6. Seawater Ion Concentrations IonAtomic WeightConcentrationConcentration mg/L (ppm)mole/L Cl - 35.51.90 x 10 4 5.3 x 10 -1 Na + 231.08 x 10 4 4.7 x 10 -1 Mg ++ 24.31.29 x 10 3 5.3 x 10 -2 Ca ++ 404.12 x 10 2 1.0 x 10 -2 Fe +3 55.8 6 x 10 -6 1 x 10 -10 "best" current estimate *Fe +3 55.82 x 10 -3 4 x 10 -8 * Text tables - Seawater: Its composition, properties and behavior, Open University, 1989.

7. Inventory of H 2 O on Earth (S ~ 1.5 x 10 9 km 3 ) World water supply consists mainly of the salt water contained in the oceans (left). The world's fresh water comprises only about 3% of the total supply; three-quarters of it is locked up in the world's polar ice caps and glaciers and most of the rest is found as ground water or in lakes. The very small amount of water in the atmosphere at any one time (top right) is nonetheless of vital importance as a major energizer of weather systems. (Penman, Scientific American, 223, 98-108, 1970 (Sept).) Equivalent Depths (m) if spread over entire Earth (5.1 x 10 8 km 2 ) Water vapor0.03 Surface water (lakes and rivers)0.4 - 1.0 Groundwater15 - 45 Ice and snow50 - 120 Oceans2700

8. Mean Annual H 2 O Fluxes (cm/yr) P E Q Earth 100 100 Ocean 110 120 -10 Land 70 45 25 * ** * River discharge (Q) from land equals Q to ocean, but total surface area used for ocean and land differ by a factor of ~2.5. ** Land average Q/P ~ 35%

9. Water Vapor in the Atmosphere (mm) Polar (winter) 2 Polar (summer) 8 Mid latitude (winter) 10 Mid latitude (summer) 20 Equatorial 44 factor of 20 in amounts of water vapor throughout entire atmosphere colummn at any given time: high in tropics, low at poles. results primarily from very large difference in amount of water vapor that warm air can hold, compared to cold air. t (H 2 O vapor) ~25 mm /????????

12. Hydrologic Budget: Reservoirs and Fluxes Figure 2.1 - The hydrologic cycle. Numbers in parentheses represent inventories (in 10 6 km 3 for each reservoir. Fluxes are in 10 6 km 3 per year. (Data from Tables 2.1 and 2.2). 1. River Q (3.7x10 4 km 3 /yr) = Vapor (NET) from ocean 2. Q/P (fraction of runoff) = (3.7x10 4 ) / (11x10 4 ) = 34% 3. tH 2 O(ocean) = (mass of water in ocean) / Q(rivers) = (1.37x10 9 km 3 ) / (3.7x10 4 km 3 /yr) = 4x10 4 yrs 4. tH 2 O(vapor) = (mass of water in atm) / [P(land) + P(ocean)] = (1.3x10 4 km 3 ) / [(11 + 39) x 10 4 km 3 /yr] = (2.6x10 -2 yr) x (3.65x10 2 ) day/yr = 9.5 days

17. Hadley Cell Circulation ITCZ - air from both hemispheres, flowing toward equator, must rise. rain forms, releasing more energy to cause further vertical convection (positive feedback). 30° N and S zones of subsiding air - hence low precip rates, and includes many of the major deserts of the world.