Forecast Sensitivity to Regional and Global Targeting of the Initial State

9714291佩格尔美国天气研究计划(USWRP)是一项跨部门活动，旨在开展和实施必要的研究，以改善向国家提供的天气服务。根据这一计划，国家科学基金会、国家海洋和大气管理局、国家航空航天局和海军研究办公室正在联合评估和支持USWRP高度优先的研究。在这项研究中，首席调查员将调查区域和全球尺度的初始不确定性对模式预测敏感性的相对贡献。最近的几项研究强调了局部目标观测的好处，这些观测基于对伴随、“繁殖模式”和奇异向量分析产生的不确定性增长的估计。这种方法识别动态不稳定的区域，在这些区域内局部初始状态的细节可能与随后的预测演变具有特殊的相关性。目前尚不清楚这些方法是否区分了预测的敏感性，因为全球范围的背景流的规格略有不确定。1996年3月12-14日“超级风暴”的样本预报表明，上游区域的细节，包括导致风暴的初始位涡极大值，对于96小时的预报是重要的。这些发现推动了拟议的工作，该工作将估计大气状态规范中的不确定性，并将量化不确定性对数值天气预报的影响，作为不确定性位置和尺度的函数。这项研究的工作假设是，通过数值方法进行的当地天气预报往往更敏感地依赖于初始全球尺度状态的相对较小的不确定性，而不是初始区域状态的不确定性。三种不同的全球再分析产品将进行比较。不同的、同样可信的大气分析的差异提供了一种对初始状态下当前不确定性的衡量，并将被光谱量化。这样估计的不确定性将被插入到全球变分辨率模式的初始状态中，以确定随后预报灵敏度的尺度相关性。敏感性研究将集中于从春季和冬季条件中选择的一些初始状态。最初的目标域名还将包括太平洋数据空白。这项研究的成功完成可能会对业务预测的数据收集战略产生重要影响。***

9714291 Paegle The U.S. Weather Research Program (USWRP) is an interagency activity designed to perform and implement the research necessary to improve the delivery of weather services to the nation. Under this Program, the National Science Foundation, the National Oceanic and Atmospheric Administration, the National Aeronautics and Space Administration and the Office of Naval Research are jointly evaluating and supporting research of high priority to the USWRP. In this research, the Principal Investigator will investigate the relative contributions of regional and global-scale initial uncertainties on model forecasting sensitivity. Several recent studies emphasize benefits of locally targeted observations, based upon estimates of uncertainty growth produced by adjoint, "bred mode", and singular vector analyses. Such methods identify dynamically unstable regions within which details of the local initial state may have special relevance for subsequent forecast evolution. It is unclear whether those approaches distinguish forecast sensitivities due to slightly uncertain specification of the global-scale, background flow. Sample forecasts of the "superstorm" of 12-14 March 1996 suggest that details of the upstream domain that includes the initial potential vorticity maxima leading to the storm are important for a 96 h forecast. Such findings motivate the proposed work which will estimate uncertainty in specification of the atmospheric state, and will quantify impact of the uncertainty upon numerical weather prediction as a function of uncertainty location and scale. The working hypothesis of the research is that local weather prediction by numerical methods often depends more sensitively on relatively small uncertainties of the initial global-scale state than upon uncertainties of the initial regional state. Three separate global reanalysis products will be compared. The differences of different, equally credible atmospheric analyses prov ide a measure of current uncertainty in the initial state, and will be spectrally quantified. The uncertainties thus estimated will be inserted into the initial states of a global variable resolution model to determine the scale dependence of subsequent forecast sensitivity. Sensitivity studies will focus on a number of initial states selected from Spring and Winter conditions. Initially targeted domains will also include the Pacific data void. Successful completion of this research potentially will have important implications for data collection strategies for operational forecasting. ***