Description: Epithermal neutron fluxes measured using the Neutron Spectrometer component of the Mars OdysscNGamma-Ray Spectrometer suite of instruments were studied to determ i ne the spatial and temporal dependence of CO2 frost cover of the nor t h polar cap for L, between 329 and 99 arcoccntric longitude. This time period spans the la t e northern xvinter through summer solstice . In the absence of a CO, cuvcr, the entire basement terrain p o l eward of about +55 latitude is vm, rich in I1 :0 . The consequent enhanced abundance of hydrogen in near-surface soils leads to an anomaluusly low flux of oumardly leaking cpithcrmal ncutrons, wh i ch is a prominent signatu r e of epi t hermal neutron maps measured after about L, = 90 . Because the epithermal neutron flux rises monotonically w i t h increasing thickness of t h e CO . fros t cover, it provides a robust measure of the CO2 thickness in space and time .
Date: January 1, 2003
Creator: Feldman, W. C. (William C.); Boynton, W. V. (William V.); Prettyman, T. H. (Thomas H.); Kelly, N. & Maurice, S. (Sylvestre)
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Partner: UNT Libraries Government Documents Department