Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 (1)The International AMMA Programme...

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009

(1) The International AMMA Programme

(2) AMMA activities directly related to THORPEX

(1)(1) To improve our understanding of the WAM & itsTo improve our understanding of the WAM & itsinfluence on environment regionally & globallyinfluence on environment regionally & globally

A coordinated international program on West African monsoon (WAM), its variability and impacts with an emphasis on daily-to-interannual timescales

(2)(2) To provide the underpinning science that relates To provide the underpinning science that relates WAM variability to related societal issues in WAM variability to related societal issues in defining & implementing relevant monitoring & defining & implementing relevant monitoring & prediction strategiesprediction strategies

(3)(3) To ensure that the research carried out in AMMA is To ensure that the research carried out in AMMA is effectively integrated with prediction & decision effectively integrated with prediction & decision making activitymaking activity

A long term program launched in 2002, including field experiments and long term observations

AMMA continues to discuss and agree the priorities for the 2nd phase of AMMA


Jean-Luc Redelsperger, THORPEX Sept 2008

Enhanced Obs. Period

Long term Observation Period

2002

Supra-regional(WAM + Ocean)

Meso

Regional

Local

SPACE (km)

2005 2006 2007 2008

1000

10

100

104

Catch, Idaf, PhotonPirata, ….

SOP0: Dry phase

SOP1: Monsoon Onset

SOP2: Monsoon Max

SOP3: Late Monsoon, TC1

IOPs

2

IOPs

3

IOPs

SOPs

00

Monsoon Phases 0 1 0

September

<----------------------------------> <------------------------------------------------->

AMMA SOPs

SO

P0_

a1

SO

P0_

a2

SO

P2_

a2

SO

P1_

a

3

October November DecemberJune July August

AMMA SOP Year: 2006

2

January March April MayFebruary

SOP1

<---- SOP Ground instruments remaining on site for the whole annual cycle (AMF, Aerosol Measurements, Lidars, …) ----->

<----------------->

SO

P3_

a1

SOP3<------->

SO

P2_

a3

SO

P2_

a1

SOP0 SOP2

Nested Observation Strategy


West African radiosonde network during AMMA West African radiosonde network during AMMA EOP 2005-2007EOP 2005-2007

21 stations were active during EOP

Greatest density of RS ever launched (even greater than during GATE 1974)

200 radiosonde operators and technicians working on the network + students and researchers from Africa, the Americas and Europe

ASECNA responsible for consumable management

Parker et al. 2008

established

new

reactivated

2006 only

1/day

2/day

4/day

4/day, up to8/day duringtwo IOPs

inactive


Summary statistics for EOP 2005-2007Summary statistics for EOP 2005-2007

Improvement of the radiosonde network is one of the big successes of AMMA

During 2006 & 2007 many more sondes were received at operational centers

The success rate was sustained and improved in 2007, with GTS gradually taking over from email transmission

Parker et al. 2008

Month

ly m

ean s

ondes

per

day,

shaded)

Success rate GTS Success rate including satellite and email communication

Dakar RTH failure

Niamey lightningdamage


(2) AMMA activities directly related to THORPEX

(1)(1) Improved knowledge and understanding of nature and causes of WAM variability Improved knowledge and understanding of nature and causes of WAM variability at 1-15 day timescalesat 1-15 day timescales

Easterly waves including relationship with hurricanesEasterly waves including relationship with hurricanes

Intraseasonal variability including monsoon onsetIntraseasonal variability including monsoon onset

(2)(2) Tailoring and evaluation of forecast products for users in tropical regionsTailoring and evaluation of forecast products for users in tropical regions

Forecasting Methods and ProductsForecasting Methods and Products

Evaluation of Forecast Models Evaluation of Forecast Models

(3) Predictability studies and observing system experiments(3) Predictability studies and observing system experiments

Focus on Humidity: Sounding correction and use of micro-wave over land Focus on Humidity: Sounding correction and use of micro-wave over land

Making use of the enhanced sounding network provided by AMMA Making use of the enhanced sounding network provided by AMMA in in 2006/20072006/2007


(1) Improved Knowledge and Understanding - AEWs

Hopsch et al , 2009

Developing AEWs Non-Developing AEWs

AEWs that became named storms in Atlantic tend to be more intense than those that do not.

