Chemical Modeling with CHASER and WRF/Chem in Japan

Masayuki TAKIGAWAFrontier Research Center for Global Change, Kanagawa, Japan

Contents

1. Introduction

2. Chemical weather forecasting system with global chemical transport model CHASER

3. Global/regional nested model using WRF/Chem and CHASER

4. Summary

virtual tour to our institute

1. Introduction

Our institute (Frontier Research Center for Global Change) mainly focused on global change issues, and the result of two models (CHASER and FRCGC/UCI) are contributed to IPCC AR4.Short-time forecast is also an important topic, and we developed global version in 2002, and are developing regional version since 2006.

2. Global Chemical Weather Forecast System

• 7-day forecast was offered everyday at PEACE-A and PEACE-B campaign period (6 Jan. to 23 Jan., 2002 and 21 Apr. to 17 May, 2002, respectively) for the decision of flight course.• To compare the model results with aircraft and/or ground-based observations. • To evaluate the inter-continental transport of chemical species (e.g., Europe→Asia, Asia→North America, North America→Europe).• To offer air-quality information to the public via WWW and so on.

http://www.jamstec.go.jp/frcgc/gcwm/index.html

Example of applications for a public informationScience Museum in Tokyo

Aichi EXPO in 2005

NCEPreanalysis data

12Z,18Z

photochemicallycoupled GCM

initialize(12Z)

• Global Chemical Weather Forecast System =photochemically coupled CCSR/NIES AGCM (named as CHASER [Sudo et al., JGR, 2002])

+ NCEP operational reanalysis / forecast U,V,T

NCEPforecast data

00Z,06Z,12Z

forecast

10-day forecast (every 6hr)

O3, NOx, etc.model (U,V,T)

U,V,T

U,V,T

0600-0800JST

0530-0600JST

What is the “Global Chemical Weather Forecast System” ?

initialize(12Z)

Outline of CHASER• Global model (based on CCSR/FRCGC/NIES AGCM 5.7)

• It treats 54 chemical species, 94 gas-phase reactions, 25 photodissotiations, 4 liquid-phase reactions, and 1 heterogeneous reaction on the surface of sulfate aerosols

• Online coupling of the meteorological field and the transport of chemical species

• Online coupling of radiation and the distribution of chemical species

• Horizontal resolution : T42 (about 300km ´ 300km)

• Vertical resolution: 32 layers (up to 45 km, and 1 km interval in the free troposphere)

• Emission: mainly based on EDGAR and GEIA • Biomass burning: parameterized by the hot spot data from AVHRR and ATSR

• Aircraft NOx: EDGAR

• Lightning NOx: Price and Rind (1992)

108hr Forecast 84hr Forecast 60hr Forecast

36hr Forecast 12hr Forecast Reanalysis

Lat-Lon distributions of CO at 1km height at 00Z 21 January

Calculated CO mixing ratio at 1km height

Observed CO mixing ratio at 2km height or lower

Horizontal transport following to the passing of low pressure system

（PEACE-A flight 2, 7 January, 2002）

Observed (red solid line) and calculated (green solid line) CO mixing ratio on the flight cource of flight2 (7 January, 2002).

Around the cold front, Asian polluted airmas was detected

CO=200ppbv

O3

NOy

LowPrecipitation

LowLow

High

High

Cold Front

Fright#2

00Z/06/Jan/2002

06Z/07/Jan/200206Z/07/Jan/2002

00Z/06/Jan/2002

Observed (red solid line) and calculated (green solid line) CO mixing ratio on the flight course of flight 10 in PEACE-B.

X - 48TAKIGAWA ET AL.: ESTIMATION OF THE CONTRIBUTION OF INTERCONTINENTAL TRANSPORT

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Mixing ratio of CO [ppbv]

CO (PEACE-B Flight#10 14/May/2002)a)

Obs.Model

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Mixing ratio of Tagged CO [ppbv]

Tagged CO for PEACE-B Flight#10b)

Model (N.China)Model (S.China)Model (Europe)Model (N.America)Model (Japan)

Figure 17. As in Figure 10, but from flight 10 of the PEACE–B campaign on 14 May 2002.

The bold line indicates CO values from 6:48 UTC to 7:22 UTC, respectively.

