The volumetric heat capacity of the soil, A is defined as the sum of the volumetric heat capacities of the solid, liquid, and ice, phase multiplied by their respective volumetric fractions.

phrase前但逗号应该删去。the solid, liquid and ice phase意为固态、液态和冰态。multiplied by为过去分词短语作定语修饰the volumetric heat capacities.

土壤的体积热容量A被定义为固态体积热容量、液态体积热容量和冰态体积热容量与它们各自的体积分数的乘积之和。