Ice Band Research Articles

DETECTION OF WATER ICE GRAINS ON THE SURFACE OF THE CIRCUMSTELLAR DISK AROUND HD 142527

Coronagraphic imaging for the Herbig Ae star, HD 142527, was performed using the Coronagraphic Imager with Adaptive Optics (CIAO) on the 8.2 m Subaru Telescope. The images were obtained in the H2O ice filter (λ = 3.08 μm) using adaptive optics (AO), and in the L' band without AO. Combining these data with previous observational results in the H and K bands, we derived the spectra of the scattered light from the circumstellar disk around HD 142527 and detected an H2O ice absorption feature in the spectra. This result can be explained by the presence of silicate and H2O ice grains of ∼1 μm in size, according to the prediction model by Inoue et al. This grain size is consistent with previous observational study by Fukagawa et al. and Fujiwara et al. The present result demonstrates that high-resolution imaging of disk-scattered light in the ice band is useful for detecting H2O ice grain distributions in circumstellar disks.

MRO/CRISM Retrieval of Surface Lambert Albedos for Multispectral Mapping of Mars With DISORT-Based Radiative Transfer Modeling: Phase 1—Using Historical Climatology for Temperatures, Aerosol Optical Depths, and Atmospheric Pressures

We discuss the DISORT-based radiative transfer pipeline (ldquoCRISM_LambertAlbrdquo) for atmospheric and thermal correction of MRO/CRISM data acquired in multispectral mapping mode (~200 m/pixel, 72 spectral channels). Currently, in this phase-one version of the system, we use aerosol optical depths, surface temperatures, and lower atmospheric temperatures, all from climatology derived from Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) data and from surface altimetry derived from MGS Mars Orbiter Laser Altimeter (MOLA). The DISORT-based model takes the dust and ice aerosol optical depths (scaled to the CRISM wavelength range), the surface pressures (computed from MOLA altimetry, MGS-TES lower atmospheric thermometry, and Viking-based pressure climatology), the surface temperatures, the reconstructed instrumental photometric angles, and the measured I/F spectrum as inputs, and then a Lambertian albedo spectrum is computed as the output. The Lambertian albedo spectrum is valuable geologically because it allows the mineralogical composition to be estimated. Here, I/F is defined as the ratio of the radiance measured by CRISM to the solar irradiance at Mars divided by pi; if there was no martian atmosphere, I/F divided by the cosine of the incidence angle would be equal to the Lambert albedo for a Lambertian surface. After discussing the capabilities and limitations of the pipeline software system, we demonstrate its application on several multispectral data cubes-particularly, the outer reaches of the northern ice cap of Mars, the Tyrrhena Terra area that is northeast of the Hellas basin, and an area near the landing site for the Phoenix mission in the northern plains. For the icy spectra near the northern polar cap, aerosols need to be included in order to properly correct for the CO2 absorption in the H2O ice bands at wavelengths near 2.0 mum. In future phases of software development, we intend to use CRISM data directly in order to retrieve the spatiotemporal maps of aerosol optical depths, surface pressure, and surface temperature. This will allow a second level of refinement in the atmospheric and thermal correction of CRISM multispectral data.

Digging into the surface of the icy dwarf planet Eris

We describe optical spectroscopic observations of the icy dwarf planet Eris with the 6.5-m MMT telescope and the Red Channel Spectrograph. We report a correlation, that is at the edge of statistical significance, between blue shift and albedo at maximum absorption for five methane ice bands. We interpret the correlation as an increasing dilution of methane ice with another ice component, probably nitrogen, with increasing depth into the surface. We suggest a mechanism to explain the apparent increase in nitrogen with depth. Specifically, if we are seeing Eris 50 degrees from pole-on [Brown, M.E., Schaller, L., 2008. Science 316, 1585], the pole we are seeing now at aphelion was in winter darkness at perihelion. Near perihelion, sublimation could have built up atmospheric pressure on the sunlit (summer) hemisphere sufficient to drive winds toward the dark (winter) hemisphere, where the winds would condense. Because nitrogen is more volatile and scarcer than methane, it sublimated from the sunlit hemisphere relatively early in the season, so the early summer atmosphere was nitrogen rich, and so was the ice deposited on the winter pole. Later in the season, much of the nitrogen was exhausted from the summer pole, but there was plenty of methane, which continued to sublimate. At this point, the atmosphere was more depleted in nitrogen, as was the ice freezing out on top of the earlier deposited nitrogen rich ice. Our increasing nitrogen abundance with depth apparently contradicts the Licandro et al. [Licandro, J., Grundy, W.M., Pinilla-Alonso, N., Leisy, P., 2006. Astron. Astrophys. 458, L5–L8] result of a decreasing nitrogen abundance with depth. A comparison of observational, data reduction, and analysis techniques between the two works, suggests the difference between the two works is real. If so, we may be witnessing the signature of weather on Eris. The work reported here is intended to trigger further observational effort by the community.

