THE OPTICAL PROPERTIES OF ATMOSPHERE DURING NATURAL FIRE EXPERIMENT IN CENTRAL RUSSIA AND THEIR IMPACT ON UV IRRADIANCE Nataly Ye. Chubarova Moscow State.

THE OPTICAL PROPERTIES OF ATMOSPHERE DURING NATURAL FIRE EXPERIMENT IN CENTRAL RUSSIA AND

THEIR IMPACT ON UV IRRADIANCE

Nataly Ye. ChubarovaMoscow State University, Geographical Department, Meteorological Observatory, email: [email protected]

Alexei N. RublevIMP, KURCHATOV Center, Moscow,Russia

Allen R. Riebau USDA Forest Service Wildlife, Fisheries, Watershed and Air Research Washington, DC

Meteorological parameters in summer-fall 2002 and climatic values (1960-1990):

june july august septembert_air,2002 17.8 23.4 17.9 12.5t_air_1960-1990 17 18.3 16.7 11.1precipitation,2002 50 16 51 72precipitation,1960-1990 78 91 79 63

30.07.02

Clear sky conditions

Average Aerosol Optical Thickness for 30.07.02: AOT_500=1.6

MOSCOWMoscow river

MO MSU

5.09.02

Average

AOT_500=1.72

CLEAR SKY FIRE SMOKE (1.08.02)

TAGANSKAYA SQUARE, MOSCOW

CLEAR SKY FIRE SMOKE, 4.09.02

(COURTESY OF ROBERT MUSSELMAN)

RED SQUARE, MOSCOW

AEROSOL OPTICAL THICKNESS IN MOSCOW AND MOSCOW SUBURBS (Zvenigorod) FROM CIMEL AND HAND

HELD HASEMETERS. MAY- SEPTEMBER 02.

00.20.40.60.8

11.21.41.61.8

22.22.42.62.8

33.23.43.6

24.0

4.02

27.0

4.02

30.0

4.02

03.0

5.02

06.0

5.02

09.0

5.02

12.0

5.02

15.0

5.02

18.0

5.02

21.0

5.02

24.0

5.02

27.0

5.02

30.0

5.02

02.0

6.02

05.0

6.02

08.0

6.02

11.0

6.02

14.0

6.02

17.0

6.02

20.0

6.02

23.0

6.02

26.0

6.02

29.0

6.02

02.0

7.02

05.0

7.02

08.0

7.02

11.0

7.02

14.0

7.02

17.0

7.02

20.0

7.02

23.0

7.02

26.0

7.02

29.0

7.02

01.0

8.02

04.0

8.02

07.0

8.02

10.0

8.02

13.0

8.02

16.0

8.02

19.0

8.02

22.0

8.02

25.0

8.02

28.0

8.02

31.0

8.02

03.0

9.02

06.0

9.02

09.0

9.02

12.0

9.02

15.0

9.02

18.0

9.02

21.0

9.02

24.0

9.02

27.0

9.02

30.0

9.02

AO

T 5

00

nm

AOT_500, MoscowAOT500, ZVEN HAZEAOT500, MOS HAZEmean AOT

Monthly mean aerosol optical thickness from Cimel in 2002 (in blue) and AOT retrieved from

actinometer following the method Yarkho& Tarasova [1991]

19

72

19

7219

72

20

02

20

02

20

02

_C

ime

l

20

02

_C

ime

l

20

02

_C

ime

l

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

july august september

AO

T_

50

0

AOT_CLIMATE, T&Y[1991] AOT_1972, T&Y[1991]AOT_2002 T&Y[1991] AOT_CIMEL

2002

20

02

Single scattering albedo (SSA) in conditions with forest fires and in typical optical conditions.

Moscow, 2001-2002.

