Distributed snowpack simulation using weather radar with an hydrologic-land surface scheme model.

摘要

Snow serves as a reservoir of water for the earth. In fact, the volume of water stored in the snowpack and the timing of the snowmelt runoff are crucial to water supply. To determine runoff volumes, empirical relationships have been developed that relate snow accumulations at point locations to downstream flows. However, modelling of the snowmelt process is required to generate peak flow estimates.; Continuous hydrological modelling requires precipitation and other meteorological data that are representative of the study watershed. In this research, weather radar is used as the winter precipitation input to model the snowpack throughout the snow season in order to produce streamflow estimates.; While it was difficult to choose an optimal radar adjustment strategy, it was shown that addressing the local scaling issue yielded accumulation underestimates and the subsequent consideration of mixed precipitation provided improved estimates. The subsequent consideration of snow particle shape did not further improve the radar accumulation estimates.; Secondary results from this research included the development of a method to estimate the daytime cloud cover fraction for computing longwave radiation, the derivation of a relationship for the relative specific surface area as a function of formation temperature, and the collection of fresh snow density data in order to assess the applicability of several existing functions.; This thesis has illustrated that ground based weather radar can be used as the winter precipitation input to a hydrological model, however, the radar data should be adjusted to consider the variability in phase and shape of winter hydrometeors. One new snow process has been added and five other processes have been enhanced in the CLASS model. All of these processes should be incorporated into hydrological models. (Abstract shortened by UMI.)