WAACM-X Output (lon and mlon, lat and mlat)

[proctor]

Hello,

I am using the WAACM-X output posted on the Climate Data Gateway at NCAR website. There are two different longitude and latitude outputs, mlon and mlat as well as lon and lat. The mlon and mlat seem to correspond to the electric field outputs while lon and lat correspond to the majority of the other outputs. I am wondering if these are different coordinate systems from each other as the length and step size are different. Also the electric field outputs seem to not have an altitude dimension. So I am wondering at what altitude is it reported at. The electric field outputs I am looking at are ED1 and ED2.

Matthew Proctor

 

[npedatella]

Hi Matthew - There are two coordinate systems in WACCM-X, one defined in geographic coordinates and the other in geomagnetic. The geomagnetic coordinate system (mlat, mlon) is used for the electrodynamics, and this is a different coordinate system then the geographic coordinate system (lat, lon). The ED1 and ED2 outputs are the two dimensional electric field which is calculated from the two dimensional electric potential. The electric potential is solved in two dimensions under the assumption that the field lines are equipotential. Note that the electrodynamics in WACCMX are similar to the TIE-GCM (see https://www.hao.ucar.edu/modeling/tgcm/doc/description/model_description.pdf).

Nick