|
National Weather Service |
Assess the results of the snowpack modeling process as applied to current and forecast hydrometeorologic conditions.
In much of the country, snow accumulation and ablation is a critical part of the hydrologic cycle and snowmelt is a significant contributor to runoff generation. Accurate representation of the state of the precipitation input and the current state of the snowpack is critical to simulating the timing and quantity of the resultant runoff.
1. Understand the hydrologic and meteorological factors that affect snowmelt.
2. Understand the inputs of the snow model.
3. Account for the assumptions made in the snow model and the impact on the simulations when these assumptions are not met.
4. Know the sequence of operations performed in the snow model and how various snow modeling situations are handled, including snow falling on snowpack, rain falling on snowpack, and melting of snowpack.
5. Account for snow accumulation and melt from glaciers and permanent snow fields.
Instructional Component 2.1: - Web Module (Proposed): Scientific Aspects of Snow Hydrology. This module will provide an introduction to the scientific aspects of snow hydrology. This module will be based on a lecture and supporting material developed by the National Operational Hydrologic Remote Sensing Center and will cover the following topics:
Instructional Component 2.2: - Web Module (Proposed): Operational Modeling of Snow Accumulation and Ablation. Serving as a companion to the snow modeling workshop, this module will cover: (1) an energy balance model for snowpack accumulation and ablation and (2) the snow modeling approach used in NWSRFS, which incorporates simplifying assumptions that allow readily available meteorological data to serve as input. The energy balance portion of the module will closely parallel the NWSRFS documentation, but use improved graphics. The snow model section will cover the same subjects as the documentation, but the subject matter will be expanded and reorganized to follow a sequence more appropriate for operational training. Examples of the snow modeling process will be provided for a basin given an assumed set of parameters. Note: calibration of the snow model will be covered in PCU #4, Model Calibration and Hydrologic and Hydrologic Procedure Development.
Instructional Component 2.3: - Workshop: Snow Modeling. This workshop covers the scientific background and implementation of the NWSRFS snow model (SNOW-17). It begins with an overview of general snow physics followed by the theory and simplifying assumptions behind the snow model. The remainder of the workshop covers calibration of the snow model for a forecast point, with hands-on exercises addressing key features and parameters of SNOW-17.
Instructional Component 2.4 - NWSRFS Documentation: Section II.2-SNOW-17: SNOW-17 Model describes mathematical representations used in the model and explains their physical basis. Section V.3.3-SNOW-17 describes input and output information for the SNOW-17 operation. Section IV.2.3-SNOW-17 describes the influence of snow model parameter values on model response, with particular emphasis on the response as depicted by the daily flow hydrograph.
Instructional Component 2.5 - NWSRFS Documentation: Section II.2-SNOW-43: NWS-43 Snow Model describes how Kalman filtering is used in the NWS-43 Snow Model to update simulated water-equivalent model states with external estimates based on observations. Section V.3.3-SNOW-43 describes input and output information for the SNOW-43 operation.
Instructional Component 2.6 - NWSRFS Documentation: Section V.3.3-RSNWELEV describes inputs and output information for the operation which computes the elevation which separates rain from snow.
Return to Hydrologic Forecasting PDS page