The GATE Grind

GATE 2017 CE (CE2) – Question 19

Air Pollution and Municipal Solid Wastes · Air pollution: pollutants, sources, impacts, control and air quality index · 1 mark · Multiple choice

Elevation and temperature observations are (10 m, 15.5°C), (60 m, 15.0°C) and (130 m, 14.3°C). The atmosphere is classified as ______.

  1. Stable
  2. Unstable
  3. Neutral
  4. Inverse

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Show answer and explanation

Correct answer: (B) Unstable

Explanation

The observed lapse rates are $0.5/50=0.01$ °C/m and $0.7/70=0.01$ °C/m, or 10 °C/km. This slightly exceeds the dry adiabatic lapse rate of about 9.8 °C/km. A rising dry parcel remains warmer than its surroundings and continues rising: unstable (B).