Transcript
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Lecture Lecture 17 17
The dashed land-use change line does not include management-climate interactions
The land sink was a source in 1987 and 1998 (1997 visible as an emission)Source: Le Quéré et al. 2012; Global Carbon Project 2012
Carbon Cycle Diagram
Carbon in Atmosphere
Plants use carbon to make food
Animals eat plants and
take in carbon
Plants and animals die
Decomposers break down dead things,
releasing carbon to
atmosphere andsoil
Bodies not decomposed —
after many years, become part of oil or coal deposits
Fossil fuels are burned; carbon is
returned to atmosphere
Carbon slowly released from
these substances returns to
atmosphere
6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2
PhotosynthesisPhotosynthesis
Using light converts carbon and water into sugars
Autotrophic respiration (plants respiration)
Heterotrophic respiration (soil respiration)
RespirationRespirationOrganic matter is converted back into CO2
Atmosphere
Biosphere
Photosynthesis
Respiration
The ecosystem acts as The ecosystem acts as A Carbon SinkA Carbon Sink
Atmosphere
Biosphere
Photosynthesis
Respiration
The ecosystem acts as The ecosystem acts as A Carbon SourceA Carbon Source
Eddy Flux TowerEddy Flux Tower
COCO22
HH22OO
CHCH44 T T
COCO22
HH22OO
CHCH44 T T
COCO22
HH22OO
CHCH44 T T
Ecosystem-Atmosphere Ecosystem-Atmosphere ExchangesExchangesEddy flux towers in the Rocky Mountains of ColoradoEddy flux towers in the Rocky Mountains of Colorado
Tower-1
Tower-2
(a) (b)
(c)
Acknowledgements to
Supports from NSF AGS under Grant No. 0930015,Queens College Research Enhance Award (90935-0102), many people from CUNY and Black Rock Forest
1.1. Turbulent fluxTurbulent flux
2.2. Eddy-covariance techniqueEddy-covariance technique
TurbulenceTurbulence
No regular No regular patternpattern
What we will learn todayWhat we will learn today
FluxFlux Flux is defined as Flux is defined as the amount that the amount that flows through a flows through a unit area per unit unit area per unit time.time.
areatime
energyor mass
ImportantImportant
DifficultDifficult
COCO22 turbulent flux turbulent flux Eddy CovarianceEddy Covariance
w c
Eddy Covariance Turbulent Eddy Covariance Turbulent FluxFlux w c
Sonic AnemometerSonic Anemometer
w
Infrared gas analyzer
c
w w w Vertical Vertical velocityvelocity
flu
ctu
ati
on
flu
ctu
ati
on
velo
cit
yvelo
cit
y
mean
valu
em
ean
valu
e(3
0-m
in.)
(30-m
in.)
10/s*1800s=18,000/30min.10/s*1800s=18,000/30min.
COCO22 c c c
flu
ctu
ati
on
flu
ctu
ati
on
CO
2C
O2
mean
valu
em
ean
valu
e(3
0-m
in.)
(30-m
in.)
1 1 2 2 18000 18000...18000
w c w c w cw c
P3=10kgP3=10kgP1=20kgP1=20kg P2=30kgP2=30kg
FluctuationFluctuation
++
33 = 20P kg
Question:Question:
If the biggest one moves in If the biggest one moves in the group, is his weight the group, is his weight fluctuation positive or fluctuation positive or negative?negative?
P’>0P’>0
FluctuationFluctuation
P’>0P’>0
O Mean air temperature over a desert 50 T C
O20T C O20 T C Question:Question:
Is the temperature fluctuation Is the temperature fluctuation of the parcel of cool air of the parcel of cool air positive or negative?positive or negative?
0 T
COCO
22
w c =Respiration>0
w c Night
c
ZZ ( )c z
wc
>0
wc
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