CLIMATE ANOMALIES AND EXTREME EVENTS IN AFRICA IN 2003, INCLUDING HEAVY RAINS AND FLOODS THAT OCCURRED DURING NORTHERN HEMISPHERE SUMMER

The climate of 2003, particularly during Northern Hemisphere summer, was marked by exceptionally abnormal events throughout the world, and Africa was no exception. As record heat waves prevailed over Europe, heavy rains and floods occurred over the west-central Sahara, across the Sudano-Sahelian region and western Kenya, while drought conditions gripped the Guinea Coast and southeastern Southern Africa, and cold waves hit southern South Africa. Among the most remarkable events were record rainfall in the western portion of the Sahara-Sahel and drought conditions over the Guinea Coast that were both caused by an extreme northward penetration of the ITCZ relative to normal years. In addition, record-breaking cold weather occurred in southern South Africa in mid-August by a strong extratropical cyclone accompanied by a cold front. During Southern Hemisphere summer, Madagascar, Mozambique, Zimbabwe, and Malawi frequently experienced heavy rains and fl oods associated with tropical cyclones and their remnants. More than 550 people died and over 2.5 million were displaced because of fl oods in Africa in 2003. Africa's vulnerability to climate hazards could be reduced through enhancements of both short- and long-term coping strategies, climate monitoring and early warning systems, fl ood control infrastructures, and other disaster preparedness measures at all levels, including sub-regional, national, and local levels. Mechanisms that caused various events in Africa in 2003, events which can be viewed as regional responses in Africa to anthropogenic global warming, must be explored from the perspective of global change

Studies of anthropogenic landform transformation in japan : a perspective

In Japanese geography, the explicit perception of man as an important geomorphological agent dates back to 25 or more years ago. Throughout the past years various efforts have been made to study man\u27s role in changing the land surface form and the geomorphic processes both in the past and present. The argument has been reiterated that the man-induced changes in physical environment should be considered as an important causative factor leading to natural disasters due to geomorphic accidents. In the last few years, organized studies and related symposia have brought about great progress in the twin aspects of the subject;- i.e. direct transformation and induced changes in geomorphic processes. Tasks for further development in this field are summarized

Late glacial-early holocene environmental changes in tropical africa : a comparative analysis with deglaciation history

In tropical Africa, glacial-postglacial contrast in precipitation pattern is very great; glacial maximum extreme aridity was followed by the period of increased rainfall during 12,000-5,000 yr B.P. A map showing environmental conditions prevailed in the culmination of the early Holocene wet period at 9,000-8,000 yr B.P. was constructed using published data. The timing of onset and interruptions of the wet period by marked dry episodes at 10,500-10,000 yr B.P. and c. 7,500 yr B.P. were analyzed in connection with the deglaciation history

Predicting the areas in danger from natural disasters due to soft ground conditions : an application of aerial photo analysis

This paper is a study of physical geography of alluvial and deltaic lowlands, by using aerial photographs, for the purpose of disaster prevention and regional development. The methods and procedures for predicting the areas in danger from natural disasters due to soft ground conditions, especially earthquake disasters, are presented and discussed, in case of the Shizuoka-Shimizu Region situated on the Pacific coast of Central Japan. Both by photo-geomorphological analysis and by regional analysis of geologic and engineering soil data obtained from previous boring investigations, the nature of the ground of the region has been made clear and mapped. The danger areas from earthquake damage as inferred from ground conditions are classified and mapped based on the relationship between ground conditions and earthquake damages occurring in this region and in other regions having similar ground conditions, by assuming magnitude and intensity of a destructive earthquake. As a result of this study, the problems of disaster prevention, in relation to the future development of the region are summarized

Basic concepts of photo-geomorphological analysis of soft ground conditions

The analysis of micro-features of the terrain surface is most important to allow interpretation in geology and soils by using aerial photographs to be accomplished. The basic concepts, methods and techniques used to analyze and interpret engineering soils in Recent alluvial lowlands, above all those forming soft ground conditions, from a systematic analysis of micro-landforms are discussed. A procedure for soft ground investigation by means of photo-geomorphological analysis is presented

The landforms in the tsavo-voi area, southern kenya : an interim report on the geomorphology in the basement system rocks in a tropical semi-arid region of east africa

The nature and evolution of landforms which are formed on the Basement System rocks in the semi-arid region of southern Kenya are examined on the basis of field reconnaissance surveys and aerial photo interpretation. The occurrence of inselbergs, bornhardt domes, ribs and pediments is primarily controlled by the structures of bedrock. Pediments having a smooth surface slope are preserved only on the non-dissected plains of the end-Tertiary erosion surface, and are found around the inselbergs which stand abruptly over the plain with a relative height of 100-350 m, as observed in the vicinity of Voi town. On the other hand, in the area of dissected plain pediments have almost been destroyed by river incision, and rock outcrops of gneisses form bornhardt domes and ribs as in the Tsavo area are evident. The anual rainfall in the Tsavo-Voi area is somewhat less than 500 mm. The dissection of pediments and pediplains by gullies and rills is more distinct in the peripheral zone of the higher hill masses such as the Taita and Sagala Hills where annual rainfall exceeds 750 mm. Within the area along the Nairobi-Mombasa Road the typical examples of pediments being dissected are found at the southern foot slopes of the Mbatini and Mbitini Hills, north of Sultan Hamud. In general, the dissection both of pediment slopes and of end-Tertiary peneplain is distinguished in the area along the Athi-Galana River system and in the scarp-foot zone of high and large hill masses receiving a larger amount of precipitation. Though the smoothly curved pediment slopes are recognized on the non-dissected plains as in the vicinity of Voi town, pediment surfaces have been slightly modified by gullying and sheetwash erosion under the present climatic condition. These processes caused only minor changes to the surface, and the movement of surface materials is not pronounced. However, they are the most important active processes that modify the surface of pediment slopes at the present time. It seems probable that most of the pediments and pediplains in the area surveyed appear to be in the stage of gradual destruction under the present climatic condition rather than being formed. Rill incision in the scarp-foot zone is thought to be a significant process that maintains the abrupt transition of slopes from the pediment slopes, even of dissected slopes, to the hills. This process is remarkable in the scarp-foot zone of the Taita and Sagala Hills. Gullying and sheetwash erosion in the semi-arid savanna region of southern Kenya have been accelerated due to both over-grazing and to engineering activities by man as construction of roads. Morpho-conservation should be necessary for future environmental conservation of savanna ecosystem