General Meteorology

• Atmospheric Phenomena and Pioneer Scientists:
• Climatic Classification: Carl Troll developed a widely recognized ecoclimatic classification based on seasonal temperatures and humid/arid months $\rightarrow$ (I)
• Solar Radiation Distribution: Milutin Milankovitch formulated the astronomical theory of orbital eccentricity, obliquity, and precession governing earth's solar radiation cycles $\rightarrow$ (II)
• Potential Evapotranspiration: H.L. Penman (1948) formulated the combination energy balance-aerodynamic equation for potential evaporation $\rightarrow$ (III)
• Origin of Monsoon: Edmond Halley (1686) first proposed the thermal contrast theory of monsoon as a grand seasonal land-sea breeze $\rightarrow$ (IV)
• Systematic Match: (A)-(I), (B)-(II), (C)-(III), (D)-(IV) corresponds to Option 4.

Correct option: (4) (A) - (II), (B) - (IV), (C) - (1), (DB) - (Ill)

• Assertion (A) is True: Delhi experiences a continental semi-arid climate where January is consistently the coldest month of the year due to cold northwesterly winds descending from the Himalayas following western disturbances.
• Reason (R) is False: The Earth is actually at perihelion (closest to the Sun, $\approx 147.1\text{ million km}$) in early January, and at aphelion (farthest from the Sun, $\approx 152.1\text{ million km}$) in early July.
• Climatic Mechanism: Winter in Delhi is caused by the $23.5^\circ$ axial tilt of the Earth tilting the Northern Hemisphere away from the Sun, reducing solar declination and daily insolation, not the Earth-Sun distance.

Correct option: (3) (A) is true but (R) is false

• Balanced Geostrophic Wind Flow:
• In the frictionless free atmosphere above the planetary boundary layer, steady horizontal airflow occurs along straight, parallel isobars.
• Represents an exact dynamic equilibrium where the horizontal Pressure Gradient Force ($PGF$) is precisely balanced by the Coriolis force ($CF$):

• Results in a steady-state horizontal wind called the geostrophic wind. (Correct answer: Option 2)