sensitivities analyses of atmospheric radiocesium simulation...
TRANSCRIPT
Sensitivities Analyses of
Atmospheric Radiocesium Simulation
based on Atmospheric Concentration
and Deposition
International Workshop on Dispersion and Deposition Modeling for Nuclear Accident Releases
-Transfer of science from academic to operational models- Fukushima University, 2 Mar 2015 Acknowledgments: We acknowledge Y. Katsumura and M. Ishimoto in the University of Tokyo for supporting the measurements of 137Cs
concentrations.
Yu Morino ([email protected])1, Toshimasa Ohara1,
Haruo Tsuruta2, Yasuji Oura3, Mitsuru Ebihara3, and Teruyuki Nakajima2
(1National Institute for Environmental Studies, 2University of Tokyo, 3Tokyo Metropolitan University)
CONTENTS of this talk
INTRODUCTION
Activities of atmospheric modelers
Current research themes
METHODOLOGY
Observations (depositions/concentrations)
Modelling
UNCERTAINTY ANALYSES of atmospheric models
① Source term scenarios
② Wet deposition modules
③ Meteorological schemes
INTRODUCTION
ACTIVITIES of atmospheric modelers after the Fukushima accident
Forecast of radioactive plumes [SPEEDI and other models]
Inverse analysis of radionuclides’ release rates [e.g., Chino et al., 2011; Stohl et al., 2012; TEPCO, 2012]
Understanding of radionuclides’ behaviors [e.g., Katata et al., 2012; Morino et al., 2011; Takemura et al., 2011]
Provide deposition data to land/ocean modelers [e.g., Tsumune et al., 2013; Kobayashi et al., 2013]
Estimate of public radiation exposure [e.g., Ten Hoeve et al., 2012; Itubo et al., 2013]
Support of revision of disaster prevention plan [Japanese local governments, including Hyogo prefecture (2013)]
① Local scale (~100km) Released in June 2011
②Regional scale (~500km) Released in August 2011
③ Global scale Released in June 2011
INTRODUCTION
ATMOSPHERIC SIMULATIONS of radionuclides after the Fukushima accident (within half a year)
Katata et al., JER, 2012 (JAEA)
Takemura et al., SOLA, 2011 (Kyusyu Univ.)
Morino et al., GRL, 2011 (NIES)
INTRODUCTION
Current RESEARCH THEMES of atmospheric modelers after the Fukushima accident
Refinement of release rate estimation
Model inter-comparison for model evaluation
Uncertainty analyses of atmospheric models
Reproduction of initial radionuclides’ fields
Estimate of re-suspension from ground
INTRODUCTION
Current RESEARCH THEMES of atmospheric modelers after the Fukushima accident
Refinement of release rate estimation
Model inter-comparison for model evaluation
Uncertainty analyses of atmospheric models
Reproduction of initial radionuclides’ fields
Estimate of re-suspension from ground
Refinement of release rate estimation
Model inter-comparison for model evaluation
Uncertainty analyses of atmospheric models
Reproduction of initial radionuclides’ fields
Estimate of re-suspension from ground OBJECTIVES of this study
Evaluations of model performance in simulating both atmospheric concentrations and depositions of radiocesium.
METHODOLOGY
OBSERVATIONAL DATA – atmospheric deposition
Monitoring : Aug-Nov 2011 Space of flight path: 1.8~3 km
Monitoring of surface deposition (MEXT, 2011)
Bulk samplers Sampling duration: 1 day
Aircraft monitoring over Eastern Japan (MEXT, 2011)
北海道立衛生研究所 http://www.iph.pref.hokkaido.jp/eiken_housyanou/radinst.pdf
日本原子力研究開発機構 http://jolisfukyu.tokai-sc.jaea.go.jp/fukyu/mirai/2012/1_6.html
METHODOLOGY
OBSERVATIONAL DATA – atmospheric concentration
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1000
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600
400
200
0
Te
rrain
he
igh
t (m)
① Measurement at several stations
using high-volume samplers
■ ~5 sites
■ sampling duration: 1hr~several days
(mostly ≥24 hr)
② Filter-tapes of operational air
pollution monitoring stations
■ ~90 sites
■ sampling duration: 1-hr
東亜ディーケーケー http://www.toadkk.co.jp/product/env/ap/dub.html
国立環境研究所 http://www.nies.go.jp/shinsai/measurement.html
Tsuruta et al. (2014)
Meteorological model (WRF) Wind field, precipitation, etc.
Emission (JAEA) Release rates of 131I and 137Cs
1013
1014
1015
I-1
31
em
issio
n (
Bq
/hr)
3/13 3/17 3/21 3/25
Local time (year of 2011)
1012
1013
1014
Cs-1
37
em
issio
n (B
q/h
r)
Chemical transport model (CMAQ) Process: emission, transport, deposition, and radioactive decay.
