Polarimetric Radar Operation in Support of North American Monsoon Experiment (NAME)

北美季风实验（NAME）是一项多方面的研究工作，致力于提高北美暖季降水的可预测性。 目前，在从墨西哥南部延伸到美国的区域，对短到中期时间尺度的暖季降水的预测受到了季风内降水系统缺乏了解以及无法在数值天气预报模型中准确地对这些降水系统进行参数化的阻碍。 对了解和预测季风系统至关重要的几个关键的相互关联的物理过程仍然缺乏量化，包括：季风的整体结构;单个降水系统的结构，运动学，形态学和日周期（包括中尺度对流系统）;以及西马德雷西方（SMO）地区降水系统与可变表面特性的相互作用，加州湾和沿海平原的影响，以及海洋强迫对附近大陆降水的影响（反之亦然），陆面记忆过程，地表通量和蒸散。为了详细研究这些过程，计划在2004年夏季进行一个全面的NAME增强观测期（EOP）。 NAME EOP目标的核心是研究偏振多普勒雷达的持续运行，这将补充正在进行的长期观测和同步EOP观测，如增强的无线电探空仪，pibal和剖面仪网络。 具体名称EOP目标的关键运动，将在这项研究中解决包括：o文件的水平分布的降雨量和强度划分的对流和层状成分，作为一个功能的风暴类型，位置和环境强迫; o测量降雨的日循环、对流强度、风暴形态，和微物理学，这将是至关重要的诊断物理过程背后的降水在该地区，从而链接到可预测性，区域; o识别降水特征中的二维气流，以及其他边界层气流，包括微风锋、海湾涌，以及它们在对流启动中的作用;o识别水凝物，以评估云解析模式中的微物理参数化和数值天气预报模式中的对流参数化。 偏振数据将用于识别对流和周围层状降水中的主要降水粒子类型。 这项研究的学术价值包括探索热带对流的物理和动力学特征的显着地形附近。 预计将从NAME获得关于热带降水性质的新结果。 多普勒数据将通过获取数据来验证季风降水的数值模型，特别是提高模拟进入美国西南部的水分输送的能力，从而对整体科学产生更广泛的影响。 因此，更好的预测强季风降雨在美国西南部预计作为一个结果的名称。

The North American Monsoon Experiment (NAME) is a multi faceted research effort that strives to improve predictability of warm season precipitation over North America. Currently, the prediction of warm season precipitation on short- to medium-range timescales in the region extending from southern Mexico into the United States is hampered by a lack of understanding of precipitating systems within the monsoon, and the inability to accurately parameterize these precipitating systems in numerical weather prediction models. Several key interrelated physical processes fundamental to understanding and predicting the monsoon system remain poorly quantified, including: the bulk structure of the monsoon; the structure, kinematics, morphology, and diurnal cycle of individual precipitating systems (including mesoscale convective systems) within the monsoon; and, the interaction of precipitating systems with the variable surface properties in the region over the Sierra Madre Occidental (SMO), the Gulf of California and the intervening coastal plain, as well as the influence of the oceanic forcing on nearby continental precipitation (and vice versa), land surface memory processes, surface fluxes, and evapotransporation.To study these processes in detail, a comprehensive NAME Enhanced Observing Period (EOP) is planned for the Summer of 2004. Central to the goals of the NAME EOP is the continuous operation of the a research polarimetric Doppler radar, which will complement ongoing, long term observations and coincident EOP observations such as enhanced radiosonde, pibal, and profiler networks. Specific NAME EOP objectives key to the campaign that will be addressed under this research include:o documentation of the horizontal distribution of rainfall amount and intensity partitioned by convective and stratiform components, as a function of storm type, location, and environmental forcing;o measurement of the diurnal cycle of rainfall, convective intensity, storm morphology, and microphysics that will be crucial in diagnosing the physical processes behind precipitation in the region and thus links to predictability in the region;o identification of 2-D airflow within precipitating features, as well as other boundary layer flows including breeze fronts, gulf surges, and their role in convective initiation;o hydrometeor identification allowing evaluation of microphysical parameterizations in cloud resolving models and convective parameterizations in numerical weather prediction models.The Doppler and polarimetric data from NAME will be carefully analyzed using several existing methods. The polarimetric data will be used to identify dominant precipitation particle types in the convection and surrounding stratiform precipitation. The intellectual merit of this research consists of exploring the physical and dynamical characteristics of tropical convection in the immediate vicinity of significant topography. New results on the nature of tropical precipitation are expected to be gained from NAME. The Doppler data will provide for broader impact on the overall science by acquiring data to validate numerical models of the monsoon precipitation, and in particular, improving the ability to model the moisture transport into the southwest U.S. that drives the late summer rainfall in those regions. Hence better forecasts of heavy monsoonal rainfall in the southwest U.S. are expected as an outcome of NAME.