[Seminar] Prof. Hyungjun Kim

New approach for estimating soil moisture and soil organic matter from microwave brightness temperature

Runoff is one of key component in water cycle which partitions precipitation with evapotranspiration and storage changes as the results of energy and water balance at the Earth’s surface. In numerical model, it is defined as water draining out from a soil column of which amount is greater than field capacity. River is an integrated pathway to transport runoff to ocean. It has important roles not only lateral distribution of water but also energy and biogeochemical constituents.

Since Oki et al. (1998, 1999) introduced Total Runoff Integrated Pathway (TRIP), a digital global map of river network, and a numerical modeling scheme, they have been broadly adopted into many GCMs to properly reproduce seasonality of freshwater discharge in global river basins to the oceans. However, it only conserves mass balance at GCM grids and does not consider floodplain dynamics because of lacking the regulation of storage and movement of surface waters by small-scale topography. Yamazaki et al. (2011) proposed a new global river routing model, the Catchment-based Macro-scale Floodplain model (CaMa-Flood), which explicitly parameterizes the sub-grid-scale topography of a floodplain, thus describing floodplain inundation dynamics. It has been widely used in a broad filed of research, such as impact assessment of climate change, disaster prevention, and land-atmosphere interaction.

Further, Tokuda et al. (2019) developed the Heat Exchange and AdvecTion with fLood and Ice NumeriKs (HEAT-LINK) on top of CaMa-Flood, a physically-based river water temperature scheme that enables to explicitly represent fluvial- and thermo-dynamics through global river networks simultaneously and to simulates seasonal freeze-thaw cycles as well. This seminar, focusing on the role of riverine dynamics for energy and water exchanges, will introduce history of terrestrial hydrological modeling with some details of CaMa-Flood and HEAT-LINK model development, and a few selected applications of the models.