GODAE Final Symposium, 12 – 15 November 2008, Nice, France REGIONAL HIGH RESOLUTION ANALYSES AND...

GODAE Final Symposium, 12 – 15 November 2008, Nice, France

REGIONAL HIGH RESOLUTION ANALYSES AND FORECASTS AT THE MESOSCALE

Masa. KAMACHI1, G. Brassington2, J.A. Cummings3, F. Davidson4,

Y.-H. Kim5, J.-M. Lellouche6, C. Rowley7, D. Storkey8, K. Thompson9, and J.-H. Yoon10

1MRI, Tsukuba, Japan

2 BoM, Melbournw, Australia 3 NRL, Monterey, USA

4 DFO, St. John's, Canada 5 KORDI, Seoul, Korea

6 MERCATOR, Toulouse, France 7 NRL, Stennis Space Center, USA

8 UKMO, Exeter, UK 9 Dalhousie U., Halifax, Canada

10 Kyushu U., Fukuoka, Japan


Contents

1. Introduction

2. Overview of Regional Systems

3. Examples of Special Features

3.1 ocean view

3.2 validation and special assimilation method

3.3 prediction

4. Examples of Special Applications

5. Summary and Future Issues


1. Introduction

GODAE Strategic Plan (2000): Chapter 5 The unique nature of GODAE outputs 5.2 Synoptic ocean analyses… GODAE places high priority on the wide distribution of products, in a timely manner

and at set times (i.e., regularly). These products will issue from a range of models. The following lists some of the unique characteristics from GODAE

# Global, consistent analyses, available regulary and routinely# Increased attention given to end applications, e.g., nesting with a very high-

resolution regional model# A hierachy of products at different resolution, with assessment of the impact of

resolution…Then the initial objective of GODAE was to cover global (focus on the global capability)

and regional systems (e.g., basin scale at high resolution - zoom on a specific region such as the Kuroshio) that are the core of GODAE systems.

What is regional analysis & prediction system? It is in between global and coastal/shelf sea systems (Nesting of B.C. & I.C. : Global <-> Regional <-> Coastal/Shelf Sea) Definition of Regional system is one for Basin or its large portion with special

regional phenomena


1. Introduction

Why regional?

• Computational burden of the global eddy resolving system. • Real time operation with very short period (e.g., 1 hour for SAR, 1 day

for open ocean forecast)• One solution is regional, or the other solution is to buy a bigger

supercomputer (like Earth Simulator). • Time limitation for operational public release of forecast data (GODAE

operational center needs real time operational treatments from receiving/taking observation data through GTS or internet, real time QC, preprocessing data for assimilation, assimilation, prediction, physical check after prediction with knowledge of other elements/oceanography, and public release in a time frame.) Then each center needs faster system with shorter cpu time.

• Each GODAE center is interested in its targeted region/phenomena in its operation. Then it selects a target region (e.g., North Atlantic, western North Pacific, around Australia) (except for US Navy in the seven seas !).


2. Regional systems under GODAE activity

In this presentation:Each GODAE center has each global version of the system or

each center uses outputs of global system.

The description of the system structure is almost the same as global one in other presentations.

Then, the tables of the system conditions are similar to ones that were/will be shown in the presentations yesterday, today and tomorrow especially by Dombrowsky, Hurlburt, Cummings, and Zhu.

Also some examples are/will be shown in the briefing by Brassington and International forecast team.

Instead of the detailed conditions in tables, I would like to report here the unique features of regional system for the regional phenomena.


2. Regional systems under GODAE activity

North Atlantic• PSY2v3 (Mercator, Fr) • FOAM/North Atlantic System (UKMO) • RTOFS (NCEP, HYCOM consortium)• TOPAZ (NERSC, METNO)• C-NOOFS (Canada)Med Ocean• MFS (Bologna U.) North Pacific• MOVE-MRI.COM-WNP (JMA/MRI, Jpn) • NWPROM, ESROM (KORDI+univ., Korea)• RIAMOM-JADE, JCOPE2, etc. (Japan GODAE Team)Southern Ocean (Australia)• CLAM (Coupled Limited-Area Model) (BoM, Au) • ROAM (Relocatable Ocean Atmosphere Model) (CSIRO, Au) (US Navy)• 9 Areas: e.g., western and eastern North Pacific, western North Atlantic, northern Indian Ocean,

