Radiosonde Surface Observing Instrumentation System (RSOIS)

As part of an upper-air observation, a complete surface weather observation is required. To standardize and improve the quality of this observation, RSOIS is being deployed at NWS upper-air stations. RSOIS measures the temperature, relative humidity (RH), and winds near the location where the radiosonde is released. NOTE: Air pressure is measured by a separate digital barometer and clouds/weather are determined by the upper-air observer. Below are photographs of RSOIS taken at two upper-air stations.

The aspirated temperature and relative humidity sensors are installed on a boom. In this case, RSOIS was installed on an existing tower.

Here's a closer look at the temperature and RH sensor.

The three prong sonic anemometer (no moving parts) is also mounted on a boom 6 to 10 meters above the ground. At the top of the tower is the ground tracking system "Target Antenna" being illuminated by the setting sun.

Here is the RSOIS base station containing the electronic hardware for processing and transmitting the weather measurements.

Here is the RSOIS base station with the door opened.

Above is the RSOIS data display case inside the weather office. Observations are sent to the display via radio or a fiber optic cable link.