MAP – Where do we stand?

Philippe Bougeault

Chairman of the MAP Steering Committee

Météo-France, CNRM, Toulouse

ICAM/MAP, Brig, May 2003

Mesoscale Alpine Programme:Objectives

Improve the understanding and numerical prediction of:

• 1. Orographically influenced precipitation and related floods (Wet-MAP)

• 2. Foehn, Gap Flows, Breaking Gravity waves, PV Banners (Dry-MAP)

• 3. PBL structure in deep valleys

MAP essentials

• 14 countries have joined an initial proposal of Switzerland

• MAP is the first Research and Development Program of WMO/WWRP

• MAP main infrastructure is supported by MAP-NWS, a EUMETNET program

• MAP-SOP took place for 10 weeks in September-November 1999

A meteorological and instrumental success

• All events more frequent than average, 1999 was the best ‘MAP year’ of the decade

• 17 IOPs totalling 35 days of observations• 110 research aircraft missions• 6800 radios-sondes launched, 84 constant level

balloons• 864 hours of research radars, 187 hours of lidars• This extraordinary dataset must be promoted• All data are freely accessible on the Internet from the

MDC http://www.map.ethz.ch

P1: Orographic precipitation mechanisms

• Basic mechanisms of production or enhancement of precipitation by orography

• Small scale dynamics of precipitating systems interacting with orography

• Growth mechanisms for precipitating particles

Medina and Houze, 2003: Paradigmatic models of rain Medina and Houze, 2003: Paradigmatic models of rain productionproduction

U/Nh < 1 (IOP8)

U/Nh > 1 (IOP2b)

dry snow

wet snow

rain

graupel

riming

large drops

coalescence

1D Water Continuity Model

Cc – condensation of cloud waterAc – autoconversion of cloud waterKc – collection of cloud water by rainKci – collection of cloud water by iceFr – fallout of rainFi – fall out of iceGl – glaciation

Water Vapor Cloud Water

Ice

RainCc

Kc

Gl

Fi

Fr

Kci

Ac

Assumes saturated parcel (no evaporation or entrainment)

Yuter and Houze, 2003: Microphysical modes of precipitation growth

Best Z-R relation for 10 min data: Z=216 R1.5

Slight overestimation of rain by French, Austrian and Italian radars, slight underestimation of rain by Swiss radars

Hagen and Yuter, 2003

Steiner et al., 2003: Evidence of systematic drainage flows Steiner et al., 2003: Evidence of systematic drainage flows during rainy eventsduring rainy events

Chong and Pradier: The mesoNH model is able to Chong and Pradier: The mesoNH model is able to reproduce these drainage flowsreproduce these drainage flows

REFERENCEREFERENCE NO EVAPORATIONNO EVAPORATION NO MELTINGNO MELTING

Chong and Pradier: the model indicates that downslope Chong and Pradier: the model indicates that downslope flow is strongly influenced by dry dynamics (classical flow is strongly influenced by dry dynamics (classical blocking)blocking)

Asencio and Asencio and Stein, 2003Stein, 2003

MODEL INTERCOMPARISON ON IOP2BMODEL INTERCOMPARISON ON IOP2B

1H PRECIP1H PRECIP 27H PRECIP27H PRECIP

P2: Incident upper-tropospheric PV anomalies

• Dynamics of large PV anomalies approaching the Alps (PV-streamers)

• Role as precursor of severe precipitation

• Modification by diabatic effects generated by orography

• Significance of small-scale structures seen on water-vapor satellite images

Liniger and Davies (2003) : Comparison of upper atmosphere water vapor from Meteosat WV channel (Contours) and reconstructed from ECMWF analysis via Lagrangian Forward Projection technique (gray shades). This is 12UTC 6 November 1999 (IOP15)

Hoinka et al (2003) Cross section of WV mixing ratio (ppmv) on 6/11/99:

Comparison between ECMWF, MesoNH, and observations from the DIAL Lidar

P3: Hydrological measurements and flood forecasting

• Near-real time trial to forecast floods with coupled systems

• Testing soil moisture monitoring techniques

• Evaluate the significance of soil moisture initial value and water storage in dams for flood forecasting

Ranzi et al 2003:

Inverse modelling method allows to reconstruct rainfall on 17 small sub-basins of the Toce-Ticino

24-hr rainfall of IOP2b event

Jasper and Kaufmann, 2003: Poor performance of MC2-3km to force the fydrological model, due to a strong negative rainfall bias. If MC2 rainfall are rescaled by a factor 1.77, better results.

Kouwen and Benoit, 2003: MC2 better than radars to force the hydrological model on IOP2b case.