0.75

0.8

0.85

0.9

0.95

1

0.4 0.6 0.8 1 1.2wavelength

SS

A

fires in boreal forest;Dubovik et al.[2002]

september_01

march_02

april_02

may_02

june_02

july_02

august_02

september_02

from Dubovik et al.,2002

Surface ozone concentration (active ozone monitor 2B Technologies, Inc) and aerosol optical

thickness (CIMEL) changes in summer 2002

0

0.5

1

1.5

2

2.5

3

30.0

4.02

05.0

5.02

10.0

5.02

15.0

5.02

20.0

5.02

25.0

5.02

30.0

5.02

04.0

6.02

09.0

6.02

14.0

6.02

19.0

6.02

24.0

6.02

29.0

6.02

04.0

7.02

09.0

7.02

14.0

7.02

19.0

7.02

24.0

7.02

29.0

7.02

03.0

8.02

08.0

8.02

13.0

8.02

18.0

8.02

23.0

8.02

28.0

8.02

02.0

9.02

07.0

9.02

12.0

9.02

17.0

9.02

22.0

9.02

27.0

9.02

02.1

0.02

07.1

0.02

12.1

0.02

AO

T 5

00

0

20

40

60

80

100

120

140

ozo

ne

, pp

b

AOT_500 MONTHLY_MEAN_AOT MAXIMUM SURFACE OZONE

ozone maximum allowable concentration

0

10

20

30

40

50

60

70

80

90

100

0.29 0.3 0.31 0.32 0.33 0.34 0.35 0.36 0.37 0.38 0.39 0.4

wavelength

cros

s se

ctio

ns 1

0^20

cm

2NO2 (Harwood, Jones, 1994)SO2 (Brassington, 1981)HCHO (Cantrell et all,1990)O3 ( Pour, Bass, 1985)

Gas concentration in low troposphere in summer 2002 and absorption coefficients for different gases

Maximum allowable concentration (Russian standard) for

NO2: 80 mg/m3

O3: 160 mg/m3

SO2:

HCHO:

NO2,mg/m3 O3,mg/m3 (MAX) SO2,mg/m3 HCHO,mg/m3mean 73 104 6 15min 15 35 1 1max 251 252 96 91

Concentration of several atmospheric gases in summer 2002.

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

30

.05

.02

04

.06

.02

09

.06

.02

14

.06

.02

19

.06

.02

24

.06

.02

29

.06

.02

04

.07

.02

09

.07

.02

14

.07

.02

19

.07

.02

24

.07

.02

29

.07

.02

03

.08

.02

08

.08

.02

13

.08

.02

18

.08

.02

23

.08

.02

28

.08

.02

02

.09

.02

07

.09

.02

12

.09

.02

17

.09

.02

22

.09

.02

27

.09

.02

02

.10

.02

07

.10

.02

12

.10

.02

17

.10

.02

22

.10

.02

27

.10

.02

NO

2, S

O2

, mill

igra

m/m

3

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

HC

HO

, mill

igra

m/m

3

NO2 SO2

HCHO

Spectral dependence of optical thickness for the average concentrations of different

gas species. Summer 2002.

00.010.020.030.040.050.060.070.080.09

0.29

5

0.3

0.30

5

0.31

0.31

5

0.32

0.32

5

0.33

0.33

5

0.34

0.34

5

0.35

0.35

5

0.36

0.36

5

0.37

0.37

5

0.38

wavelength

O3

and

NO

2 op

tical

th

ickn

ess

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

HC

HO

, S

O2

optic

al

thic

knes

s

OZONE NO2 SO2 HCHO

Solar angle dependence of solar fluxes in different spectral ranges. Clear sky conditions, 1999-2002.

0

100

200

300

400

500

600

700

800

900

1000

0 10 20 30 40 50 60 70

Q_i

r

2000

1999

2001

2002

0

50

100

150

200

250

300

350

400

0 10 20 30 40 50 60 70

Q_P

AR

2000

1999

2001

2002

0

5

10

15

20

25

30

35

40

45

0 10 20 30 40 50 60 70

Q_u

v380

2000199920012002

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0 10 20 30 40 50 60 70

Q_r

ek

2000199920012002

UV380UV380 Q_erythQ_eryth

SISI PARPAR

Loss of solar irradiance in different spectral ranges. Clear sky conditions normalized at ho=30 degrees

and X=300DU.

