CSIR NET June 2016 Q126: Meteorology

Total column ozone is defined as the integral of the ozone concentration C(z) over all heights z, from the surface (z=0) to the top of the atmosphere (z to infinity): integral from 0 to infinity of C(z) dz, expressed in Dobson Units (1 DU = 0.01 mm of pure ozone at STP if compressed into a layer at the surface). Option 1 is correct.

1) Correct -- direct vertical integration of concentration gives the standard Dobson-unit column amount. 2) Incorrect -- multiplying by a scale height H would apply to an exponentially distributed quantity's total burden under a specific simplifying assumption, not the general definition. 3) Incorrect -- integrating the derivative dC/dz over height just returns the endpoint difference in concentration (via the fundamental theorem of calculus), not the column amount. 4) Incorrect -- weighting by an absorption cross-section v(z) would give an optical-depth-like quantity, not the column ozone amount itself.