WS600 Ultrasonic Weather Sensor Precipitation Accuracy

Weather instruments are used on a daily basis to provide accurate information regarding current weather conditions. They record measurements of temperature, humidity, wind speed and direction and precipitation quantity, amount and rate. Precipitation is considered to be one of the most important elements we can measure. Precipitation affects our ecosystems, climate, hydrologic systems, and weather forecasting. While precipitation remains one of the most important measurable element, it is also challenging to gain accurate measurements through weather sensors. Typical instruments for measuring precipitation include the tipping bucket and weighing gauges. The Lufft WS600, however, measures precipitation in a different way. This instrument measures precipitation (type and rate) by means of a built in 24GHz vertically-pointing Doppler Radar. It measures the fall-speed and dimensions of the falling precipitation particles, determines their type and calculates the equivalent liquid equivalent intensity in mm/h.

Since no studies have been done to determine the accuracy of the WS600 precipitation sensor, data collected from this sensor was compared against other co-located sensors at the National Center for Atmospheric Research (NCAR) Marshall Field site. A Vaisala PWD22 sensor, which is a common optical-based sensor that detects precipitation using a forward scatter meter, was used for comparing precipitation types. A GEONOR T-200B all-weather weighing gauge inside a Double Fence Intercomparison Reference (DFIR) shield was used to determine precipitation rates. Data from all three sensors was collected during both rain and snow events and the data from the WS600 was compared to the PWD22 for precipitation type and the GEONOR in the DFIR for precipitation rate. The results of my findings on the accuracy of the WS600 with the comparisons of the PWD22 and the GEONOR sensors are detailed in this presentation.