Póster presentado en: 7th EMS Annual Meeting celebrado del 1 al 5 de octubre de 2007 en El Escorial, Madrid

Baldasano, José María

Cuevas Agulló, Emilio

Jorba, Oriol

Marrero, Carlos

English

Agencia Estatal de Meteorología

Contact: ; Observatorio AtmosfØrico de Izaæa (INM),        C/La Marina,20-Planta 6, 38071 Santa Cruz de Tenerife - SPAIN                                         phone: +34-922151718 fax: +34-922574475cmarrero@inm.esFactor Separation MethodologyTo quantify the impact on  the 10 m wind solution due to modifications of the setup parameters, we have used the factor separation technique formulated by Stein and Alpert (1993),  following the methodology adopted by Jankov et al. (2005). Based on this methodology:where   represents the chosen solution variable of the Control Run Experiment (CRE). Our CRE  corresponded to the phys5 (Fig. 6) option, 27-9-3 km two-ways nesting centred grid and 31  levels  scheme configuration. The CRE choice was based in computational economy (most of the experiments are run with this domain and physics configuration). The solution variable used  was the maximum grid point 10 m horizontal wind speed in the 48 hours run (Fig. 9). Now,     represents the maximum 10 m wind speed produced by a run that has one of the configuration parameters of the model changed,    the maximum wind speed when  another parameter is changed, and     when the two simultaneous parameters are changed.       stands for a synergistic term reflecting the nonlinear interaction between the two different configuration parameters. The notation presented  in Table 2 will be used to indicate the different model configurations used with this technique.WRF-ARW model 0fxffxyffyffxffxyfˆ000 +-+-=- ÷÷łöççŁæ÷÷łöççŁæyfxyfxyfˆConfiguration Parameters  Notation   Microphysics Options MP Lin et al. LIN WSM 3-class simple ice WSM Ferrier (new Eta) microphysics FER   Surface-Layer Options & Boundary-Layer Options SL&BL Monin-Obukhov & YSU Scheme MO-YSU Monin-Obukhov (Janjic Eta) & Mellor-Yamada-Janjic (Eta) TKE MOJ-MYJ   Cumulus Options CU Kain-Fritsch (new Eta) KF Betts-Mill er-Janjic BMJ   Most Inner Grid Resolution GR  27, 9, 6, 3, 2 or 1 km Nesting Two-Ways Activation NA  Yes or No Number of WRF-ETA scheme Vertical Levels NL  31, 41 or 61 Percentage of Mother Grid Reduction PGR  25% or 50% Position of Mother Grid PMG  0” Centered, 10” E, 10”W or 10”S Hydrostaticity HY  Yes or No    Table 2. Configuration Parameter options available in the 27 experiments to evaluate their impact using the factor separation methodology.Fig. 9. Example (experiment 11 in Table 3) of the solution variable    used. Different Colors represent values of maximum 10 m horizontal wind speed in the 48 hours run.fThe numerical solutions of Limited-Area Models (LAM) are sensitive to changes in their configurations. One of the most common ways of utilizing those models is by performing sensitivity experiments (Stein and Alpert, 1993). In this study, continuation of recent works of Jorba et al., 2007 and  Marrero et al., 2007,  we show  preliminary results associated with 27 configurations of the Weather Research & Forecasting Model (WRF-ARW) (Michalakes et al., 2005)  initialized with the 0.25º reanalysis of the European Center for Medium Range Weather Forecasting (ECMWF) for the extratropical storm Delta. Delta affected the Canary Islands (Fig.1) with a warm core associated in 850 hPa (Fig. 2) on 28 November 2005, causing significant damage related to high sustained wind and intense gusts over some of the islands (Table 1). Modifications in domain dimension and location, horizontal resolution, number of vertical levels and physics permit us to survey their impact in the 10 m wind solution. The factor separation method was used to quantify in detail the effect  of the variation of these parameters on the simulated 10 m wind speed. Highly  non linear interaction of flow with topography due to the existence of the warm core at the mountain top level was the main factor that produced gusts over 160 km/h at La Palma, 90 km/h at the coast in Tenerife, and over 215 km/h in its mountain top (Jorba et al.,2007; Marrero et al., 2007).SENSITIVITY STUDY WITH A LIMITED AREA MODEL:EXTRATROPICAL STORM DELTA OVER THE CANARY ISLANDSCarlos Marrero1, Oriol Jorba2, Emilio Cuevas1 and José M. Baldasano2,3(1) Observatorio Atmosferico de Izaæa, Instituto Nacional de Meteorolog í a , Tenerife, SPAIN.