Ninth International Conference on Permafrost ... - IARC Research

Ni n t h In t e r n at i o n a l Co n f e r e n c e o n Pe r m a f r o s tAlbedo50S80N80S50N180 360 0 180 360Surface Cover Thermal Inertia (60–400 J m -2 K -1 s -0.5 )Temperature Derived Permafrost Depth (3-33 cm)Temperature Derived Permafrost DepthNeutron Derived Water DepthFigure 1. Albedo, surface cover thermal inertia, andpermafrost/water depth maps. The temperature-derived depthmap is shown twice: at full resolution (third from top) andspatially filtered and masked (fourth from top) to match thecoverage and resolution of the neutron-derived water depth maps.The maps cover all longitudes and 50–80 N/S latitude.70 NIt is clear that there are regional variations in permafrostdepth at the scale of the TES and Neutron Spectrometermeasurements. Local slopes, surface cover thermal inertia,and albedo can all have significant effects on the depth ofthe permafrost. Permafrost depths have been shown to havethis variability at the sub-km scale (Bandfield 2007). Figure2 displays permafrost depths determined from THEMISseasonal temperature data over the region of the 2007Mars Scout Phoenix spacecraft landing site. The averagepermafrost depth retrieved from the TES data for the regionis 4.5 cm. The THEMIS data has slightly higher valuesof 6.2 cm. This comparison shows that the low resolutionmeasurements retain an overall accuracy, but are not able toresolve a large amount of detailed variability that is clearlypresent. Spatial variability in water ice/permafrost depthsis present at all scales and the THEMIS data provide animportant bridge between the tens to hundreds of km scalesof the TES and Neutron Spectrometer measurements and the