Climate Decomposition Index

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How to Calculate the Climate Decomposition Index (CDI) A CDI is a multiplicative function that describes the effect of monthly variation in temperature and water on decomposition. The water function assumes that water controls decomposition primarily through water stress. Thus, extremely high levels of soil moisture (e.g., waterlogged soils) may not be well represented by these CDIs. Annual CDIs are the mean value of monthly CDI_i's, which are calculated as a function of mean monthly air temperature (T_i), monthly precipitation (PPT_i), and monthly PET_i of the i^th month: In Adair et al. (2008), multiple temperature equations were compared using the Long-term Intersite Decomposition Experiment Team (LIDET) data set. For this data set, the best equation was the Lloyd and Taylor (1994) variable Q₁₀ temperature function (shown above as F_T(T_i)). CDI may be calculated using monthly precipitation and temperature data. If climate data are not available, it is possible to use simulated data from CRU. Two options are available for calculating CDI (excel files): CDI using the Lloyd and Taylor (1994) temperature function CDI using an arctangent temperature function (Del Grosso et al. 2005) Please feel free to contact me (adair(at)nceas(dot)ucsb(dot)edu) with questions.