The ability of the land/water to absorb/release heat? That I'll explain:
You see, the ability of the land to absorb heat depends upon its composition, but sometimes, when mixed with chemicals, can affect its molecules - and so its absorbency. It's the same reason for releasing heat from the soil.
On the water, it absorbs heat because of its temperature. When the heat's temperature is defeated by coldness, the water's temperature will go up, but it won't heat up. However, if the heat is too much, the water will heat up. The reverse happens with releasing heat.