Why Study Oceanography? n Earth is the water planet n Oceans Modulate the Climate n Human Civilization in Littoral (waves govern the coastal processes and habitat) n Life began in the Oceans, but ocean biological productivity is poor n We are caught in a Malthusian Trap

Earthrise over Smythii impact basin with Schubert impact crater on horizon. Views like this during Apollo missions made it clear that Earth is part of a planetary system rather than an isolated sphere, subject to the same bombardment that battered the surface of the Moon. (Apollo 11 AS )

The Solar System

Earth, the “Third Rock from Sun” is also called the “Lonely Planet” because, to our knowledge as yet, earth is the only planet with evidence of life and it is water that creates this uniqueness.

The joint NASA/Centre National d'Etudes Spatiales Topex/Poseidon oceanography satellite ceased operations after nearly 62,000 orbits of Earth. The spacecraft lost its ability to maneuver, bringing to a close a successful 13-year mission. Topex/Poseidon data have helped in hurricane and El Nino/La Nina forecasting, ocean and climate research, ship routing, offshore industries, fisheries... NASA - Topex / Poseidon Oceanography Mission Ends

This uniqueness comes from two cycles that define the Earth... hydrological cycle; and plate tectonics.

Evaporation 320,000 km 3 Precipitation 285,000 km 3 Precipitation 95,000 km 3 Run-off: 35,000 km 3 Ocean Storage 1,370,000,000 km 3 Evaporation 60,000 km 3 Sediments A conceptual look at the hydrological. Notice three aspects of it: cycle. Notice three aspects of it: 1.Evaporation exceeds precipitation over the oceans, but precipitation exceeds evaporation on land. 2.Currently, atmosphere transfers by precipitation all the water it receives by evaporation. 3.Run-off carries excess water as also rock materials from land to to oceans.

Present is the key to the past, i.e., the geological processes today are the same as they have always been. Mount Annapoorna, 26,545 ft (8,091 m)

Earth Venus Mars

Some images of the Martian surface

Mount Annapoorna, 26,545 ft (8,091 m)

The World Ocean Area (10 6 km 2 ) Mean Depth (km) Volume (10 6 km 3 ) Pacific Ocean Atlantic Ocean Indian Ocean

Bibi ka Makbara, Aurangabad

Sun setting on Mount Everest (29,028 ft = 8,848 m)

Another view of Mount Everest

Mount Kanchenjunga: 28,169 ft (8,586 m)

Evaporation 320,000 km 3 Ocean Storage 1,370,000,000 km 3 Precipitation 285,000 km 3 Precipitation 95,000 km 3 Evaporation 60,000 km 3 Run-off: 35,000 km 3 A conceptual look at the hydrological cycle

A trio of frames from Polar's Visible Imaging System (VIS), taken 6 seconds apart on December 31, 1998, captures an object rapidly descending toward northern Europe. Because the camera's filter isolates emission from hydroxyl (OH) radicals, the incoming object must have contained abundant water.

NOAA Current SST Anomalies: 2/14/1998

Tsunami!

cover ~71% of earth’s surface and have an average depth of ~3.8 km; carry most ( %) of the hydrospheric water supply; evolved ~4 Ga ago, in an event that created the atmosphere, the hydrosphere and the biosphere; The Oceans

evolved ~4.7 Ga ago, together with the rest of the Solar System, from a hydrogen-helium dust cloud; is largely spherical, with ~6371 km average radius, an equatorial bulge and polar flattening; is a multilayered body, with core, mantle and the crust; is unique in having water; and has a hemispherically asymmetric distribution of land and oceans. The Earth

O E C A 7 N ( % 8 0. ) L ( A N D % ) Ocean ridges (22.1%) Continental platforms (18.9%) Ocean basin floors (29.8%) Continental shelf and slope (11.4%) Continental mountains (10.3%) Island arcs, trenches, guyots etc. (3.7%) Continental rise (3.8%)

90 o N 0 o 30 o N 60 o N 90 o S 30 o S 60 o S Latitude Land Whole Earth Surface Area (million km 2) 25 Oceans

Hydrogen Helium Oxygen Carbon Nitrogen Silicon Neon Magnesium Iron Sulphur Aluminum Calcium Nickel Sodium Argon Chromium Phosphorous Manganese Chlorine Potassium Other elements H He O C N Si Ne Mg Fe S Al Ca Ni Na Ar Cr P Mn Cl K Universe Whole Earth Earth’ s Crust Outer core The whole earth is richer in Fe, Mg and Ni, and poorer in Si, K and Al, than what is found on the earth’s surface. Whole Earth density = 5.5 gm/cm 3 Density of the crust = 2.7 gm/cm 3 Mantle Core Crust Rocky Metallic Inner core

Earth has an equatorial bulge and polar flatenning, the equatorial radius (r eq ) being ~21 km greater than the polar radius (r pole ). The radius (r) of an equivalent sphere is 6,371 km. r pole r eq r = 6371 km) Equivalent sphere - 30 m 10 m Based on satellite mapping, the earth is now known to be truly pear-shaped, in that, added to facts of earth’s equatorial bulge and polar flatenning, the south pole is ~40 m closer to the earth’s center than the north pole.

Oceans Pore water in sediments Glacier and polar icecaps Surface water (rivers, lakes) Atmospheric moisture 1,370, ,000 25, % 17.7% 1.5% 0.018% % 1,370,000 10,000 25, % 0.7% 1.8% 0.02% % How much water in the hydrosphere ? An average person needs ~300,000 gallons of water per year (1 metric ton = 263 gallons), including 250,000 gallons for growing food. Indeed, nations with <150,000 gallons annual per capita water availability face severe limits to economic growth. Including all the land and marine sedimentary formations worldwide* Excluding the coastal marine sediments * Based on Karl Turekian: GLOBAL ENVIRONMENTAL CHANGE (Prentice Hall, 1996) Hydrospheric mass in trillion metric tons

A panoramic view of the Martian surface, as seen by the Pathfinder