Michiko Masutani

Joint OSSE Nature runsIs higher resolution model better?

http://www.emc.ncep.noaa.gov/research/JointOSSEshttp://www.emc.ncep.noaa.gov/research/THORPEX/osse

New Nature Run by ECMWF based on recommendations from

JCSDA, NCEP, GMAO, NESDIS, ESRL, GLA, SIVO, SWA,

Low Resolution Nature Run Spectral resolution : T511

Vertical levels: L9113 month long 3 hourly dump

Initial conditions: 12Z May 1st, 2005 Ends at: 0Z Jun 1,2006

Daily SST and ICE: provided by NCEPModel: Version cy31r1

Two High Resolution Nature Run35 days long

T799 resolution, 91 levels, one hourly dumpGet initial conditions from T511 NR

Hurricane season: Starting at 12z September 27,2005,

Convective precipitation over US: Starting at 12Z April 10, 2006

[Usage and credit ]

This data must not be used for commercial purposes. ECMWF and the Joint OSSEs must be given credit in any publications in which these data are used. A user list will be kept at ECMWF and the Joint OSSE. Redistribution rights are not given.

saved at ECMWF, NCEP, ESRL, and NASA/GSFC

ECMWF: Archived in the MARS system as expver=etwu

NASA/GSFC portal: ID and password required contact: Harper Prior (Harper.Pryor@nasa.gov)

Gradsdods access is available for T511 NR. The data can be down loaded  in grib1, NetCDF, binary. The data can be retrieved globally or selected region.

Provide IP number to :Arlindo da Silva (Arlindo.Dasilva@nasa.gov)NCEP: Require account at NCEPNature Runs are available to designated users for research purpose& users known to ECMWF The user list outside of the EC is maintained by :Michiko Masutani (michiko.masutani@noaa.gov) and reported to ECMWF

Archive and Distribution The Complete data set

Archive and DistributionSupplemental data

Supplemental low resolution regular lat lon data 1degx1deg for T511 NR, 0.5degx0.5deg for T799 NR

Pressure level data: 31 levels, Potential temperature level data: 315,330,350,370,530KSelected surface data for T511 NR: Convective precip, Large scale precip,

MSLP,T2m,TD2m, U10,V10, HCC, LCC, MCC, TCC, Sfc Skin Temp

Complete surface data for T799 NR

Available from NCAR CISL Research Data Archive. Data set ID ds621.0 Currently NCAR account is required for access.

(Also available from NCEP hpss, NASA/GSFC Portal, ESRL, NCAR/MMM, NRL/MRY, JMA, MSU, Utah)

Note: This data must not be used for commercial purposes and re-distribution rights are not given.

Diagnostics of T511 Nature Run

Nature Run cloud diagnostics (A. Tompkins) One year mean total cloud cover T511NR and MODIS

This has improved greatly in recent cycles of the model. In particular, the stratocumulus regions have improved.- The apparent underestimation relative to ISCCP over the Sahara is because this product is thought to overestimate cloud cover there. MODIS shows better agreement with the model over the deserts.- The MODIS product over sea ice is unreliable

T511 NRRed: NRBlack:MODIS

MODIS

NR-MODIS

lat

lon

lon

Comparison between the ECMWF T511 Nature Run against climatology

of observation 20050601-20060531, exp=eskb, cycle=31r1

Adrian Tompkins, ECMWF

Total PrecipNR vs. Xie Arkin

TechMemo 452 Tompkins et al. (2004) Plot files are also posted athttp://www.emc.ncep.noaa.gov/research/osse/NR/ECMWF_NR_Diag/ECMWF_T511_diagThe description of the datahttp://www.emc.ncep.noaa.gov/research/osse/NR/ECMWF_T511_diag/climplot_README.html

NR

Xie Arkin

NR-Xie_Arkin

Red: NRBlack:Xie Arkin

1) Extract cyclone information using Goddard’s objective cyclone tracker

• Nature Run• One degree operational NCEP analyses (from several surrounding years)• NCEP reanalysis for specific years (La Nina, El Nino, FGGE)

2) Produce diagnostics using the cyclone track information(comparisons between Nature Run and NCEP analyses for same month)

• Distribution of cyclone strength across pressure spectrum• Cyclone lifespan• Cyclone deepening• Regions of cyclogenesis and cyclolysis• Distributions of cyclone speed and direction

Extratropical Cyclone StatisticsJoe Terry

NASA/GSFC

Comparison of zonal mean zonal wind jet maxima, NR and ECMWF analysis, Northern Hemisphere By Nikki Prive, ESRL

blue – ECMWF

green star – Nature Run

Nikki Prive also presented realistic Rossby wave and many good storm to test T-PARC experiments

Hurricane-like (HL) vortices

Only two relatively strong HL vortices are observed until Aug 31st. (slp mins of about 970 hPa and 975 hPa in the 1deg res. ).

However, early recurvers do occur in packs

Example of a number of early recurving systems in an active season, 2004.

HL vortices: vertical structure

Vertical structure of a HL vortex shows, even at the degraded resolution of 1 deg, a distinct eye-like feature and a very prominent warm core.

