top
top| Earth's surface as a 20 x 25 Megameter rectangle |
|
The idea: You can think of Earth's surface as a 20x25 Mm rectangle. A surface area of 500 square Megameters. Sketching areas of interest on graph paper (land vs sea, assorted continents, sky clear/clouded/stormy, etc) is a nice way to get a feel for them.
Earth's surface area is 500 Mm2
Well, it's actually 510 Mm^2, not 500.
A -2% approximation error.
That's 10 missing squares.
Ecosystems example
Earth 20 9 8 7 6 5 4 3 2 110 9 8 7 6 5 4 3 2 1 Mm MegaMeter 10^6 m 1,000,000 meters 1 o o o o o o o o o o|o o o o o o o o o o ~600 miles 1000 km 2 o o o o o o o o o o|o o o o o o o o o o 3 o o o o o o o o o o|o o o o o o o o o o Each letter is a square Megameter Mm^2 4 o o o o o o o o o o|o o o o o o o o o o 5 o o o o o o o o o o|o o o o o o o o o o 6 o o o o o o o o o o|o o o o o o o o o o 7 o o o o o o o o o o|o o o o o o o o o o Productivity color code 8 o o o o o o o o o o|o o o o o o o o o o Most, less, little 9 o o o o o o o o o o|o o o o o o o o o o 10 o o o o o o o o o o|o o o o o o o o o o 11 o o o o o o o o o o|o o o o o o o o o o 12 o o o o o o o o o o|o o o o o o o o o o open ocean (332 Mm^2) 13 o o o o o o o o o o|o o o \ \ \ \ \ \ \ continental shelf (27 Mm^2) 14 o o o o o o o o o o|o o \ \ M M E R l l Marsh/swamp, Estuary, Reef/algal-bed; lake 15 o o o o o o o o o o|o \ n n n n n n n n tundra & alpine meadow (8 Mm^2) 16 o o o o o o o o o o|\ \ w w w w w w w w wood/shrubland (8 Mm^2) 17 o o o o o o o o \ \|\ g g g g g g g g g grassland (9 Mm^2) 18 o o o o o o o \ b b|b b b b b b b b b b boreal forest (12 Mm^2) 19 o o o o o o o \ t t|t t t t t t t t t t temperate forest (12 Mm^2) 20 o o o o o o o \ T T|T T T T T T T T T T Tropical forest (25 Mm^2) 21 o o o o o o \ \ T T|T T T T T T T T T T Tropical forest 22 o o o o o \ % % % %|% % % % % % % % % % cultivated (14 Mm^2) 23 \ \ \ \ \ s s s s s|s s s s s s s s s s savanna (15 Mm^2) 24 - - - d d d d d d d|d d d d d d d d d d desert scrub (18 Mm^2) [total ] 25 - - - - - - - - - -|- - - - - - - - - - ice, sand & rock (24 Mm^2) [land 148 Mm^2]
Links
Biomes
|
Major Biomes of the World The World's Biomes Tour of Biomes Biomes of the World |
Comments encouraged. - Mitchell N Charity <mcharity@lcs.mit.edu> |
Notes: 1 Mm^2 = 10^6 km^2 =~ 400,000 mile^2 (statute miles, not nautical)
Data for the grid above...
ecosystem type area average net primary
(10^12 m^2) productivity (kg(C)/m^2/yr)
tropical forests 24.5 0.83
temperate forests 12.0 0.56
boreal forests 12.0 0.36
woodland and shrubland 8.0 0.27
savanna 15.0 0.32
grassland 9.0 0.23
tundra and alpine meadow 8.0 0.065
desert scrub 18.0 0.032
rock, ice, and sand 24.0 0.015
cultivated land 14.0 0.29
swamp and marsh 2.0 1.13
lake and stream 2.5 0.23
open ocean 332.0 0.057
upwelling zones 0.4 0.23
continental shelf 26.6 0.16
algal bed and reef 0.6 0.90
estuaries 1.4 0.81
[From Consider a Spherical Cow, pg 257]
There is a version sorted by npp here (near the bottom).
|
Doables:
Say the words "graph paper".
Point out richness of biome graph.
Discuss tradeoffs on size, shape, arrangement. Extra ten line.
Exercises section -
on a blank 20x25 grid, draw boxes for Earth's continents.
land/sea, clear/cloud/storm, insolation,
Include links to data for exercises.
On biome grid
sketch productivities.
`The sea is a desert (productivity-wise), but there is a lot of it. (x10)'
describe errors?
Point out percentages (100Mmsq-20%, etc).
History:
2003-Feb-03 Fixed links - 1 repaired, 3 removed.
1999.Dec.14 Created page.
1999.Dec.09 Nice biome grid. Page sketch.
1999.Mar.03 Play.