Analysis of extreme precipitation and cyclogenesis at the weather-climate interface

强降水、长时间冰暴和快速气旋形成等极端天气可能造成特别严重的后果，造成人员伤亡、洪水、海岸侵蚀和财产损失。 科学家们一致认为，气候变暖是最近这种极端情况增加的原因，特别是降水。我的研究计划的长期目标是提高我们对持续极端天气的理解和预测，这些极端天气往往有助于亚季节气候状态。 这些极端天气的相对长的时间段通常超过天气预报的可预测性的典型限制，朝向未来大气状态只能统计地预测的时间范围。 这个从10天到一个月的扩展时间尺度被定义为“天气-气候界面”时间尺度。持续的天气状况延长了降水和干旱状况的持续时间，从而增加了暴雨和干旱的机会。 对这些极端情况的进一步了解将使学术研究人员受益，并使天气和气候科学家进行必要的综合和合作。这项研究建议最直接的短期目标包括从天气-气候交叉点的角度对极端降水和气旋发生进行全面分析。在这些短期目标中隐含的假设是，降水和气旋生成是我们追求理解持续天气及其季节内变化的关键过程。我的研究重点是分析基本的热力学和动力学原理，作为定义促进极端降水（包括冻雨和气旋）发展的环境的基础。 研究内容包括气团、天气尺度强迫、静力稳定度、动力对流层顶急流和最大斜压增长率的分析。 这些指标为降水和气旋生成提供了必要的环境条件，也可作为天气和气候模式的验证工具。 此外，这些环境指标很容易从相对粗分辨率的全球再分析中计算出来。随后分析这些天气尺度和中尺度过程对行星尺度环境的反馈，包括负反馈和正反馈，将有助于深入了解气旋生成、降水和环境之间复杂的相互作用，这些相互作用要么鼓励，要么阻碍它们的存在。

Weather extremes in the form of heavy precipitation, long-duration ice storms, and rapid cyclogenesis can have especially significant consequences in the form of human injuries and fatalities, flooding, coastal erosion and property losses. There is a consensus among scientists that a warming climate is responsible for recent increases in such extremes, particularly precipitation.***The long-term objective of my research program is to enhance our understanding and forecasting of persistent weather extremes that often contribute to the sub-seasonal climate state. The relatively long time periods of these weather extremes typically exceed the typical limit of a weather forecast's predictability, towards a time range in which the future atmospheric state can only be predicted statistically. This extended time scale, ranging from 10 days to one month is defined to be the “weather-climate interface” time scale. Persistent weather regimes enhance the durations of precipitation and dry conditions, and thus increase the chances of heavy precipitation and droughts. An improved understanding of these extremes will benefit academic researchers with a needed synthesis and collaboration of weather and climate scientists.***The most immediate shorter-term objectives of this research proposal include comprehensive analyses of extreme precipitation and cyclogenesis from a weather-climate intersection perspective. Implicit in these shorter-term objectives is the assumption that precipitation, and cyclogenesis, are key processes to analyze in our pursuit of understanding persistent weather and its intra-seasonal variability.***My research focuses on analyses of fundamental thermodynamic and dynamic principles as foundations for defining environments that facilitate the developments of extreme precipitation, including freezing rain, and cyclogenesis. This research includes analyses of air masses, synoptic-scale forcing, static stability, the dynamic tropopause jet stream, and maximum baroclinic growth rates. These metrics provide the necessary environmental conditions for precipitation and cyclogenesis, and also serve as validation tools for both weather- and climate-models. Furthermore, these environmental metrics are readily computed from the relatively coarse-resolution global reanalyses.***Subsequent analyses of feedbacks, both negative and positive, of these synoptic- and meso-scale processes onto the planetary-scale environments will provide insight into the complex set of interactions among cyclogenesis, precipitation, and the environment that either encourages or discourages their existence.**