(2) Earth Sciences Department, Barcelona Supercomputing Center  Centro Nacional de Supercomputaci ó n, Barcelona SPAIN.(3) Environmental Modelling Laboratory, Technical University of Catalonia, Barcelona, SPAIN .IntroductionFig. 2. ECMWF reanalysis of extratropical  storm Delta showing the warm core in 850 hPa  when going through the Canary Islands.850 hPa Warm Core850 hPa Warm Core850 hPa Warm CoreNumerical Modeling Setup    To explore their impact in the numerical solution we have designed several non hydrostatic experiments taking into account geometrical factors, like the size and position of the mother domain, number of nested grids, horizontal resolution and number of vertical levels (Fig. 5); and physical parameterizations (Fig. 6). To specify the size of the mother domain we have used HYSPLIT backward trajectories (Fig. 7 and 8) to evaluate the propagation of the advective lateral boundary condition error at several levels. The 31 level scheme has been interpolated to obtain the 41 and 61 level distributions. The size of the mother domain has been positioned 10º S, 10º E y 10ºW in relation to the base case configuration, and a reduction of 25% and 50% has also been applied to the centred case. Twelve combinations of physical schemes has been obtained using 3 microphysics, 2 surface layers, 2 boundary layers and 2 cumulus options. Non-nested domains have been defined to resolutions of 2 km, 3 km, 6 km, 9 km and 27 km. An additional  hydrostatic case forms a cluster of 27 experiments to explore the variability of the numerical solution.27-9-3-1 kmd01:164x120 ; d02:250x181d03: 424x325 ; d04: 724x54727-9-3 kmd01:165x120 ; d02:142x109d03: 250x18718-6-2 kmd01:245x179 ; d02:220x163d03: 382x28027-9-3 km 10” Wd01:165x120 ; d02:142x109d03: 250x18727-9-3 km 10” Ed01:165x120 ; d02:142x109d03: 250x18727-9-3 km 10” Ed01:165x120 ; d02:142x109d03: 250x18727-9-3 km 25% Reductiond01:143x104 ; d02:142x109d03: 250x18427-9-3 km 50% Reductiond01:117x87 ; d02:157x109d03: 256x175Sigma Levels00.10.20.30.40.50.60.70.80.911 6 11 16 21 26 31 36 41 46 51 56 61LevelSigma 31 Levels41 Levels61 LevelsSigmaSigmamicrophysics options1.b) Lin et al. 1.c) WSM 3-class simple ice 1.e) Ferrier (new Eta) microphysicssurface-layer option 3.1.a) Monin-Obukhov3.1.b) Monin-Obukhov (Janjic Eta) boundary-layer option4.a) YSU scheme4.b) Mellor-Yamada-Janjic (Eta) TKEcumulus option5.a) Kain-Fritsch (new Eta ) 5.b) Betts-Miller-JanjicFig. 6. Combinations of WRF-ARW physics   schemes used. . Fig. 8. NHC Best track and the 27-9-3-1km multiple nested grid case. Initialization on November 28th 00Z guarantees a well posed lateral boundary condition configuration.28 Nov  00ZMother DomainFig. 7.  HYSPLIT backward trajectories at several levels used toevaluate the size of the mother domain to diminish the effect ofLBC advective errors in 48 forecast hours. ResultsA total of 24 configurations have been compared against the CRE, with cursive and bold letters in Table 3 identifying the options that were varied. Nonlinear interactions were calculated in cases  5,6,7,8 y 9. In experiments 11, 20, 22, 23 and 24 only the factor      was determined. Percentage changes for every grid point were plotted in order to measure the magnitude of variation in a common domain of 3 km resolution. This percentage change was calculated asH is togram d iagrams fo r  every  experiment showing the number of grid points per percentage class into  a limited area around La Palma and Tenerife (Fig. 8) were added to summarize this information. Maximum and minimum values and statistics moments of order 0,1 and 2 (Table 4) are also shown. Only the most  relevant graphics and histograms  are presented  in Figure 11. Experiment Configuration Parameters   MP SL&BL CU GR NA NL PGR PMG HY CRE WSM MO-YSU KF 3 Y 31 0 C N EXP. 1 WSM MO-YSU BMJ 3 Y 31 0 C N EXP. 2 WSM MOJ-MYJ KF 3 Y 31 0 C N EXP. 3 L MO-YSU KF 3 Y 31 0 C N EXP. 4 F MO-YSU KF 3 Y 31 0 C N EXP. 5 WSM MOJ-MYJ BMJ 3 Y 31 0 C N EXP. 6 L MOJ-MYJ KF 3 Y 31 0 C N EXP. 7 F MOJ-MYJ KF 3 Y 31 0 C N EXP. 8 L MO-YSU BMJ 3 Y 31 0 C N EXP. 9 F MO-YSU BMJ 3 Y 31 0 C N EXP. 10 WSM MO-YSU KF 2 Y 31 0 C N EXP. 11 WSM MO-YSU KF 1 Y 61 0 C N EXP. 12 WSM MO-YSU KF 3 Y 41 0 C N EXP. 13 WSM MO-YSU KF 3 Y 61 0 C N EXP. 14 WSM MO-YSU KF 3 Y 31 25 C N EXP. 15 WSM MO-YSU KF 3 Y 31 50 C N EXP. 16 WSM MO-YSU KF 3 Y 31 0 E N EXP. 17 WSM MO-YSU KF 3 Y 31 0 W N EXP. 18 WSM MO-YSU KF 3 Y 31 0 S N EXP. 19 WSM MO-YSU KF 3 Y 31 0 C Y EXP. 20 WSM MO-YSU KF 2 N 31 0 C N EXP. 21 WSM MO-YSU KF 3 N 31 0 C N EXP. 22 WSM MO-YSU KF 6 N 31 0 C N EXP. 23 WSM MO-YSU KF 9 N 31 0 C N EXP. 24 WSM MO-YSU KF 27 N 31 0 C N Table 3. Experiments setting used to compare against the CRE. Cursive and bold letters indicate the parameters (notation defined in Table 2.) that have been varied in every experiment.xyf10000ˆ10000,10000 xffxyforxffxyfxffxf ÷÷÷łöçççŁæ÷÷łöççŁæ÷÷łöççŁæ---Fig. 10. Histogram and Statistics are calculated in the square areas.Table 4. Statistics associated to  La Palma and Tenerife area values. 25% of the highest values are marked in red, and 25% of the lowest in blue. This is useful to distinguish the relative most relevant changes.DiscussionThe study of the results shows that most of the modifications of the model parameters had a moderated to strong impact in the 10 m maximum wind speed solution. The most important positive variations were associated to modifications of the BL&SL  parameterization, increase in horizontal resolution and size domain diminishing without nesting. The most negative percentages of change were due to the nonlinear interaction between MP and BL&SL in the case of L and MOJ-MYJ , decreasing of horizontal resolution and to the  hydrostaticity activation. Neither Increasing in number of levels to 41 or 61 nor changes in cumulus parameterization showed a significant variation. Size mother domain reduction with two-ways nesting grids activated had a minor impact in the position of the storm modifying  slightly the pattern of stagnation areas and the position of the maximum winds. The hydrostatic case showed a systematic diminishing of the maximum wind speed in leeside locations. Symmetric histograms in experiments 4, 7 and 8 demonstrated an spatial shift in the positions of the wave pattern associated to the maximum winds. Percentage change graphics depict wavelike features associated to the capability of the model to reproduce the amplitude and spatial phase of the mountain wave structures. Strong hydraulic jumps at leeside of Tenerife and La Palma are emphasized by some of the configurations (experiments 11, 20 and 21) or minimized by others (experiments 22, 23 , 24 and 19). These variations are related to resolution, nesting capability and hydrostaticity. To conclude, and taking into account that more cases need to be run to reach  more conclusive results, it appears that If an ensemble for 10 m wind speed were to be designed, model runs with different BL&SL schemes, horizontal resolutions, hysdrostaticity options and number of nested grids should be included as an efficient way to increase the spread. Future work will focus on other strong wind cases with and without warm core interacting with Canary Islands topography. La PalmaTenerifeFig. 1. Location of the Canary Islands. Tenerife and La Palma are the islands of the archipelago with the steepest orography and were the most affected by Delta storm. 