Transcript Diapositiva 1 - Cosmo Public area

COSMO-LEPS:
present status and plans
Andrea Montani,
C. Marsigli, T. Paccagnella
ARPA-SIMC
HydroMeteoClimate Regional Service of Emilia-Romagna, Bologna, Italy
COSMO General meeting
Sibiu, 2-5 September 2013
A.Montani; The COSMO-LEPS system.
Outline
• Present status of COSMO-LEPS:
 about the operational verification,
 about the calibrated precipitation,
 about the convection schemes,
 about the clustering technique,
 about the future plans.
A.Montani; The COSMO-LEPS system.
COSMO-LEPS suite @ ECMWF: present status
d
d-1
d+1
d+2
older EPS
00
d+3
d+4
d+5
4 variables
ZUVQ
3 levels
500 700 850 hPa
Cluster
ClusterAnalysis
Analysisand
andRM
RMidentification
identification
younger EPS
12
COSMOLEPS
clustering
area
2
time
steps
European
area
COSMOLEPS
Integration
Domain
Complete
Linkage
•
•
•
•
A.Montani; The COSMO-LEPS system.
suite runs twice a day (00 and
12UTC)
as
a
“time-critical
application” managed by ARPASIMC;
Δx ~ 7 km; 40 ML; fc+132h;
COSM0 v4.26 since Jan 2013;
computer time (50 million BUs for
2013) provided by the ECMWF
member states in COSMO.
Main changes during the COSMO year
• 16 January 2013: COSMO upgrade: 4.21  4.26;
int2lm upgrade: 1.18  1.20.
• 17 January 2013: operational dissemination implemented for ARPA-Veneto.
• 22 January 2013, technical changes at ECMWF:
• change of ECMWF super-computer and of the user running the suite: itm  zcl;
• introduction of a new “dissemination stream” for COSMO-LEPS: “ad-hoc”
initial and boundary conditions do not have to be retrieved any more, but are
prepared on a dedicated file system; product dissemination starts about 40
minutes earlier than before (at 9UTC and 21UTC).
• 7 May 2013: enriched test dissemination implemented for HNMS.
• 13 May 2013: in the framework of GEOWOW research project, COSMOLEPS was the first system to populate TIGGE-LAM archive at ECMWF (highpriority parameters in grib2 format).
• 25 June 2013: tests with Fieldextra 11.1.0 started.
A.Montani; The COSMO-LEPS system.
Outline
• Present status of COSMO-LEPS:
 about the operational verification,
A.Montani; The COSMO-LEPS system.
Time-series verification of COSMO-LEPS
–
SYNOP on the GTS
Main features:
variable:
12h cumulated precip (18-06, 06-18 UTC);
period :
from Dec 2002 to Jul 2013;
region:
43-50N, 2-18E (MAP D-PHASE area);
method:
nearest grid point; no-weighted fcst;
obs:
synop reports (about 470 stations/day);
fcst ranges: 6-18h, 18-30h, …, 102-114h, 114-126h;
thresholds: 1, 5, 10, 15, 25, 50 mm/12h;
system:
COSMO-LEPS;
scores:
ROC area, BSS, RPSS, Outliers, …
both monthly and seasonal scores were computed
A.Montani; The COSMO-LEPS system.
Brier Skill Score:
time series and seasonal scores
 BSS is written as 1-BS/BSref. Sample climate is the reference system. Useful forecast systems if BSS > 0.
 BS measures the mean squared difference between forecast and observation in probability space.
 Performance of the system assessed as time series (6-month running mean) and for the last 4 springs (MAM).
 Time series: high monthto-month variability, but a
positive trend can be
noticed.
 Good scores in 2012 and
2013; BSS positive for all
thresholds since April 2009;
fewer and fewer problems
with high thresholds.
 Seasonal scores for a
fixed event (“12h precip
> 10mm”): need to take
into account the different
statistics for each season
(last MAM was the wettest).
