Chuixiang Yi1, Daniel Ricciuto2, and 150 more co-authors

1School of Earth and Environmental SciencesQueens College, City University of New York

2Oak Ridge National Laboratory, Oak Ridge, TN

We know that global warming is caused by increasing of atmospheric CO2.

positive coupling

We do not know how climate affects atmosphere-biosphere CO2 exchanges

on annual or longer time scale.

positive coupling

The temperature at northern-high latitudes will be increased much more than others near the end of 21th

century, as predicted by many climate models (IPCC, 2007)

Projected decreases in precipitation are likely in most subtropical land regions near the end of 21th century, as

predicted by many climate models (IPCC, 2007)

positive coupling

8

http://www.ncdsnet.net/~kinney/library/biome2.gif

Grouping method is described on the webhttp://iopscience.iop.org/1748-9326/5/3/034007/media/erl10_3_034007_supp.pdf

3 2

0.001 0.0143 0.0271 0.2399TNEE T T T

: Prototype T - Group

3 2

0.5726 0.7323 5.7007 9.9968DNEE D D D

Prototype D - Gro : up

mean annual temperature; drynessT D

D T

D T

RE RERI

RE RE

30% RI T - Group

30% RI D - Group

30% RI B - Group

100%D obsD

obs

NEE NEERE

NEE

100%T obsT

obs

NEE NEERE

NEE

Acknowledgements

This work was financially supported by the U.S. National Science Foundation DEB under

Grant No. 0949637.

http://iopscience.iop.org/1748-9326/5/3/034007/fulltexthttp://environmentalresearchweb.org/cws/article/news/43529

These PPTs are posted on my homepage. You are welcome to use them in

your presentations!

http://qcpages.qc.cuny.edu/~cyi/

research-control.htm

C4T-independent

Tropical/subtropical

J. Ehleringer

C3T-dependent

Most located above 45oN

Map of C3 and C4 grasses: All forests are C3

0-30% C4

(Arctic and alpine tundra are 100% C3)

60-100% of grasses is T-independent C4

Dryness IndexnRDP

nR= Annual sum of net radiation (MJ m-2 yr-1)= 2.5 MJ kg-1 , the enthalpy of vaporizationP= Annual sum of precipitation (mm yr-1)

nR

= Annual sum of potential evaporation (mm yr-1)

M.I. Budyko(1920-2001)

Dryness Index nRDP

M.I. Budyko(1920-2001)

nR E H

max nn P

RE R E E E

Potential evapotranspiration EP

Maximum evapotranspiration, or capacity of evapotranspiration by available energy

Dryness Index PEDP

1D what does this mean?1D what does this mean?

M.I. Budyko(1920-2001)

Needle

Steppe, prairieDeciduous

Subtropical

Wet Savanna

20

40

60

80

100

R (

kcal cm

-2 y

r-1)

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Dryness index

Tropical

Savanna

Tund

ra