Question map
Consider the following statements : 1. High clouds primarily reflect solar radiation and cool the surface of the Earth. 2. Low clouds have a high absorption of infrared radiation emanating from the Earth's surface and thus cause warming effect. Which of the statements given above is/are correct ?
Explanation
The correct answer is Option 4 (Neither 1 nor 2) because both statements inaccurately describe the radiative forcing of clouds.
Statement 1 is incorrect because high clouds (such as Cirrus) are thin and allow most solar radiation to pass through. However, they are highly effective at trapping outgoing longwave infrared radiation. Consequently, their net effect is warming the Earth's surface, rather than cooling it.
Statement 2 is incorrect because low clouds (such as Stratocumulus) are thick and opaque. Their primary role is to reflect a large portion of incoming solar radiation back into space (high albedo). While they do emit infrared radiation, their cooling effect due to solar reflection far outweighs their warming potential, resulting in a net cooling of the Earth.
In summary, high clouds warm the Earth and low clouds cool it, making both statements technically reversed and thus incorrect.
PROVENANCE & STUDY PATTERN
Guest previewThis question bridges Static Geography (Cloud types) and Environment (Global Warming mechanisms). While basic NCERTs define cloud shapes, the specific 'Net Radiative Forcing' (Warming vs. Cooling) is a concept found in advanced texts like PMF IAS or Climate Change reports. It tests functional climatology rather than just morphology.
This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.
- Statement 1: Do high clouds (e.g., cirrus) primarily reflect incoming solar radiation in Earth's atmosphere?
- Statement 2: Do high clouds (e.g., cirrus) produce a net cooling effect on the Earth's surface?
- Statement 3: Do low clouds (e.g., stratus and stratocumulus) have high absorption of infrared (longwave) radiation emitted from the Earth's surface?
- Statement 4: Do low clouds (e.g., stratus and stratocumulus) cause a net warming effect on the Earth's surface?
- Explicitly states high, thin clouds primarily transmit incoming solar radiation rather than reflecting it.
- Notes that high clouds instead trap outgoing infrared radiation and warm the surface, implying reflection of shortwave is not their primary effect.
- Describes high clouds as capturing energy that would otherwise escape to space, making the world warmer — emphasizing trapping of outgoing radiation over shortwave reflection.
- States high clouds make the world a warmer place, which contrasts with the idea that their primary role is reflecting incoming solar radiation.
- Explains that high clouds capture energy that would otherwise escape to space, raising global temperatures.
- Implies high clouds enhance the greenhouse effect by trapping infrared, not primarily by reflecting incoming solar radiation.
Gives a comparative rule: high clouds are thin with low albedo (25–30%) and 'let through most of the incoming short-wave radiation' while low thick clouds have much higher albedo (70–80%).
A student can combine this with the basic fact that lower albedo means less reflection of incoming solar radiation to infer high clouds are less effective reflectors than low clouds.
Defines cirrus as high-altitude, thin, feathery, and always white — a morphological example of the 'high, thin' cloud type mentioned above.
Knowing cirrus are thin and composed of ice crystals, a student can expect limited bulk scattering/reflectance of solar rays compared with thicker clouds and check satellite albedo data for cirrus.
Also states cirrus are high (8,000–12,000 m) and made of ice crystals and thin, reinforcing the pattern that high clouds are geometrically thin.
Combine thin geometric thickness with typical optical depth concepts (thin layers reflect less) to judge that cirrus likely do not primarily reflect incoming solar radiation.
Provides a quantitative planetary energy-budget example: '27 units' are reflected from the top of the clouds, showing clouds as a significant overall reflector of solar radiation but not distinguishing cloud types.
A student can use this to reason that while clouds in aggregate reflect much solar energy, one must separate contributions by cloud type (high vs low) to assess whether high clouds 'primarily' cause that reflection.
Explains mechanisms (scattering, reflection, absorption) and links absorption by clouds to greenhouse effects, indicating clouds can both reflect incoming shortwave and absorb/emit longwave differently depending on particle size and composition.
Using this mechanism rule, a student can consider that ice-crystal, thin high clouds may scatter/absorb less shortwave and more strongly affect longwave, so they are less likely to be primary shortwave reflectors.
This statement analysis shows book citations, web sources and indirect clues. The first statement (S1) is open for preview.
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This statement analysis shows book citations, web sources and indirect clues. The first statement (S1) is open for preview.
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This statement analysis shows book citations, web sources and indirect clues. The first statement (S1) is open for preview.
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