Laboratory set-up for studying ices at the MIR and FIR region

H 2 O, CO and CO 2 ices are condensed on carbonaceous and silicate dust grains in dense interstellar clouds and circumstellar environments. The presence of these ices is inferred by analysing their infrared (IR) spectra. The upcoming Herschel space observatory (HERSCHEL) and ground-based astronomy project (ALMA) will provide new spectral data in the unexplored far infrared (FIR) and sub-millimetre range. In our laboratory we are developing instrumentation to study ices at IR region. One of the key components of our laboratory is a silicon composite bolometer in our IFS. This detector allows us to obtain spectra with a sensitivity much greater than that obtained with a standard deuterated triglycine sulphate (DTGS) detector working at room temperature and under vacuum conditions. We plan to collect mid infrared (MIR) and FIR spectra of simple ices and their mixtures and compare these with observational data. It is also planned to do a systematic laboratory study of the effects that ultraviolet (UV) photolysis and thermal annealing have on the ice band profiles and their structure.

Surface characterization of Pluto and Charon by L and M band spectra

Context. One of the main scientific objectives of NASA's New Horizons mission is to map the icy surface compositions of Pluto and its moon Charon. The encounter will be in 2015. Meanwhile remote observations from earth and space are the most suitable means to enhance further our knowledge of the Pluto/Charon system. Aims. We intend to assist the New Horizons mission by improving our knowledge of Pluto's and Charon's surface compositions. Specifically, we extend the wavelength coverage of the surface spectroscopy beyond the K band, with the goal to detect further surface ice absorption bands predicted from the models that are based on the available JHK spectra, and to search for signatures of yet unknown ices. In particular we aim to resolve the binary system Pluto/Charon and to obtain, for the first time, spectra up to 5 μ m of the two objects resolved. Methods. Spectroscopic measurements of Pluto/Charon taken with the adaptive optics instrument NACO at the ESO VLT in the interval 3–7 August 2005 were obtained. The nature and properties of the compounds present on the surface of Pluto and Charon are investigated by applying a Hapke radiative transfer model to the measured spectra. Results. We present Pluto's reflectance spectrum in the wavelength range (1–5) μ m. Apart from known and expected absorption bands of methane ice, our Pluto spectrum reveals a new absorption band centered near 4.6 μ m, not previously detected. This absorption band could be related to the presence of CO and nitriles (compounds of C and N connected with a triple bond). A geographic mixture of pure methane ice with two different grain sizes, methane and CO ice diluted in nitrogen, CH 2 CHCN and titan tholin gives the best fit to Pluto's spectrum, although not in all details. Differences compared to published Pluto spectra from 2001 taken at similar longitude could be due to a different surface coverage in latitude or to a possible resurfacing process on Pluto. Charon's spectrum is measured in the wavelength range (1–4) μ m. The surface of Charon can be modeled by pure water ice darkened by a spectrally neutral continuum absorber.

Impact of irradiated methane ice crusts on compositional interpretations of TNOs

Context. Minor bodies in the outer solar system show a wide variety of spectral colors related to both composition and surface processing, e.g. cosmic ion irradiation. Aims. We investigate the effect of an irradiation mantle on the reflectance spectrum in the V-NIR (visible-near-infrared) range. In particular we investigate the condition needed for a weathering crust to mask the presence of water ice. Methods. We start from laboratory experiments of ion irradiated methane ice to study the optical properties of the hydrocarbon residue by-product of the space weathering process. We compare the real and imaginary index of refraction with those of Titan and ice tholins and with those of amorphous carbon. We use the estimated optical constants to model a layered configuration using the Hapke theory, varying the thickness and grain size of the modeled crust. Results. We find that a relatively thin (tens of microns) crust of irradiated methane by-products can mask the presence of water ice bands in the spectrum, while a much larger layer of tholins would be required to produce a similar effect. We also estimate the conditions for the detection of water ice on trans-Neptunian objects (TNOs). We discuss the results in view of the astrophysical timescale.

