E10 Atmospheric and climatic effects of suspended particles

Topic

When particulate matter—soot, dust, aerosols—is injected into the atmosphere in sufficient quantities, it alters the planet's radiative balance by reflecting or absorbing a portion of the solar radiation that would otherwise reach the surface; the extent to which it does either depends on the particles' composition and the altitude they reach. Altitude determines the duration of the effect: particles remaining in the troposphere settle out within days or weeks, whereas those that reach the stratosphere can persist there for months or years—far longer than in the lower layer.

This difference in persistence based on altitude distinguishes a local, transient effect—such as reduced visibility or short-lived microclimatic changes—from a potentially global impact, should the quantity of material injected into the stratosphere be sufficiently large; a subsequent model in this series explores this scenario in detail.

Thus, this model—which begins with particles altering the planet's solar radiation balance—links atmospheric aerosol physics with climatology: the same global climate models used to study massive volcanic eruptions can be employed to estimate this effect, allowing their assumptions to be validated using observational evidence entirely unrelated to a military context.

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