Land Cover Dynamics (1990-2002) in Binh Thuan Province, Southern Central Vietnam

in International Journal of Asian Social Science (2012), 2(3), 336-349

This paper describes the use of satellite imageries and GIS data for identifying key environmental characteristics of Binh Thuan Province in south central Vietnam and for detecting the major changes ... [more ▼]

This paper describes the use of satellite imageries and GIS data for identifying key environmental characteristics of Binh Thuan Province in south central Vietnam and for detecting the major changes patterns within this region. Landsat TM (1990) and Landsat ETM+ (2002) imageries were used to classify the study area into seven land use and land cover (LULC) classes. A post-classification comparison analysis was used to quantify and illustrate the various LULC conversions that took place over the 12-year span of time. Results showed that a steady growth in population has caused extensive changes of land cover throughout the area. The maps also indicate that the loss of woody land (forest) and the extension of wetlands (irrigated area), combined with built-up encroachment, remains one of the most serious environmental problems facing the Binh Thuan Province today. The post-classification change detection analysis showed that critical habitats accounted for nearly 38.5% of the intensive study area between 1990 and 2002 while 61.5% remained stable. Results also showed over the 12-year span, approximately 1151.2 km² (115.120 ha) forest were converted respectively to brush, irrigated area (wetlands), cropland and built-up. This is an overall average decrease of 9594 hectares of forested area per year. Throughout the study area, districts most affected by forest conversion to another land cover are: Bac Bihn (2798 ha/year), Than Linh (2717 ha/year), Ham Thuan Nam (1601 ha/year) and Ham Thuan Bac (1524 ha/year). Based on the identified causes of these changes, we made policy recommendations for better management of land use and land cover. [less ▲]

Trends in extreme rainfall events in Benin (West Africa), 1960-2000

in Proceedings of the 1st International Conference on Energy, Environment and Climate Change (2011, August 26)

Global dataset of derived indicators has been compiled to clarify whether the frequency and / or the severity of rainfall extremes changed during the 1960 – 2000 period in the Republic of Benin in West ... [more ▼]

Global dataset of derived indicators has been compiled to clarify whether the frequency and / or the severity of rainfall extremes changed during the 1960 – 2000 period in the Republic of Benin in West Africa. This period provides the best spatial coverage of homogenous daily series, which can be used for calculating the proportion of global land area exhibiting a significant change in extreme or severe rainfall. We selected 12 indicators of extreme climatic events that are based on daily totals of precipitation. The six first indicators are the annual total precipitation (RTOT); the annual total of wet days (with daily rainfall >= 1mm, Rd); the simple day intensity index (SDII) calculated as the average rainfall from wet days; the annual maximum rainfall recorded during 1, 5, and 30 days (Rx1d, Rx5d, and Rx30d). The other six indices are based on the 95th and 99th percentiles calculated from the daily rainfall data over the 1961-1990 period, that is the 30-year period required by the World Meteorological Organization (WMO) for the calculation of normals. The 95th percentile defines a very wet day. The 99th percentile corresponds to an extreme rainfall event. Based on these percentiles, three extreme precipitation indices were chosen. Very wet day and extreme rainfall frequency are based on the annual count of days with rainfall >= 95th and 99th percentiles of 1961-1990 (R95p and R99p). Very wet day and extreme rainfall intensity corresponds to the annual total precipitation recorded from days with rainfall >= 95th and 99th percentiles of 1961-1990 (R95pSUM and R99pSUM). Very wet day and extreme rainfall proportion is the percentage of the annual total precipitation recorded from days with rainfall >= 95th and 99th percentiles of 1961-1990 (R95pTOT and R99pTOT) and measures how much of the total rain comes from very wet or extreme events. Only time series which had complete records from 1960 to 2000 were used. A total of 21 stations time series were extracted from national climate archives and collated into the unique dataset described here. National maps showing trends during the 1960-2000 period were produced. Results show that only the annual total precipitation, the annual total of wet days and the annual maximum rainfall recorded during 30 days present a significant decreasing trend while the other nine rainfall indicators appear to remain stable. These results are important findings for Benin since scarce works realized in neighbouring regions of West Africa describe a situation more prone to increases in extreme rainfall (in Nigeria [1]) or the opposite (in Guinea Conakry [2] and in Niger [3]) in a similar context of a clear reduction in the yearly precipitation amount. We call for further research on this topic in West Africa since water management is a major tool for sustainable development and poverty alleviation. [1] M. New, B. Hewitson, D.B. Stephenson, et al., “Evidence of trends in daily climate extremes over southern and West Africa,” J. Geophys. Res., vol. 111, 2006, D14102, doi:10.1029/2005JD006289. [2] E. Aguilar, A. Aziz Barry, M. Brunet, et al., “Changes in temperature and precipitation extremes in western central Africa, Guinea Conakry, and Zimbabwe, 1955–2006,” J. Geophys. Res., vol. 114, 2009, D02115, doi: 10.1029/2008JD011010. [3] P. Ozer, Y.C. Hountondji, O. Laminou Manzo, “Evolution des caractéristiques pluviométriques dans l’est du Niger de 1940 à 2007,” GEO-ECO-TROP, Vol. 33, pp. 11-30, 2009. [less ▲]

