If the residence time of water in the oceans is 4,100 years, estimate the annual
ID: 943997 • Letter: I
Question
If the residence time of water in the oceans is 4,100 years, estimate the annual water mass evaporation rate from the oceans per unit sea surface area. (Answer should have units kg m2 yr1 .)
Useful Values • Mass of ocean = 1.4 × 1021 kg. • Mass of ice on Earth = 2.2 × 1019 kg. • Area of ocean = 3.61 × 1014 m2 . • Representative salinity of seawater = 35‰. • Representative density of seawater = 1035 kg m3 . • Representative density of fresh water = 1000 kg m3 . • Specific heat of seawater = 3.994 J g1 C 1 . • Latent heat of fusion of water/ice = 334 J g1 .
Explanation / Answer
we know,
Residence Time = Inventory/ Flux
4100 years = (1.4 E21 Kg / 3.61 E14 sq.m) / Mass of evaporation
Mass of evaporation is 945 (kg / sq.m yr) approx is 1 tonne