please help me to polish the sentence more academic：This index can be derived by evaluating the concurrence of drought and saltwater intrusion events within a specific period with Z = 1 indicating tha

This metric can be determined through the examination of the simultaneous occurrence of drought and saltwater intrusion phenomena over a designated time frame. A value of Z = 1 signifies the presence of a combined drought-saltwater intrusion event, while a value of Z = 0 indicates the absence of such an event.