Intense AEWs that do not develop appear to have stronger interactions with mid and upper tropospheric dry air


0

50

100

150

200

250

300

350

400

5/1

5/11

5/21

5/31

6/10

6/20

6/30

7/10

7/20

7/30 8/

98/

198/

29 9/8

9/18

9/28

Co

un

ts

Daily Total CS

(1) Improved Knowledge and Understanding - Intraseasonal

Courtesy Karen Mohr

Number of West African MCSs

A quasi-biweekly zonal mode has been identified by Mounier et al (2008)This 2-week variability is manifested in dry and wet spells and likely has significant societal impacts – affecting crop growth and river flow for example


(2) Tailoring and Evaluation of Forecast Products

Weather analyses and forecast charts based on the SYNERGIE system

The system provides a means through which key features (e.g. convection, AEWs, AEJ) can be graphically represented on a chart to facilitate the transfer of information based on satellite, model analyses and forecasts onto a single chart.


Long-term documentation of existing weather forecasting methods;

Sharing of existing good practice in Africa and elsewhere;

Testing of existing forecasting tools, new methods and new data sources;

Development of new tools for forecaster training and wider meteorological education.

The Forecasters’ Handbook for West AfricaThe Forecasters’ Handbook for West Africa

Project TimetableProject TimetableOctober 2009: 1-day workshop session at ICTP, Trieste

2010-2011: 2 further workshops to develop written material for the HandbookStudy / exchange visits

2012: Target for publication see D. Parker for more details


Evaluation of forecast models

-Taking place in several groups in AMMA – mainly in the 1-15 day range

-Development of metrics appropriate for the West African region and strong interactions with NWP centers – especially ECMWF, Meteo-France, NCEP and the UK Met Office

-Regional NWP models are being run in West Africa including new high resolution forecast models (few km scale) and cloud-resolving models on West Africa domain (e.g. CASCADE project in UK, Meso-NH France/ECMWF)

Some examples of model evaluations taking place follow

(2) Tailoring and Evaluation of Forecast Products

Berry et al

Evaluation of AEWs in different NWP models (objective tracking technique)

Example: 3-day forecasts of curvature vorticity (shaded) and location of analysed AEW-trough (lines).

-Large model-to-model differences are noted

-Some AEWs appear to be more predictable than others (see x,y)

(b) GFS(a) ECMWF

(c) UKMO (d) MF

x

y

x

y

x

y

x

y

Analysis Forecast

Day 0

Day 2

Day 1

Day 3

Day 4

Day 5

Berry et al: Composite AEW structures in ECMWF analyses and forecasts – shading is rainfall, contours are curvature vorticity – comparisons with other models are in the paper

All models tend to have poor phase relationship between trough and rainfall – too coupled?


(3) Predictability Studies and Observing System Experiments

Focus on Humidity

(i) Humidity bias correction

a. Automatic correction in NWP system (ECMWF) in CY32r3

b. Taking into account the dependence of bias on the observed RH values

(ii) Correction of sounding humidity biases (AMMA database):

CDF approach and function of (P, RH)

Comparison to AMMA GPS stations

Dedicated campaign for dry biases(1-13 Sept. 2008, Snow white reference)

(iii) Assimilation of microwave observations over land


Radiosonde (RS) RH Bias correctionRadiosonde (RS) RH Bias correction

Comparison with GPS TCWVComparison with GPS TCWV

UNCORRECTED RS

CORRECTED RS

Agusti-Panareda et al

Correction of humidity biases of radiosondes during the AMMA SOP-2006 Correction of humidity biases of radiosondes during the AMMA SOP-2006

• Differential Differential humidity biashumidity bias (left panel) between Vaisala RS80-A & RS92 sondes (left panel) between Vaisala RS80-A & RS92 sondes resulting from the CDF matching applied to AMMA2006 Niamey soundings as resulting from the CDF matching applied to AMMA2006 Niamey soundings as confirmed by the GPS independent measurements. confirmed by the GPS independent measurements.

