MAP D-PHASE Description

This site documents the status of MAP and MAP D-PHASE as of 28.4.2009, the publication date of the report on the WWRP Forecast Demonstration Project D-PHASE entitled "MAP D-PHASE: Demonstrating forecast capabilities for flood events in the Alpine region". Updated information on D-PHASE can be obtained from www.meteoschweiz.admin.ch/web/en/research/current_projects/forecast/dphase.html

Summary

The main objective of MAP D-PHASE, the MAP Forecast Demonstration Project, is to demonstrate the benefits in forecasting heavy precipitation and related (flash) flood events, as gained from the improved understanding, refined atmospheric and hydrological modelling, and advanced technological abilities acquired through research work during the Mesoscale Alpine Programme (MAP).

Specifically, an end-to-end forecasting system for Alpine flood events is set up to demonstrate state-of-the-art forecasting of precipitation-related high-impact weather. This system includes probabilistic forecasting based on atmospheric and hydrological ensemble prediction systems with a lead time of a few days, followed by short-range forecasts based on high-resolution deterministic atmospheric and hydrological models for selected regions or catchments, and is completed with real-time nowcasting tools. Throughout the forecasting chain, warnings are issued and re-evaluated as the potential flooding event approaches, allowing forecasters and end users to alert and make decisions in due time.

MAP and D-PHASE

As the first Research and Development Project (RDP) of the World Weather Research Programme (WWRP), the Mesoscale Alpine Programme (MAP) has seen three phases: a development phase (1993 - 1999; Binder and Schär 1996) when the plans were made and the project was designed, the field phase with the Special Observing Period (SOP; Bougeault et al. 2001) in autumn 1999, and the analysis phase (Volkert 2005) that is still ongoing and has brought a wealth of exciting new results and insight in Alpine meteorology.

In 2004, the MAP Steering Committee mandated a working group to explore the possibility and interest in a fourth phase: a demonstration phase. From the many achievements of MAP (Volkert 2005), forecasting heavy precipitation and related flooding events in the Alpine region and the associated issues of orographically enhanced precipitation, high-resolution numerical weather prediction, and hydrological processes have subsequently been chosen as the topic for the MAP Forecast Demonstration Project (MAP FDP). The project thereby addresses the entire forecasting chain ranging from observations, ensemble forecasting, high-resolution cloud-resolving atmospheric modelling (km-scale), hydrological modelling, and nowcasting to decision making by end users (civil protection authorities, water management and hydrological agencies, etc.), i.e., it sets up an end-to-end forecasting system. To emphasize the main objective of the fourth phase of MAP, the MAP FDP is referred to as D-PHASE, which stands for Demonstration of Probabilistic Hydrological and Atmospheric Simulation of flood Events in the Alpine region.

The WWRP endorsed MAP D-PHASE as the second WWRP Forecast Demonstration Project (FDP) in October 2005.

The D-PHASE Operations Period (DOP) has been from 1 June to 30 November 2007.

Objectives of D-PHASE

MAP has brought significant progress in the following fields of research that are relevant for MAP D-PHASE:

Mechanisms of orographic precipitation events, including the ability of numerical weather prediction models to appropriately simulate dynamical and microphysical properties of precipitating systems in mountainous regions (e.g. Medina and Houze 2003, Rotunno and Ferretti 2003, Bousquet and Smull 2003).
Precipitation fields from radar networks in complex terrain (Germann et al. 2005): the radar fields are instrumental not only for assimilation in mesoscale atmospheric and hydrological models (Ducrocq et al. 2002, Leuenberger 2005) but also for nowcasting and verification.
High-resolution (3 km mesh-size) operational mesoscale modelling used in the decision making process for the operational field phase decisions during the SOP (Benoit et al. 2002, Benoit et al. 2003) and high-resolution numerical weather prediction in hindcast mode (Richard et al. 2003, Buzzi et al. 2004, Richard et al. 2005).
Hydrological modelling: coupling of atmospheric and hydrological models to establish the link to the needs of the end users (Bacchi et al. 2003, Ranzi et al. 2003).
Ensemble prediction approach: Research studies on the feasibility of small-scale ensemble forecasts especially in the area of heavy precipitation forecasting (Molteni et al. 2001, Marsigli et al. 2001, Walser and Schär 2004, Walser et al. 2004).