D R A F T August 23, 2005, 10:47am D R A F T

vertical transport by convection（PEACE-B flight10, 14 May, 2002）

vertical transport by convection

（PEACE-B flight10, 14 May, 2002）upper right：Sea level pressure (contour) and CO increase rate at 300hPa by convection (pixel)lower right：CO mixing ratio at

300hPalower left：Satellite image on 14

May, 2002red line：flight course

Cause of net CO change over south China (<30N)

Net CO change by advection:= influx - outflux (vertical transport is included)Emission:= surface emission + vertical diffusion

In winter, the budget of emission and advection is almost same.That means almost all CO emitted over China is advected.

In spring, convection plays an important role.

Free Troposphere

(>2km)

boundary(<2km)

Budget analysis of CO over Japan

In winter, long-range transport plays an important role for the budget of CO over Japan. The fraction of China CO is also quite large.

takigawa et al. (2005)

X - 50TAKIGAWA ET AL.: ESTIMATION OF THE CONTRIBUTION OF INTERCONTINENTAL TRANSPORT

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CO budget over Japan (120-145E,30-45N) in FT(>2km)a)

Asian LRT ChemicalN.China+KoreaS.ChinaS.AsiaJapanB.B.(Asia)

EuropeN.Americaother regionB.B.(Siberia)B.B.(other)

Produded fromVOC oxidation

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CO budget over Japan (120-145E,30-45N) in LT(<2km)b)

Asian LRT ChemicalN.China+KoreaS.ChinaS.AsiaJapanB.B.(Asia)

EuropeN.Americaother regionB.B.(Siberia)B.B.(other)

Produded fromVOC oxidation

Figure 19. The calculated monthly mean net CO budget over Japan (120!-145!E, 30!-45!N).

The units are TgCO. a) the CO budget for the free troposphere (above 2 km). b) the CO budget

for the lower troposphere (below 2 km).

D R A F T August 23, 2005, 10:47am D R A F T

Example of long-range transport of ozone precursors

Colored plumes denote the isosurface of pollutants(yellow: CO, green: NOx, and blue: SO2).

The color of sea level is also denotes the surface ozone level.The transport of plumes from Europe to Asia can be seen.

The transport of surface ozone from Asia to North America can be seen.

• The model well captured the transport of ozone precursors corresponding with synoptic scale weather.

• Convective transport seems to be important over Southern China in spring.

• Long-range transport should be taken into account to reproduce CO distribution, especially in winter.

Summary for global chemical weather forecast

3. Regional-scale chemical weather forecasting

1. The main objective of “urban-scale chemical weather forecast” project is:

• Offering daily forecast of ozone and other chemical species over Kanto region by using high-resolution(3km?) CTM.

2. For this purpose, we are now developing a nested global/regional chemical transport model based on CHASER and WRF/Chem.

Besides offering information to the Public, we are planning to investigate:

1. WRF/Chem calculation during PEACE-B period, and compare with CHASER. CHASER shows worse correlation with airborne observations compared to PEACE-A period.

2. WRF/Chem calculation with 2-way nesting over China, and evaluate the effect of small-scale perturbations to the intra-continental transport.

3. By using the output of future change run calculated by CCSR/NIES AGCM as a boundary condition, estimate the effect of global warming on the air quality over Asia (emission is fixed to present level, or changed).

4. Linking with 3, the impact of ozone increase on crops (wheat, rice, soybeans,...) should be estimated.

WRF/Chem (regional model part)

1. Based on WRF-ARW version 2.1.2

2. 2-domain nesting (15-km resolution for Japan and 5-km resolution for Kanto)

3. RADM2 chemistry with aerosols

4. initial and lateral boundary for chemical species from CHASER (every 3 hour)

5. initial and lateral boundary for meteorology from JMA/MSM (every 3 hour)

6. Emission: EAGrid 2000 with 1km resolution over Japan. Hourly, weekly (automobile only), an monthly variation are taken into account.

7. Emissions of other species in Asia is taken from REAS, and emissions in other regions taken from EDGAR20000.

1. Horizontal resolution: about 2.8 degree x 2.8 degree

2. Vertical resolution: 32 layers up to 45km

3. Meteorological field: driven by NCEP ds083.2

CHASER (global model part)

outline of “1-way nested global/regional chemical transport model system” 2 Takigawa et al., The impact of the meteorological field on air–quality forecasting

regional CTM part. The outer domain covers Japan with15–km horizontal resolution, and the inner domain coversthe Kanto region with 5–km resolution. The inner and outerdomains in the regional CTM have 31 vertical layers up to100 hPa. The two–way nesting calculation is applied in theregional CTM part.

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Model domains for WRF/Chem

Fig. 1 Model domains for the regional CTM part. The outerdomain covers Japan with a 15–km horizontal resolution,and the inner domain covers the Kanto region with a 5–kmresolution.

