The Dynamic Model Chilling Portions (DMCP) is an index which measures the impact of winter temperatures on dormancy completion of deciduous fruit trees. The dormancy period, visually observed by leaf drop, extends from early November to the end of March, during which the dynamic model portions are accumulated. Model input consists of hourly temperatures which affect the level of dormancy completion and subsequent bud break and flowering in the spring.
Details of the model are given by the developers (Erez et al, 1989), which may be applied to varieties and types of deciduous fruit trees which have different chilling requirements during dormancy. The model is based on the assumption that dormancy completion may be estimated as a dynamic two-stage process controlling an accumulated bud break factor.
The model is “dynamic” in the sense that relatively high temperatures, typically 19^oC and above, effectively negate earlier chilling; alternatively, moderate temperatures, typically around 13-14^oC effectively enhance moderate earlier chilling temperatures.

The Israel Meteorological Service has been calculating accumulated DMCP over 10-day periods between November and March for several stations over several years.
In earlier periods hourly temperatures were interpolated from a model based on
observations of maximum and minimum daily temperatures as well as
observations at 08:00, 14:00 and 20:00 local time. In recent years hourly temperatures from the automatic station network are input into the model. Both current and earlier DMCP calculations are based on the collaboration of the Agricultural Meteorology Section
of the Israel Meteorological Service  with the model developers Professor  Amnon Erez  at the Agricultural Research Organization and associates at the University of Virginia in the United States.

There is good correlation between the DMCP and elevation. In hill regions,
seasonal accumulated DMCP are typically 70-80 units. Temperature variations do not result in major DMCP fluctuations year-to-year, as compared with fluctuations in the coastal regions and valleys, typically 30% below and above DMCP normals which are typically between 40-50 units.
It should be noted that other models exist to evaluate chilling effects during dormancy.
A relatively simple model, for example, is based on the number of hours below
A threshold , typically around 7^oC.