Data Impact Studies in the CMC Global NWP system

Transcription

1 Third WMO Workshop on the Impact of Various Observing Systems on WP Alpbach, Austria 9 12 March 2004 Data Impact Studies in the CMC Global WP system Gilles Verner, Réal Sarrazin and Yulia Zaitseva Canadian Meteorological Centre Meteorological Service of Canada Environnement Canada Centre météorologique canadien Environment Canada Canadian Meteorological Centre

2 Outline CMC current global WP suite and observations usage Impact of observation types from OSE s with the global WP system Recent OSE: Impact of Russian radiosonde data Outlook of the future CMC WP system Conclusions and final remarks

3

4 CMC Operational Models GEM model (global, regional, meso) 3D-Var assimilation on model η levels (T108) Background errors from method Observations QC with BG check and QC-VAR Global Model Uniform grid Resolution of.9º (~100 km) 28 eta levels Kuo convection scheme Sundqvist stratiform scheme Force-restore surface module with climatogical soil moisture 10 day forecasts at 00Z and 6 day forecasts at 12Z. Cut-off of T+3h00 Regional Model Variable resolution grid Resolution of.22º (~24 km) 28 eta levels Fritsch-Chappell scheme Sundqvist stratiform scheme ISBA surface module with soil moisture pseudo-analysis (error feedback, no data) 48-hour forecasts (00Z -12Z) Cut-off of T+1h40

5 Observations for 3D-Var analyses Upper air soundings radiosonde pilot dropsonde land stations ships aircraft (dropsonde) Surface observations synoptic land stations ships fixed buoys drifting buoys Satellite OAA ATOVS amsu-a & amsu-b Aircrafts ACARS / AMDAR AIREP / ADS temperature moisture winds sfc pressure temperature moisture sfc pressure winds (marine) circumpolar radiance (global) (no amsub in regional) GOES imager geostationary radiance (global) AMVs geostationary (METEOSAT & GOES) Aircrafts (single level & profiles) HUMSAT (regional) derived winds temperature winds

6 Operational WMO Verification

7 Data Impact Studies (OSE s) Series of experiments with the exclusion of a type (or combination of types) of observation in order to evaluate the importance of the impact of various observation systems in the CMC Global WP suite Two 6 weeks periods: Winter Period: 18 Dec 01 to 27 Jan 02 ( DJ ) Summer Period: 17 June 02 to 31 July 02 ( JJ ) 6-day forecasts every 12 hours (00UTC and 12UTC) from final analyses (long cut-off) (total of 82 and 90 forecasts respectively)

8 Data Impact Studies Control cycle was operational global WP system, following major implementation of Dec. 01. ote: o AMSUB data, HUMSAT data for GOES. Three set of experiments: Satellite: Conventional: Aircraft: OTO OSW OHU OSAT OUA OAI OSF OSAT AITT AIUV OAI TO - amsua radiance (3-10) OAA-15&16 HU - humsat (GOES-8&10) UA - raobs (TEMP, PILOT, DROP) SF - surface (SYOP, SHIP, BUOY, DRIFTER) AITT - without aircraft temperature SW - AMW GOES-8&10, METEOSAT-5&7, GMS OSAT - OTO + OSW + OHU AI - aircraft (AIREP, AMDAR, ACARS, ADS) CTRL - control (with all data, long cut-off) AIUV - without aircraft wind

9 Mean Winter Flow (December-January) GZ 500 hpa

10 Mean Summer Flow (June-July) GZ 500 hpa

11 C T R L - O S A T C T R L - O T O V Anal differences winter GZ 500 hpa D e c - J a n

12 C T R L - O S A T C T R L - O U A Anal differences winter GZ 500 hpa D e c - J a n

13 C T R L - O S A T C T R L - O T O V Anal diff. - Summer GZ 500 hpa J u n e - J u l y

14 C T R L - O S A T C T R L - O U A Anal diff. - Summer GZ 500 hpa J u n e - J u l y

15 Verif vs Raobs O-P6hr orthern Hemis. CTRL OUA JunJul RMS BIAS DecJan

16 O-P6hr orthern Hemis. CTRL OSAT JunJul DecJan

17 O-P6hr Southern Hemis. CTRL OSAT JunJul DecJan

18 O-P6hr orth America CTRL OAI JunJul DecJan

19 Verification vs raobs O-P6hr Tropics Jun-Jul CTRL OSW Bias + EQM

20 Verification vs raobs O-P6hr Tropics Jun-Jul CTRL OTO Bias + EQM

21 Verification vs raobs O-P6hr Tropics Jun-Jul CTRL OSAT Bias + EQM

22 RMS Forecast Impact (FI) Zapotocny et al., x (RMS experiment - RMS control) / RMS control % impact resulting from the removal of one (or a few) type of observation (+ive means +ive impact of data) Results presented as histograms Done using verification against soundings

