Recent Developments of JM A Operational NWP Systems and WGNE - PowerPoint PPT Presentation

Recent Developments of JM A Operational NWP Systems and WGNE Intercomparison of Tropical Cyclone Track Forecast M asayuki Nakagawa and colleagues at JM A Numerical Prediction Division Japan M eteorological Agency 1

RECENT DEVELOPM ENTS OF J M A OPERATIONAL NWP SYSTEM S 2

Sequence of M eteorological Data Processing OBSERVATION Satellites Rockets verification Radiosondes Aircrafts Radars Surface obs. Ships/Buoys analysis-forecast cycle OBS.DATA PROCESSION Objective Quality Decoding Analysis GTS lines Control NUMERICAL PREDICTION Numerical Prediction Initialization GSM,MSM,LFM,WEPS,TEPS information feedback APPLICATION Guidance, Graphics, Statistics Facsimiles PUBLIC RELATION Meteorological Weather forecast Information 3

History of operational NWP models at JM A JMA has been actively developing numerical weather prediction (NWP) systems since the commencement of operational numerical prediction in 1959. 4

Current NWP models of NPD/ J M A Global Spectral Meso-Scale One-week Typhoon Local Forecast Model Model Model Ensemble Ensemble LFM WEPS TEPS GSM MSM Short- and Medium- Disaster reduction Aviation forecast One-week range Objectives Typhoon forecast forecast Aviation forecast Disaster reduction forecast Japan and its Japan and its Global Global surroundings surroundings (4080km x 3300km) (3160km x 2600km) Forecast domain Horizontal TL959(0.1875 deg) TL479(0.375 deg) 5km 2km resolution New! Coming 60 → 100 Vertical 50 60 60 soon! 0.1 → 0.01 hPa levels / Top 21.8km 20.2km 0.1 hPa 84 hours 132 hours 264 hours Forecast 39 hours (00, 06, 18 UTC) 9 hours (00, 06, 12, 18 Hours (00, 12 UTC) (00, 03, 06, 09, 12, 15, UTC) 264 hours (00-23 UTC hourly) (Initial time) 18, 21 UTC) 27 members 25 members (12 UTC) Global Analysis Meso-scale Analysis Local Analysis Global Analysis Initial Condition (4D-Var) (4D-Var) (3D-Var) with ensemble perturbations (SV) As of 12 March 2014 5

Data assimilation systems of NPD/ J M A Global Analysis Meso-scale Analysis Local Analysis (GA) (MA) (LA) Analysis scheme 4D-Var 3D-Var 00, 03, 06, 09, 12, 15, Analysis time 00, 06, 12, 18 UTC hourly 18, 21 UTC 2 hours 20 minutes [Early Analysis] 11 hours 50 minutes (00, 12 UTC) Data cut-off time 50 minutes 30 minutes 7 hours 50 minutes (06, 18 UTC) [Cycle Analysis] Horizontal resolution TL959 / 0.1875 deg 5 km 5km (inner-model (TL319 / 0.5625 deg) (15 km) resolution) Coming soon! 60 levels up to 0.1 hPa → 50 levels up to Vertical levels 50 levels up to 21.8km 21.8km 100 levels up to 0.01 hPa -3 hours to +3 hours of analysis -3 hours to analysis Assimilation window - time time As of 12 March 2014 6

The accuracy of 3-day forecast in 2013 compares with that of 1-day forecast in 1980 ’ s. Smaller error 7 2 0 1 3 6 0 L - G S M Verification score of global model RM SE of 500 hPa geopotential height in Northern Hemisphere (20-90N) 2 0 1 2 6 0 L - G S M 2 0 1 1 6 0 L - G S M 2 0 1 0 6 0 L - G S M 2 0 0 9 _6 0 L - G S M 1 -day forecast 2 -day forecast 3 -day forecast 2 0 0 8 _6 0 L - G S M A v e ( 7 2 h ) 2 0 0 7 _4 0 L - G S M 2 0 0 6 _4 0 L - G S M 0 0 U T C / 1 2 U T C 2 0 0 5 _4 0 L - G S M A v e ( 4 8 h ) 2 0 0 4 _4 0 L - G S M 2 0 0 3 _4 0 L - G S M 2 0 0 2 _4 0 L - G S M R M S E 2 0 0 1 _4 0 L - G S M A v e ( 2 4 h ) 2 0 0 0 _3 0 L - G S M 1 9 9 9 _3 0 L - G S M Z 5 0 0 ( 2 0 N - 9 0 N ) 1 9 9 8 _3 0 L - G S M 7 2 h _ F c s t 1 9 9 7 _3 0 L - G S M 1 9 9 6 _3 0 L - G S M 1 9 9 5 _2 1 L - G S M 4 8 h _ F c s t 1 9 9 4 _2 1 L - G S M 1 9 9 3 _2 1 L - G S M 1 9 9 2 _2 1 L - G S M G S M 2 4 h _ F c s t 1 9 9 1 _2 1 L - G S M 1 9 9 0 _2 1 L - G S M 1 9 8 9 _1 6 L - G S M 1 9 8 8 _1 6 L - G S M 1 9 8 7 _1 2 L - H S M 1 9 8 6 _1 2 L - H S M 1 9 8 5 _1 2 L - H S M 1 9 8 4 _1 2 L - H S M 8 0 7 0 6 0 5 0 4 0 3 0 2 0 1 0 0 RMSE of geopotential height (m)