southern ocean etc. … • NCOM (Navy Coastal Ocean Model• COAMPS (Coupled Ocean Atmosphere Mesoscale Prediction System) +NCODA (Navy Coupled Ocean Data Assimilation SystemResoluton: 1/4°to 1/32°, 50-70L ; OI-3DVAR-EnKFMore detailed system conditions: presentations by Dombrowsky, Hurlburt, Cumming, and Zhu, see also the review paper in the proceedings published in December


Fig.1 Geographical relations of global, regional, and coastal/shelf sea systems related to the North Atlantic

(just some examples, NOT all systems) Global MERCATOR PSY3V2

Coastal / ShelfSea

Regional MERCATOR OCEAN

UK Coastal / Shelf Sea

Regional Canada

RegionalUKMO


Fig.2 Geographical relations of global, regional, and coastal/shelf sea systems related to the North Pacific

(just some examples, NOT all systems)

115oE 120oE 125oE 130oE 135oE 140oE 145oE 15oN

20oN

25oN

30oN

35oN

40oN

Surface Current

50 cm/sec 129oE 30’ 130oE 30’ 131oE 30’ 132o E 30’ 133oE 30’

36oN

30’

37oN

30’

38oN

30’

21 DEC 1999oC

0

2

4

6

GlobalMRI MOVE-G

RegionalJMA-MRIMOVE-NP

RegionalKORDINPROM

Shelf Sea KORDIESROM

RegionalJMA-MRIMOVE-WNP

Shelf Sea - Tokyo BayRIAMROPSKyushu Univ.-JWAL1=3km


3. Special features of the regional systems

Questions about the uniqueness of the regional systems have were arisen from 1997 (among IGSTs, esp., P. Oke, H. Hurlburt, P.-Y. LeTraon, N. Smith, M. Kamachi): What is unique to the various regional high resolution systems? (not complete answers, but…)(1) How has the data assimilation systems been changed for high resolution limited area

applications? Partitioned error statistics are adopted in each smaller/divided areas Non Gaussian statistics (nonlinear constraint, flow dependent B) are adopted for

frontal/filament structures(2) Do they do anything special to deal with high resolution features? Mesoscale/smaller/sub-mesoscale eddies, Frontal/filament structure, tide included(3) Are they tuned for specific regional applications (e.g., sea fog around airports, fisheries

management, border protection, military operations)? Four categories in the Next slide for regional analysis/prediction and its application(4) Do they take advantage of high resolution observations and/or atmospheric forcing ? GHRSST, HF radar; Satellite wind (for analysis, but not for prediction), regional

coupled/atmospheric forcing(5) Do they update boundary fields as well as initial conditions of their regional models, and how

often? 6 hourly, daily, 2-days …(6) How do the regional analysis/forecasts compare to the global forecasts? It was/will be done in the intercomparison project (forecast for class 4).


Special features of the regional systems - special applications -

Tuned for specific regional applications oriented towards societal needs:Four categories have been considered (MERCATOR & others): (1) Institutional Operational applications; (2) Research; (3) Private sector Operational Recreational and Commercial applications (4) Environment Policy Makers.

Examples:(1) Oil Spill drifts experiments (Météo-France, Met.No, CEDRE, Canadian Coast Guard, JMA),

Navy operations (US Navy, Fr. SHOM, UK Roy. Navy, …), Ocean inputs for Typhoon/Hurricane Atms.-Wave-Ocean coupled prediction (JMA/MRI, US Navy, …), Education (schools (MERCATOR, Japan Assim. Summer School), user training sessions, individual requests).

(2) To provide boundary conditions to coastal models, ocean inputs for biogeochemical models and seasonal forecasting systems, and involved in various Research Sea campaign (IRD, Ifremer, CNRS, IFM Kiel, NCEP, US Navy, KORDI, Japan Mar. Sci. Found., Japan Wea. Assoc., JAMSTEC/Frontier, JMA/MRI, and many more).

