#1. Fog is reported when visibility is reduced to
Fog is defined as a cloud on the ground that reduces horizontal visibility to less than 1000 meters.
#2. RVR is reported when visibility falls below
Runway Visual Range (RVR) is reported when visibility at the runway drops below 500 meters for aircraft operations.
#3. Radiation fog occurs
Radiation fog forms over land at night due to radiational cooling, typically under clear skies and light winds.
#4. When visibility reduces between 5000m and 1000m and RH is almost 100%, it is
Mist is defined as visibility between 1000 m and 5000 m with high humidity near 100%.
#5. Radiation Fog forms over N India during
Winter months (Dec to Feb) have long nights and calm clear conditions, favoring radiation fog formation.
#6. Warm and moist air moving over a cold ground gives rise to:
When warm, moist air flows over a cold surface, condensation occurs near the ground forming fog or stratus clouds.
#7. Warm and moist air moving over a cold surface causes
Advection fog occurs when warm, moist air moves horizontally over a colder surface and cools to saturation.
#8. The radiation fog forms due to
Radiation fog forms at night when the ground loses heat by radiation, cooling the air above to saturation.
#9. The radiation fog activity increases after the passage of a
Western Disturbances (WD) increase moisture and stabilize air, enhancing radiation fog formation in Northern India.
#10. Radiation fog is essentially a ______ phenomena
Radiation fog occurs mainly during the night and early morning hours due to overnight cooling.
#11. The radiation fog forms over
Radiation fog primarily forms over land where the ground cools quickly at night, unlike water surfaces.
#12. The _____ fog forms due to horizontal movement of warm moist air over cold surface
Advection fog forms when warm air moves horizontally over a colder surface and cools to saturation.
#13. Advection fog forms during
Advection fog can occur any time since it depends on horizontal movement of air over cold surfaces, not day/night cycle.
#14. For formation of Radiation fog
Clear skies, light wind, and sufficient moisture favor radiation fog, allowing night cooling near the surface.
#15. Instrument used for measuring visibility is called
Transmissometers measure horizontal visibility by detecting attenuation of light over a distance.
#16. Advection fog forms
Advection fog can form over both land and sea when warm moist air moves over a cooler surface.
#17. Fog is ______ cloud on ground
Fog is essentially a stratus cloud formed at the ground level.
#18. Frontal Fog is more common with a
Frontal fog commonly forms when moist air is lifted over a frontal surface associated with Western Disturbances.
#19. The favourable pressure system for formation of fog is
Fog is more likely in low-pressure areas or cols where air tends to converge and stabilize near the ground.
#20. Thermal processes/temperature distribution which favours formation of fog is
Temperature inversions trap cool, moist air near the ground, favoring fog formation.
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