MOSART Technical Guide
This guide provides scientific and technical details about MOSART.
Physics
MOSART is a one-dimension river transport model that is designed for river routing at local, regional, and global scales (Li et al., 2013). Its primary function is to supply freshwater inputs to ocean models within coupled Earth System Models.
MOSART divides each spatial unit, such as a latitude/longitude grid or a sub-basin, into three hydrologic categories: hillslopes, tributaries, and a main channel (see figure below). The hillslopes receive runoff and send into tributaries, which then converge into a single main channel. This main channel connects adjacent upstream and downstream units through the river network. MOSART simplifies the multiple tributaries within a spatial unit into a single hypothetical sub-network channel, which has a transport capacity equivalent to all combined tributaries.
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Hillslope Routing: Within each spatial unit, surface runoff is directed as overland flow to the sub-network channel, while subsurface runoff enters the sub-network channel directly.
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Sub-network Channel Routing: This channel aggregates water from the hillslopes, routes it through the channel system, and discharges it into the main channel.
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Main Channel Routing: The main channel collects water from the sub-network channel and any inflow from upstream spatial units, eventually discharging the accumulated water downstream to the next spatial unit or directly to the ocean.
Parameters
Main parameters required in the MOSART parameter file
| Variable Name | Description [unit] |
|---|---|
| fdir | Flow direction [unitless] |
| lat | Latitude at cell center [degree] |
| lon | Longitude at cell center [degree] |
| frac | fraction of the unit draining to the outlet [0-1] |
| rslp | main channel slope [unitless] |
| rlen | main channel length [m] |
| tslp | mean tributary channel slope averaged through the unit [unitless] |
| area | local drainage area [m^2] |
| areaTotal | total upstream drainage area, local unit included; multi flow direction [m^2] |
| areaTotal2 | total upstream drainage area, local unit included; single flow direction [m^2] |
| rdep | bankfull depth of main channel [m] |
| rwid | bankfull width of main channel [m] |
| rwid0 | floodplain width linked to main channel [m] |
| gxr | drainage density [m^-1] |
| hslp | topographic slope [unitless] |
| twid | bankfull width of local tributaries [m] |
| nr | Manning''s roughness coefficient for main channel flow [unitless] |
| nt | Manning''s roughness coefficient for tributary channel flow [unitless] |
| nh | Manning''s roughness coefficient for overland flow [unitless] |
Parameters required by additional MOSART features
Coming soon.