 Best performance for the
last spring, with BSS
positive for all forecast
ranges.
A.Montani; The COSMO-LEPS system.
Outline
• Present status of COSMO-LEPS:
 about operational verification (time-series scores show improvements),
 about the calibrated precipitation;
A.Montani; The COSMO-LEPS system.
about calibrated precipitation
• For each COSMO-LEPS member, calibrated precipitation is operationally generated
over Germany, Switzerland and Emilia-Romagna; the calibration technique is based on
CDF-based corrections, making use of COSMO-LEPS reforecast.
• For MAM2013, inter-comparison between raw and calibrated 24h TP forecast.
Main features:
variable:
24h cumulated precip (06-06 UTC);
period :
DJF 2012-13 and MAM 2013;
region:
Germany, Switzerland, Emilia-Romagna;
method:
nearest grid point; no-weighted fcst;
obs:
synop reports (about 300 stations/day);
fcst ranges: 18-42h, 42-66h, 66-90h, 90-114h;
thresholds: 1, 5, 10, 15, 25, 50 mm/12h;
system:
opecleps and Calibcleps;
scores:
ROC area, BSS, RPSS, Outliers, RelDiag, …
A.Montani; The COSMO-LEPS system.
opecleps vs Calibcleps
fc 42-66h; 10mm/24h
A.Montani; The COSMO-LEPS system.
Outline
• Present status of COSMO-LEPS:
 about operational verification (time-series scores show improvements),
 about calibration (positive impact, especially over Emilia-Romagna);
 about convection schemes;
 about the clustering technique;
 about the future plans.
A.Montani; The COSMO-LEPS system.
about the future plans
• Adapt COSMO-LEPS suite to ECWMF forthcoming upgrades:
– increase of vertical resolution in ECMWF-EPS: 62  91;
– change of Member-State server: ecaccess  ecgb;
– change of super-computer: IBM  Cray.
• Keep an eye (possibly, two) to the performance of ECMWF EPS.
• Carry on study about the clustering methodology.
• Analysis of the performance of COSMO-HYBEPS (COSMO-LEPS + 2-3
COSMO runs nested on IFS/GME/GFS): tests ongoing.
• Increase of COSMO-LEPS vertical resolution (40  50ML): tests start in October.
• Use of high-resolution ECMWF-EPS boundaries (LAMEPS_BC project): tests
start by the end of 2013.
• Support verification with Versus.
A.Montani; The COSMO-LEPS system.
Thank you for the attention !
A.Montani; The COSMO-LEPS system.
Extra slides on configuration
• European Conference on Applications of
Meteorology / EMS annual meeting
• 09 – 13 September 2013, Reading (UK)
• Session NWP4 (on 13 September): Probabilistic and ensemble
forecasting at short and and medium-range
• http://www.ems2013.net/home.html
A.Montani; The COSMO-LEPS system.
COSMO-LEPS methodology
Possible
evolution
scenarios
ensemble size
reduction
Cluster members chosen
as representative
members (RMs)
Initial conditions
Dim 1
LAM scenario
LAM scenario
LAM integrations driven by
RMs
LAM scenario
Initial conditions
A.Montani; The COSMO-LEPS system.
Dim 1
COSMO-HYBrid Ensemble Prediction System
From the results of CONSENS PP, come to a synthesis with the different ensemble
systems / strategies, considering scientific, implementation, solidity aspects.
Generate 20-member hybrid ensemble (COSMO-HYBEPS) , where:
a) 16 members comes from COSMO-LEPS,
b) 1 member is nested on IFS (uses Tiedtke scheme),
c) 1 member is nested on IFS (uses Kain-Fritsch scheme),
d) 1 member is nested on GME,
e) 1 member is nested on GFS.
already existing taken from CONSENS.
All members have Δx ~ 7 km; 40 ML; fc+132h;
Study performance of different members’ combinations with the same ensemble size.
