Dynamic Phenology

Dynamic simulation of vegetation development

Starting with WaSiM 7.8.x the seasonal phenological development of the vegetation can be modelled dynamically. WaSiM provides four differently complex phenology approaches:

• "Thermal Time Model 1" for dynamically determining the starting point of the development of vegetation, used for trees
• "Sequential model 1" using chilling forces for dynamically determining the starting point of the development of vegetation with regard to dormancy (otherwise like thermal time model, used for trees)
• "Thermal Time Model 2" with phase starts for the dynamic determination of the intra-annual vegetation development (grasses, arable crops)
• "sequential model 2" dynamically simulated starting points for vegetation start and beginn of leaf fall using chilling and forcing units. Used for decidual trees.

For the calculation of phenological development not only temperatures but also location factors such as the current soil moisture are taken into account. Thus, effects of drought periods can be appropriate considered.

The results of the phenology module (e.g. the start date of the phenological development) can be written as time-varying grid and as statistics file for each vegetation component. This enables a detailed visual validation of the calculation results (e.g. by visualizing the grids using Showgrid).

Detailed information on the implemented phenology module contains the section Dynamic calculation of plant development in the current WaSiM Manual.

Detailed information on the implemented phenology module can be found in the section on Dynamic calculation of plant development in the actual WaSiM model documentation.

Starting with WaSiM ETH-8.0.11 it is even possible to accumulate phenology output grids based on the growing seasons. This means that values ??are included in these accumulated grids only then, if the current date falls within the growing season. The new output options allow the calculation of an water budget explicitly for the dynamically calculated growing season.