(3) Commercial activities (offshore and fisheries) and many recreational marine activities (sailing races, rowing races …) (MERCATOR, Canadian DFO, Jpn Fish. Agency, …)

(4) Assessment on observation network (satellite and in situ) for decision makers (MERCATOR, JAMSTEC-MRI), monitoring and expertise on extreme ocean climate events or new indicators for ocean pollution risk (MERCATOR, JMA), real-time Search and Rescue (Canadian and Japan Coast Guard, JMA, …)


3.1 Example: typical ocean view

Fig. 3.1 Sea-surface temperature analysis (deg C) for 00Z 7/10/2008 from the UKMO FOAM 1/12 degree North Atlantic system.

RegionalMRIMOVE-WNP

Fig. 3.2 Sea-surface current analysis (speed) for 00Z 1/7/2004 (before the Large Meander) from the JMA-MRI MOVE-MRI.COM-WNP 1/10 deg. North Pacific system.


3.2 Validation: Comparison with velocity obs.

Fig. 7. Comparison of near surface velocity fields. (a): plan view, (b): zonal velocity, (c): meridional velocity. Black: assimilation, Red: independent observation by ADCP. (corr=0.84, 0.47)


3.2 Example: comparison with observation (deveopment and movement of the Ulleng Warm

Eddy in the Japan Sea )

Fig. 10. 100m Temperature fields (a) measured by PIES, and (b) produced by the ESROM from December, 1999 to June, 2000.

Ulleung Basin Temperature at 100 dbar (PIES)

129oE 30 130oE 30’ 131oE 30’ 132oE 30’ 133oE 30’

36oN

30’

37oN

30’

38oN

30’

21 DEC 1999oC

0

2

4

6

8

10

12

14

16

18

20


129oE 30 130oE 30’ 131oE 30’ 132oE 30’ 133oE 30’

36oN

30’

37oN

30’

38oN

30’

19 APR 2000oC

0

2

4

6

8

10

12

14

16

18

20


129oE 30 130oE 30’ 131oE 30’ 132oE 30’ 133oE 30’

36oN

30’

37oN

30’

38oN

30’

18 J UN 2000oC

0

2

4

6

8

10

12

14

16

18

20

)

129oE 30’ 130oE 30’ 131oE 30’ 132oE 30’ 133oE 30’

36oN

30’

37oN

30’

38oN

30’

19 FEB 2000oC

0

2

4

6

8

10

12

14

16

18

20


129oE 30 130oE 30’ 131oE 30’ 132oE 30’ 133oE 30’

36oN

30’

37oN

30’

38oN

30’

19 FEB 2000oC

0

2

4

6

8

10

12

14

16

18

20

)

129oE 30’ 130oE 30’ 131oE 30’ 132oE 30’ 133oE 30’

36oN

30’

37oN

30’

38oN

30’

21 DEC 1999oC

0

2

4

6

8

10

12

14

16

18

20

)

129oE 30’ 130oE 30’ 131oE 30’ 132oE 30’ 133oE 30’

36oN

30’

37oN

30’

38oN

30’

19 APR 2000oC

0

2

4

6

8

10

12

14

16

18

20

)

129oE 30’ 130oE 30’ 131oE 30’ 132oE 30’ 133oE 30’

36oN

30’

37oN

30’

38oN

30’

18 J UN 2000oC

0

2

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(a)

(b)

N

The reanalysis by the ESROM was verified through comparing with a independent observation dataset by the PIES (Pressure-equipped Inverted Echo Sounder) in the Ulleung Basin located in the western side of the East/Japan Sea. This system reproduces the mesoscale variability as well as the general circulation in the East/Japan Sea for the mean correlation between the 100m/100-dbar temperature fields of the reanalyzed products and from the PIES measurments (corr=0.79).


3.2 Example of Validation: error fields

Fig. 4 RMS of innovation (observation minus model) of vertical temperature (left) and salinity (right) profiles from November 2006 to February 2008.

Many statistics have been calculated to check the consistency of the system. Some of them constitutes analysis and forecast scores at seven days. For instance, Figure 4 represents temporal series of RMS value of the innovation (observation minus model) allowing to check the performance of the system continuously with a set of independent observations. This RMS moves very little during the simulation and is of the order of the observations errors, as well for salinity as for the temperature, with a maximum at the thermocline depth.


