What do isobars indicate and how do they relate to wind direction and speed?

What do isobars indicate and how do they relate to wind direction and speed?

• A. Isobars are lines of equal temperature; wind speed remains constant regardless of spacing.
• B. Isobars are lines of equal pressure; wind blows parallel to isobars with a component from high to low pressure; tighter spacing means stronger winds.
• C. Isobars indicate humidity.
• D. Isobars show cloud cover probabilities.

Answer: (B)

Isobars mark locations where the atmospheric pressure is the same. Since wind arises from pressure differences, air moves from high toward low pressure. In practice, the flow is deflected by the Coriolis effect, so winds tend to run roughly parallel to the lines of equal pressure, with a small cross‑isobar component near the surface where friction matters. The spacing of the isobars shows how strong the wind will be: tightly spaced isobars indicate a steep pressure gradient and thus stronger winds, while widely spaced isobars indicate a weaker gradient and lighter winds. The other statements mix up what isobars measure (they’re not about temperature, humidity, or cloud cover).

Isobars mark locations where the atmospheric pressure is the same. Since wind arises from pressure differences, air moves from high toward low pressure. In practice, the flow is deflected by the Coriolis effect, so winds tend to run roughly parallel to the lines of equal pressure, with a small cross‑isobar component near the surface where friction matters. The spacing of the isobars shows how strong the wind will be: tightly spaced isobars indicate a steep pressure gradient and thus stronger winds, while widely spaced isobars indicate a weaker gradient and lighter winds. The other statements mix up what isobars measure (they’re not about temperature, humidity, or cloud cover).