Difference between revisions of "Hybrid Energy Balance"
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| − | The Hybrid Energy Balance Method (HY) for snow melt is based on the [[Energy Balance]] Method, but includes the effects of [[Heat Deficits]]. | + | The Hybrid Energy Balance Method (HY) for snow melt is based on the ''[[Energy Balance]]'' Method, but includes the effects of ''[[Heat Deficits]]''. By simply accounting for the heat deficit within the melting algorithms of the Energy Balance method, the melting processes as well as the snow pack dynamics (in the form of heat deficit) are accounted for, making the model more accurate. Equation 15 shows the simple adjustment that creates the HY method. Equations 1-5 under the ''[[Heat Deficits]]'' page show how the heat deficit is calculated. Because the EB method has no calibration parameters and the calibration parameters associated with the heat deficit equations are relatively insensitive, the HY method requires few, if any, calibration parameters. Although GSSHA employs a global variable time step which can be sub-minute, the heat deficit is calculated at an hourly timestep. Therefore, the HY method is also run at an hourly time step. The melt generated during the hour time step is distributed to the other GSSHA model processes at the global variable time step. |
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| + | | width=550 | ''M<sub>HY</sub> = M<sub>EB</sub> - D2 || (15) | ||
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| + | M<sub>HY</sub> = melt calculated using hybrid snow melt routine (mm SWE) | ||
| + | M<sub>EB</sub> = melt calculated using ''[[Energy Balance]]'' snow melt routine (mm SWE) | ||
| + | D2 = ''[[Heat Deficits]]'' of snowpack during current time step, expressed in water equivalent (mm SWE) | ||
Latest revision as of 19:27, 15 August 2012
The Hybrid Energy Balance Method (HY) for snow melt is based on the Energy Balance Method, but includes the effects of Heat Deficits. By simply accounting for the heat deficit within the melting algorithms of the Energy Balance method, the melting processes as well as the snow pack dynamics (in the form of heat deficit) are accounted for, making the model more accurate. Equation 15 shows the simple adjustment that creates the HY method. Equations 1-5 under the Heat Deficits page show how the heat deficit is calculated. Because the EB method has no calibration parameters and the calibration parameters associated with the heat deficit equations are relatively insensitive, the HY method requires few, if any, calibration parameters. Although GSSHA employs a global variable time step which can be sub-minute, the heat deficit is calculated at an hourly timestep. Therefore, the HY method is also run at an hourly time step. The melt generated during the hour time step is distributed to the other GSSHA model processes at the global variable time step.
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MHY = MEB - D2 | (15) |
MHY = melt calculated using hybrid snow melt routine (mm SWE) MEB = melt calculated using Energy Balance snow melt routine (mm SWE) D2 = Heat Deficits of snowpack during current time step, expressed in water equivalent (mm SWE)
