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Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Forced And Unforced Permafrost Changes In The Northern Hemisphere During 1901-2100, Hong Guo Dec 2021

Forced And Unforced Permafrost Changes In The Northern Hemisphere During 1901-2100, Hong Guo

Graduate Theses and Dissertations

Permafrost regions are very sensitive to rapid changes in climate and environment. In recent decades, there has been growing interest to better understand the permafrost degradation over the Northern Hemisphere in the context of human-induced climate change. Understanding permafrost dynamics is not only important for infrastructure but also for environmental protection in cold regions. In-situ permafrost measurements are important for assessing permafrost conditions. However, direct permafrost observations are sparse and asymmetrical in both spatial and temporal coverage. Active layer thickness (ALT) modeling is another approach that can overcome many of these limitations, but the models have large uncertainty in predicting …


Assimilation Of Seasonal Moisture Variability In North America And Asia For The Last Millennium, Chang Liu Jul 2021

Assimilation Of Seasonal Moisture Variability In North America And Asia For The Last Millennium, Chang Liu

Graduate Theses and Dissertations

The seasonal tree-ring chronologies that recorded discrete moisture signal for warm and cool season have been used to reconstruct the North America Seasonal Precipitation Atlas (NASPA) by the point-by-point regression method, and the results indicated that they can fairly reproduce the seasonal precipitation variability in the past. Compared with reconstructions using only paleoclimate proxy data, the paleoclimate data assimilation (PDA) considers both proxy data and climate model output, so the PDA reconstructions are consistent with both the climate signals reflected by the proxy data and the physical mechanisms represented by climate models. Based on the tree rings with discrete seasonal …