ABSTRACT. The method of Brillouin spectroscopy has been used to measure the dynamic elastic moduli of local homogeneous regions in ice samples representing four different environments of formation . These included artificial ice frozen from distilled water, clear monocrystalline glacial ice, bubbly lake ice, and sea ice. The samples studied were found to have identical local elastic properties. Accordingly the elastic properties of homogeneo us monocrystalline ice have been found not to vary with sa mple age, with impurities present at the time of freezing , or with crystal quality. The bulk elastic properties of ice remain , of course, subject to modification by different crystal grain textures and the presence of inclusions of various sorts. Because the elastic constants obtained in the present work are subject to smaller overall uncertainty than values meas ured previously, it is believed that they are the most reliable obtained to date. The values at -16°C were determined to be c II = 139.29 ± 0.41 , Cl2 = 70.82 ± 0.39, Cl3 = 57.65 ± 0.23 , C33 = 150.10 ± 0.46, C44 = 30.14 ± 0. 11 (units of 10 8 N m -2 or kbar). A full range of derived elastic parameters for monocrystalline ice and for homogeneous isotropic polycrystalline ice has been calculated. RESUME . Conslanles idasliques d'echanlillons de glace arlificielle el nalurelle par speclrographie deBril/ouin. On a utilise la methode de la spectrographie de Brillouin pour mesurer les modules dynamiques elastiques de region s localement homogenes dans des echantillons de glace representant quatre diffe re ntes circonstances de formation. [\ s'agissa it d'une glace artificielle obtenue a partir d'eau distillee, d' une glace c laire monocri stalline, d' une glace bulleuse de lac et d' une glace de mer. On a trouve que les ec hantillons etudies avaient des proprietes elastiques locales identiques. Logiquement, les proprietes elastiques d ' une glace homogene mo nocri stalline ont ete trouvees independantes de I'age de I'echantillon, des impuretes pfl!Sentes au moment de la congelation ou de la qualite du crista!' Les proprietes elastiques globales de la glace demeurent, naturellement, s ujettes a modificatio ns selon les differentes textures cri stallines des grain s et la presence d'in c lu sion de differentes sortes. Comme les constantes eIastiques obtenues dan s la presente etude son t affectees d ' un e incertitude globa le inferieure aux va leurs precedemment mesurees on pense qu'elles sont les plu s dignes de con fiance obtenues jusqu 'ici. Les valcurs obtenues a -16°C ont ete: cll = 139, 29 ± 0 ,41 , CI2 =70,82± 0,39, cl3 =S 7.6S ± 0,23, c33= ISO, 10 ± 0,46 , c44 = 30,14 ± 0, 11 (unites: 10 8 Nm -2 ou kbars). Toute une serie de para metres eIas tiques derives ont ete calcules pour de la glace monocristalline et pour une glace polycristalline homogene et isotrope. ZUSAMMENFASSUNG. Elasliche Konslanlen von kiinsllichen und Ilalurlichen E isp roben, gel\lonnen mil Brillollin-speklroskopie.Das Verfahren der Brillouin-Spektroskopie wurde zur Mess ung der dyn...

The adiabatic elastic constants of single crystals of ice Ih from the Mendenhall Glacier, and the longitudinal and transverse speeds of sound of polycrystalline ice aggregates, have been measured in the range 0–2.8 kbar at −35.5 °C by Brillouin spectroscopy. The ice was held in a 10 kbar optical cell that allowed the sample to be rotated under loads of up to 10 kbar about one axis from outside the cell. The elastic constants C11, C12, C13, C33, and C44, and the bulk modulus are quadratic in the pressure range 0–2.8 kbar.

The longitudinal and transverse speeds of sound of ice Ih, II, III, V, and VI have been measured by Brillouin spectroscopy in the range 0–10 kbar at −35.5 °C. The bulk adiabatic moduli derived from these measurements are 138.9, 98.7, 141.9, and 181.4 kbar for ice II, III, V, and VI, respectively, at pressures of 2.83, 2.76, 4.80, and 7.77 kbar, respectively. The isothermal compressions of the five phases have been measured directly by the contraction of a sample that was confined to a stainless-steel tube.

The method of Brillouin spectroscopy has been used to measure the dynamic elastic moduli of local homogeneous regions in ice samples representing four different environments of formation. These included artificial ice frozen from distilled water, clear monocrystalline glacial ice, bubbly lake ice, and sea ice. The samples studied were found to have identical local elastic properties. Accordingly the elastic properties of homogeneous monocrystalline ice have been found not to vary with sample age, with impurities present at the time of freezing, or with crystal quality. The bulk elastic properties of ice remain, of course, subject to modification by different crystal grain textures and the presence of inclusions of various sorts. Because the elastic constants obtained in the present work are subject to smaller overall uncertainty than values measured previously, it is believed that they are the most reliable obtained to date. The values at −16 °C were determined to be c11 = 139.29 ± 0.41, c12 = 70.82 ± 0.39, c13 = 57.65 ± 0.23, c33 = 150.10 ± 0.46, c44 = 30.14 ± 0.11 (units of 108 N m− 2 or kbar). A full range of derived elastic parameters for monocrystalline ice and for homogeneous isotropic polycrystalline ice has been calculated.

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