Simulation of heavy precipitation events in Madeira Island using

resolution of 1 km

Simulation de précipitations orographiques intenses sur Madère (résolution 1km)

Flavio T. Couto

Évora University, Physics Department, Évora, Portugal.Geophysics Centre of Évora – CGE, Évora, Portugal.

Email: couto.ft@gmail.com

Introduction about the Madeira island

Materials and model configuration

Results and Conclusions

OUTLINEOUTLINE

The Madeira Island is:

situated at 32◦45N and 17◦W;

a little island with an area of 737 km2 and a maximum altitude of 1.861 m at Pico Ruivo;

completely formed by volcanic materials with an approximately E–W-elongated form (58 km long and 23 km width), able to block and deviate the wind around and above;

IntroductionIntroduction

Fig.1: Orography of Madeira simulated with the Meso-NH, using the GTOPO30 data base and 1km resolution.

The precipitation in the island is influenced by subtropical anticyclone winds, (summer season), low pressure and frontal systems passage (winter), as well as the persistent covering of fog, which normally exists between the 800–1,600 m altitude.

MOTIVATION

Evidences of heavy precipitation during the winter 2009/2010, for example, the disaster occurred on 20 February 2010, when the Madeira Island was hit by intense precipitation, causing more than 40 deaths, and a vast range of material losses, including the destruction of houses, roads and bridges.

IntroductionIntroduction

IntroductionIntroduction

GOALS:GOALS:

to analyze the main atmospheric characteristics associated with the events;

to expand the understanding of the interaction between the Island and the atmospheric circulation, mainly the effects of the orography in the generation/intensification of precipitation;

to evaluate the performance of Meso-NH in simulate heavy precipitation over Madeira with high-resolution.

MaterialsMaterials

Simulations of the Meso-NH model;

Rain gauge data and synoptic charts obtained from Portuguese Meteorological Institute;

Precipitable water from satellite observations;

Areeiro station:

1) 15/12/2009 – 129,2 mm

2) 17/12/2009 – 131,5 mm

3) 22/12/2009 – 127,7 mm

4) 28/12/2009 – 135,1 mm

5) 02/01/2010 – 168,5 mm

6) 02/02/2010 – 273,1 mm

7) 20/02/2010 – 387,1 mm

Rain gauge analysisRain gauge analysis

MaterialsMaterials

most intense event Day

Day

Day

Atmospheric River

MaterialsMaterials Model configuration:Model configuration:

3 horizontal 3 horizontal domainsdomains::

D1: 40x40 points, 9 km resolution;

D2: 60x60 points, 3 km resolution;

D3: 90x60 points, 1 km resolution;

Vertical grid with 45 levels.

MaterialsMaterials Model configuration:Model configuration:

-Diagnostic mode

Initial and boundary conditions updated every 6 hours and obtained from the ECMWF analyses;

-Prognostic mode

Initial and boundary conditions updated every 3 hours and obtained from the ECMWF prognostics;

MaterialsMaterials Model configuration:Model configuration:

Accumulated precipitation Accumulated precipitation (Diagnostic Mode)(Diagnostic Mode)Results and conclusionsResults and conclusions

Results and conclusionsResults and conclusions

Accumulated and hourly precipitation well represented

Accumulated and hourly precipitation poor represented

Areeiro station - Case 02 Feb Calheta station - Case 02 Feb

Caniçal station - Case 02 Feb Lombo da Terça station - Case 22 Dec

Accumulated precipitation (Prognostic Mode)Accumulated precipitation (Prognostic Mode)Case 20 February 2010Case 20 February 2010

Results and conclusionsResults and conclusions

Results and conclusionsResults and conclusions

Some preliminary conclusions

In general, the Meso-NH have been responded satisfactorily to the aims of this study:

- Confirming the orographic effect in intensification of the precipitation;

- Identifying some aspects of mesoscale related to some mechanisms of orographic

precipitation, for example:

- Interaction between the mesoscale (e.g. orography) and large scale (e.g.

Atmospheric Rivers);

Houze (1993)

Thank you for your attention !Thank you for your attention !