Earth Observation Services to Support Environment Monitoring for the World Bank
After analysis of information requirements expressed by the World Bank's sectoral experts, LuxSpace specified EO services in close collaboration with ESA and organized their service procurement.
The following projects are completed for the World Bank:
Change in the Coastline of Bangladesh
In the context of Climate Change, many projections estimate a sea level rise of around 1 meter by the year 2100 in Bangladesh. This would mean an inundation of approximately 18% of the land surface of the country. However, what these estimates fail to recognize is the extremely dynamic and changing nature of the river delta. The river morphology is constantly changing, depositing over a billion of tons of sediment a year into the delta. These processes are critical to renewing the fertility of the flood plain - Bangladesh itself would not exist otherwise. This service aimed at contributing to the scientific debate on the net result of high accretion and deposition rates which add land surface, against the erosion and compaction rates which reduce the land surface.
Two projects - intended more as proof of concept studies - were implemented following different methodologies for the monitoring of the coastline and its changes.
Remote Sensing Monitoring of Coral Reef in the Belize Region
- Review state-of-the-art remote sensing capabilities (space borne and airborne) to help supporting the monitoring of coral reefs
- Deliver high-resolution maps and time-series of sea-state parameters helping reef managers to quantify possible stress (e.g. thermal) on the coral reef off the Belize coast
- Deliver coral reef habitat maps based on appropriate EO data from various missions (e.g. Proba, Landsat, Spot, Envisat, MSG) in combination with ancillary data.
Monitoring of Historical Land Motion of North African Coastal Cities
In the framework of the World Bank study on “Climate Change Adaptation and Natural Disasters Preparedness in the Coastal cities of North Africa” two EO services were carried out. The study aims to identify and assess natural risks and vulnerabilities in some of the main North African countries. Earth observation services were used to estimate ground movement process in Tunis and Alexandria, in support to surveys and expertise on land stability and seismic issues.
In Alexandria, ALTAMIRA Information applied InSAR technologies for the reconstitution of the monthly historical ground displacement in the urban and rural area of Alexandria during the 1992 to 2009. The results of ALOS data processing are covering 30 months (from March 2007), ERS data are covering 103 months (from May 1992 to December 2000) and ENVISAT data are covering 76 months (from July 2003 to November 2009). The executive summary of the final report can be downloaded here.
In Tunis, TRE applied an upgraded InSAR technology, called SqueeSARTM. It is an advanced second generation PSInSAR™ analysis, exploiting both “point wise” (permanent scatterers) and spatially “distributed scatterers” (DS). SqueeSARTM provides information in low-reflectivity homogeneous areas, previously unidentified by PSInSAR™. The study analyzed potential movements between 1993-2000 and 2003–2009, the periods for which respectively ERS and ENVISAT satellite data were available over this area. A brief description of the results can be downloaded here.
The results of both EO services have been integrated in the analysis performed by EGIS, a specialized consultant implementing the World Bank study. The utility of both EO services has been assessed by the users as follows:
- At present there seems to be no alternative to interferometry technologies for ground movement monitoring on wide surface areas (several hundred or thousand kilometers). In other words, there is no usual source of information to be compared to the satellite-derived information we have been supplied with.
- I can ask for the same type of information for any part of the world, and it is relatively cheap.
- This type of EO service opens up new perspectives on land management issues, provides new monitoring tools, is cost effective and can be implemented with very short deadlines.
- The progress in technology development, i.e. the new technique applied on Tunis with Distributed Scatterers in addition to Point Scatterers together with the use of ascending and descending datasets improves the reliability of the results.
- Another crucial element of the success of the exercise was the excellent management of the services, i.e. cooperation, communication and quality assurance with ESA and the service providers ensured by LuxSpace.
- A main drawback of persistent scatterer interferometry technology seems to be the lack of satellite data over a longer period, i.e. more than the 20 years.
- Another weak point is the sensitivity of the results with regard to the reference point. The absolute velocities resulting from the PS/DS analyses are indeed relative to a reference point, which is assumed to be motionless. The absolute results are falling in value with this assumption. Ground truth information on the reference point over the entire time period is absolutely necessary.