Predictability of Forced, Dissipated and Bounded AtmospheresFor Global, Synoptic, and Mesoscales

全球、天气和中尺度的强迫、耗散和有界大气的可预测性

• 批准号: 9014650
• 负责人: Jan Paegle
• 金额: $ 25.58万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-01-15 至 1994-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9014650&HistoricalAwards=false
• 关键词: Predictability; Forced; Dissipated; Bounded; AtmospheresFor

In a classic 1969 paper, Lorenz proved that the predictability in a simple (frictionless and unheated) model of the earth's atmosphere was, in principle, limited to about five days. Specifically, this meant that the forecast error would exceed the variability (say of wind, or pressure) on the actual map at the verification time of the forecast, after some forecast period. A better model and/or a more complete and accurate set of observations at initial time might reach this time of "useless" forecasts later, but even the best combination of these would have to reach it in about five days. The predictability, by this measure, in an actual operational forecast model now used in the ECMWF has gone from five days in 1980 to eight days in 1990. This operational model does include the effects of heating, and frictional and topographic interference with the flow caused by the earth's surface. With these complications it is not amenable to the type of theoretical treatment used by Lorenz. However, it is possible that precisely these complicating processes somehow enhance the predictability of the operational model. Thus the time limit on useful forecasts has yet to be determined, and ways to enhance the predictability deserve extended exploration. The objective of the research supported under this award is to estimate the attainable enhancement of predictability by: i) Improving the model's treatment of the larger-scale flow components, which have the most obvious forecast errors, and which are most directly linked to pole to equator and continent- ocean contrasts in heating and frictional/topographic interference; ii) Fitting a research version of the model with more detailed formulas for the calculation of momentum, heat, and water exchanges with the underlaying surface, and iii) Studying the sensitivity of the global-scale forecast error growth rate to simulated observational errors in selected regions which are presumed to require fine mesh specification of the initial state. The PI's prior research in Numerical Weather Prediction,and tropical, boundary layer, and mountain meteorology is especially relevant to the proposed work. These studies will increase our understanding of the factors affecting predictability, and are likely to contribute to further improvements in Numerical Weather Prediction over the next decade.

在1969年的经典论文中，洛伦兹证明了地球大气层的简单（无摩擦和未加热）模型中的可预测性原则上仅限于大约五天。 具体而言，这意味着在预测期之后，在预测时间的验证时间，预测误差将超过实际地图上的可变性（例如风或压力）。 更好的模型和/或更完整，更准确的观测值在初始时间可能达到此稍后的“无用”预测的时间，但是即使是最佳组合也必须在大约五天之内达到。通过这种措施，在ECMWF现在使用的实际操作预测模型中的可预测性已从1980年的五天变成了1990年的八天。该操作模型确实包括加热的影响以及对地球表面引起的流动的摩擦和地形干扰。 通过这些并发症，它不适合洛伦兹使用的理论治疗类型。 但是，这些复杂的过程可能会以某种方式提高操作模型的可预测性。 因此，尚未确定对有用预测的时间限制，以及增强可预测性的方法应得到扩展的勘探。 该奖项支持的研究的目的是通过以下方式估算可预测性的可实现的可实现性增强性，以下方法）改善模型对大规模流量组件的处理，这些流量组件具有最明显的预测误差，这些误差最直接与赤道和大陆 - 在供暖和摩擦和摩擦/摩擦/地形干扰方面与赤道和大陆相反； ii）将模型的研究版本与更详细的公式拟合，以计算具有底层表面的动量，热量和水交换，以及iii）研究全球尺度预测误差增长速率的敏感性，以模拟所选区域中的观察性观察错误，这些误差要求最初的最初状态的细分市场规格。 PI先前在数值天气预测以及热带，边界层和山气象学方面的研究与拟议的工作特别相关。 这些研究将增加我们对影响可预测性的因素的理解，并可能有助于进一步改善未来十年的数值天气预测。