Collaborative Research: Measurement and Analysis of the Preconvective Boundary Layer and Convection Initiation during International H2O Project (IHOP)

这个俄克拉荷马州大学和宾夕法尼亚州立大学之间的合作项目是国际水项目（IHOP）的一部分。 IHOP是一个大型的多机构、多研究者项目，重点是测量水蒸气和水蒸气变化。 该项目的目标是提高对对流启动的理解，提高短期降水预报技能，并测试各种仪器测量水汽四维特征的能力。 IHOP的现场阶段将在2002年春季和夏季进行，并将提供广泛的中尺度气象观测研究，以获得更好的理解的尺度，和过程的影响，水汽变率。 虽然有几项研究已经考察了边界层结构的某些方面，但对引起对流发生的原因知之甚少。 IHOP将提供开始评价和修正有关对流开始过程和边界层水汽作用的假设所需的综合数据集。 主要研究人员将从移动的设施获取并分析三维雷达导出的边界层气流以及风和热力学参数的现场测量结果。 边界层气流与现场测量的绝对湿度和虚拟温度相结合，提供了唯一的手段来记录在边界层中起作用的动力学和运输过程，以调节可降水量并迫使二次环流的发展。 因此，这些观测对于评估关于水汽供应和气流演变对边界形成和对流启动的影响的假设是必不可少的。 主观分析和可视化将结合所有可用的数据在有关尺度对流启动。 将利用先进的时空转换方案，通过在多多普勒风综合的基础上沿着拉格朗日轨迹分布接近保守的变量，提高观测密度。 最后，这些增强的观测结果将被同化到中尺度模式中，以确定控制局部边界层环流发展的动力强迫过程，这些环流是促进还是阻止对流的形成，这一努力将导致收集和分析前所未有的数据集，其尺度是以前没有观测到的。 通过这项工作，将对低层边界附近发生的过程以及这些过程如何调节雷暴的形成产生全新的理解。 知识将是有用的，在定量降水预报的发展新的进展，无论是数值和主观的，通过提高预测能力，如果，何时，以及在哪里对流将发展。

This collaborative project between the University of Oklahoma and the Pennsylvania State University is part of the International H2O Project (IHOP). The IHOP is a large multi-agency, multi-investigator project that focuses on the measurement of water vapor and water vapor variability. The goal of this project is to improve understanding of convective initiation, increase short-term precipitation forecast skills and test the capabilities of various instruments to measure the four dimensional characteristics of water vapor. The field phase of the IHOP will be conducted during the Spring and Summer of 2002 and will provide a wide range of mesoscale meteorological observations for studies to gain a better understanding of the scales of, and processes influencing, water vapor variability.The goal of this hypothesis-driven research is to improve understanding of the processes leading to the initiation of deep, moist cumulus convection. Though several studies have examined certain aspects of boundary layer structure little is known about what causes convective initiation. IHOP will provide the comprehensive data sets needed to begin evaluating and revising hypotheses concerning convection initiation processes and the role of boundary layer water vapor. The Principal Investigators will acquire and analyze three dimensional radar-derived boundary layer airflow and in-situ measurements of winds and thermodynamic parameters from mobile facilities. The combination of boundary layer airflow with in-situ measurements of absolute humidity and virtual temperature provides the only means of documenting the dynamical and transport processes acting in the boundary layer to regulate precipitable water and force the development of secondary circulations. Thus these observations are essential for evaluating hypotheses concerning the impact of water vapor supply and airflow evolution on boundary formation and convection initiation.Detailed observations will be analyzed in several different ways. Subjective analyses and visualizations will be produced incorporating all available data on relevant scales for convection initiation. Observation density will be enhanced utilizing an advanced time-to-space conversion scheme by distributing nearly conservative variables along Lagrangian trajectories based on multi-Doppler wind syntheses. Finally, these enhanced observations will be assimilated into mesoscale models to determine the dynamical forcing processes controlling the development of localized boundary layer circulations that either promote or prevent convection initiation.This effort will result in the collection and analysis of an unprecedented data set at scales previously not observed. Through this work, a completely new understanding will emerge regarding the processes occurring near low-level boundaries and how these processes regulate the formation of thunderstorms. The knowledge will be useful for developing new advances, both numerical and subjective, in quantitative precipitation forecasting by improving the ability to forecast if, when, and where convection will develop.