What is the purpose of an isobar on a weather map?

Isobars serve a crucial role on weather maps by connecting points of equal atmospheric pressure. This is significant because atmospheric pressure influences weather patterns; areas of high and low pressure can indicate different weather conditions. When isobars are closely spaced, it signifies a steep pressure gradient, which can lead to stronger winds. Conversely, when isobars are spaced far apart, it indicates a gentle pressure change, typically associated with calmer weather. By analyzing isobars, meteorologists can infer wind patterns and predict weather changes, making them an essential element of weather forecasting.

The other choices do not accurately depict the purpose of isobars. Temperature gradients are shown using isotherms, while humidity levels are represented using different metrics such as dew point or relative humidity. Wind direction is often depicted by arrows on a weather map rather than through isobars. This specificity highlights the unique role that isobars play in the ensemble of weather data.