Ross Sea polynyas: Response of ice concentration retrievals to large areas of thin ice

For a 3‐month period between May and July of 2005, we examine the response of the Advanced Microwave Scanning Radiometer (AMSR‐E) Enhanced NASA Team 2 (NT2) and AMSR‐E Bootstrap (ABA) ice concentration algorithms to large areas of thin ice of the Ross Sea polynyas. Coincident Envisat Synthetic Aperture Radar (SAR) coverage of the region during this period offers a detailed look at the development of the polynyas within several hundred kilometers of the ice front. The high‐resolution imagery and derived ice motion fields show bands of polynya ice, covering up to ∼105 km2 of the Ross Sea, that are associated with wind‐forced advection. In this study, ice thickness from AMSR‐E 36 GHz polarization information serves as the basis for examination of the response. The quality of the thickness of newly formed sea ice (<10 cm) from AMSR‐E is first assessed with thickness estimates derived from ice surface temperatures from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. The effect of large areas of thin ice in lowering the ice concentration estimates from both NT2/ABA approaches is clearly demonstrated. Results show relatively robust relationships between retrieved ice concentrations and thin ice thickness estimates that differ between the two algorithms. These relationships define the approximate spatial coincidence of ice concentration and thickness isopleths. Using the 83% (ABA) and 91% (NT2) isopleths as polynya boundaries, we show that the computed coverage compares well with that using the estimated 10‐cm thickness contour. The thin ice response characterized here suggests that in regions with polynyas, the retrieval results could be used to provide useful geophysical information, namely thickness and coverage.

Evolution of Dust and Ice Features around FU Orionis Objects

(abridged) We present spectroscopy data for a sample of 14 FUors and 2 TTauri stars observed with the Spitzer Space Telescope or with the Infrared Space Observatory (ISO). Based on the appearance of the 10 micron silicate feature we define 2 categories of FUors. Objects showing the silicate feature in absorption (Category 1) are still embedded in a dusty and icy envelope. The shape of the 10 micron silicate absorption bands is compared to typical dust compositions of the interstellar medium and found to be in general agreement. Only one object (RNO 1B) appears to be too rich in amorphous pyroxene dust, but a superposed emission feature can explain the observed shape. We derive optical depths and extinction values from the silicate band and additional ice bands at 6.0, 6.8 and 15.2 micron. In particular the analysis of the CO_2 ice band at 15.2 micron allows us to search for evidence for ice processing and constrains whether the absorbing material is physically linked to the central object or in the foreground. For objects showing the silicate feature in emission (Category 2), we argue that the emission comes from the surface layer of accretion disks. Analyzing the dust composition reveals that significant grain growth has already taken place within the accretion disks, but no clear indications for crystallization are present. We discuss how these observational results can be explained in the picture of a young, and highly active accretion disk. Finally, a framework is proposed as to how the two categories of FUors can be understood in a general paradigm of the evolution of young, low-mass stars. Only one object (Parsamian 21) shows PAH emission features. Their shapes, however, are often seen toward evolved stars and we question the object's status as a FUor and discuss other possible classifications.

Spectroscopic Search for Water Ice on Jovian Trojan Asteroids

The Jovian Trojans likely formed beyond the snow line and so may contain considerable amounts of water ice. We seek near-infrared spectroscopic evidence for the 1.5 and 2.0 μm water ice bands in the Trojans. Our sample is focused on objects identified in previous measurements as being of special interest. The unusual Trojan (4709) Ennomos has a geometric albedo significantly above the mean Trojan albedo, perhaps because a recent impact has coated part of the surface with freshly excavated ice. Trojans (911) Agamemnon, (617) Patroclus, (1143) Odysseus, and (2797) Teucer were also observed. These objects have been independently reported to show possible weak absorptions at 1.7 and 2.3 μm, respectively. If real, the latter features may be due to organic materials present on the surfaces. However, all five targets appear spectrally featureless, even in our highest signal-to-noise ratio data. Simple models consisting of mixtures of water ice and a spectrally featureless material were used to quantify the limits to surface ice.

