Detection of Surface Water with Spot/Vegetation. Monitoring and Assessing CILSS Countries Surface Water Availability

The detection of surface water with Spot/VEGETATION, at 1km resolution, is done every 10-days. The quality of the detection in arid and semi-arid regions in western Africa, and the regular time step of the observations, allow monitoring the surface water availability. The seasonal surface water can be mapped and its date of avail-ability is known. From this information, some indicators were generated for assessing the relative amount of re-plenishment and delays in availability between two years. The overall information, detections and dates assessments based on Spot/VEGETATION is broadcasted every 10-days to African users thanks to the EumetCAST system. The processing of the water availability indicators, such as those demonstrated in this document, can thus be implemented at the user level.JRC.H.3-Global environement monitorin

A Land Cover Map of Africa. Carte de l'Occupation du Sol de l'Afrique.

Abstract not availableJRC.H-Institute for environment and sustainability (Ispra

Harmonisation, Mosaicing and Production of the Global Land Cover 2000 Database.

Abstract not availableJRC.H-Institute for environment and sustainability (Ispra

Monitoring the Environment in Africa: the VGT4Africa and AMESD projects

This paper describes two complementary projects. The VGT4Africa project is a R &D project financed by the EC 6th framework Programme for Research and Technological Development whose objective is to bring into operational exploitation prototype EO data processing chains for data coming from the VEGETATION instrument and distribute the derived products to Africa, whereas the AMESD project is a continental-wide project implemented under the aegis of the African Union Commission together with the regional economic groupings of Africa and with the support of the European Development Fund. Its objective is to improve environmental monitoring for the sustainable management of natural resources in Africa, thus making use, i. a. of data provided by the VGT4Africa project.JRC.H.3-Global environement monitorin

Retrieving Phenological Stages from Low Resolution Earth Observation Data

This paper illustrates the usefulness of retrieving from Earth Observation data information on phenological stages, i. e. the date of occurrence of key development stages of the vegetation. It provides a short review of existing methods to retrieve such information from 1-km resolution data time series from the SPOTVEGETATION instrument, it gives indications about key properties that a processing chain must include to retrieve and update such information throughout the season and it supplies the description of the algorithms successfully tested and implemented at continental scale for Africa.JRC.DDG.H.3-Global environement monitorin

Climate, vegetation phenology and forest fires in Siberia

A time series of 18 years of fAPAR (fraction of photosynthetically active radiation absorbed by the green parts of vegetation) data from the NOAA AVHRR instrument series was analyzed for interannual variations in the start, peak, end and length of the season of vegetation photosynthetic activity in Central and East Siberia. Variations in these indicators of seasonality can give important information on interactions between the biosphere and atmosphere. A second order local moving window regression model called the “camel back method” was developed to determine the dates of phenological events at subcontinental scale. The algorithm was validated by comparing the estimated dates to phenological field observations. Using spatial correlations with temperature and recipitation data and climatic oscillation indices, we postulate two geographically distinct mechanisms in the system of climatic controls of the biosphere in Siberia: Central Siberia is controlled by an “Arctic Oscillation/temperature mechanism” while East Siberia is controlled by an “El Niño/precipitation mechanism”. While the analysis of data from 1982 to 1991 indicates a slight increase in the length of the growing season for some land cover types due to an earlier beginning of the growing season, the overall trend from 1982 to 1999 is towards a slightly shorter season for some land cover types caused by an earlier end of season. The Arctic Oscillation tended towards a more positive phase in the Eighties leading to enhanced high pressure system prevalence but towards a less positive phase in the Nineties. We suggest that the two mechanisms also control the fire regimes in Central and East Siberia. Several extreme fire years in Central Siberia were associated with a highly positive Arctic Oscillation phase, while several years with high fire damage in East Siberia occurred in El Niño years. An analysis of remote sensing data of forest fire partially supports this hypothesis

Time Series Analysis of Optical Remote Sensing Data for the Mapping of Temporary Surface Water Bodies in Sub-Saharan Western Africa

