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Tropical Africa is currently the subject of major scientific research commissioned by international organisations and major powers. The studies on drought partly aim at a better understanding of the atmospheric system : they presuppose the use of very costly means and sometimes only result in the possibility of distant scientific breakthrough. But Africans are essentially concerned with their immediate future and problems (malnutrition, food self-support) . Therefore research should primarily be oriented towards topics narrowly based on field observation (agroclimatology, bioclimatology) . It is true international organisations are also interested in a spatially-limited approach. Yet regional studies that require lesser means than most programs offered by these organisations seem better adapted to African demands.

Traditional knowledge, being empirical, rigid and transmissible, is not sufficient any more to warrant the nomad's life as well as rational development of herding area ; they also need modern knowledge based upon scientific progress.

Case studies at different scales show that interesting results can be obtained from diachronic studies of the relations between climate and agriculture. A systematic study of deviations from trends for agricultural index numbers during the last twelve years is briefly outlined, as well as a discussion of the origins of the « agricultural accidents » at the global scale.

Many scientists are now studying the influence of the weather and climate on the various physiological and pathological phenomena associated with the diseases of man, especially with the onset of ischaemic heart disease. But they all are confronted with a bewildering diversity of prospects. To offer a rational explanation of the biologic mechanisms of meteorotropic effects locally observed in heart patients remains the ultimate and essential purpose of the physician. But the geographer is not so directly concerned in aetiopathogenesis. Conversely it rests with him to point out to what extent different climates are conductive to different pathologies. Lastly the knowledge of both climate and meteorotropic correlations aims at designing maps of the infarction hazard, at several time scales. These maps may have a great practical interest.

This study try to show the common meteorological characteristics of three catastrophes who are touching the East of the « Massif Central » : the wind storm in november 1982, the eigghtest snowfall in november 1982, the swelling of the Loire in september 1980.

In this paper, we state some results of a long experience of regional climatology in the eastern Pyrenees. For such a region of contrasts, it was necessary to modify the climatological methods and also to choose an improved terminology. In order to understand more concretly how climate acts, we had to precise the relation between the generating synoptic structures and the resulting types of weather. This point of view of making weather caused a special approach of seasons which among other characteristics gives a non-statistical mode of evaluation of variability.

The icy cold of january 1985 disturbed the Parisians customs and brought many difficulties (heating, transport, food). The Parisians accustomed themselves but their health was affected (increase of mortality and children absences).

It is today unconceivable to get some climatic studies up without to design the human climatic environment as a whole. Climatology is herself a « Social science ». To use System approach allows us to conceive a large climatic system, comprising man himself, as an earth-inhabitant, as a scientist, and as a decision-maker. This paper suggests a schematic system, in wich are used two new concepts : Climatic context and Ultra-forecast (in french : «Transprévision»).

We approach unusual atmospheric phenomena by studying the fractal dimensional resolution of measuring networks and the intermittency of the day to day temperature fluctuations.

Interannual and seasonal variations of the Southern Oscillation phenomenon — a global exchange of mass between the South Pacific subtropical high and the Indonesian equatorial low — are studied in conjonction with some rainfall anomalies patterns over intertropical domain. Effects of these relationships are discussed and compared with Bjerknes's and Wyrtki's hypothesis.

Weather hazard such as heat wave, cold wave and frost, excessive or low rainfall is a multivariate concept. First of all we show that perception is one dimension of this concept. Then a comparative study is made between two regions, French Riviera and Francfort country. Some rules are confirmed.