qlawton/QTrack

Python module to track African Easterly Waves (AEW) in reanalysis and model output data. # QTrack: An African Easterly Wave Tracker **Version: 0.0.4** The AEW tracker was developed by **Quinton Lawton**, currently affiliated with the NSF National Center for Atmospheric Research (NSF NCAR). This python module was developed with the support of **Zachary Moon** (NOAA ARL/Texas A&M University) and **Kelly Núñez Ocasio** (Texas A&M University). This is similar to the AEW Tracker described by Lawton et al. (2022), which can be found here: doi.org. Existing AEW tracks for ERA5 and MERRA-2 from 1979 - 2023 are already produced and available here: zenodo.org ## Module Installation The easiest way to install is through pip and the PyPi repository. `pip install qtrack` ## How the tracker works The AEW tracker uses an input file containing 700hPa zonal (u) and meridional (v) wind and computes a curvature vorticity (CV) term that is smoothed using a 600km average around each gridpoint. Local maxima in this CV are then tracked in two different ways. Over the African continent, meridional averages of CV are used to find longitudinal local maxima, which are used as a first guess for a centroid location. Set thresholds of CV value define when a new AEW is initialized and whether an existing one continues being tracked. Over the Atlantic, the first guess for an existing AEW's location is estimated by the AEW's propagation speed, and it is later found again using a centroid. A post processing script cleans up some of the tracks. More detailed information on the tracking, not provided in the Lawton et al. (2022) paper or here, can be found in an online technical guide here: osf.io ### Important Note on Non-Divergent Wind Step Due to inconsistencies in the windspharm package, which computes the non-divergent wind using spherical harmonics, the non-divergent wind step is currently not included in the package. This step was largely superfluous and thus not including this step is is not anticipated …