Methane Emission to the Atmosphere

Bazhin N.M.

Institute of Chemical Kinetics and Combustion

Novosibirsk RUSSIA

Methane in Atmosphere – Concentration 1.8 ppm Content in Atmosphere 5000 Tg  (1 Tg = 1012 g = 1 mln of tons)

Flux 500 Tg /year

-20 0 20 40 60 80 100 120 140

0.3

0.4

0.5

0.6

0.7M

etha

ne c

once

ntra

tion,

ppm

Time BC, 103 years

Methane concentration dependence on time

1600 1700 1800 1900 20000.6

0.8

1.0

1.2

1.4

1.6

1.8

Met

hane

con

cent

ratio

n, p

pm

Year

Methane concentration dependence on time

Methane concentration and world population

0 1 2 3 4 5 6 70.6

0.8

1.0

1.2

1.4

1.6

1.8

20001850M

etha

ne c

once

ntra

tion,

ppm

Population, 109 persons

Year1600

LandfillsLakes

Gas

Mines

Biomass burning

TermitsRice fields

Cattle

OceansMethanehydrates

Swamps

15%

2%1%

21%1%8%

8%

7%

10%

7% 20%

Methane sources

Emission from Swamps, Rice fields, Lakes and Oceans - 44%

Square of the Swamps: 5.5·1012 m2 - all world, 1.3·1012m2 – Russia, 0.7·1012m2 – West Siberia

Active layer

0.0 0.2 0.4 0.6 0.8 1.0

PlantAtmosphere

b

[N 2]

[CH4 ]h

Water column

Region II

Region I

Active layer

Active layer

0

Dep

th,

Z

Methane, nitrogen concentration, arb. units

ww DDKK 2,

- 1 0

- 2 0

D e p t h , m m

R o t h f u s s F . , C o n r a d R . , 1 9 9 8L i m n o l . O c e a n o g r . 4 3 , 1 5 1 1 - 1 5 1 8

- 1 0

- 2 0

D e p t h , m m

R o t h f u s s F . , C o n r a d R . , 1 9 9 8L i m n o l . O c e a n o g r . 4 3 , 1 5 1 1 - 1 5 1 8

-10

-20

D epth , m m

R othfuss F.,C onrad R ., 1998L im nol. O ceanogr. 43 , 1511-1518

Bubbles formation in rice field model

0 400 800 1200-60

-40

-20

0

20

Summer Winter

Chanton J.P., Martens C.S., Kelley C.A., 1989. Limnol. Oceanogr. 34, 807-819, fig 3

Dep

th, c

m

Methane concentration, M

Methane concentrations

0.0 0.2 0.4 0.6 0.8 1.0

10012

101

/)1(

/)(

WPKr

WhCC

)//1(

/)()(

000 zbzzP

KzCzPi

iii

i

)2/( 12 Dhh

Atmosphere

h

Region II

Region I

Active layer

Active layer

0

Dep

th,

Z

b Water

Upper border of bubbles position

Dimensionless unit of depth

10011 /WPDKl

lhh ~

100112 /)1(2 WPDKXh N

-1.6 -1.2 -0.8 -0.4 0.0-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

lnh

/ cm

ln(1-XN2)

lnh = 0.74 + 0.6 ln(1-XN2)

Artificial atmospheres: nitrogen - oxygen

Kuzmin et all, Limnology and Oceanology

1011114 /)()(~

0)(~~

CH WzWzWzWC

01~

1 C If W1(z) = W10 then

Transport in region I

Border conditions

10~1

~rC

z

)

~(

~~1~~1 hCC

hz

N2 0~

2 C

Transport in region II

jiji XXSS // Main idea:

0)()( zSzWCD iiii

- sink to the bubblesiS

iX - molar part in the bubbles

1/~~

221 uCC 122

~~CuC

221 quq  

1

11 ~

1

~1~

Cq

CC

     

1

111 ~

1

~1

)~(~~

Cq

CzWC

0~

~~1 Hz

C )~

(~~

1~~1 hCChz

Border conditions

0 5 10 15 20 25 30 35 40 45

0

20

40

60

80

100

Y = 116*exp(-x/17)

T.J.Popp et all, Biogeochemistry,fig. 5, v.51, p.259-281 (2000)

CH

4 pro

duct

ion,

g

/g(p

eat)

d-1

Depth, cm

Exponential approximation to W(z) W1(z) = W10exp(-νz)

0 2 4 6 8 10 12 14

0.0

0.2

0.4

0.6

0.8

G.W.Kipphut, C.Martens, Geochimica et Cosmochimica Acta,1982, 46, p.2049-2060

40 cm

N2

CH4

Nu = 1.15

h = 0.932

CH

4, N

2 co

ncen

trat

ion,

arb

. un.

Depth, arb. un.

CH4 and N2 concentrations on depth,

W1(z) = W10exp(-νz)

1,5 2,0 2,5 3,0 3,5 4,040

50

60

70

80

- theory

- theory

- experiment

F.Rothfuss, R.ConradLimnol. Oceanogr. 43(7), 1998, 1511-1518

Me

tha

ne

co

nce

ntr

atio

n in

th

e b

ub

blts

, %

Depth, cm

Bubbles composition on depth

0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0

2

4

6

8

10M

eth

ane

bubb

le f

lux,

arb

.un.

Methane molar ratio in bubbles X1B

Points from Chanton et allLimnol.Oceanog.,34,p.807,1989

BJ1

~BJ1

~on X1B

Active layer

0.0 0.2 0.4 0.6 0.8 1.0

PlantAtmosphere

b

[N 2]

[CH4 ]h

Water column

Region II

Region I

Active layer

Active layer

0

Dep

th,

Z

Methane, nitrogen concentration, arb. units

ww DDKK 2,

M e t h a n e p l a n t s i n k s

)]0()()[()( 11 CzCzfzQ 1R

N i t r o g e n p l a n t s o u r c e

)]()0()[()( 22 zCCzfzQ 2R

D i f f e r e n t i a l e q u a t i o n

0])~(~

[~

1~

112''

1 rzCC

1012 /

~DPfK

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.00.0

0.2

0.4

0.6

0.8

1.0

C

C

= 0.428

= 0.644

= 1C

Po

sitio

n o

f b

ub

ble

s2

1

0C

H4 C

on

cen

tra

tion

, a

rb.

un

its

Depth, arb. units

Methane concentration on depth

2~

0 10 20 30 40 50 60

0.0

0.1

0.2

0.3

0.4

0.5

0.6

2~

Roots, = 4.5

Wilson J.O. et all, 1989Biogeochemistry , Vol. 8, pp. 55-712Bubbles - 22.5 % CH

4, theory - 28 % CH

4

Met

hane

con

cent

rati

on, a

rb.u

n.

Depth, cm

Methane concentration on depth

C O N C L U S I O N W E H A V E T O K N O W I N D E P E N D E N C E O N Z :

[ C H 4 ] , [ N 2 ] , [ C O 2 ] , [ A r ] ,

B u b b l e s C o m p o s i t i o n , V o l u m e o f B u b b l e s

iW pH,,Porosity,, TDK

ii

W E H A V E T O K N O W T H E D I F F U S I O N , B U B B L E S A N D P L A N T S F L U X E S F O R A L L C O M P O N E N T S