Correct Option
Albedo refers to the fraction of solar radiation reflected by a surface. A higher albedo indicates greater reflectivity. The ecosystems, arranged in decreasing order of their albedo values, are:
- Tundra (4): This ecosystem typically exhibits the highest albedo due to the prevalence of snow and ice cover for significant periods, as well as sparse, low-lying vegetation. Snow and ice are highly reflective surfaces.
- Taiga (1): Also known as boreal forest, taiga consists primarily of coniferous trees. While evergreen conifers are darker than snow, the presence of snow on the ground and on tree branches during winter significantly increases the overall albedo of this region compared to warmer forests.
- Tropical Deciduous (3): These forests shed their leaves during the dry season, leading to a less dense canopy compared to evergreen forests. The bare ground and lighter canopy in the dry season result in a higher albedo than tropical evergreen forests.
- Tropical Evergreen (2): Characterized by dense, multi-layered canopies of dark green foliage throughout the year, these forests absorb a large proportion of incident solar radiation. Consequently, they have the lowest albedo among the given ecosystems.
Incorrect Options
Options (a), (c), and (d) present sequences that do not accurately reflect the decreasing order of albedo values for the given ecosystems. They incorrectly position Tundra, which has the highest albedo, or Tropical Evergreen, which has the lowest albedo, or misrepresent the relative reflectivity of Taiga and Tropical Deciduous forests. The correct order, from highest to lowest albedo, is Tundra, Taiga, Tropical Deciduous, and Tropical Evergreen.