All these components contribute to the ability of forecasting heavy precipitation events in complex terrain, the residence times of the precipitated water in the various water bodies such as rivers, lakes, or ground water, and hence the ability to adequately predict water levels and runoff for timely warnings. Previous events of heavy precipitation in the Alps (and elsewhere in mountainous terrain) have demonstrated their devastating potential in harming both human lives and property. There is no doubt that heavy precipitation events belong to the group of high-impact weather events. Also, these events are of international scale - simply due to the fact that the original driving meteorological system(s), when first being identified on the medium-range forecast, may well finally lead to flooding in different countries, dependent on the actual development.

As more specific objectives, MAP D-PHASE is setting up a distributed real-time end-to-end forecasting system with which it aims at

assessing the degree of predictability for precipitation and flood events as a function of event size, precipitation amount, event character (e.g. convective versus stratiform), and lead time;
demonstrating the potential of operational high-resolution atmospheric models in capturing the relevant processes responsible for heavy precipitation events in complex terrain;
demonstrating the ability of hydrological models to provide a timely and skilful forecast of runoff and water levels;
assessing the prospects of very short-term prediction of heavy precipitation and severe convection over orography, using tailored heuristic techniques and real-time observations from radar, automated surface networks, soundings, and satellite (nowcasting);
establishing a better link between atmospheric and hydrological scientists on the one hand and the actual end users on the other hand. This includes matching the improved possibilities from the hydro-meteorological models with the relevant needs of the end users.

End-to-end forecasting system

MAP D-PHASE aims at establishing a distributed real-time end-to-end forecasting system for heavy precipitation and subsequent flood events in the Alpine region. It is based on the following items (in chronological order):

Probabilistic forecast of rain intensity and spatial distribution for lead times between 2 and 5 days. This allows issuing (pre-) alerts (including amount and probability) for different target regions. These (pre-) alerts are sent out to all the participants including atmospheric and hydrological modellers, forecasters, and end users.
In the days following a (pre-) alert, the warnings are re-iterated, refined (in space, time, or amplitude), or discontinued. This is also based on the probabilistic modelling approach.
If a (pre-) alert is maintained up to two days ahead of the potential event, short-range (up to 48 hours lead time) high-resolution deterministic forecasts are performed using all the atmospheric models covering the likely affected region. A poor man’s ensemble is constructed from these simulations. The simulations are using a wide range of data-assimilation systems as used by the participating institutions. Also, surface fields from the VERA (Vienna Enhanced Resolution Analysis) are provided for assimilation and online monitoring purposes.
For the (pre-) alerted events, the output of the high-resolution deterministic atmospheric models is used to drive hydrological models if the event affects an impact area (i.e., if one or more participants have established a hydrological modelling system for the area). Output goes to the concerned forecasters and end user(s) and is tailored towards their specific needs. Possibilities of performing hydrological ensemble predictions (based on an atmospheric ensemble prediction system, different atmospheric models, stochastic techniques, or parameter perturbations in hydrological models) are explored.
Very short-range forecasting (0 to 6 hours lead time, i.e., nowcasting) is done with existing nowcasting tools at the various involved forecasting centres. This includes, where available, nowcasting based on high-quality radar data (e.g., automatic tracking of convective cells and automatic short-term alerts for heavy precipitation), and specific warnings by forecasters. Additionally, quantitative radar estimates of surface precipitation are used as input for hydrological models.

Figure 1 gives a graphical impression of the forecasting procedure. Real-time observational data are required as input for data assimilation and to drive the nowcasting tools. These are obtained from the existing networks to demonstrate operational forecasting capabilities.

Figure 1: Conceptual sketch of the real-time end-to-end forecasting system for D-PHASE.

For more details on the practical implementation of the distributed real-time end-to-end forecasting system and its evaluation, see the MAP D-PHASE Implementation Plan.

For more on the organisational structure of D-PHASE (i.e., Steering Committee, Working Groups, etc), check out ´Organisation´.

References:

Bacchi, B., R. Ranzi, and E. Richard (Editors), 2003: Hydrometeorological processes and floods in the Alps. Hydrology and Earth Systems Sciences, 7, 783-948.

Benoit, R., C. Schär, P. Binder, S. Chamberland, H. C. Davies, M. Desgagne, C. Girard, C. Keil, N. Kouwen, D. Lüthi, D. Maric, E. Müller, P. Pellerin, J. Schmidli, F. Schubiger, C. Schwierz, M. Sprenger, A. Walser, S. Willemse, W. Yu, and E. Zala, 2002: The real-time ultrafinescale forecast support during the special observing period of the MAP. Bulletin of the American Meteorological Society, 83, 85-109.

Benoit R, N. Kouwen, W. Yu, S. Chamberland, and P. Pellerin, 2003: Hydrometeorological aspects of the Real-Time Ultrafinescale Forecast Support during the Special Observing Period of the MAP. Hydrology and Earth System Sciences, 7, 877-889.

