Dome A Inverse Model

This is the result of a geophysical inversion for the ice sheet and basal hydrological state around Dome A, East Antarctica. The datasets used to constrain the inversion are observations of basal water, basal freeze-on, internal layers, and aeromagnetic data. The inversion solved for best-fit geothermal flux and accumulation rate fields, along with their respective uncertainty and skewness, and also partitioned the fractional contribution of each individual data type towards constraining the final answer. 

Also included is the ice sheet state produced by the best-fit forward model, including: englacial and basal temperatures, basal melt/freeze rate and water flux, strain heating, hydraulic heating (ie, supercooling_viscous dissipation in the water system), ice velocity, strain rate, viscosity, and shape function; plus post-processing variables like ice age, best-fit H* in a D-J model, freeze-on thickness, model echo-free-zone thickness, isotopic smoothing due to diffusion, and the oldest useful ice for ice coring.

Parameters included in the inversion results for both geothermal flux and accumulation rate: output of evolutionary algorithm, local optimization correction, best-fit fields, uncertainty estimate, skewness estimate, and fractional constraints contributed by the five constraints used in the inversion (water observations, freeze-on observations, internal layer observations, prior geothermal flux estimate based on aeromagnetic observations, and smoothness contraint). Also contains an estimate of the bias in geothermal flux induced by the use of smoothed gridded topography that does not fully capture the deep narrow valleys where water is present. All inversion results variables are 2D.

Best-fit model results include: englacial temperature (3D), basal temperature (2D), basal logical state (wet/dry; 2D), basal melt rate (2D), basal water flux (2 components plus magnitude, 2D), hydraulic heating (sum of viscous dissipation and supercooling in basal hydrological system, 2D), ice velocity (3 components, 3D), vertically averaged ice velocity (2 components plus magnitude, 2D), effective strain rate (3D), effective viscosity (3D), horizontal velocity shape function (3D), strain heating (3D), corner elevation in best-fit D-J model (2D), freeze-on thickness (2D), ice age (3D), spreading length from isotopic diffusion (3D), echo-free-zone thickness (2D), oldest useful ice for ice coring (2D). Best-fit model also includes a misfits structure describing the misfit with the observational constraints.

Units: all velocities (including accumulation rate and basal melt rate) are in m/yr. Water flux is in m^2/yr. Strain rate is in 1/yr. Ice age is in yr. All other variables are in MKS units (temperature is in K, geothermal heat flux and hydraulic heating are in W/m^2, strain heating is in W/m^3, viscosity is in Pa*s, etc).