Optical Spectroscopy of the Large Kuiper Belt Objects 136472 (2005 FY9) and 136108 (2003 EL61)

We present high signal precision optical reflectance spectra of the large Kuiper Belt objects 2005 FY9 and 2003 EL61. The spectrum of 2005 FY9 exhibits strong CH4 ice bands. A comparison between the spectrum and a Hapke model indicates that the CH4 bands are shifted 3.25 ± 2.25 A relative to pure CH4 ice, suggesting the presence of another ice component on the surface of 2005 FY9, possibly N2 ice, CO ice, or Ar. The spectrum of 2003 EL61 is remarkably featureless. There is a hint of an O2 ice band at 5773 A; however, this feature needs to be confirmed by future spectroscopic observations of 2003 EL61 with a higher continuum signal precision sufficient to detect a second, weaker O2 ice band at 6275 A.

Seismicity and deformation associated with ice-shelf rift propagation

Previous observations have shown that rift propagation on the Amery Ice Shelf (AIS), East Antarctica, is episodic, occurring in bursts of several hours with typical recurrence times of several weeks. Propagation events were deduced from seismic swarms (detected with seismometers) concurrent with rapid rift widening (detected with GPS receivers). In this study, we extend these results by deploying seismometers and GPS receivers in a dense network around the tip of a propagating rift on the AIS over three field seasons (2002/03, 2004/05 and 2005/06). The pattern of seismic event locations shows that icequakes cluster along the rift axis, extending several kilometers back from where the rift tip was visible in the field. Patterns of icequake event locations also appear aligned with the ice-shelf flow direction, along transverse-to-rift crevasses. However, we found some key differences in the seismicity between field seasons. Both the number of swarms and the number of events within each swarm decreased during the final field season. The timing of the slowdown closely corresponds to the rift tip entering a suture zone, formed where two ice streams merge upstream. Beneath the suture zone lies a thick band of marine ice. We propose two hypotheses for the observed slowdown: (1) defects within the ice in the suture zone cause a reduction in stress concentration ahead of the rift tip; (2) increased marine ice thickness in the rift path slows propagation. We show that the size–frequency distribution of icequakes approximately follows a power law, similar to the well-known Gutenberg–Richter law for earthquakes. However, large icequakes are not preceded by foreshocks nor are they followed by aftershocks. Thus rift-related seismicity differs from the classic foreshock and aftershock distribution that is characteristic of large earth quakes.

A two-fraction model for the calculation of the resonance spectra of the complex permittivity of ice in the far infrared

A two-fraction model that makes it possible to calculate analytically the complex dielectric permittivity of ice in the far infrared and submillimeter wavelength ranges is proposed. The librational and vibrational fractions are considered. The first fraction, consisting of rigid dipoles executing anharmonic reorientations in defects of the structure, gives rise to the librational band of ice at 800 cm−1. The second fraction consists of elastically vibrating oppositely charged H-bonded molecules. This fraction describes two bands of ice in the range 100–300 cm−1, and the nonresonant background of dielectric losses in the submillimeter wavelength range. The dielectric permittivity spectra of ice calculated for the temperature of −7°C are consistent with the experimental spectra. The spectra of ice at the temperature −30°C are predicted.

Distributions of H 2O and CO 2 ices on Ariel, Umbriel, Titania, and Oberon from IRTF/SpeX observations

We present 0.8–2.4 μm spectral observations of uranian satellites, obtained at IRTF/SpeX on 17 nights during 2001–2005. The spectra reveal for the first time the presence of CO 2 ice on the surfaces of Umbriel and Titania, by means of 3 narrow absorption bands near 2 μm. Several additional, weaker CO 2 ice absorptions have also been detected. No CO 2 absorption is seen in Oberon spectra, and the strengths of the CO 2 ice bands decline with planetocentric distance from Ariel through Titania. We use the CO 2 absorptions to map the longitudinal distribution of CO 2 ice on Ariel, Umbriel, and Titania, showing that it is most abundant on their trailing hemispheres. We also examine H 2O ice absorptions in the spectra, finding deeper H 2O bands on the leading hemispheres of Ariel, Umbriel, and Titania, but the opposite pattern on Oberon. Potential mechanisms to produce the observed longitudinal and planetocentric distributions of the two ices are considered.