What do we know about effects of desert dust on air quality and human health in West Africa compared to other regions?

in Science of the Total Environment (2010), 409(1), 1-8

This study aims to compare, on the one hand, the geographical distribution of the desert dust source areas, their contribution to quantities emitted into the atmosphere, the trajectories and the ... [more ▼]

This study aims to compare, on the one hand, the geographical distribution of the desert dust source areas, their contribution to quantities emitted into the atmosphere, the trajectories and the quantities deposited, with on the other hand the areas of research interest focused on the desert dust impacts on air quality and/or human health. Based on a systematic review of the literature using the ISI Web of Knowledge database, we found 231 articles published over the last decade on the desert dust impacts on air quality. Of these, 48% concerned Asian dust and 39% Saharan dust, with the remaining 13% divided between the other dust source areas. However, only one of these studies addressed the worsening air pollution in West Africa, even though it is very close to the Sahara, the greatest contributor to the global dust budget. Moreover, there have been very few studies (41) looking at the direct links between desert dust and human health; in this context too, no interest has been shown in West Africa. Yet this region is also among the areas in which morbidity rates have been noted to be far higher than those found in other regions of the world, and where respiratory infections alone account for more than 20% of the causes of infant mortality. This survey highlights a clear imbalance between those areas most exposed to dust and the most studied areas in terms of dust impacts. Given these findings and the often alarming results published about other regions of the world, we advocate a revival of interest in research on West Africa in order to achieve a better understanding of the desert dust impacts on air quality and health among the populations of this region. [less ▲]

Saharan Dust Pollution: Implications for the Sahel?

in Epidemiology (Cambridge, Mass.) (2009), 20(5), 780

The main source of atmospheric mineral dust is the Sahara desert, which produces about half of the yearly global mineral dust.1 About 12% of the Saharan dust moves northwards to Europe, 28% westwards to ... [more ▼]

The main source of atmospheric mineral dust is the Sahara desert, which produces about half of the yearly global mineral dust.1 About 12% of the Saharan dust moves northwards to Europe, 28% westwards to the Americas, and 60% southwards to the Gulf of Guinea. Saharan dust storms can lead to particulate matter (PM) levels that exceed internationally recommended levels. Recently, special attention has been paid to the mineral PM air pollution of dust storms, which may be a serious health threat. We took a systematic review of the literature to find relevant studies on the effects of Saharan dust on air quality or human health. We searched the ISI web of knowledge database using “PM10,” “PM2.5” or “health” AND “dust storm,” “sand storm,” “African dust,” “Saharan dust,” or “dust events” without restrictions. The search extended from January 1999 to December 2008. We selected 97 articles of which 72 studied PM air pollution in Europe, 13 in the Americas, 7 in the Near East and Asia, and 4 considered international data. Only one specifically addressed air pollution in the Sahel. Four focused on human health effects—2 in the Mediterranean and 2 in the Caribbean. [less ▲]

Bulletin agrométéorologique - Septembre 2006

in Bulletin Agrométéorologique (2006), 5(6), 1-4

Monitoring of the crop water stress in Belgium. The case of the 2003 heat wave.

