### Physical Variables written by CTIP simulations

The coordinate system consists of
• Longitude Lon with positive vector components meaning eastward,
• Latitude Lat from -90 at the south pole to 90 at the north pole with positive being northward,
• pressure level IP or height H in km.
Vector (arrow) plots of the velocities only make sense as:
• vertical cuts (meridional or at constant-latitude) if UseHeight is selected,
• synoptic maps of velocity vectors (over local time and latitude) if plotted at constant height (not constant pressure level IP).
The basic plasma and electrodynamic field variables in 3D are:
• H (height) in [km] corresponding to pressure level number IP
The height of a pressure level varies spatially and with time. Heights covered start at about 80 km (IP=0) and reach a few hundred km above ground (the maximum found for IP=14, the top layer, is typically between 450 km and 1000 km).
The height can be used as an alternative 3rd coordinate for plotting.
• Particle number density N in [m-3] with species identifier (after the "_"):
• e: electrons,
• O: oxygen ions,
• N2: nitrogen molecules,
• O2: oxygen molecules.
• Neutral gas temperature T_n in [K].
• Mean molecular mass Rmt in [amu].
• Hall and Pedersen conductivities sigma_H, sigma_P in [mho/m].
• Neutral gas velocity Vn in [m/s] with its three components
Vn_Lat (meridional; CTIP name "V_x"),
Vn_Lon (zonal, longitudinal; CTIP name "V_y") and
Vn_IP (vertical, radial; CTIP name "V_z").
• Plasma (ion) velocity Vi in [m/s] with its components
Vi_Lat ("Vi_x"),
Vi_Lon ("Vi_y").
Vi_IP ("Vi_z") is missing in the model output and assumed to be zero for vector arrow plots.
• sigmaP, sigmaH: Pedersen and Hall conductivities [S/m],
Height-integrated quantities in 3D data
available at each position in local time and latitude (obtained from 3D CTIP variables above)
• NmF2: maximum electron density N_e in [m-3] in the vertical profile
• HmF2: height in [km] of the maximum of N_e (see NmF2)
• TEC, total electron content, integrated over altitudes between 80 and 2000 km [TECU=10 electrons/m2]
• O/N2: ratio of N_O and N_N2 in the vertical column. The ratio is calculated from the pressure level where SH*N_N2=1021m-2 with SH=k_B T_n/(g*m(N2)) being the scale height of the N2 gas species (m(N2)=28 amu). The O-column density is obtained by interpolation at this pressure level using model outputs at pressure levels 8 and 9.

Last updated: Sept. 10, 2010 - Lutz Rastätter

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