The lateral boundary of chemical species in the regionalCTM part is taken from the global CTM part. The output ofthe global CTM part is monotonically interpolated from theGaussian latitude and longitude grid to the Lambert Con-formal conic projection for the use in the regional CTMpart. The lateral boundary is updated every 3 hours andlinearly interpolated for each time step. In this study, wedid not take feedback from the regional CTM part to theglobal CTM part; that is, the one–way nesting calculationhas been done between the global and regional CTMs.

The system is driven by meteorological data from theNational Centers for Environmental Prediction (NCEP) forthe global CTM part and from the mesoscale model (MSM)of the Japan Meteorological Agency (JMA) for the regionalCTM part. A 15–hour forecast has been produced fourtimes daily at 00, 06, 12, and 18Z with a lead time of 8–10hour since August 2006, following a spin–up of 1 monthfor the global distribution of chemical species. The initialcondition of the meteorological field for the regional CTMwas taken from the MSM for each forecast, and the initialcondition of chemical species was taken from the modeloutput driven by the analysis meteorology.

3. ResultsTo evaluate the model–calculated ozone, the surface

ozone mixing ratio was compared to that observed at air–quality monitoring stations. In August 2006, 251 stationsobserved ozone within the inner domain of the regionalCTM. For comparison of temporal variation, hourly ob-served and modeled surface O3 mixing ratios in August2006 are shown in Figure 2. Observed ozone exceeded100 ppbv from 3 to 6 August at Hanyuu in Saitama prefec-ture (36!10’28”N, 139!33’21”E, upper panel of Figure 2),which is downwind from the Tokyo Metropolitan Area.The maximum value in the observation was 162 ppbv at16Z on 3 August. Daily maximum ozone rapidly decreasedfrom 90 ppbv to 10 ppbv from 7 to 8 August, following thepassage of Typhoon 200607 (’Maria’). The model repro-duced the ozone maximum on 3 August well. The max-imum simulated value was 137 ppbv in the model. Themodel also successfully captured the decrease from 3 to 7August, but failed to show the rapid decrease on 8 August.Three typhoons (’Maria’, ’Somai’, and ’Bopha’) existed inthis period, and the difficulty of predicting the meteoro-logical field may have led to overestimation of ozone on8 August. Both the model and observations indicate lowlevels of ozone from 14 to 17 August as typhoon 200610(’Wukong’) approached Japan. The observed and modeledozone exceeded 100 ppbv on 11, 13 August, and the modeloverestimated ozone mixing ratio on 19 August. Modeledozone mixing ratio was 135 ppbv, whereas the observedozone mixing ratio was 86 ppbv. The modeled ozone alsoproduced a high ozone mixing ratio in the northern partof Saitama prefecture on 19 August that did not appear inthe observations. Daily variation in the ozone mixing ratioat nighttime was well reproduced by the model in August.The daily minimum of observed and modeled ozone ex-ceeded 10 ppbv on 12, 15, 27, and 28 August; except forthose days, the ozone level was almost zero in the nighttime. The model also reproduced daily variation in sur-face ozone at Kodaira in Tokyo (35!43’42”N, 139!28’38”,lower panel of Figure 2). The model tended to overestimatetemperature at 2 m by about 2 K during daytime, whichmay have caused overestimation of the daytime ozone max-imum. Maxima of observed and modeled surface ozone atHanyuu appeared on 3 August, and the observed and mod-eled ozone mixing ratio at Kodaira were 140 ppbv or highervalue on 5 and 6 August. These results suggest that themodel generally reproduces local transport well.

Figure 3 shows the horizontal distribution of observedand modeled surface ozone mixing ratios at 05Z (14 JapanStandard Time [JST]) on 4 August 2006. The observedozone mixing ratio exceeded 120 ppbv at almost all sta-tions in the western part of Tokyo Metropolitan Area andthe eastern part of Saitama prefecture. The model capturedthe horizontal distribution of the observed ozone mixing ra-tio, but the location of the most polluted area was slightlybiased westward.

Because 15–hour forecasts have been produced fourtimes daily, each time period was covered by model outputsdriven by forecasted and analyzed meteorological fields forthe initial condition and lateral boundary. To evaluate theimpact of the meteorological field on the distribution of sur-face ozone, correlation coefficients between observed andmodeled surface ozone at 251 stations in the Kanto area inAugust 2006 were compared among model outputs drivenby forecast and analysis meteorological fields. Model out-puts driven by the following meteorology were compared:

CO Emission for Domain 1 (upper left),

Domain 2 (upper right),and monthly and daily variation at Shinjuku

(lower right).