“20-members esuite” implemented on 7/9/2012;
will be run up to the end of the year
A.Montani; The COSMO-LEPS system.
COSMO-LEPS (developed at ARPA-SIM)
• What is it?
It is a Limited-area Ensemble Prediction System (LEPS),
based on COSMO-model and implemented within COSMO
(COnsortium for Small-scale MOdelling, which includes
Germany, Greece, Italy, Poland, Romania, Switzerland).
• Why?
It was developed to combine the advantages of global-model
ensembles with the high-resolution details gained by the
LAMs, so as to identify the possible occurrence of severe
and localised weather events (heavy rainfall, strong winds,
temperature anomalies, snowfall, …)
generation of COSMO-LEPS to improve the Late-Short
(48hr) to Early-Medium (132hr) range forecast of
severe weather events.
A.Montani; The COSMO-LEPS system.
Operational set-up
Core products:
 16 perturbed COSMO-model runs (ICs and 3-hourly
BCs from 16 EPS members) to generate, “via weights”,
probabilistic output: start at 12UTC; t = 132h;
Additional products:
 1 deterministic run (ICs and 3-hourly BCs from the highresolution deterministic ECMWF forecast) to “join”
deterministic and probabilistic approaches: start at
12UTC; t = 132h;
 1 hindcast (or proxy) run (ICs and 3-hourly BCs from
ECMWF analyses) to “downscale” ECMWF information:
start at 00UTC; t = 36h.
A.Montani; The COSMO-LEPS system.
Types of perturbations
As for types and values, the results from CSPERT experimentation
were followed (* denotes default values for COSMO v4.26 ):
•convection_scheme: Tiedtke* (members 1-8), Kain-Fritsch (members 9-16),
•tur_len (either 150, or 500*, or 1000),
•pat_len (either 500*, or 2000),
•crsmin (either 50, or 150*, or 200),
•rat_sea (either 1, or 20*, or 40),
•rlam_heat (either 0.1, or 1*, or 5),
•mu_rain : either 0.5* (with rain_n0_factor =0.1) or 0 (with rain_n0_factor =1.0),
•cloud_num (either 5x10^8* or 5x10^7).
A.Montani; The COSMO-LEPS system.
• convection scheme: T=Tiedtke KF=Kain-Fritsch;
• tur_len: maximal turbulent length scale (default 500m); this parameter is used mainly in the
calculation of the characteristic length scale for vertical mixing and thus into the calculation of
the vertical transport momentum coefficient;
• pat_len: length scale of thermal surface patterns (default 500m); this parameter is mainly
used in the calculation of the large-scale part of the equation addressing the heat flux
parameterisation; horizontal length;
• rlam_heat: scaling factor of the laminar layer depth (default 1); it defines the layer with nonturbulent characteristics (molecular diffusion effects only);
• rat_sea: ratio of laminar scaling factors for heat over sea (default 20);
• crsmin: minimal stomata resistance (default 150);
• Cloud_num: Cloud droplet number concentration;
• Mu_rain: Exponent of the raindrop size distribution;
•( gscp: Switch on/off of the graupel scheme).
Main results
Time-series verification
ECMWF EPS changed substantially in the last years (more and more weight to EDAbased perturbations) and it is hard to disentangle improvements related to COSMOLEPS upgrades from those due to better boundaries; nevertheless:
– high values of BSS and ROC area for the probabilistic prediction of 12-h precipitation for
autumn 2011;
– poor performance in the first months of 2012, then recovery. Need to investigate what
happened.
Case-study verification
Consistent signal for different forecast ranges of a high-impact weather event for the
snowfalls of February 2012.
A.Montani; The COSMO-LEPS system.
Extra slides on verification
A.Montani; The COSMO-LEPS system.
Time series of ROC area
(6-month running mean)
 Area under the curve in the HIT rate vs FAR diagram; the higher, the better …
 Valuable forecast systems have ROC area values > 0.6.
