Statement I : Geostrophic wind blows above a height of 600 meters, parallel to the isobars Statement I : Geostrophic wind is the horizontal wind velocity, in which the coriolis force balances the horizontal pressure force.

Statement I is true as geostrophic winds typically occur above the atmospheric boundary layer, generally above 600 meters, where frictional effects from the Earth's surface are negligible. At these altitudes, the wind blows parallel to the isobars [3]. Statement II is also true and provides the correct explanation for Statement I. Geostrophic wind is defined as a theoretical horizontal wind velocity that results from an exact balance between the horizontal pressure gradient force and the Coriolis force [3]. Near the surface, friction disrupts this balance, causing winds to cross isobars at an angle [1]. However, in the free atmosphere (above 600m), the absence of friction allows the Coriolis force to perfectly offset the pressure gradient force, resulting in a steady flow parallel to the isobars known as geostrophic equilibrium [3].

Sources

1. [1] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 9: Atmospheric Circulation and Weather Systems > Forces Affecting the Velocity and Direction of Wind > p. 78
2. [3] https://www.hko.gov.hk/en/education/weather/meteorology-basics/00010-geostrophic-wind.html