• The The impact of this correctionimpact of this correction is major as illustrated by the time series of is major as illustrated by the time series of convective available potential energy convective available potential energy CAPECAPE (right panel) at Niamey (1-12 (right panel) at Niamey (1-12 August 2006) from raw soundings (dashed line) & corrected one (straight line)August 2006) from raw soundings (dashed line) & corrected one (straight line)

Nuret el al. 2008

-4-8

-12

Strong dry bias (up to 15%) Strong dry bias (up to 15%) Hight impact on CAPE Hight impact on CAPE

Impact of assimilating µWave observations Impact of assimilating µWave observations over landover land

From 01/08/2006 to 14/09/2006From 01/08/2006 to 14/09/2006

Moistening of the Atmosphere

Drying of the Atmosphere

TCWV time series from GPS TCWV time series from GPS (Ouagadougou) compared to(Ouagadougou) compared to REFREF &&

EXPEXP

Karbou et al 2008

ReferenceReference ExperimentExperiment

REF

EXPGPS

Density of assimilated AMSU-B Ch5 Density of assimilated AMSU-B Ch5 during August 2006during August 2006


Current numerical studies Current numerical studies

Contributing Groups listed according to Contributing Groups listed according to modelmodel

(a)(a) ECMWF (Agusti-Panareda, Beljaars, Cardinali et al)ECMWF (Agusti-Panareda, Beljaars, Cardinali et al)

* Data impact being explored by comparison with operational analyses and * Data impact being explored by comparison with operational analyses and with and withought moisture bias correction – emphasis on soundingswith and withought moisture bias correction – emphasis on soundings

*Special reanalysis for AMMA*Special reanalysis for AMMA

(b) ECMWF (R. Cornforth, B. Hoskins, T. Palmer)(b) ECMWF (R. Cornforth, B. Hoskins, T. Palmer)

* Investigating the use of Moist Singular Vectors to improve understanding of * Investigating the use of Moist Singular Vectors to improve understanding of AEWs and their predictability. Possible links to improving initialization of EPSs.AEWs and their predictability. Possible links to improving initialization of EPSs.

(c) Meteo-France (Rabier, Karbou, Nuret et al)(c) Meteo-France (Rabier, Karbou, Nuret et al)

* Testing impact of satellite measurements from AMSU and SSMI over land* Testing impact of satellite measurements from AMSU and SSMI over land

* Plans to investigate impact of SEVIRI CSR and soundings* Plans to investigate impact of SEVIRI CSR and soundings

* Tests of 4km AROME with dedicated analysis * Tests of 4km AROME with dedicated analysis




(d) NCEP (Pan, Thiaw, Vintzileos)

* New CFS-Reanalysis has completed the summer of 2006 that includes the AMMA special observations.

* Data impacts being explored by comparison with operational analyses

(e) NRL (R Langland)

* Has analyzed differences (e.g. RMS error of 500mb height globally) between several models (e.g. GFS, ECMWF, UKMO, Canada, NOGAPS etc) to see what radiosondes (including AMMA sondes) have important information.

(f) ARW (WRF) (R. Torn)

* Using ensemble-based sensitivity analysis to understand impact of initial condition errors on AEW forecasts and estimate the impact of observations including AMMA-SOP observations on forecasts over West Africa.


Data impacts Data impacts

• The humidity bias correction in the radiosoundings in the AMMA region is beneficial.The humidity bias correction in the radiosoundings in the AMMA region is beneficial.

• The additional AMMA radiosoundings has a significant positive impact on the analyses The additional AMMA radiosoundings has a significant positive impact on the analyses and rainfall rates.and rainfall rates.

• Using more satellite data over land has also had a large impact on the global tropicsUsing more satellite data over land has also had a large impact on the global tropics

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Need to coordinate NWP experiments to be able to make strong recommendations on Need to coordinate NWP experiments to be able to make strong recommendations on sounding networksounding network


Curvature Vorticity Curvature Vorticity (1day forecast) (1day forecast)

sensitivity to analysissensitivity to analysis

700 hPa Meridional Wind

Mid-Troposphere e

Ensemble-based sensitivity calculations using 96 ensemble forecasts from an ensemble Karman filter coupled to the WRF model at 36km resolution during Sep 2006 (R. Torn)


More details on AMMA in Redelsperger et al, BAMS 2006 on AMMA soundings in Parker et al, BAMS 2008

The AMMA International Science Plan is being revisited and a plan that highlights the priorities for the next 10 years is currently being written. We hope that this will be completed by the end of 2009.

A major focus will be to “pull-through” the knowledge gained in the first phase of AMMA towards improving models and our ability to make weather and climate forecasts.

This will require even closer interactions with operational weather and climate prediction centers.

AMMA – THE NEXT PHASE

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 (1)The International AMMA Programme...

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