Evaluation of In Situ Sensors: How the NWS Has Moved Forward

The National Weather Service has evaluated in-situ sensors for many decades using various measurement techniques. These techniques are continuously validated and updated to take into consideration advances in observing and measurement technology. Recent improvements to in-situ atmospheric measurements and environmental simulation capabilities (to replicate extremes or particular conditions) allow for improved assessments of sensor changes in the observing network. The NWS continues to stand on a base of industry standard test techniques, such as evaluating sensor precision, but the evolving test capabilities greatly reduce risk and increase insight during the transition to an operational product.

When specifically pursuing new capabilities for radiosonde test and evaluation, the result included a reference-quality humidity radiosonde measurement, a method to simulate and validate GPS wind calculations, and a capability to directly compare satellite sounding measurements to a specific radiosonde type measurement anywhere in the world. In addition to these independent comparisons, five radiosondes may be placed onto a single balloon for a greater number of comparisons per payload (compared to two). This paper will provide insight into the NWS test processes and capabilities of in-situ sensors using radiosonde testing as an example.