3.2 Special Feature: An Example of assimilation method - Non-Gaussian -

• Cold intrusion (filament) is too cold.

Without constraint With constraint

Usui et al., 2008

Usui et al., 2008; see Usui’s poster S3.33


3.3 Special feature: Prediction (1) North Atlantic

Fig. 6 Snapshots of sea level in cm for part of the North Atlantic model domain (Canadian GOAPP). The upper left panel shows the along track altimeter anomalies from within 5 days of the analysis time (7 August, 2004). The upper right is the analysis after the assimilation of all available Argo profile and altimeter data. The bottom panels 15 day and 45 days forecasts of sea level for the verifying time.


3.3 Special feature: Prediction (2) North Pacific

Fig. 8. Prediction of the 2004 Kuroshio Large Meander. Color bar shows the speed, and arrow shows the horizontal velocity field. (a): initial condition (1 July, 2004), (b): assimilation (25 July), (c): assimilation (25 August), (d) 25days prediction (25 July), (e): 55days prediction (25 August).


3.3 Special feature: Prediction (2) North Pacific

Fig. 9. Predictability diagram of the Kuroshio path. RMS error is calculated from 138 cases of the sea surface height in the south of Japan (see map at the upper left corner for the evaluation area) from 1993/2 to 2004/7. Blue line: prediction; red line: persistency; broken line: mean sea surface height variability. Wind is not forecasted one.


4. Special Applications: Biogeochemical process

A comparison of the MERCATOR PSY2v3 currents map with the Chlorophyll-A concentration (independent data, i.e. not assimilated) in the Gulf Stream region (Figure 5), shows a good agreement between the model and the observations. Chlorophyll fronts are coherent with the model streamlines. The subsurface drifters confirm that the model current are good in term of direction and intensity.

Fig. 5. Chlorophyll-A concentration from MODIS (upper) and MERCATOR-North Atlantic PSY2v3 currents at 15 meters (lower) on July 11th 2007. The coloured dots represent the position and velocity measurements of the drifters (the dots are shrinking as the measurement gets further from the model date).


4. Special application: Sensitivity of Boundary Condition to Coastal/shelf sea system

ADCP observation lines

Current field at 0.5m depth, Nov. 21, 2007. (Left): regional system J, (Right): RIAMROPS-L1 with B.C. of J

L1=3km

Current field at 0.5m depth, Nov. 21, 2007. (Left): regional system M, (Right): RIAMROPS-L1 with B.C. of M

RIAMROPS


S N

Comparison of east-west velocity along line B, Oct. 12, 2007. (upper): ADCP obs. (middle): B.C. is J, (lower): B.C. is M

Same as left pannel.North-south velocity


Summary

Demonstration of GODAE Regional systems

Some examples of special features/uniqueness Connection to coastal/shelf sea system:

115oE 120oE 125oE 130oE 135oE 140oE 145oE 15oN

20oN

25oN

30oN

35oN

40oN

Surface Current

50 cm/sec 129oE 30’ 130oE 30’ 131oE 30’ 132oE 30’ 133oE 30’

36oN

30’

37oN

30’

38oN

30’

21 DEC 1999oC

0246


Future issues

General future issues are clarified from each projects under GODAE. We summarise the issues or future developments needed (though the detailed discussion is omitted):

(1): sensitivity study of B.C. to coastal/shelf sea system.(2): developing model insertion method such as IAU to avoid model initial shock

with higher resolution. (3): Improving error statistics variance/covariance matrices for special regional

features.(4): increasing resolution but not much in observation => developing advanced

assimilation method such as 4DVAR.(5): OSE/OSSE type of observation sensitivity experiments for special regional

features.(6): coupling to sea ice model/assimilation.(7): regional atmosphere-wave-ocean coupled model/assimilation system for

improving prediction of local air-sea interaction such as typhoon/hurricane.

GODAE Final Symposium, 12 – 15 November 2008, Nice, France REGIONAL HIGH RESOLUTION ANALYSES AND...

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