P4: Dynamics of gap flows

• Explore the 4D velocity distribution at the Brenner pass and within the Wipp valley

• Ascertain the existence and consequences of hydraulic jumps

Durran et al, 2003

Ground Lidar and P-3 in situ wind measurements agree to within 2m/s

This allows a very detailed study of the gap flow in the Wipp valley

Flamant et al (2003): Summary on Gap

Flow event on 30 October

• The upstream flow had an inversion between the gap and crests altitudes

• Part of the jet in the Wipp valley originates from a mountain wave

• The jet (18m/s) was deviated to the eastern side of the valley because of the southwesterly synoptic wind

• Two hydraulic jumps existed along the valley, consistent with reduced-gravity hydraulic theory

• Most features were well captured by a meso-scale model

P5: Foehn in the Rhine valley

• Explore the 4D variability of Foehn in the Rhine valley

• Mechanisms for Foehn penetration to the ground

• Air quality related aspects

• Interaction of Foehn with the upper-level flow

Beffrey et al, 2003: A conceptual model of the Foehn in the Rhine valley

Dominant terms: Shear production, advection

Turbulent wake in the Foehn region (statistics on 5 flights)

(A. Druilhet)(A. Druilhet)

Lothon et al, 2003: The dissipative length appears surprisingly constant throughout the IOPs and across the range. This will have implications for turbulence parametrization

23e

L

Jaubert et al. 2003: Predictability of fine scale details of the Foehn intensity at ground level: comparison between the RASS at Rankweill and simulations by MesoNH

Potential temperature

Southerly wind component

P6: 3D Gravity wave breaking

• Explore the space and time variability of gravity wave breaking in the Alps

• Determine their predictability by meso-scale models

• Validate new observational strategies

Volkert et al (2003): Mesoscale model captures the full organization of a complex field of lee waves

ModelSatellite

Doyle and Smith, 2003:

Upstream diabatic heating due to rain enhances dramatically the lee waves during IOP2b

P7: Potential vorticity banners

• Investigate the high resolution structure of the Alpine wake at or below mountain-top level

• Validate the structure of PV-banners predicted by meso-scale models and their generation mechanisms

• Investigate the dynamic stability of these structures

Schär et al, 2003: Detailed aircraft observations of the primary PV banner generated by the western tip of the Alps allow to distinguish several PV filaments. Some of them could be traced specifically to the Pelvoux and Viso peaks. Similarly, Jiang et al. (2003) could attribute a PV filament (separating Mistral from Tramontane) specifically to Mont-Lozère.

What MAP still has to do

• Translate progress in understanding in progress in real-time NWP

• Organize a demonstration of this progress• Issue definite recommendations regarding the

evolution of the operational observing system for the prediction of intense weather in the Alps

• Set-up a program on societal and economic impacts

On-going work

• Special Issue of QJRMS January 2003 Part B• Special Issue of HESS in preparation• Special event on FORM results in preparation• Those issues represent only a small part of all MAP

publications: see the MDC list for a complete record• MAP annual science meetings: with the ICAM, Brig,

19-23 May 2003, with the AMS/MMC in June 2004• Intercomparison of numerical models on the case of

IOP2

• A final report on the DAQUAMAP project will soon be released

• A re-analysis of the SOP period with an updated assimilation system and all special observations has been performed at ECMWF. The reanalysis files are available from MDC every 3hours, for the whole SOP. The observations files are also available in BUFR format from the MDC. Use of both of these products is strongly encouraged!

• Correction of the RS moisture bias is in progress• Production of reference rainfall analyses for the

SOP (using both radars and gages) is planned

Towards a possible Forecast Demonstration Project?

• The WWRP concept of a FDP: to demonstrate progress in forecasting techniques, in a real-time operational context, with involvement of end-users and objective assessment of success

• Based on MAP history, the high-resolution NWP of rainfall and flooding risk in the area of Lago Maggiore appears as the most logical way to measure the progress achieved by MAP

Conditions of a succesful FDP

• Explore the most useful lead times and resolution for intense rain prediction: this requires to develop a deep understanding of how a variety of users are using the forecasts

• Include a probabilistic component, e.g. force MAP-proven mesoscale models by EPS products

• Investigate operating characteristics of the systems (false alarms ratio, hit rates, ROC curves, etc…)

• Develop a good working relationship with some key end-users, e.g. local water authorities, local civil protection authorities, medias, etc…

• This will need an investment of our community in societal and economic studies: a good knowledge of the various costs induced by a flood may in the end prove necessary to develop an effective forecasting system