Land use parameter
The major classification required for the J2000 hydrological model is provided in the Table below.
- grassland
- coniferous forest
- decidious forest
- mixed forest
- agriculture land
- shrubland
- bareland/per.snow
- waterbodies
- rockyMountains
- glaciers
- urban, densely
- settlement, loosely
- meadows and pastures
- bogs and wetlands
The land-use classes with similar features (such as agriculture and its rainfed and irrigated varieties) can be merged, which behaves similarly to hydrological dynamics. In case of few classes be available in the data (such as only Forest class), you can exclude other sub-classes such as deciduous or coniferous.
The J2000 hydrological model requires information of each land-cover type as provided in the table below. Some information might differ in ecological zones such as LAI. However, some information is primarily similar in every part of the world (such as root depth). You have to adjust the parameter values, which differ in different ecological zones based on the climatic and ecological conditions of the study area. For example, the LAI value is different in tropical (India) and temperate (Germany) regions. In Germany the value of LAI is low during winter season as most of the leaves fall due to low temperature. Conversely, in tropical regions, few leaves fall off trees during winter. However, certain information such as root depth remains same for each vegetation type for different zones. Users are free to change these values based on direct field measurement or literature. The detailed information about the land-use parameters and the application in different modules are provided in Table below.
| parameter | description |
|---|---|
| LID | land use ID |
| albedo | albedo in % |
| RSC0_1 | minimum surface resistance for water-saturated soil in January |
| ... | |
| RSC0_12 | minimum surface resistance for water-saturated soil in December |
| LAI_d1 | leaf area index (LAI) at the beginning of the vegetation period (Jan-Mar) |
| ... | |
| LAI_d4 | leaf area index (LAI) at the end of the vegetation period (Oct-Dec) |
| effHeight_d1 | effective vegetation height at the beginning of the vegetation period (Jan-Mar) |
| ... | |
| effHeight_d4 | effective vegetation height at the end of the vegetation period (Oct-Dec) |
| rootDepth | root depth |
| sealedGrade | sealed grade of surface |
The information of these variables are used to calculate different hydrological components during the modelling application. The LAI is used for Interception Module to calculate interception storage. Similarly, RSC0_1...12, effHeight, and root depth is required for estimation of evapotranspiration and soil module. The relevancies of these variables in calculation of differnt water cycle components are provided in the following documents.
Krause 2001, Krause 2010, Nepal 2012
The land-use parameter file of two regions are provided herewith, as an example land-use parameter file (Thuringia region, Germany) land-use parameter file (Dudh Kosi, Nepal, Himalaya)
The land-cover map has to be prepared in a raster format with certain resolution as discussed earlier.
