DOI: 10.5061/dryad.63xsj3v88
title: CESM2 and E3SM variables used for diagnosing westerly wind events

description: This data set contains variables needed to identify and evaluate westerly
 wind events (WWEs) in a simulation using the Community Earth System Model
 version 2 (CESM2) and a simulation using the Energy Exascale Earth System
 Model (E3SM). The CESM2 simulation was a historical run from 1980–1999
 that was restarted from the CMIP6 historical simulation. The E3SM was a
 400-year pre-industrial simulation from which we analyzed the last 39
 years. Only those last 39 years are included in the E3SM files. 
 For both the CESM2 and E3SM simulations, meridionally-averaged zonal wind
 stress from 2.5°S – 2.5°N filtered from 5–90 days was used to identify
 westerly wind events in the Pacific Ocean (120°E – 280°E). Events were
 defined as patches of zonal wind stress in the time-longitude plane with
 zonal wind stress values of 0.04 Nm-2 or larger that lasted at least 5
 days and were at least 10° longitude long. Meridional wind stress was also
 used along with the zonal wind stress to make spatiotemporal composite
 wind-stress vectors across all WWEs for each model. Outgoing longwave
 radiation (OLR) was also used as a proxy for convection. Again
 spatiotemporal composites were made of OLR centered on WWEs for each
 model. Finally, 1000-mb zonal wind speed was used to determine if WWEs
 defined by 5-90 day filtered zonal wind stress actually correspond to
 unfiltered westerly wind speeds. These simulations were part of a larger
 set of simulations used to evalute the fidelity of WWEs in CMIP6
 simulations through a variety of model diagnostics. WWEs are important to
 air-sea feedbacks as they can initiate ocean Kelvin waves that then
 propagate eastward altering the thermodynamic structure of the upper
 ocean. Most importantly, these WWE-generated Kelvin waves can play an
 important role in El Nino Southern Oscillation dynamics.
description: # CESM2 and E3SM variables used for diagnosing westerly wind events
 [https://doi.org/10.5061/dryad.63xsj3v88](https://doi.org/10.5061/dryad.63xsj3v88) There is a .tar.gz file for both the CESM2 and E3SM variables that were used to diagnose westerly wind events in each simulation. Af the tar files are unpacked there will be 4 directories that contain files for zonal and meridional wind stress, outgoing longwave radiation, and 1000-mb zonal wind speed. ## Description of the data and file structure The CESM2\_rlut\_tauu\_tauv\_ua.tar.gz file contains the following directories and files when unpacked, where each file contains one 3D variable with 64°lat x 288° lon and 7301 days. An ncdump on each file will show the metadata. rlut -&gt; CESM2.0\_B1850.cam.h1.FLUT.30S-30N.00010101-00210101.nc The rlut variable is the outgoing longwave radiation (W/m2) tauu -&gt; CESM2.0\_B1850.cam.h1.TAUX.30S-30N.00010101-00210101.nc The tauu variable is the zonal wind stress (N/m2) tauv -&gt; CESM2.0\_B1850.cam.h1.TAUY.30S-30N.00010101-00210101.nc The tauv variable is the meridional wind stress (N/m2) ua -&gt; level1000mb -&gt; CESM2.0\_BHIST.cam.h1.U1000.30S-30N.00010101-00210101.time\_bnds.nc The ua variable is the 1000-mb zonal wind speed (m/s) \-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\- The E3SM\_rlut\_tauu\_tauv\_ua.tar.gz file contains the following directories and files when unpacked, where each file contains one 3D variable with 60°lat x 360° lon and 14235 days. An ncdump on each file will show the metadata. rlut -&gt; CESM2.0\_B1850.cam.h1.FLUT.30S-30N.00010101-00210101.nc The rlut variable is the outgoing longwave radiation (W/m2) tauu -&gt; CESM2.0\_B1850.cam.h1.TAUX.30S-30N.00010101-00210101.nc The tauu variable is the zonal wind stress (N/m2) tauv -&gt; CESM2.0\_B1850.cam.h1.TAUY.30S-30N.00010101-00210101.nc The tauv variable is the meridional wind stress (N/m2) ua -&gt; level1000mb -&gt; ua\_timeNOTrecordDim -&gt; E3SM.ctrl.ua000.0362-0400.2p5NSavg.nc The ua variable is the 1000-mb zonal wind speed (m/s) averaged between 2.5°S-2.5°N, so the latitude dimension has been dropped ## Code/Software Python 3.8 was used to analyze this data