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. Ambient noise seismology has revolutionized seismic characterization of the Earth's crust from local to global scales. The estimate of Green'sfunction (GF) between two receivers, representing the impulse response of elastic media, can be reconstructed via cross-correlation of the ambientnoise seismograms. A homogenized wave field illuminating the propagation medium in all directions is a prerequisite for obtaining an accurate GF. Forseismic data recorded on glaciers, this condition imposes strong limitations on GF convergence because of minimal seismic scattering in homogeneousice and limitations in network coverage. We address this difficulty by investigating three patterns of seismic wave fields: a favorable distributionof icequakes and noise sources recorded on a dense array of 98 sensors on Glacier d'Argentiere (France), a dominant noise source constituted bya moulin within a smaller seismic array on the Greenland Ice Sheet, and crevasse-generated scattering at Gornergletscher (Switzerland). In Glacierd'Argentiere, surface melt routing through englacial channels produces turbulent water flow, creating sustained ambient seismic sources and thusfavorable conditions for GF estimates. Analysis of the cross-correlation functions reveals non-equally distributed noise sources outside and withinthe recording network. The dense sampling of sensors allows for spatial averaging and accurate GF estimates when stacked on lines of receivers. Theaveraged GFs contain high-frequency ( >30 Hz ) direct and refracted P waves in addition to the fundamental mode of dispersive Rayleigh waves above1  Hz . From seismic velocity measurements, we invert bed properties and depth profiles and map seismic anisotropy, which is likelyintroduced by crevassing. In Greenland, we employ an advanced preprocessing scheme which includes match-field processing and eigenspectralequalization of the cross spectra to remove the moulin source signature and reduce the effect of inhomogeneous wave fields on the GFs. AtGornergletscher, cross-correlations of icequake coda waves show evidence for homogenized incident directions of the scatteredwave field. Optimization of coda correlation windows via a Bayesian inversion based on the GF cross coherency and symmetry further promotes the GFestimate convergence. This study presents new processing schemes on suitable array geometries for passive seismic imaging and monitoring of glaciersand ice sheets.

the cryosphere

On the Green's function emergence from interferometry of seismic wave fields generated in high-melt glaciers: implications for passive imaging and monitoring