Collaborative Research: Doppler on Wheels International H2O Project Participation and Studies of Convective Initiation

国际H20项目（IHOP）是一个多研究者、多机构的项目，其主要目标是改进对水蒸气四维分布的表征，并将其应用于提高对对流的理解和预测。项目重点关注四个重要研究领域：定量降水预报；对流起始、大气边界层过程；以及仪器测试。IHOP成功的关键是测量风和跨越几个运动尺度的热力学值。这将通过独特和多样的仪器来完成。为了促进实现IHOP的目标，主要研究人员提交了合作提案。作为所需IHOP仪器套件的一部分，主要研究人员将部署俄克拉何马大学的多普勒车轮（DOW）雷达。这些雷达为IHOP的研究人员提供了一种高分辨率的仪器，可以获得详细的风力测量数据。这些测量适用于IHOP研究的所有四个组成部分。DOWs将与固定站点和移动观测平台协调，以前所未有的数据密度和分辨率对对流前环境进行采样，包括边界和辐合线内部和沿线的风和热力学特性。为了对IHOP的研究贡献，首席研究员将分析这些数据，以阐明水蒸汽场的梯度大小以及风场在聚焦这些不均匀性方面的作用。例如，首席研究人员将确定沿边界或辐合带之间的交叉点的局部辐合中尺度环流，可能与水平对流卷（hcr）有关，是否会产生高水蒸气含量的小块。他们将进一步评估水汽梯度相对于hcr的方向。除了边界研究外，首席研究员还将对没有明显辐合区的日子收集的数据进行分析，以确定在没有实质性聚焦机制的情况下水蒸气场的变化程度。在了解对流前环境中水蒸气变率的性质和程度之后，将基于现有的假设进一步分析这些不均匀性与对流开始过程的关系。例如，如果发现存在高水蒸汽含量的小袋，那么首席研究人员将检查这些地方是否确实有利于深层对流。他们将详细研究与观测到的非常小尺度环流和辐合带相关的抬升深度，以确定边界层中水蒸气的输送。目标是更好地理解对流前环境中控制水蒸气变率的机制，以及这种变率在对流起始过程中表现出来的动力学过程。

The International H20 Project (IHOP) is a multi-investigator, multi-agency program whose chief aim is improved characterization of the four-dimensional distribution of water vapor and its application to improving the understanding and prediction of convection. Program emphasis is on four important research areas: quantitative precipitation forecasting; convective initiation, atmospheric boundary layer processes; and instrumentation testing. Critical to the success of the IHOP is the measurement of wind and thermodynamic values spanning several scales of motion. This will be accomplished with unique and varied instrumentation. To contribute to achieving the goals of IHOP, the Principal Investigators have submitted collaborative proposals. As part of the required IHOP instrumentation suite, the Principal Investigators will deploy the University of Oklahoma Doppler on Wheels (DOW) radars. These radars provide the IHOP researchers with a high resolution instrument for obtaining detailed wind measurements. These measurements have applications to all four IHOP research components. The DOWs will coordinate with both fixed-site and mobile observing platforms to sample with unprecedented data density and resolution the pre-convective environment, including wind and thermodynamic properties within and along boundaries and convergence lines.For their research contribution to the IHOP, the Principal Investigators will analyze these data to elucidate the magnitude of gradients in the water vapor field and the role of the wind field in focusing these inhomogeneities. For example, the Principal Investigators will determine if locally convergent mesoscale circulations along boundaries or intersections between convergence zones, possibly associated with horizontal convective rolls (HCRs), create pockets of high water vapor content. They will further assess the orientation of water vapor gradients with respect to the HCRs. In addition to boundary studies, the Principal Investigators will perform analyses of data collected on days without obvious convergence zones to determine the degree of variability in the water vapor field in the absence of substantial focusing mechanisms. After understanding the nature and degree of water vapor variability in the pre-convective environment further analysis will focus on the relationship of these inhomogeneities to the convective initiation process based on current hypotheses. For example, if pockets of high water vapor content are found to exist, the Principal Investigators will then examine whether deep convection indeed is favored at these locations. They will examine in detail the depth of lifting associated with observed very small scale circulations and convergence zones to determine the transport of water vapor in the boundary layer. The goal is a better understanding of the mechanisms governing water vapor variability in the preconvective environment and the dynamical processes by which this variability is manifested in the convective initiation process.