How Accurate are They? A Rain Gauge Quality Comparison

Chicago is a city that takes up a small domain of land and yet is a densely populated, complex environment home to numerous microclimates that often vary on a fine scale, sometimes even block to block. This becomes a problem as models often do not perform well in this region owing to Chicago fitting within the grid spacing of the models (Argonne National Laboratory, 2023). While the broad grid spacing and resulting modeled weather phenomena may not be as big of a problem in a sparsely populated area, in Chicago, heavily populated neighborhoods just blocks away from each other can experience drastically different weather while expecting the broad modeled weather. This issue of inaccurate representation of localized weather phenomena by models highlights the need for correspondingly localized weather observations to create better initial conditions for the models, improving the accuracy of models on a finer scale. These more localized weather observations also help to improve the understanding of the impacts weather has on local communities. The focus of this research is to determine the most accurate rain gauge from a broad selection of gauges including low-cost consumer grade rain gauges, three tipping bucket rain gauges, a weighted bucket rain gauge, three optical rain gauges, and three standard rain gauges whose average was taken as the true rainfall value. During the period examined, the rain gauges collected data during varying conditions including light, moderate, and heavy rainfall events. The preliminary results from the data show that the low-cost rain gauges as well as the weighted bucket rain gauge performed well, especially on a case-by-case basis and when compared to the other instruments being evaluated. The low-cost rain gauge’s performance is particularly interesting as the low-cost makes it more feasible to deploy a denser network of instruments throughout Chicago. With more rain gauges deployed in the Chicago area, the additional fine-scale rainfall and flooding data recorded can be used to improve models and the understanding of how localized weather affects the people who live within Chicago.