Question

1. an air temperature of -75°c exists in which layer? type a response

Explanation:

The Earth's atmosphere has layers with distinct temperature profiles. The stratosphere has the ozone layer, but the mesosphere (above stratosphere) has temperatures dropping to around -90°C, and -75°C is typical in the mesosphere. Also, the stratosphere's lower part warms, but the mesosphere (or sometimes considered in the stratosphere's upper transition, but more accurately mesosphere) or the stratosphere? Wait, correction: The stratosphere's temperature increases with altitude due to ozone, but the mesosphere (above stratosphere, below thermosphere) has temperatures decreasing with altitude, reaching around -90°C. However, -75°C is also found in the stratosphere? No, wait, the troposphere (surface to ~12km) cools with altitude, stratosphere (12 - 50km) warms (ozone), mesosphere (50 - 85km) cools (to ~-90°C), thermosphere warms. So -75°C is likely in the mesosphere or the upper stratosphere? Wait, no, the stratosphere's temperature at the top (50km) is around 0°C (from -50 at 12km to 0 at 50km). Then mesosphere: 50 - 85km, temperature drops from 0 to -90°C. So -75°C is in the mesosphere. Alternatively, sometimes the stratosphere's upper part? No, the mesosphere is where temperatures are very cold, including -75°C. Also, the stratosphere: no, stratosphere warms. So the correct layer is the mesosphere? Wait, or the stratosphere? Wait, maybe I confused. Let's recall: Troposphere: surface to ~10 - 15km, temperature decreases with altitude (average lapse rate 6.5°C/km). Stratosphere: 10 - 50km, temperature increases with altitude (ozone absorption of UV). Mesosphere: 50 - 85km, temperature decreases with altitude (to ~-90°C at 85km). Thermosphere: 85km+, temperature increases. So at 50km (stratopause), stratosphere temperature is ~0°C. Then mesosphere: 50 - 85km, temperature drops from 0 to -90°C. So -75°C would be in the mesosphere (since 0 at 50km, dropping to -90 at 85km, so -75 is between 50 and 85km, in mesosphere). Alternatively, maybe the stratosphere? No, stratosphere warms. So the layer with -75°C is the mesosphere. Or sometimes the stratosphere is considered, but more accurately mesosphere. Wait, another source: The stratosphere's temperature at 20km is ~-50°C, 30km ~-40, 40km ~-20, 50km ~0. Then mesosphere: 50km (0°C) to 80km (-90°C). So -75°C is at ~70km, which is mesosphere. So the answer is the mesosphere. Or is it the stratosphere? No, stratosphere warms. So the correct layer is the mesosphere. Alternatively, the stratosphere? Wait, maybe I made a mistake. Let's check: The temperature profile: Troposphere (surface to ~12km): T decreases with z (altitude). Stratosphere (12 - 50km): T increases with z (ozone). Mesosphere (50 - 85km): T decreases with z (no ozone, CO2 radiates). Thermosphere (85+): T increases (solar radiation). So at 50km (stratopause), T is ~0°C (from -50 at 12km to 0 at 50km). Then mesosphere: 50 - 85km, T drops from 0 to -90°C. So -75°C is at (0 - (-75))/(0 - (-90)) = 75/90 = 5/6 of the way from 50 to 85km: 50 + (85-50)*(5/6) ≈ 50 + 29.17 ≈ 79.17km, which is in the mesosphere. So the layer is the mesosphere. Alternatively, sometimes the stratosphere is said to have lower temperatures? No, stratosphere warms. So the answer is the mesosphere. Or the stratosphere? Wait, maybe the question is about the stratosphere? No, I think mesosphere. Wait, another approach: The temperature of -75°C is typical of the mesosphere. So the layer is the mesosphere.

Answer:

The air temperature of \(-75^\circ\text{C}\) exists in the mesosphere (a layer of Earth’s atmosphere, located above the stratosphere and below the thermosphere, where temperatures decrease with altitude, reaching extremely cold values like \(-75^\circ\text{C}\) as altitude increases).