Collaborative Research: Experimental Investigation of X-band Polarimetric-Radar Rainfall Estimation

0003054山洪和城市水文预报系统需要精确的降水定量测量，时间尺度以分钟为单位，空间尺度以一平方公里为单位。我们建议探索x波段极化分集雷达提供高分辨率降雨产品的潜力。极化雷达测量增加了有关降雨系统的信息，对降雨率变率有更好的敏感性。然而，使用高频雷达的一个主要缺点是，在高降雨强度下，波束功率衰减和后向散射相移都可能很明显，从而对降雨产品的准确性产生负面影响。提出的研究目标是开发一种方法，将x波段雷达系统的优势与极化分集技术的优势相结合。我们的目标是证明这种方法可以在适合小尺度水文预测的时空尺度上产生可靠的定量降雨估计。我们的调查将通过两次实地实验来促进，以便在设备齐全的地点获得高分辨率极化雷达数据。第一个实验将在爱荷华州东南部的爱荷华水力研究所的水文气象监测设施中进行。这些设施包括一个二维视频测量仪，光学雨量计，一个移动垂直指向多普勒雷达，以及一个非常密集的倾卸桶雨量计网络。我们将利用雅典国家天文台收集极化雷达测量数据。（NOA）移动双偏振x波段雷达（X-POL）我们会利用这些资料制订雨量估计计划。我们将利用高分辨率雨量计集群数据，评估该方案在不同时空尺度聚集的估计误差结构。第二个实验将在密西西比州的古德温河盆地进行。高密度雨量计和水流网络将与数个测量仪相补充，noaa X-POL雷达将加入另一个由普林斯顿大学研究人员操作的x波段移动雷达（车轮上的多普勒）。这项研究的成功完成可能提供一种新的遥感工具，如果证明可靠，将是一个有吸引力和经济上负担得起的解决办法，以监测NEXRAD雷达网络覆盖不足的偏远流域和城市地区的问题。

0003054AnagnostouFlash-flood and urban hydrologic forecast systems required accurate quantitative measurements of precipitation at temporal scales of minutes and spatial scales on the order of one square kilometer. We propose to explore the potential of X-band polarization diversity radar to provide such high-resolution rainfall products. Polarimetric radar measurements add information about rainfall system and have better sensitivity to rainfall rate variability. However, a major drawback of using high frequency radar is that both beam power attenuation and backscattering phase shift can be significant at high rainfall intensities and thus negatively affect the accuracy of rainfall products. The goal of the proposed research is to develop a methodology, which would combine the advantages of X-band radar systems with those of polarization diversity techniques. We aim at demonstrating that such a methodology can lead to reliable quantitative rainfall estimates at spatio-temporal scales suitable for small-scale hydrologic predictions. Our investigation will be facilitated through two field experiments to obtain high-resolution polarimetric radar data at well-instrumented sites. The first experiment will take place in Southeast Iowa at the hydrometeorological monitoring facilities of the Iowa Institute of Hydraulic Research. These facilities include a two-dimensional video disdrometer, optical rain gauges, a mobile vertically pointing Doppler radar, and a very dense network of tipping bucket rain gauges. We will collect the polarimetric radar measurements using the National Observatory of Athens. (NOA) mobile dual-polarization X-band radar (X-POL). We will use the data in the development of a rainfall estimation scheme. We will assess the error structure of the scheme's estimates a various spatial and temporal scales of aggregation using high-resolution rain gauge cluster data. The second experiment will take place at Goodwin Creek basin in Mississippi. A high-density rain gauge and streamflow network there will be complemented with several disdrometers, and the NOA X-POL radar will join another X-band mobile radar (Doppler on Wheels) operated by researchers from Princeton University. Successful completion of this research may provide a new remote sensing tool that, if proven reliable, would be an attractive and economically affordable solution to the problem of monitoring remote basins and urban areas that are poorly covered by the NEXRAD radar network.