`Major’ hurricane over the Gulf: vertical structure

Vertical structure of a HL vortex shows, even at the degraded resolution of 1 deg, a distinct eye-like feature and a very prominent warm core. Structure even more impressive than the system observed in August. Low-level wind speed exceeds 55 m/s

Wind speed (m/s)Temp (oC)

Vertical structure of a HL vortex shows, even at the degraded resolution of 1 deg, a distinct eye-like feature and a very prominent warm core. Structure even more impressive than the system observed in August. Low-level wind speed exceeds 55 m/s

These findings, albeit preliminary, are suggestive that the ECMWF NR simulates a realistic meteorology over tropical Africa and nearby Atlantic and may prove itself beneficial to OSSE research focused over the AMMA or the Atlantic Hurricane regions.

Reale O., J. Terry, M. Masutani, E. Andersson, L. P. Riishojgaard, J. C. Jusem (2007), Preliminary evaluation of the European Centre for Medium-Range Weather Forecasts' (ECMWF) Nature Run over the tropical Atlantic and African monsoon region, Geophys. Res. Lett., 34, L22810, doi:10.1029/2007GL031640.

TropicsOreste Reale (NASA/GSFC/GLA)

T799 October Joint OSSE Nature Run:

very preliminary assessment of tropical cyclone activity

Oreste Reale

Evaluation based on interpolated pressure level fields

T511

T799

Min MSLP T799 OCT05 period

By Michiko Masutani

Quick look using 1degree data

Convective Precipitation

T511

T799By Michiko Masutani

Quick look using 1degree data3 hour mean 12z-15Z Oct05 2005

Atlantic tropical systems

Extremely suspicious eastern Atlantic TC tracks

Strongest `Hurricane’ in the Atlantic

Perplexingly large scale, relatively modest intensity. T511 contains equallystrong systems, and better confined.

Poor vertical structure

Eye-like feature extremely unrealistic, scale resembles diluted vorticestypical of much lower resolution models

Western-central Pacific Tropical Systems

Perplexing lack of strong activity on the western Pacific: however, the intensity of the strongest system is quite good (max of 60 m/s at 900hPa)

Strongest TC in the T799 NR

The system is strong, however there is a perplexing mid-tropospheric windmax. The scale is good: the system appears very compact as to be expectedat such resolution.

Summary• AEJ is 40% weaker than climatology• Atlantic TC activity contains some highly

suspicious tracks• Eastern Pacific seems to present excessive

proliferation of weak TCs• The intensity of the strongest ATL systems is not

superior to T511• Different behavior in different basins• Structure of some intense system not very

satisfactory in terms of scale and size of eye-like feature

Preliminary conclusions• The increased resolution does not necessarily

provide stronger confidence in a much better Nature Run for the tropics

• Representation of TC activity does not immediately appear superior to the T511

• Caution should perhaps be used in adopting this NR for applications centered on future instruments targeting hurricanes

• Further investigation is needed

Zonal mean high pass eddy KE at 250hPaThree day running mean subtracted

Interpolated to 1degree3 hour sampling

Toward end of October, SH become erroneously active in T799 NR.

10 day average sfc skin temperature

10 day average sfc skin temperature

Comments from Anton Beljaars on the performance of the T799 Nature Run

Tropical convection, and the frequency of small scale vortices appearing in the T799 Nature Run.

The balance between convection and the resolved flow depends very subtly on the convective parameterisationThis is resolution dependent – and changes significantly each time we change anything in the convection scheme.More active convection paramaterisation generally gives rise to fewer small-scale vortices – and vice versa.

Some substantial progress was made with IFS 32r3, which was made operational in November 2007. The convective closure assumption was changes to no-longer depend on the large-scale moisture convergence (in the boundary layer).This change resulted in improved simulation of the large-scale divergent flows in the tropics, better MJO and fewer small scale vortices associated with strong convective rainfall.

Response from ECMWF

Good hurricanes and storms in T799 run even for meso scale OSSEs.

Before producing regional NR, it is highly recommended to perform regional OSSEs (40-60km resolution) with T799 global NR.

Mesoscale NR must be another Joint OSSE NR which will be shared within Joint OSSE

Regional OSSEs are affordable to Universities. Simulation of observations may be difficult.

Regional OSSE must present evaluation of effect of lateral boundary conditions.

Integrations of meso/regional OSSE effort into Joint OSSEs

Note: There are global meso-scale model (NICAM, GFDL, ESRL) and relatively low resolution regional OSSEs are considered.

Strong demands for high resolution NR

Potential candidate for the next NRNICAMNonhydrostatic icosahedral atmospheric modelGlobal cloud resolving model

www.nicam.jp

3.5 km model integrations are done for one week (stop due to computing resource)7 and14km model integrated for 100-200 days40 levels

Forecast skill is yet to be provedOnly seven day integration was performed

26DEC2006 21:00 JSTObserved NICAM

Local high resolution global modelUsing Fibonacci grid

Jim Purser (NCEP)

H. Tomita (2007) "A stretched grid on a sphere by new grid transformation and its applications "submitted to J. Meteor. Soc. Japan, special issue.

Requirement for the meso scale (can be global) Nature run- sample suggestions-

♦Could be either global or regional.♦The NWP model must have good forecast skill Great visualization does not guarantee good forecast skill.♦At least 3 month lower resolution run with same model is required to provide a period for spin up for bias correction. ♦Must have a good TC or a severe storm in the nature run period.♦Sufficient number of vertical levels. Minimum 91 levels.♦Some degree of coupling with ocean and land surface♦If it is regional, the effect of the lateral boundary must be evaluated.♦ A list of verification method must be produced by Joint OSSE.♦ Need NR to be shared within Joint OSSE♦ User friendly archive