Methane Emission to the Atmosphere Bazhin N.M. Institute of Chemical Kinetics and Combustion Novosibirsk RUSSIA.

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