<br/>
<h2> Cain Mars crustal model magnetic field</h2>
<UL> 
<li> <b>Brief description of Cain model</b>:
A potential function using spherical harmonics up to degree and order 90 
was derived from a selection of Mars Global Surveyor (MGS) vector data. 
These included all three components of those taken below 200 km 
altitude during the two aerobraking phases (AB1 and AB2), the Science 
Phase Orbits (SPO), and the higher altitude (367435 km) data
taken on the nightside during the Mapping Phase Orbits (MPO). 
The merger of these sets of data provided total global coverage. 
The technique used was a least squares minimization developed for 
Earth field analysis whereby the relative weighting of each data 
source was determined by the width of a Gaussian fit to the residual 
distribution about the potential function. Also, data selection by area 
and area weight functions were used to improve normalization. 
<b>Comparisons with 
other published maps and models for Mars show general agreement with 
the field representations at MPO altitudes, but disagreements up to several 
hundred nT in components calculated for areodetic altitudes below 200 km</b>  
<li> A detailed description along with complete references is available 
<a href="http://geomag.gfdi.fsu.edu/mars/papers/n_90/index.htm" target=_BLANK>here</a>.    
</UL>