23 Conventional data experiment GZ 500 Jun-Jul Dec-Jan

24 Satellite data experiment GZ 500 Jun-Jul Dec-Jan

25 Aircraft data experiment Jun-Jul orth America UU 250 UU-250 UU-500 TT-700 GZ-500 Es-700

26 Dec-Jan orth Amer. Jun-Jul UV-250 UV-500 TT-700 GZ-500 Es-700

27 OSE Results: Verification vs Control Analyses Winter period, impact of the removal of TOVS vs Radiosondes Dec-Jan Anomaly correlation Geopotential Heights 500 hpa

28 OSE Results: Verification vs Control Analyses Summer period, impact of the removal of TOVS vs Radiosondes Jun-Jul Anomaly correlation Geopotential Heights 500 hpa

29 Dec-Jan. Amer. - ACOR - GZ 500 Jun-Jul

30 Jun-Jul Conventional data experiment 24Hr RMS UV 250 orthern Hemisphere orth America

31 ew OSE: Impact of Russian radiosondes Control cycle was current operational global WP system. One month period of September 2003 (24 Aug 04 Oct). ote: AMSUB data and GOES radiance data included. 73 Russian radiosonde stations. Two experiments: RU00: RU12: Removal at 00 AD 12 UTC Removal at 12 UTC only orth Pacific

32 Mean September Flow GZ 500 hpa

33 C T R L - R U 0 0 C T R L - R U 1 2 Anal differences Sept. GZ 500 hpa Anal Diff. S e p t e m b e r

34 C T R L - R U 0 0 C T R L - R U 1 2 Difference in Fcst Error. GZ 500 hpa 48hr Abs. Err. Difference S e p t e m b e r

35 Verif vs Raobs O-F 24hr orth Pacific CTRL RU00 RU12

36 Verif. vs Anal RMS GZ 250 CORA GZ 850 orth Pacific CTRL RU00 RU12

37 C T R L - R U 0 0 C T R L - R U 1 2 Difference in Fcst Error. GZ 500 hpa 48hr Abs. Err. Difference Valid 13 Sept 12 UTC

38 Outlook: CMC Global System ow: - Uniform resolution of 100 km (400 X 200 X 28) - 3D-Var at T108 on model levels, 6-hr cycle, use of raw radiances from AMSUA, AMSUB and GOES 2004: - Resolution to ~35 km (800 X 600 X 56) - 4D-Var assimilation, 6-hr time window with 3 outer loops at full model resolution and inner loops at T108 - new datasets: profilers, MODIS winds, AMSUA on AQUA -EnKFfor EPS 2005: - Top at 0.1 hpa (instead of 10 hpa) with additional AMSUA and AMSUB channels (Clément`s presentation) - assimilation of AIRS, MSG, MTSAT, QuikScat, SSM/IS - revised 4D-Var statistics : - Additional datasets: IASI, GIFTS, COSMIC - very large increase in volume of assimilated data

39 Summary and final remarks Clear and positive impact from all types of observations in 3D-Var Major impact of satellite observations (mostly ATOVS): dominant in the Southern Hemisphere; and equivalent to radiosondes in the orthern Hemisphere and orth America (Summer) Major impact of radiosondes in Winter (H, OAM) Some synergy observed (sometimes large) between some observations Impact varies on verifying element, vertical level, period, season, etc. Wind data from Aircraft gave more impact than temperature data eed to consider a long enough period, and use many diagnostics Impact from Russian RAOBS clearly detected, with a quite stronger signal when both 00 and 12 UTC soundings are removed Average impact on scores small but statistically significant (00 and 12) Individual cases show significant impact in Western Pacific and Arctic Period chosen (Sept.) not the best and too short, more tests needed

40 DJ JJ common (JJ/DJ) Impact: Forecast Improvement Soundings Aircraft eutral to weak Surface orthern Atovs Hemisphere Satwinds Humsat Satellite Soundings Aircraft Surface Tropics Atovs Satwinds Humsat Satellite Soundings Aircraft Surface Southern Atovs Hemisphere Satwinds Humsat Satellite