Michiko Masutani Joint OSSE Nature runs Is higher resolution model better? http://www.emc.ncep.noaa.gov/research/ JointOSSEs http://www.emc.ncep.noaa.gov/research/ THORPEX/osse
Jan 19, 2018
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 ([email protected])
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 ([email protected])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 ([email protected]) 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