Conference (2006, October)

In this paper the crop water stress is evaluated with three different indices: (i) the Relative Soil Moisture Index [RSMI] resulting from agrometeorological model simulations, (ii) the Normalized ... [more ▼]

In this paper the crop water stress is evaluated with three different indices: (i) the Relative Soil Moisture Index [RSMI] resulting from agrometeorological model simulations, (ii) the Normalized Difference Vegetation Index, [NDVI] applied on S10 SPOT-VGT imagery, (iii) the Normalized Difference Water Index, [NDWI] applied on S10 SPOT-VGT imagery. The RSMI is one of the outputs of the Belgian Crop Growth Monitoring System. It indicates the soil water availability for crops. Crop water stress is assumed when soil water availability is lower than the crop potential evapotranspiration. One of the potential applications for drought monitoring is the calculation of the number of days with a crop water stress during the growing season or more precisely during the “moisture-sensitive period” of the crop. The two others (well-known) indices are derived from low resolution satellite imagery. Complete time series of S10 SPOT-VGT NDVI and NDWI data - i.e. from April 1998 onwards – have been acquired for the research. Using spatial information on land-uses in Belgium, a simple unmixing method is implemented to partly reduce the problem of mixed values occurring inevitably in 1x1km² pixels. Only the most agricultural pixels are considered for the analysis. The heat wave occurred during the summer 2003 has been chosen as a study case for the comparison. This summer was particularly hot, dry and sunny with the highest averaged temperature ever recorded from June to August in Uccle-Belgium. Many human activities were affected by this particular climatic condition, among which agriculture. In order to make the comparison possible, a standardization of the outputs of the 3 indexes is realised, taking into account the times series of each indexes. Moreover all the outputs are aggregated at municipality level. [less ▲]

Pour 80 milliards de dollars de catastrophes naturelles

Article for general public (2006)

Début 2006, nous y sommes. Les sociétés de réassurances, la «Swiss Re» et la «Munich Re» en fer de lance, ont bouclé leurs comptes. Et l'heure est grave: les catastrophes naturelles de 2005 leur auront ... [more ▼]

Début 2006, nous y sommes. Les sociétés de réassurances, la «Swiss Re» et la «Munich Re» en fer de lance, ont bouclé leurs comptes. Et l'heure est grave: les catastrophes naturelles de 2005 leur auront coûté plus de 80 milliards de dollars. Record battu, non, pulvérisé, comme l'effet d'une bombe à fragmentation américaine tombée malencontreusement sur un hôpital irakien ou, moins polémique, comme un séisme qui balaye toute une génération d'écoliers au Cachemire lors d'un tremblement de terre, pourtant attendu, faute de constructions parasismiques... [...] [less ▲]

Tsunami en Asie du Sud-Est : analyse de son importance dans la presse écrite, des coûts assurés et du nombre de victimes à Sumatra

in Bulletin de la Société Géographique de Liège (2005), 46

The tsunami that affected the Indian ocean’s rims on December 26, 2004 claimed close to 300 000 deaths, essentially on the island of Sumatra, Indonesia, which suffered overwhelming devastation. This ... [more ▼]

The tsunami that affected the Indian ocean’s rims on December 26, 2004 claimed close to 300 000 deaths, essentially on the island of Sumatra, Indonesia, which suffered overwhelming devastation. This article is focused on three specific aspects of the disaster. On one side, we analyse the tribune offered to the tsunami catastrophe by the press in Le Soir and Le Monde. On the other side, we present an analysis of the distribution of insured losses from the latest data made available by the two largest reinsurance world companies, Swiss Re and Munich Re. Finally, we try to compare the estimated death toll with available demographic data for the province of Aceh. Here we show that the place given to the tsunami is enormous when compared to other natural tragedies, and we try to explain what motivated such a coverage. In addition, the analysis of insured losses highlights the North-South differences as local victims (99 %) concentrate less than 10 % of the losses supported by insurers. For what regards the death toll, we conclude that the number of about 235 000 for northern Indonesia is a broad estimation and that a realistic approach is impossible since no census was made in this region over the last three decades. [less ▲]