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GATE 2019 CE (CE1) – Question 25

Hydrology · Hydrologic cycle, precipitation, evaporation, evapo-transpiration, infiltration · 1 mark · Multiple choice

A rectangular catchment contains three rain gauges at arbitrary locations. Mean precipitation is estimated by arithmetic mean PA and Thiessen polygons PT. Which is correct?

  1. PA is always smaller than PT.
  2. PA is always greater than PT.
  3. PA is always equal to PT.
  4. There is no definite relationship between PA and PT.

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Correct answer: (D) There is no definite relationship between PA and PT.

Explanation

Arithmetic averaging assigns each gauge equal weight. Thiessen averaging weights by represented area,which depends on gauge placement. Different weights can raise or lower the result depending on the rainfall values. Thus **no definite ordering,D**,holds in general.