6hr spin-up

6hr spin-up

6hr spin-up

6hr spin-up

6hr spin-up 15hr forecast

15hr forecast

15hr forecast

15hr forecast

15hr forecast

Calculation is done three times (1: initial/boundary cnd. for meteorology are forecast, 2: initial is analysis and boundary is forecast, and 3: initial/boundary are analysis).

Time Schedule of forecast calculations

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Observed and calculated ozone in Aug.2006

熊谷(Saitama) 羽生(Saitama)

千代田区神田司町(Tokyo)南区横浜商業高校(Kanagawa)

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Surface ozone mixing ratio at 05Z/04/Aug./2006

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Surface ozone mixing ratio at 04Z/04/Aug./2006

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Surface ozone mixing ratio at 03Z/04/Aug./2006

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Observed and calculated ozone on 4 August, 2006

03Z (12JST) 04Z (13JST) 05Z (14JST)

The model well captured the most polluted area (140ppbv or higher) in the west part of Tokyo Metropolitan area and south part of Saitama prefecture at 05Z. But, the polluted area calculated in

the model seems to be biased westward. It seems the wind direction in the night time (sea breeze) is not well reproduced in

the model.

Why the model can not reploduce low ozone on 8 August?Isosurface of Ozone(80ppbv) colored by the height during 05-08 August

Eastward movement of Typhoon 200607(MARIA) was quite slow in the model. There were three typhoons on 8 August, and the movement of

Typhoon MARIA seems to be affected by other tyophoons.

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06-11hr fcst met.00-05hr fcst met.analysis met.

Change of the distribution of correlation coefficient caused by the difference of met. field (251 stations in Domain 2)

The correlation coefficient is 0.7 or higher at about 70% of all stations,even if the 06-11hr forecasted meteorology field was applied.

In 00-05hr forecast and analysis meteorology, the initial condition of meteorological field is same. It seems the impact of lateral boundary is not so large compared to that

of initial condition for the short-range forecast.

Time-height section of DIAL(DIfferential Absorption Lidar) O3 over Tsukuba

00JST 27 – 00 JST30 Jul, 2005

00JST 16 – 00 JST19 Aug

00JST 19 – 00 JST22 Aug

• Layer structure at 1-1.5 km on 12LT 28 Jul-02 LT 29 Jul

• Scarce enhancement in the PBL during 16-18 Aug

• Enhancement at 0.5-2 km on 9-15 LT 20 Aug

• Enhancement at 2-5 km until 19 Aug, but not after 19 Aug

Nakazato et al. [2007, Appl. Opt.][2006, MSJ spring meeting]

Time-height section of modeled O3 over Tsukuba00JST 27 – 00 JST30 Jul, 2005

• Simulation from 00UTC 25 Jul to 00UCT 23 Aug 2005

• Run WITH chemical lateral boundary data from CHASER

• Good representation of layer structure in model

00JST 16 – 00 JST19 Aug

00JST 19 – 00 JST22 Aug

Time-height section of modeled O3 over Tsukuba00JST 27 – 00 JST30 Jul, 2005

00JST 16 – 00 JST19 Aug

00JST 19 – 00 JST22 Aug

• Test run WITHOUT data from CHASER (WITH fixed vertical profile)

• Layer structure above 2 km disappear or is weaken.

Today’s air quality over Japan(14JST 21 May, 2007)

upper right: Kanto region→lower right: Kyusyu region↘

Weather pattern at 12Z.It is fine weather, and covered by

high pressure.

Why Kyushu region is so polluted today?

surface ozone calculated by CHASER(19-20 May, 2007)

Sea level pressure(12JST 20 May, 2007

It seems ozone was transported from the northern part of China.Ozone are also produced from precursors, during the

transportation from China continent.

Calculated surface ozone from 00Z 17 to 09Z 21 May, 2007

• The model well captured ozone increase events, and the correlation coefficient between forecasted and observed ozone showed 0.7 or higher at 70% of air-quality monitoring stations over Kanto region.

• The initial condition of meteorological field can affect the distribution of chemical species. The initial condition of chemical species would be also important (data assimilation would be needed for the initialization of chemical species?)

• Layer structure can be seen in modeled and observed ozone. Some of them are supposed to be local pollutants, and others are supposed to be from outside of model domain. Vertical transport within the boundary layer (and between the boundary layer and the free troposphere) would be important for such layer structures.

• Intra-continental transport of pollutants from China plays an important role for the air quality over Japan.

Summary for regional chemical weather forecast