What is the function of dive tables or dive computers during the ascent phase?

Dive tables and dive computers play a critical role in ensuring the safety of divers during the ascent phase of a dive. Their primary function is to provide guidance on safe ascent rates and decompression obligations. This is essential because ascending too quickly can lead to decompression sickness, commonly known as "the bends," which occurs when dissolved gases come out of solution too rapidly as pressure decreases.

By adhering to the ascent rates and decompression schedules recommended in dive tables or indicated by dive computers, divers can safely allow nitrogen, which accumulates in their bodies during the dive, to be released gradually. This controlled ascent helps to minimize the risk of injury and ensures that divers follow established safety protocols.

The other options relate to aspects of diving that do not directly pertain to the ascent phase. For example, reducing dive time does not enhance safety during ascent, calculating weight needed for diving is unrelated to decompression, and tracking water temperature does not impact the physiological processes involved during ascent.