Consider the following characteristics of a type of wind: 1. They occur at upper levels in the atmosphere 2. They are subjected to two forces, a pressure gradient force and the Coriolis force 3. When the forces balance, air moves at right angles to the pressure gradient, parallel to the isobars Identify the type of wind on the basis of the given characteristics:

The characteristics described define the geostrophic wind. These winds occur in the upper atmosphere, typically 2-3 km above the surface, where they are free from the frictional effects of the Earth's surface [1][2]. In this region, the wind is primarily controlled by two forces: the pressure gradient force and the Coriolis force [1]. When the isobars are straight and friction is absent, the pressure gradient force is exactly balanced by the Coriolis force [2]. Under this state of geostrophic balance, the air parcel ceases to accelerate and moves at a constant speed in a direction perpendicular to the pressure gradient, which results in the wind blowing parallel to the isobars [3]. While jet streams and westerlies are types of upper-level winds, the specific theoretical balance of forces described is the fundamental definition of geostrophic flow [1][3].

Sources

1. [1] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 9: Atmospheric Circulation and Weather Systems > Pressure and Wind > p. 79
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 27: Jet streams > Geostrophic Wind > p. 384
3. [3] https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2000-6A%20Chap%204-6.pdf