Tropical cyclone track forecast error of global model 1 2 0 0 1 2 0 1 1 0 0 9 6 1 0 0 0 7 2 9 0 0 4 8 TC track forecast error (km) 8 0 0 2 4 Smaller error 7 0 0 6 0 0 5 0 0 4 0 0 3 0 0 2 0 0 1 0 0 0 1 9 9 1 1 9 9 3 1 9 9 5 1 9 9 7 1 9 9 9 2 0 0 1 2 0 0 3 2 0 0 5 2 0 0 7 2 0 0 9 2 0 1 1 2 0 1 3 Year As a result of continuous development, typhoon position error has been continuously decreasing. The accuracy of 120 hr forecast in 2013 compares with that of 72 hr forecast in early 1990 ’ s. 8

Example of Typhoon Forecast by 20km-GSM  Accuracy of current NWP is generally good.  GSM predicted typhoons track well. Obs. 9

Development – physics and dynamics- • Recent changes – 28 M ar 2013: 11 days forecast (<- 9 days) for both deterministic and ensemble systems. – 25 Apr. 2013: Revise radiation scheme • Update aerosol optical depth climatology • Revise shortwave absorption by water vapor in radiation scheme （ Collins et al. 2006 ） – 18? M ar. 2014: • Increasing the number of vertical layers from 60 to 100 (top: 0.1->0.01 hPa) • Revise physical processes 10

Enhancement of GSM (M ar 2014) • JM A plans to upgrade its L60 L100 operational GSM . – The number of vertical layers in GSM will be enhanced from 60 to 100. – the top level of the model will be raised from 0.1 hPa to 0.01 hPa. • The physical processes will be revised. 11

Update of physical processes 1. Revising a stable boundary layer scheme → Improving wind fields and diurnal temperature variation in stable conditions 2. Revising albedo parameters in the desert areas → Reducing clear sky radiation biases 3. Introducing two-stream approximation for long wave radiation scheme → Accelerating radiation code and improving the middle atmosphere temperature structure 4. Introducing a non-orographic gravity wave forcing scheme → Improving the middle atmosphere climate and representation of long- term oscillation in the tropical lower stratosphere such as QBO 5. Changing the application criteria of energy correction terms in convective parameterization → Improving general circulation and global precipitation distribution 6. Applying 2nd-order linear horizontal diffusion in the divergence equation and adjusting 4th-order linear diffusion as a sponge layer around the model top region → Improving the middle atmosphere forecast accuracy 12

Tropospheric scores (improvement rate of RM SE against analysis) Better Summer (Jun-Sep Worse 2013) Better Winter (Dec 2012 Worse -Feb 2013) Psea T850 Z500 Wspd850 Wspd250 Improvement rate of root mean square errors (RMSEs) against analysis between upgraded GSM and current GSM for Jun-Sep 2013 (top) and Dec 2012-Feb 2013 (bottom). Lines over yellow (gray) background area mean upgraded GSM shows better (worse) scores than current GSM. The results of experiments show that the upgrade will have a positive impact on forecast scores mainly in the extra-tropics. Negative impacts are seen for Psea and Z500 in the early forecast hours and for T850 in the tropics. 13

Precipitation Current Upgraded Aug 2013, FT=216 24-hour precipitation GPCP CMORPH [mm/day] Excessive precipitation over the ITCZ, Indian Ocean and Atlantic Ocean is reduced. 14

General circulation Current Upgraded Velocity potential at 200hPa Stream function at 200hPa Jul-Aug 2013, FT=216 Contour: forecast field Shade: mean error Representation of general circulation in the late forecast hours is improved. 15

Tropical cyclone track forecast errors Upgraded North-Western Pacific North-Eastern Pacific Current with bogus without bogus JMA-Best Track NOAA b-decks 6/21/2013 - 9/11/2013 6/21/2013 - 9/11/2013 Atlantic Southern Hemisphere without bogus without bogus NOAA b-decks NOAA b-decks 6/21/2013 - 9/11/2013 12/21/2012-2/11/2013 The upgrade reduces TC track forecast errors in all four regions. Another verification shows that the performance of new model for detection of cyclone existence is better than that of old model. 16

Tropical cyclone intensity errors FT=0 FT=24 FT=48 FT=72 Current Upgraded The upgrade reduces excessive development of TC. 17

Development – assimilation, data- • Recent changes – 15 Nov. 2012: RTM upgrades (RTTOVv9.3  v10) – 18 Dec. 2012: GNSS-RO observation operator upgrades – 02 J ul. 2013: AVHRR, LEOGEO AM V – 12 Sep. 2013: Assimilation of J AXA's GCOM -W1/ AM SR2 radiance data started – 16 Oct. 2013: Assimilation of SYNOP BUFR started – 28 Nov 2013: Assimilation of GRAS, AM SU-A, M HS, ASCAT and AVHRR-AM V data from M etop-B started. – 18? M ar. 2014: • Assimilating AM SU-A channel 14 • Assimilating GNSS-RO bending angle data at the altitude up to 60km (currently, refractivity data up to 30 km) • Assimilating ground-based GNSS-ZTD (Zenith T otal Delay) data 18