-80%-70%

-60%-50%

-40%-30%-20%

-10%0%

10%20%

02

.05

.02

07

.05

.02

12

.05

.02

17

.05

.02

22

.05

.02

27

.05

.02

01

.06

.02

06

.06

.02

11.0

6.0

21

6.0

6.0

22

1.0

6.0

22

6.0

6.0

20

1.0

7.0

20

6.0

7.0

211

.07

.02

16

.07

.02

21

.07

.02

26

.07

.02

31

.07

.02

05

.08

.02

10

.08

.02

15

.08

.02

20

.08

.02

25

.08

.02

30

.08

.02

04

.09

.02

09

.09

.02

14

.09

.02

irr

ad

ian

ce

lo

ss

uvb uv380 par ir

MODEL INPUT PARAMETERS:

1. Aerosol characteristics from Cimel sun photometer: AOT at 340-380nm , SSA at 441nm, asymmetry factor at 441nm.

2. NO2, SO2, O3, HCHO gaz concentration for the low 0-1 km layer from ground measurements. For surface ozone we take daily maximum concentration.

TOMS data for total O3.

3.VERTICAL PROFILES:In Troposphere: HCHO - 0.2ppb, NO2 - 1ppb (aircraft measurements), SO2- 0.1 ppb. In Stratosphere: -WCP 112, 1986. Ozone distribution: Subarctic summer model

Effect of different gases on attenuation of Q erythema (dQe = Qe_gaz/ Qe_clear_from_all_gases,%)

observed in 2002 in clear sky conditions. Model simulations.

-45%

-40%

-35%

-30%

-25%

-20%

-15%

-10%

-5%

0%

0 0.5 1 1.5 2 2.5 3 3.5

AOT_380

dQe

due

to N

O2

-10%-9%-8%-7%-6%-5%-4%-3%-2%-1%0%

dQe

due

to H

CH

O,

O3,

S

O2

NO2 O3 HCHO SO2

Relative difference between Q erythema calculations with gaseous absorption (red

circles) and without it (black circles) and Qer measurements as a function of AOT. ho>25

degrees.The remaining dependence on AOT may be the indicator of

1. Less value of SSA?

2. Problems with non account of forward scattering at large AOT?

3. Larger gas concentration in upper troposphere or existence of other gas ?

-30%-20%-10%

0%10%20%30%40%50%60%70%80%

0 0.5 1 1.5 2 2.5 3 3.5

AOT380

Qer

_cal

c/Q

er_m

eas,

%

with SSA=0.9 o3no2 so2hcho out of gasincluding all gas

Relative difference between Q less 380nm calculations with gaseous absorption (red circles) and without it (black circles) and Q less 380nm measurements as a

function of AOT. ho>25 degrees.

10% of difference is in accordance with the difference in calibration factor CF utilized and CF obtained in Greece in 1999, which was not applied to these data.

NOTE THAT:NOTE THAT:

Brewer UV spectral measurements are lower than TOMS estimations [Fioletov et al., 2002]. Also there were different biases between TOMS and New Zealand (zero!) and European spectral measurements [MkKenzie et al., 2000]

-50%

-40%

-30%

-20%

-10%

0%

10%

20%

30%

40%

50%

0 0.5 1 1.5 2 2.5 3 3.5AOT_380

QU

V38

0_C

AL

C/Q

UV

380_

ME

AS Q UV less 380 with SSA=0.9

Q UV less 380 out of gasQ UV less 380 with NO2 account

Effect of diffuse irradiance to aerosol optical thickness underestimation

Close AOT values for NIP and A-50 and their difference from CIMEL sunphotometer MEAN the presence of coarse aerosol particles responsible for scattering in the instrument FOV.

00.20.40.60.8

11.21.41.61.8

22.22.4

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6

АО

Т50

0

AOT_500нм,CIMEL

NIP 5.7 degrees

A-50 10 degrees

DIFFERENCE IN AOT = 0.2-0.7

Single scattering account in the instrument FOV:

w h e r e

b = 0 . 6 f o r C I M E L s u n p h o t o m e t e r b = 2 . 8 f o r E p p l e y p y r h e l i o m e t e r b = 5 f o r A - 8 0 ( R u s s i a n p y r h e l i o m e t e r )

)(

))(

(*expln'

_ Pm

DKKP

m

R

aaerRR

measaer

dxxPKb

RR 1

)cos(

)(2

dxxPKb

aa 1

)co s(

)(2

)exp(1 mD

Aerosol size distribution according to Dubovik&King retrieval method [2000] during clear

conditions (blue lines) and fires (red lines).