A variational approach to ice stream flow

Ice sheets are susceptible to the formation of ice streams, or narrow bands of fast-flowing ice whose high velocities are caused by rapid sliding at the contact between ice and the underlying bed. Based on recent geophysical work which has shown that the sliding motion of ice streams may be described by a Coulomb friction law, we investigate how the location of ice streams depends on the geometry of an ice sheet and on the mechanical properties of the underlying bed. More generally, this problem is relevant to the flow of thin films with Coulomb (or ‘solid’) friction laws applied at their base. By analogy with friction problems in elasticity, we construct a variational formulation for the free boundary between ice streams, where bed failure occurs, and the surrounding ice ridges, where there is little or no sliding. This variational problem takes the form of a non-coercive variational inequality, and we show that solutions exist provided a force and moment balance condition is satisfied. In that case, solutions are also unique except under certain specialized circumstances which are unlikely to arise for a real ice sheet. Further, we show how the variational formulation of the ice flow problem can be exploited to calculate numerical solutions, and to simulate the effect of changing ice geometry and bed friction on the location and velocities of streaming flow. Lastly, we study the effect of ice-shelf buttressing on the flow of ice streams whose spatial extent is determined by the yield stress distribution of the bed. In line with previous studies of ice-shelf buttressing, we find that the removal of an ice shelf can cause an ice stream feeding the ice shelf to speed up considerably, which underlines the important role ice shelves may play in controlling the dynamics of marine ice sheets.

Nonharmonic transverse vibration of the H-bonded molecules and the THz spectra in ice and water

A nonlinear equation of motion is found for the dimer comprising two charged H 2O molecules. The THz dielectric response to nonharmonic vibration of a nonrigid dipole, forming the hydrogen bond (HB), is found in the direction transverse to this bond. An explicit expression is derived for the autocorrelator that governs the spectrum generated by transverse vibration (TV) of such a dipole. This expression is obtained by analytical solution of the truncated set of recurrence equations. The far infrared (FIR) spectra of ice at the temperature − 7 °C are calculated. The wideband, in the wavenumber (frequency) ν range 0…1000 cm − 1 , spectra are obtained for liquid water at room temperature and for supercooled water at − 5.6 °C. All spectra are represented in terms of the complex permittivity ε( ν) and the absorption coefficient α( ν). The obtained analytical formula for ε comprises the term ε ⊥ pertinent to the studied TV mechanism with three additional terms Δ ε q , Δ ε μ , and ε or arising, respectively, from: elastic harmonic vibration of charged molecules along the H-bond; elastic reorientation of HB permanent dipoles; and rather free libration of permanent dipoles in ‘defects’ of water/ice structure. The suggested TV-dielectric relaxation mechanism allows us: (a) to remove the THz ‘deficit’ of loss ε″ inherent in previous theoretical studies; (b) to explain the THz loss and absorption spectra in supercooled (SC) water; and (c) to describe, in agreement with the experiment, the low- and high-frequency tails of the two bands of ice H 2O located in the range 10…300 cm − 1 . Specific THz dielectric properties of SC water are ascribed to association of water molecules, revealed in our study by transverse vibration of HB charged molecules.

Spitzer Observations of Deeply Obscured Galactic Nuclei

We report on our first results from a mid-infrared spectroscopic study of ISM features in a sample of deeply obscured ULIRG nuclei using the InfraRed Spectrograph (IRS) on the Spitzer Space Telescope. The spectra are extremely rich and complex, revealing absorption features of both amorphous and crystalline silicates, aliphatic hydrocarbons, water ice and gas-phase bands of hot CO and warm C2H2, HCN and CO2. PAH emission bands were found to be generally weak and in some cases absent. The features probe a dense and warm environment, in which crystalline silicates and water ice are able to survive but volatile ices, commonly detected in Galactic dense molecular clouds, cannot. If powered largely by star formation, the stellar density and conditions of the gas and dust have to be extreme not to give rise to the commonly detected emission features associated with starbursts.

Transverse englacial debris-rich ice bands at Kvíárjökull, southeast Iceland

Thick exposures of debris-rich ice at various Icelandic glaciers are central to the debate over the prevalence of glacial sediment transfer by glaciohydraulic supercooling. We present physical analyses of ice and debris at Kvíárjökull, a temperate glacier in southeast Iceland with a terminal glacier-bed overdeepening, where stratified debris-rich ice forms up to metre-thick transverse englacial bands. Our results are not consistent with debris-rich ice formation predominantly by supercooling because: (1) 137Cs was absent from sediment filtered from debris-rich ice; (2) isotopic analysis ( δD and δ 18O) demonstrated no clear pattern of isotopic enrichment of debris-rich ice with respect to englacial ice; and (3) melt-out debris from debris-rich ice included large striated clasts from both fluvial and basal sources. We support transverse englacial debris-rich ice band formation by the thickening and elevation of basal materials in a region of longitudinally compressive ice flow situated between the reverse slope of the overdeepening and the base of an ice fall. Debris band form and distribution are likely to be controlled by thrusting along transverse englacial foliae associated with the formation of band ogives on the glacier surface.

