。相对于低纬度地区，北极变暖的可能放大意味着热量输送应该随着极地温度梯度的放松而减少，但是水分通量和势能是如何响应的呢？它们能抵消减少的热传递吗？平流如何受到厄尔尼诺、南方涛动等大尺度气候特征和热带海面温度变化的影响？交通运输在哪些地区和季节受影响最大？该活动将尝试使用数据源的新组合来回答这些问题。欧洲中期天气预报再分析中心（ERA-40）将用于无线电探空仪和其他观测丰富的70°N以南地区。然而，在北极上空，可供再分析吸收的信息很少，这导致许多参数存在很大的不确定性，并且观测到与独立测量的差异。为了改善这一问题，从卫星检索中获得的新产品将与ERA-40输出合并，以创建一个混合半球数据集。这项工作将利用这一资源来调查过去23年里水平能量通量的表现，在这段时间里，北极系统经历了广泛的变化。这项工作通过关注北极气候系统的主要能源，探索其作为北极变化可能的减缓剂的作用，以及调查其与全球气候系统的关系，有助于系统理解。本课题的目标和方法是：1。从北极地区的卫星温度剖面计算势能的日平均通量。感热通量和感湿通量已经完成。计算ERA-40场的日平均能量和水分通量，并将其与70°c以北地区的卫星衍生通量合并。N来创建整个北半球（NH）的混合数据集。3 .利用各种空间统计技术和时间序列分析，研究整个北半球若干大气水平的通量和辐合的时空格局（年度和季节异常和趋势、主要变率模式）。利用多元相关方法将观测到的北极各种参数的变化与水平通量的变化联系起来，并将能量平流与ENSO和NAO等大尺度环流模式联系起来。

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.