## 2.14.4. Parameters and Input Data[¶](#parameters-and-input-data "Permalink to this headline")
---------------------------------------------------------------------------------------------

MOSART is supported by a comprehensive, global hydrography dataset at 0.5 ° resolution. As such, the fundamental spatial unit of MOSART is a 0.5 ° lat/lon grid. The topographic parameters (such as flow direction, channel length, topographic and channel slopes, etc.) were derived using the Dominant River Tracing (DRT) algorithm ([Wu et al., 2011](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#wuetal2011); [Wu et al. 2012](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#wuetal2012)). The DRT algorithm produces the topographic parameters in a scale-consistent way to preserve/upscale the key features of a baseline high-resolution hydrography dataset at multiple coarser spatial resolutions. Here the baseline high-resolution hydrography dataset is the 1km resolution Hydrological data and maps based on SHuttle Elevation Derivatives at multiple Scales (HydroSHEDS) ([Lehner and Döll, 2004](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#lehnerdoll2004); [Lehner et al., 2008](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#lehneretal2008)). The channel geometry parameters, e.g., bankfull width and depth, were estimated from empirical hydraulic geometry relationships as functions of the mean annual discharge. The Manning roughness coefficients for overland and channel flow were calculated as functions of landcover and water depth. For more details on the methodology to derive channel geometry and the Manning’s roughness coefficients, please refer to [Getirana et al. (2012)](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#getiranaetal2012). The full list of parameters included in this global hydrography dataset is provided in [Table 2.14.1](#table-mosart-parameters). Evaluation of global simulations by MOSART using the aforementioned parameters is described in [Li et al. (2015b)](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#lietal2015b).

Table 2.14.1 List of parameters in the global hydrography dataset[¶](#id3 "Permalink to this table")   
| Name
 | Unit

 | Description

 |
| --- | --- | --- |
| \\(F\_{dir}\\)

 | \-

 | The D8 single flow direction for each coarse grid cell coded using 1 (E), 2 (SE), 4 (S), 8 (SW), 16 (W), 32 (NW), 64 (N), 128 (NE)

 |
| \\(A\_{total}\\)

 | km 2

 | The upstream drainage area of each coarse grid cell

 |
| \\(F\_{dis}\\)

 | m

 | The dominant river length for each coarse grid cell

 |
| \\(S\_{channel}\\)

 | \-

 | The average channel slope for each coarse grid cell

 |
| \\(S\_{topographic}\\)

 | \-

 | The average topographic slope (for overland flow routing) for each coarse grid cell

 |
| \\(A\_{local}\\)

 | km 2

 | The surface area for each coarse grid cell

 |
| \\(D\_{p}\\)

 | m \-1

 | Drainage density, calculated as the total channel length within each coarse grid cell divided by the local cell area

 |
| \\(D\_{r}\\)

 | m

 | The bankfull depth of main channel

 |
| \\(W\_{r}\\)

 | m

 | The bankfull width of main channel

 |
| \\(D\_{t}\\)

 | m

 | The average bankfull depth of tributary channels

 |
| \\(W\_{t}\\)

 | m

 | The average bankfull width of tributary channels

 |
| \\(n\_{r}\\)

 | \-

 | Manning’s roughness coefficient for channel flow routing

 |
| \\(n\_{h}\\)

 | \-

 | Manning’s roughness coefficient for overland flow routing

 |

