Irminger Sea Wind Speed Validation
The Irminger Sea in the North Atlantic is a stormy, windy place. Consequently, it is an area of interest for studying the flux balance of heat, momentum, and biogeochemically important gasses such as CO2. The Ocean Observatories Initiative (OOI) deploys meteorological instruments in the Irminger Sea, as part of the OOI Global Irminger Sea Array, to collect in-situ observations in this relatively undersampled region. The goal is to deliver high-quality, long-term observations to the ocean science community to study these, and many more, questions of interest.
Validating these measurements is an important part of delivering quality data to the ocean science community. This summer, rising senior at California State University – Monterey Bay Aaron Wickware took on the challenge of validating OOI wind measurements in the Irminger Sea. Aaron was a Woods Hole Partnership in Education Program (PEP) scholar. PEP is a program designed primarily for college juniors and seniors from underrepresented groups who want to spend a summer gaining practical experience in marine and environmental science. The program consists of an accredited course in global climate change and a ten-week research project.
At Aaron’s disposal were six different sensors: a Gill Windobserver II two-axis sonic anemometer, R.M. Young Wind Monitor propeller-driven anemometer, and a Gill R3 three-axis sonic anemometer integrated into the direct flux covariance instrument (FDCHP) on the recently deployed Irminger Sea surface mooring; a Gill Windobserver II on the surface mooring to be recovered; and the two Vaisala sonic anemometers located on the ship’s mast. Aaron downloaded all the data, identified the overlapping time periods, calculated the wind speeds from the u-and-v-vector components, adjusted the speeds to a common-height using a community standard bulk flux algorithm (COARE 3.5), and took the 1-hour averages. His resulting comparison demonstrated that the two Gill two-axis sonic anemometers under-reported wind at speeds greater than 8 m/s. His workflow and analysis code are accessible on his GitHub page at https://github.com/Aaron-Wickware/ooicgsn-wind-validation.
Aaron’s results are part of a broader OOI Data Team investigation into the accuracy of buoy-based sonic anemometer wind measurements. This work is being followed up by similar sensor cross-comparisons at other mooring arrays. The results will be incorporated into a report to facilitate the use of data from the OOI-deployed buoy-based anemometers.
Figure 1. Comparison of hourly-averaged wind speeds with standard deviations from the six available wind sensors all operating at the same time at the OOI Global Irminger Sea Array.