Late Quaternary frozen ground distributions in the Northern and Southern Hemisphere: Examination of the GCM-derived maps with the observations

KAZUYUKI SAITO; SERGEI MARCHENKO; SERGEI MARCHENKO; VLADIMIR ROMANOVSKY; JOHN WALSH; AMY HENDRICKS; KENJI YOSHIKAWA; DARIO TROMBOTTO LIAUDAT; TOSHIO SONE; JUNKO MORI; TETSUO SUEYOSHI

Nagoya

Congreso; XIX INQUA Congress; 2015

We reconstructed late Quaternary potential distributions of frozen ground (permafrost and seasonally frozen ground) on a global scale, using air freezing and thawing indices derived from CMIP5/PMIP3 surface air temperature, and the observationtraineddiagnosing criteria, for the present-day, mid-Holocene and the Last Glacial Maximum. The original frozen ground distribution maps produced reasonable results on a large scale. The reconstruction from the PMIP3 products showed a better result with respect to the observation-based knowledge than the PMIP2 ones, owing to finer horizontal resolution and morerealistically-simulated climatology, for example, in the western half of Eurasia. However, both maps failed to capture regional to local features, such as permafrost present in the Tibetan Plateau and the Andes.Northeastern Asia (90-150◦E, 25-60◦N) is one of the regions where our knowledge on geographical distributions of frozenground is limited for the glaciation period with sparse coverage of observational evidence. The areas in the Southern Hemisphere underlain by frozen ground, most of which have been in South America in late Quaternary, have not been intensively mapped in comparison to the Northern Hemisphere. These scale and recognition gaps have partly led to less usage of the global-scale model outputs in geographical or geomorphological investigations and applications, although field surveys in these disciplines have been conducted intensively in those regions, to evidence the periglacial processes and to determine the distribution, and their change, in the Quaternary. Downscaling of the maps were performed with help of a fine-scale digital elevation model of one-arc minute resolution for the regions?Northeastern Asia, South America, and Beringia, and compared to the observationbased proxies. The downscaled maps successfully produced the regional features showing the complex distribution of seasonal and multi-year freezing in NE Asia, as well as presence of mountain and lowland permafrost in the Andes.