Concentration/Deposition of 131I/137Cs Simulation domain
Meteo. Model:
WRF v3.1 (JMA/MSM)
CTM:CMAQ v4.6
Grid:237 x 237 x 34
Δx, Δy:3km
Dry dep: Wesely (1989)
Wet dep:
Binkowski and Roselle (2003)
Properties of 137Cs:
- Particles of 1μm
Properties of 131I
- Gas:particle = 8:2
- Particles of 1μm
- Vd of gas-131I: same as SO2
METHODOLOGY
MODEL SETUPS ーatmospheric simulation model
Morino et al. ES&T (2013)
Meteorological model (WRF) Wind field, precipitation, etc.
Emission (JAEA) Release rates of 131I and 137Cs
1013
1014
1015
I-1
31
em
issio
n (
Bq
/hr)
3/13 3/17 3/21 3/25
Local time (year of 2011)
1012
1013
1014
Cs-1
37
em
issio
n (B
q/h
r)
Chemical transport model (CMAQ) Process: emission, transport, deposition, and radioactive decay.
Concentration/Deposition of 131I/137Cs Simulation domain
Meteo. Model:
WRF v3.1 (JMA/MSM)
CTM:CMAQ v4.6
Grid:237 x 237 x 34
Δx, Δy:3km
Dry dep: Wesely (1989)
Wet dep:
Binkowski and Roselle (2003)
Properties of 137Cs:
- Particles of 1μm
Properties of 131I
- Gas:particle = 8:2
- Particles of 1μm
- Vd of gas-131I: same as SO2
② Wet deposition modules
① Source term senarios
③ Physical schemes/ parameterizations
METHODOLOGY
MODEL SETUPS ーatmospheric simulation model
Morino et al. ES&T (2013)
UNCERTAINTY ANALYSES
METHODOLOGY
MODEL SETUPS ーSensitivity simulations
Morino et al. ES&T (2013)
JAEA NILU TEPCO
Model WSPEEDI FLEXPART DIANA
Scale Local/Regional (Dx=3km)
Global Local (Dx=1km)
ObsPoint Eastern Japan (conc. and dep.)
World-wide (6 in Japan, 5 in N-Pacific, 12 in N-America)
Fukushima (monitoring car)
137Cs (PBq) 8.8 36.6 10.0
References Terada et al., 2012 Stohl et al., 2012 TEPCO, 2012
METHODOLOGY
Available 137Cs SOURCE TERM
Morino et al. ES&T (2013)
RESULTS
137Cs deposition ーSensitivity to SOURCE TERM
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Model (EM2)
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Model (EM3)
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Model (STD)
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Aircraft monitoring
Cs-137 (kBq/m2)
3000 <
1000 - 3000
600 - 1000
300 - 600
100 - 300
60 - 100
30 - 60
10 - 30
0.5 - 10
Obs JAEA (regional)
TEPCO (local)
NILU (global)
JAEA: Deposition patterns was generally reproduced NILU: largely overestimated TEPCO: large underestimation in Fukushima and different spatial patterns
2.4PBq 2.2PBq
5.0PBq 0.95PBq
Morino et al. ES&T (2013)
JAEA NILU TEPCO
Agreement within a factor of 2
Agreement within a factor of 10
Correlation coefficients
10-2
10-1
100
101
102
103
104
Md
l ,k
Bq m
-2
10-2 10
0 102 10
4
Obs ,kBq m-2
STD case
10-2
10-1
100
101
102
103
104
Md
l ,k
Bq m
-2
10-2 10
0 102 10
4
Obs ,kBq m-2
EM2 case
10-2
10-1
100
101
102
103
104
Md
l ,k
Bq
m-2
10-2 10
0 102 10
4
Obs ,kBq m-2
1000
800
600
400
200
0
Dis
tan
ce
from
FD
NP
P (k
m)
EM3 case
JAEA (regional) TEPCO (local) NILU (global)
RESULTS
137Cs deposition ーSensitivity to SOURCE TERM
Morino et al. ES&T (2013)
CMAQ (Byun and Ching, 1999)
cld
washoutcldQdt
dQ
1exp
02 p
zW
OH
Twashout
D
Precipitation rate
Water in cloud and rain
Q is in-cloud concentrations, cld is the cloud timescale washout is washout time WT is the mean total water content Dz is the cloud thickness, H2O is the density of water p0 is precipitation rate
WSPEEDI (Terada et al., JNST, 2005)
