Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 (1)The International AMMA Programme (2) AMMA activities directly related to THORPEX

(1)To improve our understanding of the WAM & its influence 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)To provide the underpinning science that relates WAM variability to related societal issues in defining & implementing relevant monitoring & prediction strategies (3)To ensure that the research carried out in AMMA is effectively integrated with prediction & decision making 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 2 nd phase of AMMA Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009

Jean-Luc Redelsperger, THORPEX Sept 2008 E nhanced O bs. P eriod Long term Observation Period 2002 Supra-regional (WAM + Ocean) Meso Regional Local SPACE (km) Catch, Idaf, Photon Pirata, …. SOP0: Dry phase SOP1: Monsoon Onset SOP2: Monsoon Max SOP3: Late Monsoon, TC 1 IOPs 2 3 SOPs 0 0 Nested Observation Strategy

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 West African radiosonde network during AMMA EOP 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 established new reactivated 2006 only 1/day 2/day 4/day 4/day, up to 8/day during two IOPs inactive

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 Summary statistics for EOP 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 transmission Parker et al Monthly mean sondes per day, shaded) Success rate GTS Success rate including satellite and communication Dakar RTH failure Niamey lightning damage

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 (2) AMMA activities directly related to THORPEX (1)Improved knowledge and understanding of nature and causes of WAM variability at 1-15 day timescales Easterly waves including relationship with hurricanes Intraseasonal variability including monsoon onset (2) Tailoring and evaluation of forecast products for users in tropical regions Forecasting Methods and Products Evaluation of Forecast Models (3) Predictability studies and observing system experiments Focus on Humidity: Sounding correction and use of micro-wave over land Making use of the enhanced sounding network provided by AMMA in 2006/2007

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2008 (1) Improved Knowledge and Understanding - AEWs Hopsch et al, 2009 Developing AEWsNon-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

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 (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

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 (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.

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 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 Africa Project Timetable October 2009: 1-day workshop session at ICTP, Trieste : 2 further workshops to develop written material for the Handbook Study / exchange visits 2012: Target for publicationsee D. Parker for more details

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 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?

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 (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

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 Radiosonde (RS) RH Bias correction Comparison with GPS TCWV UNCORRECTED RS CORRECTED RS Agusti-Panareda et al

Correction of humidity biases of radiosondes during the AMMA SOP-2006 Differential humidity bias (left panel) between Vaisala RS80-A & RS92 sondes resulting from the CDF matching applied to AMMA2006 Niamey soundings as confirmed by the GPS independent measurements.Differential humidity bias (left panel) between Vaisala RS80-A & RS92 sondes resulting from the CDF matching applied to AMMA2006 Niamey soundings as confirmed by the GPS independent measurements. The impact of this correction is major as illustrated by the time series of convective available potential energy CAPE (right panel) at Niamey (1-12 August 2006) from raw soundings (dashed line) & corrected one (straight line)The impact of this correction is major as illustrated by the time series of convective available potential energy CAPE (right panel) at Niamey (1-12 August 2006) from raw soundings (dashed line) & corrected one (straight line) Nuret el al Strong dry bias (up to 15%) Hight impact on CAPE

Impact of assimilating µWave observations over land From 01/08/2006 to 14/09/2006 Moistening of the Atmosphere Drying of the Atmosphere TCWV time series from GPS (Ouagadougou) compared to REF & EXP Karbou et al 2008 ReferenceExperiment REF EXP GPS Density of assimilated AMSU-B Ch5 during August 2006

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 Current numerical studies Contributing Groups listed according to model Contributing Groups listed according to model (a)ECMWF (Agusti-Panareda, Beljaars, Cardinali et al) * Data impact being explored by comparison with operational analyses and with and withought moisture bias correction – emphasis on soundings *Special reanalysis for AMMA (b) ECMWF (R. Cornforth, B. Hoskins, T. Palmer) * Investigating the use of Moist Singular Vectors to improve understanding of AEWs and their predictability. Possible links to improving initialization of EPSs. (c) Meteo-France (Rabier, Karbou, Nuret et al) * Testing impact of satellite measurements from AMSU and SSMI over land * Plans to investigate impact of SEVIRI CSR and soundings * Tests of 4km AROME with dedicated analysis (3) Predictability Studies and Observing System Experiments

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 (3) Predictability Studies and Observing System Experiments (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.

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 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 and rainfall rates. The additional AMMA radiosoundings has a significant positive impact on the analyses and rainfall rates. Using more satellite data over land has also had a large impact on the global tropics Using more satellite data over land has also had a large impact on the global tropics Need to coordinate NWP experiments to be able to make strong recommendations on sounding network Need to coordinate NWP experiments to be able to make strong recommendations on sounding network (3) Predictability Studies and Observing System Experiments

Curvature Vorticity (1day forecast) sensitivity 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)

Precipitation Sensitivity (1 day forecast) Mid-Troposphere e Lower-Troposphere e

Jean-Luc Redelsperger and Chris Thorncroft, THORPEX Sept 2009 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 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