20:00218180Izaæa21:4013487Tenerife south airport21:0013257S/C de Tenerife16:007030Tenerife north airport16:009248La Gomera19:00166104La Palma airport12:305931Tazacorte18:0011867 Hierro airportTime UTC28 Nov 200510 m wind gust (km/h)10 m wind speed (km/h)Station nameTable 1. Maximum wind speeds and gusts at 10 m registered by the major observatories and airports of the archipelago under the influence of Delta.Fig. 5. Domain configurations and vertical distributions. Experiment Statistics        Max. Min. Mean  Std. Deviation Skewness  EXP. 1 24 -17 0.3 4.7 0.9 EXP. 2 105 -21 17.4 25.8 1.0 EXP. 3 43 -18 2.9 4.9 1.5 EXP. 4 32 -44 -4.4 8.9 0.0 EXP. 5 27 -39 -3.9 8.3 -0.4 EXP. 6 45 -72 -3.8 10.2 -1.2 EXP. 7 44 -38 1.6 10.0 -0.2 EXP. 8 28 -39 -0.4 5.4 0.2 EXP. 9 22 -30 -0.7 7.2 -0.3 EXP. 10 39 -16 3.3 6.6 0.9 EXP. 11  93 -44 3.7 14.3 1.0 EXP. 12 41 -13 1.9 5.9 1.8 EXP. 13 41 -14 2.3 6.0 1.2 EXP. 14 84 -34 1.2 10.4 4.9 EXP. 15 39 -28 0.4 7.3 1.1 EXP. 16 60 -38 2.2 10.0 0.9 EXP. 17 43 -18 1.0 5.0 2.0 EXP. 18 42 -23 1.1 7.7 0.4 EXP. 19 31 -48 0.3 11.8 -0.3 EXP. 20 83 -19 11.5 14.0 1.2 EXP. 21 85 -19 10.3 13.5 1.1 EXP. 22 51 -37 -2.4 14.0 0.6 EXP. 23 75 -42 -6.8 17.4 0.9 EXP. 24 112 -48 -15.1 22.8 1.9 Figure 11. Percentages relatives to the CRE with histograms associated to La Palma and Tenerife areas and their statistics are show in figures a) to h), corresponding to experiments 1, 6, 19, 24, 20, 11 and 2. A shift to negative values are shown in figures a) to d). In contrast, positive increments in maximum velocities are presented in figures e) to h).c)a)b)d)e)f)g)h)7th EMS Annual Meeting / 8th European Conference on Applications of Meteorology, EMS2007-A-00584: Atmospheric Hazards Aw5 - Bibliography:Beven, J., 2006: Tropical Cyclone Report on Tropical Storm Delta 22-28 November 2005. NOAA Tech. Note, Tropical Prediction Center, N ational Hurricane Center.Jankov, I. and Gallus, W., 2005: The Impact of Different WRF Model Physical Parameterizations and Their Interactions on Warm Season MCS Rainfall. Weather and Forecasting, 20, 1048-1060. Jorba, O., Marrero, C., Baldasano, J.M., and Cuevas, E.,  2007: Impact of the Extratropical Storm Delta Over the Canary Islands on 28-30 November 2005: Severe Windstorm Event. Poster Presentation in EGU2007 Wien: NH 1.03 - Diagnosis, Modelling and Forecasting of Meteorological and Hydrological Hazards Produced by Weather and Climate ChangeMarrero, C., Jorba, O., Cuevas, E. and Baldasano, J.M., 2007: Extreme Wind Event over The Canary Islands Related to the Extratropical Storm Delta: Sensitivity Study with a Limited Area Model. Poster Presentation in IUGG 2007 Perugia - XXIV IUGG General Assembly - Ms013: Topographic Effects on Weather and Climate (ICDM).Martín, F., Alejo, C.J., de Bustos, J.J., Calvo, F.J., San Ambrosio, I., SÆnchez-LaulhØ, J.M.,  and D., Santos, 2006: Study of the tropical storm Delta and its extratropical transition: Meteorological impacts over Canary Islands (27-29 November 2005). Technical Report, Instituto Nacional de Meteorología, Madrid.Stein, U. and Alpert, P., 1993: Factor Separation in Numerical Simulations. Journal of the Atmospheric Sciences, 50, 2107-2115.Acknowledgements:The authors wish to thank to colleagues of the Barcelona Supercomputer Centre and Izaæa Atmospheric Observatory for the support received, and specially to Celia Milford and Juanjo de Bustos for their contributions. The simulations were performed w ith the Ma reNostrum Sup erc omp uter he ld  b y the Ba rc e lona  Sup erc omp uting  Center-Centro  Na c iona l d e Supercomputación. This work was funded by the Spanish Mobility Program ICTS of the Education and Science Ministry  (Orden ECI/2136/2005, BOE 

Sensitivity study with a Limited Area Model: extratropical storm Delta over the Canary Islands

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Sensitivity study with a Limited Area Model: extratropical storm Delta over the Canary Islands

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