Q is in-cloud concentrations, L is scavenging coefficient (1/s) p0 is precipitation rate (mm/hr) A and B are empirically determined parameters (A = 5.0×10-5 and B=0.8 for 137Cs)
BApΛ 0
Precipitation rate
Qdt
dQL Q: Conc. in cloud
L: Scav. coeff.(1/s)
METHODOLOGY
WET DEPOSITION modules of atmospheric models
Morino et al. ES&T (2013)
Washout (below cloud)
Rainout (in cloud)
Both for washout and rainout
WSPEEDI
BAp0L
Precipitation rate
METHODOLOGY
SCAVENGING COEFFICIENTS (L) in previous studies
Morino et al. ES&T (2013)
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Cs-137 (kBq/m2)
3000 <
1000 - 3000
600 - 1000
300 - 600
100 - 300
60 - 100
30 - 60
10 - 30
0.5 - 10
Model (WD2)
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Model (WD3)
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Model (EM2)
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Model (EM3)
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Model (STD)
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Aircraft monitoring
Cs-137 (kBq/m2)
3000 <
1000 - 3000
600 - 1000
300 - 600
100 - 300
60 - 100
30 - 60
10 - 30
0.5 - 10
Obs CMAQ
L×10 L (WSPEEDI)
STD: wet-dep. module in CMAQ WD2 (wet dep. module of WSPEEDI): deposition amount is smaller and deposition areas are far from NPP WD3 (wet dep. module of WSPEEDI: L×10): similar to standard case
2.4PBq 2.2PBq
2.0PBq 3.2PBq
RESULTS
137Cs deposition
ーSensitivity to WET DEPOSITION modules
Morino et al. ES&T (2013)
10-2
10-1
100
101
102
103
104
Mdl ,k
Bq m
-2
10-2 10
0 102 10
4
Obs ,kBq m-2
STD case
10-2
10-1
100
101
102
103
104
Mdl ,k
Bq m
-2
10-2 10
0 102 10
4
Obs ,kBq m-2
EM2 case
10-2
10-1
100
101
102
103
104
Mdl ,k
Bq m
-2
10-2 10
0 102 10
4
Obs ,kBq m-2
1000
800
600
400
200
0
Dis
tance fro
m F
DN
PP
(km
)
EM3 case
10-2
10-1
100
101
102
103
104
Mdl ,k
Bq m
-2
10-2 10
0 102 10
4
Obs ,kBq m-2
WD2 case
10-2
10-1
100
101
102
103
104
Mdl ,k
Bq m
-2
10-2 10
0 102 10
4
Obs ,kBq m-2
1000
800
600
400
200
0
Dis
tance fro
m F
DN
PP
(km
)
WD3 case
Agreement within a factor of 2
Agreement within a factor of 10
Correlation coefficients
RESULTS
137Cs deposition ーSensitivity to WET DEPOSITION modules
Morino et al. ES&T (2013)
Reproduced best by • CMAQ wetdep • JAEA emissions
RESULTS
MODEL EVALUATION using atmospheric deposition/concentration data
20
15
10
5
0FA
2 o
f co
nc.
da
ta (
%)
JAEA NILU TEPCO
Emissions
Wet dep. modules CMAQ
Scav. Coeff.
Scav. Coeff. x 10
60
40
20
0FA
2 o
f d
ep
. d
ata
(%
)
JAEA NILU TEPCO
Emissions
20
15
10
5
0FA
2 o
f co
nc.
da
ta (
%)
JAEA NILU TEPCO
Emissions
Wet dep. modules CMAQ
Scav. Coeff.
Scav. Coeff. x 10
60
40
20
0FA
2 o
f d
ep
. d
ata
(%
)
JAEA NILU TEPCO
Emissions
FA2 (% of 0.5<Model/Obs<2)
for deposition data
Best setup is different between deposition and concentration data
20
15
10
5
0FA
2 o
f co
nc.
da
ta (
%)
JAEA NILU TEPCO
Emissions
Wet dep. modules CMAQ
Scav. Coeff.
Scav. Coeff. x 10
60
40
20
0FA
2 o
f d
ep
. d
ata
(%
)
JAEA NILU TEPCO
Emissions
FA2 (% of 0.5<Model/Obs<2)
for concentration data
Reproduced best by • SPEEDI wetdep • JAEA emissions
CMAQ wetdep
SPEEDI wetdep
CMAQ wetdep
SPEEDI wetdep
0.20
0.15
0.10
0.05
0.00
FA
2 o
f co
nc. d
ata
JAEA NILU TEPCO
Emissions
Mar. 20-230.20
0.15
0.10
0.05
0.00
FA
2 o
f co
nc. d
ata
JAEA NILU TEPCO
Emissions
Mar. 15-16
20
15
10
5
0FA
2 o
f co
nc.
da
ta (
%)
JAEA NILU TEPCO
Emissions
Wet dep. modules CMAQ
Scav. Coeff.