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.01 0.1 1 10 100RADII,MKM

dV

/dln

r

SMALL_FIRE_08.07.02 SMALL_FIRE_13.07.02

FIRE-30.07.02 FIRE_31.07.02

FIRE_1.08.02 FIRE_30.08

FIRE_02.09.02 FIRE_05.09.02

FIRE_07.09.02 CLEAR_02.07.02

CLEAR_21.08.02 CLEAR_12.09.02

The effect that may present due to forward scattering into the FOV.

-3 -2 -1 0 1 21E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1

1

dN(r

)/d

lg(r

), c

m-3

lg(r)-2 -1 0 1 2

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1

1

Rmax

= 15 m R

max=250 m

n(r)

lg(r)

Aerosol size distribution in Aerosol size distribution in aerosol continental model aerosol continental model ((WCP-112, 1986)WCP-112, 1986)::

Dust aerosol size distribution Dust aerosol size distribution model as a part of continental model as a part of continental model and when is cutted off at model and when is cutted off at 1515m:m:

This particle size, if exists in nature, may be responsible for large forward peak r 4.

Illustration:

The calculated difference between exact AOT and AOT’ measured in CIMEL FOV for continental type of aerosol at different airmass m.

0.000.100.200.300.400.50

0 1 2AOT

AO

T-A

OT

' 340nm,m=2380nm,m=2550nm,m=2340nm,m=1380nm m=1550nm,m=1

Comparison with TOMS retrievals of erythemally

weighted irradiance

JULY

-40%-30%-20%-10%

0%10%

1996 1997 1998 1999 2000 2001 2002 2003

Qer

/Qer

_200

1,%

EPTOMS Zvenigorod suburbs Moscow

AUGUST

-30%

-20%

-10%

0%

10%

1996 1997 1998 1999 2000 2001 2002 2003

Qer

/Qer

_200

1,%

SEPTEMBER

-30%

-20%

-10%

0%

10%

1996 1997 1998 1999 2000 2001 2002 2003

Qer

/Qer

_200

1,% 15% of TOMS

overestimation for August and September.

CONCLUSIONS:

1. The most severe natural fire event over Central Russia. AOT is more than 1.5-3 times larger than the monthly mean aerosol optical thickness in summer-fall 2002, reaching AOT_500>3.2. Flux validation approved that smoke aerosol has very slight absorption ( SSA0.95 from CIMEL retrievals). 3. In UV spectrum we should take into account the effects of gaseous absorption (mainly by NO2) both in clear sky and fire conditions. But sometimes other gases (O3, SO2) also play significant role. 4. NO2 may be responsible for the difference in comparisons of ground UV measurements with TOMS estimates especially in the polluted regions.5. It may be the effect of forward scattering into the CIMEL FOV due to the existence of large aerosol particles that is especially significant at high solar zenith angles. If they really present in nature? Need further studies..

Acknowledgements:We would like to thank:

1. AERONET team (Brent Holben, Alexander Smirnov, Oleg Dubovik, Ilya Slutsker, David Giles, etc.) for help in maintaining of measurements and providing a lot of consultations.

2. Moscow Ecological Monitoring Office for providing the data on concentration of some gas species and «PLANETA» Scientific Center for providing satellite images of fires around Moscow .

3. Dr. Wei Min Hao from USDA Forest Service for providing the Hasemeters for aerosol studies at Moscow suburbs.

4. NOAA for producing the backward trajectories over Moscow.

5. The staff of Meteorological observatory of MSU and, personally, V. Rozental’, N. Uliumdzhieva, A. Yurova, Ye. Stolyarova for technical help with instruments maintanence.

This work was done partially under the support of the USDA Forest Service in the frame of the project ‘‘Solar Radiation and Weather Variability Influences on Russian Sub-Boreal Forest Phenology.’’