log base 2 scale [1]
log2(x) means the power you have to raise 2 to get x (i.e. 22 = 4, so log2(4) is 2)
log2(x) means the power you have to raise 2 to get x (i.e. 22 = 4, so log2(4) is 2)
Links
[1] https://discoveringthegenome.org/genomics-glossary/log-base-2-scale