Comparison Experiment for Rainfall Observation of Micro-smart Weather Stations

Abstract

In order to enhance the understanding of rainfall observation performance of micro-smart (integrated) weather stations and to promote the application in rainfall observation operations, a comparative experiment for the rainfall observation of radar, photoelectric, piezoelectric and tipping bucket micro-smart weather stations is carried out by Hebei Xiong'an New Area Meteorological Service from June to November in 2021. The rainfall observation capability of micro-smart weather stations with different rainfall observation principles are analyzed in terms of total rainfall, rainfall intensity, percentage of rainfall intensity and temporal characteristics. It shows that when the accumulated precipitation exceeds 10 mm, the precipitation measured by the tipping bucket micro-smart weather station can meet observation error control requirements compared with the precipitation observed by the standard station, while results of the radar micro-smart weather station are large and results of the photoelectric and piezoelectric micro-smart weather stations are small. When the cumulative precipitation is less than 10 mm, results of the tipping bucket and piezoelectric micro-smart weather stations can meet observation error control requirements, while results of radar micro-smart weather stations are large and results of photoelectric micro-smart weather stations are small. In terms of rainfall intensity, the double tipping bucket station is suitable for monitoring rainfall extreme, while photovoltaic and piezoelectric stations underestimate the extreme. Radar-based micro-smart weather stations can be calibrated and revised for rainfall extreme monitoring by adjusting internal parameters. Analysis of different rainfall intensities and their corresponding rainfall ratios show that the rain intensity corresponding to a rain intensity accumulation ratio greater than 95% at each micro-smart weather station is[0.3 mm·min-1, 0.6 mm·min-1] and the rain intensity corresponding to a rainfall accumulation ratio greater than 50% is[0.1 mm·min-1, 0.4 mm·min-1]. It shows that within 0.4 mm·min-1, the proportion of rainfall measured by any type of rain sensor accounts for more than half of the total rainfall, so more attention should be paid to accuracy for small rain intensity in the operational rain sensor rate determination. As the resolving capacity increases, the tipping bucket type micro-smart weather station becomes less sensitive to the starting time and will identify the ending time earlier. The radar type micro-smart weather station responds to rainfall relatively more quickly. Finer resolving capacity of the rain sensor will enhance the monitoring effectiveness of fine rainfall and the effective rainfall rate.

Keywords

• micro-smart (integrated) weather stations
• rainfall characteristics
• field comparison observation