Scav. Coeff. x 10
60
40
20
0FA
2 o
f d
ep
. d
ata
(%
)
JAEA NILU TEPCO
Emissions
FA2 (% of 0.5<Model/Obs<2) for concentration data
RESULTS
MODEL EVALUATION using atmospheric deposition/concentration data
Sensitivity to wet deposition modules is very different between the two events.
Best reproduced by SPEEDI wetdep Low sensitivity to wetdep modules
CMAQ wetdep
SPEEDI wetdep
RESULTS
MODEL RESULTS of standard simulation
Concentration of 137Cs [Bq/m3]
Accumulated deposition of 137Cs [Bq/m2]
137Cs
[Bq
/m3]
RESULTS
ATMOSPHERIC CONCENTRATIONS by the standard simulation during MARCH 14-16, 2011
137Cs
[Bq
/m3]
RESULTS
ATMOSPHERIC CONCENTRATIONS by the standard simulation during MARCH 19-23, 2011
10-3
10-1
101
103
(Bq
/m3)
3/15 3/17 3/19 3/21 3/23
(c) Tsuchiura
10-3
10-1
101
103
(Bq
/m3)
3/15 3/17 3/19 3/21 3/23
Local time (year of 2011)
(d) Machida
10-3
10-1
101
103
(Bq
/m3)
3/15 3/17 3/19 3/21 3/23
(a) Shiroishi Obs
STD WD2 WD3 EM2 E2W2 E2W3 EM3 E3W2 E3W3
10-3
10-1
101
103
(Bq
/m3)
3/15 3/17 3/19 3/21 3/23
(b) Fukushima
RESULTS
ATMOSPHERIC CONCENTRATIONS on MARCH 15, 2011
CMAQ wetdep SPEEDI wetdep
Differences between the two simulations in north of FDNPP
CMAQ wetdep
SPEEDI wetdep
10-3
10-1
101
103
(Bq
/m3)
3/15 3/17 3/19 3/21 3/23
(c) Tsuchiura
10-3
10-1
101
103
(Bq
/m3)
3/15 3/17 3/19 3/21 3/23
Local time (year of 2011)
(d) Machida
10-3
10-1
101
103
(Bq
/m3)
3/15 3/17 3/19 3/21 3/23
(a) Shiroishi Obs
STD WD2 WD3 EM2 E2W2 E2W3 EM3 E3W2 E3W3
10-3
10-1
101
103
(Bq
/m3)
3/15 3/17 3/19 3/21 3/23
(b) Fukushima
RESULTS
ATMOSPHERIC CONCENTRATIONS on MARCH 21, 2011
CMAQ wetdep SPEEDI wetdep
Highly sensitive to wet deposition modules
CMAQ wetdep
SPEEDI wetdep
Microphysics PBL Surface-layer Land-surface Cumulus Nudging STD WSM 5-class Mellor-Yamada-
Janjic (Eta) TKE Monin-Obukhov (Janjic Eta)
unified Noah land-surface model
Grell-Devenyi ensemble
guv=2.5e-4 (PBL off)
SENS_m1 STD STD STD STD STD OBSGRID
SENS_m2 WRF double moment, 5-class
STD STD STD STD STD
SENS_m3 STD YSU MM5 Monin-Obukhov STD STD STD
SENS_m4 STD ACM2 (Pleim) MM5 Monin-Obukhov STD STD STD
SENS_m5 STD ACM2 (Pleim) Pleim-Xiu Pleim-Xiu STD STD
SENS_m6 STD STD STD STD Kain-Fritsch (new Eta)
STD
SENS_m7 STD STD STD STD Betts-Miller-Janjic
STD
SENS_m8 STD STD STD STD STD guv=2.5e-4 (PBL on)
SENS_m9 STD STD STD STD STD guv=2.5e-3 (PBL on)
SENS_m10 STD STD STD STD STD guv=0.01 (PBL on)
0.00
5.00
10.00
15.00
20.00
Mar 15-16
Mar 20-23
RESULTS
Sensitivities to setups of a METEOROLOGICAL MODEL FA
2 fo
r at
mo
sph
eric
co
nce
ntr
atio
n d
ata
(%)
WRF v3.3 was used (instead of WRF v3.1)
Low sensitivity to physical modules and nudging parameters of WRF
Summary
• We evaluated sensitivities of model setups (source-term, wet
deposition and meteorological schemes) to simulations of
atmospheric depositions and concentrations of radiocesium.
• Simulation using emissions estimated with a regional-scale model
(JAEA) and a diagnostic wet deposition module (CMAQ) better
reproduced the observed deposition pattern in eastern Japan.
• However, wet deposition module using scavenging coefficients
(SPEEDI) better reproduced observed atmospheric
concentrations.
• Simulated concentration was not sensitive to physical modules
and parameterizations of a meteorological model.