 Highest scores in the 2nd
part of 2011 and, for the
highest threshold, in 2013.
Positive trend through the
years can be noticed.
 Drier seasons during 2011
and 2012 with few heavyprecipitation events: limited
significance of the results for
the 15mm threshold.
 Limited loss of predictability
with increasing forecast
range (not shown).
A.Montani; The COSMO-LEPS system.
Seasonal scores of ROC and BSS: last 4 springs
 Fixed event (“12h precip > 10mm”): consider the performance of the system for increasing forecast ranges.
 Valuable forecast systems have ROC area values > 0.6 and BSS > 0.
 Need to take into account
the different statistics for
each season (MAM 2011
was the driest).
 Best performance for the
spring 2011 and 2013, but
less marked diurnal cycle
in 2013.
 Spring 2013: BSS is
positive for all forecast
ranges
 Similar results for the
other
thresholds
(not
shown).
A.Montani; The COSMO-LEPS system.
Outliers: time series + ………seas scores
(DJF)?
 How many times the analysis is out of the forecast interval spanned by the ensemble members.
 … the lower the better …
 Performance of the system assessed as time series and for the last 4 winters.
 Evident seasonal cycle
(more outliers in winter).
 Overall
reduction
of
outliers in the years up to
2007; then, again in 2009
and 2010, but later.
 Need to take into account
the different statistics for
each season.
 In the short range, best
results for winter 20102011.
 For longer ranges, the
performance of the system
is “stable”.
 Outliers before 10% from
day 3 onwards.
A.Montani; The COSMO-LEPS system.
Seasonal scores of BSS: ……last 4 winters
 Fixed event (“12h precip > 10mm”): consider the performance of the system for increasing forecast ranges.
 Fixed forecast range (fc 30-42h): consider the performance of the system for increasing thresholds.
 Need to take into account
the different statistics for
each season (last DJF
was the driest).
 Fixed
event:
best
performance for the last
two winters (ECMWF EPS
had a record performance
for winter 2009-2010):
BSS positive for all
forecast ranges.
 Fixed forecast range:
similar results as before.
 Similar results for longer
forecast ranges and for
higher thresholds.
A.Montani; The COSMO-LEPS system.
Ranked Probability Skill Score: time series +
…….. seasonal scores (MAM)
 A sort of BSS “cumulated” over all thresholds. RPSS is written as 1-RPS/RPSref. Sample climate is the
reference system. RPS is the extension of the Brier Score to the multi-event situation.
 Useful forecast systems for RPSS > 0.
 Performance of the system assessed as time series and for the last 4 springs (MAM).
 the increase of the COSMO-LEPS skill is detectable for 3 out of 4 forecast ranges along the years, BUT
 low skill in the first months of 2012 (the problem comes from MAM), then recovery.
 Best results for MAM 2011; quick decrease of RPSS with fcst range for MAM 2012.
A.Montani; The COSMO-LEPS system.
Bias and rmse of T2M Ensemble Mean
 Consider bias (the closer to zero, the better) and rmse (the lower the better).
 Bias closer to zero (0.5 °C of decrease) and lower rmse for the 7-km suite.
 The improvement is not “massive”, but detectable for all forecast ranges, especially for day-time verification.
 The signal is stable (similar scores for 1-month or 3-month verification).
 Need to correct T2M forecasts with height to assess the impact more clearly.
A.Montani; The COSMO-LEPS system.
Overestimation of Td2m and soil moisture
 Verification period: MAM07
and MAM08.
 Obs: synop reports (about
470 stations x day).
 Region: 43-50N, 2-18E (MAP
D-PHASE area).
 Larger bias and larger rmse in
MAM08 rather than in MAM07
for COSMO-LEPS deterministic
run (in 2007, no multilayer soil model).
A.Montani; The COSMO-LEPS system.
(1)
Extra slides on LAMEPS-BC
A.Montani; The COSMO-LEPS system.
