Update README.md

Author: jannitzbon

README.md

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 # CryoGrid3
-CryoGrid 3 is a simple land-surface scheme dedicated to modeling of ground temperatures in permafrost environments.
+CryoGrid 3 is a land-surface scheme dedicated to modeling of ground temperatures in permafrost environments. Its excess ice module Xice is capable of simulating ground subsidence and thermokarst lake formation due to melting of excess ground ice. The basic version of CryoGrid 3 and Xice is described in Westermann et al. (2016).
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+This version (xice_mpi_IS_TC) has been extended to allow simulation of linear infrastructure by defining laterally coupled gravel road embankment tiles. It has been used for a research article in The Cryosphere (TCD 2020, see below).
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+References
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+Westermann, S., Langer, M., Boike, J., Heikenfeld, M., Peter, M., Etzelmüller, B., & Krinner, G. (2016). Simulating the thermal regime and thaw processes of ice-rich permafrost ground with the land-surface model CryoGrid 3. Geosci. Model Dev., 9(2), 523–546. https://doi.org/10.5194/gmd-9-523-2016
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+Schneider von Deimling, T., Lee, H., Ingeman-Nielsen, T., Westermann, S., Romanovsky, V., Lamoureux, S., Walker, D. A., Chadburn, S., Cai, L., Trochim, E., Nitzbon, J., Jacobi, S., and Langer, M.: Consequences of permafrost degradation for Arctic infrastructure – bridging the model gap between regional and engineering scales, The Cryosphere Discuss.
+https://doi.org/10.5194/tc-2020-192, 2020.