A map of temporary small water bodies (TSWB) at 1 km resolution was derived for the arid, semi-arid and dry sub-humid regions of sub-Saharan western Africa where the spatio-temporal distribution of actual surface water occurrence exhibits high inter- and intra-annual variability. Water bodies and humid areas have been mapped and characterized by the analysis of 10 daily small water bodies (SWB) maps based on SPOT VEGETATION (VGT) data spanning the period January 1999¿September 2007. Further analysis of the SWB time series provided additional information about the seasonal recurrence of water bodies as well as their hydrological function. A map derived from a continuous time series assures the inclusion of temporary features, a clear advantage compared to other datasets, which are based on several single date observations. The method described in this paper targets at a rapid creation of TSWB maps based on the SWB time series for different time intervals and regions. An accuracy assessment has been carried out with a stratified random sampling approach and a one-stage cluster analysis that relies on high-resolution satellite data to verify the detected water bodies. The overall accuracy, considering only the commission error, is 95.4% for the whole study region, with best results in the arid and semi-arid climate zone. The method to map water bodies delivers satisfactory results, particularly for sparsely vegetated areas as well as flat areas of the study region. In more humid, more vegetated areas and in mountainous areas, the possibility of false detections increases due to surface characteristics.JRC.H.3-Global environement monitorin

A Map of Temporary Water Bodies in Western Africa

An algorithm developed for the SPOT VEGETATION (VGT) sensor makes it possible to detect temporary small water bodies in arid and semi-arid areas by analysing the spectral contrast of each pixel compared to its neighbourhood. This algorithm captures surface water and humid areas, the last category being likely to include vegetation. These maps are generated every 10 days allowing to monitor the small temporary water bodies and humid area seasonality. In addition, a reference map of the temporary water bodies was prepared by validating the historical record of the small water body detection. The procedure consists in checking individually any SPOT VGT water bodies detection that lasted for more than 3 consecutive dekads between 1999 and late 2004. The validation has been done over Western Africa. Several sources of information have been used to validate the detections: the Global Lakes and Wetlands Database (GLWD), the Drainage Network of the Digital Chart of the World, Spot VGT colour composite images, the SRTM digital elevation model, Landsat quicklook images and Google Earth. Pixels of the history of occurrence that were not referenced in the GLWD or DCW database have been checked manually. This validation process resulted in a map of three categories: validated water bodies, positive vegetation anomaly with no obvious sign of water but indicating water availability in arid areas and false detections.JRC.H.3-Global environement monitorin

GLC 2000, a New Approach to Global Land Cover Mapping from Earth Observation Data.

Abstract not availableJRC.H-Institute for environment and sustainability (Ispra

Devcocast in Support of Environmental Management and Sustainable Development in Africa

The recently initiated project ¿GEONETCast for and by Developing Countries¿ (DevCoCast) project, supported by the 7th Framework Programme (FP7) of the European Community, will bring together many disparate sources of environmental information and improve the involvement of Developing Countries in the GEONETCast component of the global GEO System of Systems (GEOSS). Many Developing Countries are exposed to serious environmental risks and their need for adequate information is high. Unfortunately, reliable and continuous access to real time environmental information is often lacking. The GEONETCast concept overcomes existing data delivery limitations and is able to provide reliable and fast access to (near real-time) environmental information. The main objectives of the DevCoCast project are to disseminate existing environmental added-value datasets (both in-situ and satellite based) from various sources in Africa, South- and Central America and Europe in (near) real time and at no cost via GEONETCast to a broad range of user communities in Developing Countries. It furthermore promotes and supports the use of the GEONETCast system. By utilizing the existing EUMETCast dissemination system, supporting its expansion to the global scale, and taking direct benefit from the operational infrastructures as well as from well developed user bases in Africa and South-America, the main focus is directed towards the actual use of the data and building-maintaining capacity in Developing Countries.JRC.DDG.H.3-Global environement monitorin