Test data for LAMEPS Boundary Conditions
A.Montani; The COSMO-LEPS system.
Outline
• Introduction:
 migration to the 7-km system.
COSMO-LEPS 10 km (old)
COSMO-LEPS 7 km (new)
A.Montani; The COSMO-LEPS system.
MAM06
Average values (boxes 0.5 x 0.5)
tp > 1mm/24h
tp > 5mm/24h
COSMO-LEPS
16-MEMBER EPS
51-MEMBER EPS
As regards AVERAGE precipitation above
these two threshols, the 3 systems have
similar performance.
A.Montani; The COSMO-LEPS system.
opecleps vs Calibcleps
fc 42-66h; 1mm/24h
fc 42-66h; 10mm/24h
A.Montani; The COSMO-LEPS system.
Outline
• Present status of COSMO-LEPS:
 about operational verification (time-series scores show improvements),
 about calibration (positive impact, especially over Emilia-Romagna!);
 about convection schemes,
members 1-8 use Tiedtke convection scheme (8TD),
members 9-16 use Kain-Fritsch (8KF).
MAM 2013: compare cleps16, 8TD, 8KF.
A.Montani; The COSMO-LEPS system.
___ cleps16
___ 8TD ___ 8KF
about the convection scheme
BSS, tp > 10mm
BSS, tp > 1mm
• As expected, best performance by the full ensemble (cleps16).
• Tiedtke-members better than Kain-Fritsch members, but NOT for all scores.
ROC, tp > 1mm
ROC, tp > 10mm
A.Montani; The COSMO-LEPS system.
about the clustering technique
AIM: provide limited-area ensembles (either convection-parameterised
or convection-permitting) with the best set of boundary conditions.
Study different types of clustering analyses (over the same area, grid):
• ope: use two 12-hourly-lagged EPS, steps=96/120 (108/132) for the younger
(older) EPS, variables=Z/U/V/Q, levels=500/700/850 hPa;
• rnd0: use the younger EPS and always select members 0 to 15 (0 denotes the
control member)
• rnd1 : like rnd0, but select members 1 to 16.
• ...
Analyse properties (e.g. spread, skill) of the 16-member global ensembles for several
upper-air variables
 Outcome: modifications to the number of clusters / number of EPS considered / clustering
intervals.
A.Montani; The COSMO-LEPS system.
Test modifications of clustering methodology
• Consider distances between ECMWF EPS members according to
“COSMO-LEPS metric” (Z, U, V, Q in the mid-lower troposphere
over the clustering domain).
• Look at distances between pairs of ECMWF EPS members; to what
extent these distances grow with forecast range, using “COSMOLEPS metric”?
• Study a number of seasons.
 Outcome: modifications to the number of clusters / number of EPS
considered / clustering intervals.
A.Montani; The COSMO-LEPS system.
Extra slides on COSMO-S14-EPS
A.Montani; The COSMO-LEPS system.
Important ingredients (from 1st and 2nd FROST meetings)
1.
2.
3.
4.
5.
6.
7.
8.
9.
Provide reasonable “numbers”.
Develop experience with probabilities.
Feedback on the top-priority products.
Snow analysis.
Soil-field initialisation.
High-res obs to assess the quality of the system.
Computer time.
Timeliness in product delivery.
......
 addressed
?
 being addressed
?
 addressed
 being addressed
 addressed
 addressed
anything to add/remove?
A.Montani; The COSMO-LEPS system.
FROST-2014 vs SOCHMEL
1)
Introduction to FROST-2014:
a)
What is it?
b)
What has to do with COSMO?
2)
3)
COSMO ensemble activities within FROST-2014:
a)
introduction to SOCHMEL (the SOCHi-targeted Mesoscale EnsembLe system)
b)
methodology;
c)
phases of development;
d)
planned activity.
Final remarks.
A.Montani; The COSMO-LEPS system.