Near-infrared spectra of the leading and trailing hemispheres of Enceladus

We present individual spectra 0.8–2.5 μm of the leading and trailing hemispheres of Enceladus obtained with the CorMASS spectrograph on the 1.8 m Vatican Advanced Technology Telescope (VATT) at the Mount Graham International Observatory. While the absorption bands of water ice dominate the spectrum of both hemispheres, most of these bands are stronger on the leading hemisphere than the trailing hemisphere. In addition, longward of 1 μm, the continuum slope is greater on the leading hemisphere than the trailing hemisphere. These differences could be produced by the presence of particles on the trailing side that are smaller and/or microstructurally more complex than those on the leading side, consistent with the preferential erosion or structural degradation of regolith particle grains on the trailing side by magnetospheric sweeping. We also explore compositional differences between the two hemispheres by applying Hapke spectrophotometric mixture models to the spectra whose components include water ice and ammonia hydrate (1% NH 3⋅H 2O). We find that spectral models which include as much as 25% by weight ammonia hydrate intimately mixed with water ice and covering 80% of the illuminated area of the satellite fit the observed spectrum of both the leading and trailing hemispheres. Areal (checkerboard) mixing models of ammonia hydrate and water ice fit the leading hemisphere with 15% of the surface comprised of ammonia hydrate and the trailing hemisphere with 10% ammonia hydrate. Therefore, while these spectral data do not contain an unambiguous detection of ammonia hydrate on Enceladus, our spectral models do not preclude the presence of a modest amount of 1% NH 3⋅H 2O on both hemispheres. We examine spectral differences and similarities between both hemispheres and the tenuous E ring within which Enceladus orbits. The spectral resolution ( R = λ / Δ λ ) of these CorMASS data ( R ∼ 300 ) is comparable to but nevertheless higher than that of the Visual-Infrared Mapping Spectrometer (VIMS) ( R = 225 ) onboard the Cassini spacecraft.

Gas records from the West Greenland ice margin covering the Last Glacial Termination: a horizontal ice core

Certain sites along ice sheet margins provide an easily accessible and almost unlimited supply of ancient ice at the surface. Measurements of gases in trapped air from ice outcropping at Pakitsoq, West Greenland, demonstrate that ancient air is mostly well preserved. No alterations in δ 18O atm and δ 15N of N 2 are apparent, and alterations in methane are found in only a few ice sections. Using measurements of these gases, we have unambiguously identified a stratigraphic section containing ice from the end of last glacial period as well as Bølling–Allerød, Younger Dryas and Preboreal intervals. Extensive sections of ice from the Holocene and most ages within the last glacial period are probably also present. Very accurate dating has been possible in the ice section containing the Younger Dryas–Preboreal abrupt climate transition signal. The ice at Pakitsoq is folded and non-uniformly thinned, with many cross-cutting bands of bubble-free ice and dust. The cross-cutting features are associated with anomalies in both the gas and the ice records. With careful sampling to avoid these, the ice at Pakitsoq is suitable for recovery of large-volume samples of the ancient atmosphere for analysis of trace constituents such as 14CH 4.

Femtosecond dynamics of electron transfer, localization, and solvation processes at the ice—metal interface

AbstractThe ultrafast dynamics of excess electrons in amorphous ice layers on single‐crystal metal surfaces are investigated by femtosecond time‐ and angle‐resolved two‐photon‐photoemission spectroscopy. Photoexcited electrons are injected from the metal substrate into delocalized states of the conduction band of ice and localize in the ice layer within 100 fs. Subsequently, energetic stabilization of this localized species is observed on a time scale of ∼1 ps, which is attributed to electron solvation by nonadiabatic coupling to nuclear degrees of freedom of the surrounding polar molecular environment. Concomitant with this stabilization process, residual wave function overlap of the solvated electron with the metal substrate results in back‐transfer by tunneling through the solvation shell. At such interfaces the correlation of electronic and molecular structure with the resulting solvation dynamics can be explored using different substrates as a template. Here we compare data on molecularly thin D2O ice layers grown on Cu(111) and Ru(001). On Ru(001) both the stabilization and back‐transfer proceed about three times faster compared to Cu(111), which is attributed to different interfacial structures and the role of d‐states, and projected band gaps in the electron transfer process.