Binder, P. and C. Schär, 1996: MAP Design Proposal. Available online at http://www.map.meteoswiss.ch/map-doc/proposal.htm.

Bougeault, P., P. Binder, A. Buzzi, R. Dirks, R. Houze, J. Kuettner, R. B. Smith, R. Steinacker, and H. Volkert, 2001: The MAP special observing period. Bulletin of the American Meteorological Society, 82, 433-462.

Bousquet, O. and B. Smull, 2003: Observations and impacts of upstream blocking during a widespread orographic precipitation event. Quarterly Journal of the Royal Meteorological Society, 129, 391-409.

Buzzi A., S. Davolio, M. D'Isidoro, and P. Malguzzi, 2004: The impact of resolution and of MAP reanalysis on the simulations of heavy precipitation during MAP cases. Meteologische Zeitschrift, 13, 91-97.

Ducrocq, V., D. Ricard, J.-P. Lafore, and F. Orain, 2002: Storm-scale Numerical Rainfall Prediction for Five Precipitating Events over France: On the Importance of the Initial Humidity Field. Weather and Forecasting, 17, 1236-1256.

Germann, U., G. Galli, and M. Boscacci, 2005: Radar precipitation measurements in the Alps - big improvements triggered by MAP. Proceedings of ICAM/MAP 2005, Zadar, Croatia, 23-27 May 2005, 226-230. Available online at http://www.map.meteoswiss.ch/map-doc/icam2005/proceedings.html.

Leuenberger, D., 2005: High-Resolution Radar Rainfall Assimilation: Exploratory studies with Latent Heat Nudging. Ph.D. thesis ETH Zurich, Switzerland, Nr. 15884. Available online at http://e-collection.ethbib.ethz.ch/cgi-bin/show.pl?type=diss&nr=15884.

Marsigli, C., A. Montani, F. Nerozzi, T. Paccagnella, S. Tibaldi, F. Molteni, and R. Buizza, 2001: A strategy for high-resolution ensemble prediction. Part II: Limited-area experiments in four Alpine flood events. Quarterly Journal of the Royal Meteorological Society, 127, 2095-2115.

Medina, S. and R. A. Houze, 2003: Air motions and precipitation growth in Alpine storms. Quarterly Journal of the Royal Meteorological Society, 129, 345-371.

Molteni, F., R. Buizza, C. Marsigli, A. Montani, F. Nerozzi, and T. Paccagnella, 2001: A strategy for high-resolution ensemble prediction. Part I: Definition of representative members and global-model experiments. Quarterly Journal of the Royal Meteorological Society, 127, 2069-2094.

Ranzi, R.; B. Bacchi, and G. Grossi: 2003, Runoff measurements and hydrological modelling for the estimation of rainfall volumes in an alpine basin. Quarterly Journal of the Royal Meteorological Society, 129, 653-673.

Richard, E., S. Cosma, R. Benoit, P. Binder, A. Buzzi, and P. Kaufmann, 2003: Intercomparison of mesoscale meteorological models for precipitation forecasting. Hydrology and Earth System Sciences, 7, 799-811.

Richard, E., A. Buzzi, G. Zängl, N. Ascencio, R. Benoit, S. Chiao, R. Ferretti, C. Hohenegger, C. Keil, Y L. Lin, C. Marsigli, S. Medina, and C. Schär, 2005: Quantitative precipitation forecasting in mountaineous regions - pushed ahead by MAP. Proceedings of ICAM/MAP 2005, Zadar, Croatia, 23-27 May 2005, 65-69. Available online at http://www.map.meteoswiss.ch/map-doc/icam2005/proceedings.html.

Rotunno, R. and R. Ferretti, 2003: Orographic effects on rainfall in MAP cases IOP 2b and IOP 8. Quarterly Journal of the Royal Meteorological Society, 129, 373-390.

Volkert, H., 2005: The Mesoscale Alpine Programme (MAP) - a multi-facetted success story. Proceedings of ICAM/MAP 2005, Zadar, Croatia, 23-27 May 2005, 226-230. Available online at http://www.map.meteoswiss.ch/map-doc/icam2005/proceedings.html.

Walser, A. and C. Schär, 2004: Convection-resolving precipitation forecasting and its predictability in Alpine river catchments. Journal of Hydrology, 288, 57-73.

Walser, A., D. Lüthi, and C. Schär, 2004: Predictability of precipitation in a cloud-resolving model. Monthly Weather Review, 132, 560-577.

MAP Data Centre - April '09 - MAP WebMaster