The description of snow microstructure in microwave\nmodels is often simplified to facilitate electromagnetic\ncalculations. Within dense media radiative transfer\n(DMRT), the microstructure is commonly described by\nsticky hard spheres (SHS). An objective mapping of real\nsnow onto SHS is however missing which prevents measured\ninput parameters from being used for DMRT. In contrast, the\nmicrowave emission model of layered snowpacks (MEMLS)\nemploys a conceptually different approach, based on the twopoint\ncorrelation function which is accessible by tomography.\nHere we show the equivalence of both electromagnetic\napproaches by reformulating their microstructural models in\na common framework. Using analytical results for the twopoint\ncorrelation function of hard spheres, we show that the\nscattering coefficient in both models only differs by a factor\nwhich is close to unity, weakly dependent on ice volume fraction\nand independent of other microstructural details. Additionally,\nour analysis provides an objective retrieval method\nfor the SHS parameters (diameter and stickiness) from tomography\nimages. For a comprehensive data set we demonstrate\nthe variability of stickiness and compare the SHS diameter\nto the optical equivalent diameter. Our results confirm\nthe necessity of a large grain-size scaling when relating both\ndiameters in the non-sticky case, as previously suggested by\nseveral authors.
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