The experimental domain covers an area of about 250km (W-E) * 150km (S-N). It is bounded to the West by the Atlantic ocean, the shoreline being quite rectilinear along a NNE orientation.

The western half of the domain is characterized by the presence of the Landes forest, 80% of which is included in the Regional Experiment area (see figure below). It is mainly composed of pines (pinus pinaster). It is an artificial and commercial forest, whose parcels are regularly uprooted and then sown again. Clearings of  various sizes are composed of agricultural parcels, mainly maize, but also grasslands and pastures (mainly in the southern part of the forest), or other cultivations like vegetables. Close to the western cost, large ponds can be observed. Inside the forest, the population is scarce, and only villages and small cities can be encountered. However, several military areas occupy a large surface (at least partially deforested).

The other major landscape of the domain is composed of cultivated parcels. Most of them are cereals, with the exception of the Garonne river valley (crossing the domain from SE to NW) where there are fruit trees, and the large “Bordeaux” vineyards, east of the Bordeaux city.

The NE corner presents the extremity of a vast, little cultivated region, mainly composed of woods and pastures.

Two major cities are located close to the SE (Toulouse) and NW (Bordeaux) corners of the domain. A little less than one million inhabitants live in Toulouse and its suburbs, about one and half times that of Bordeaux. Given the dominant winds in spring (see wind roses below), the domain could be affected by the plumes of the cities. The population of the other cities inside the domain is one order of magnitude lower than that of Toulouse or Bordeaux.

The Landes forest and the valley of the Garonne river are quite flat areas, whereas the rest of the domain is mainly composed of gentle hills. Outside of the domain, to the South, the Pyrenees mountain range presents a W-E barrier culminating above 3000m height. This has a strong influence on the generation of local winds on the domain. To the East and North-East, the terrain elevates progressively toward the so-called Massif Central, culminating at 1800m and reaching about 1000m,100km far from the domain.

figure I.4-a : Land cover with 250m resolution for the south west region of France