1

1.1 Subproject

Sub-Project 1.1

Earth and Ocean Monitoring Network across Southern Africa (SADC):

a long-term regional project to support a multi-disciplinary

earth science approach

Participants * Coordinator(s)

Institutions / Names / Email addresses
Hartebeesthoek Radio Astronomy Observatory / Ludwig Combrinck* /
University of Cape Town / Geoff Brundrit
Charles Merry /

National Energy Corp of SA / Marco Andreoli /
Surveys and Mapping
National mapping agencies of SADC countries / Richard Wonnacott /
The Hydrographer,
SA Navy / Ruth Farr /
University of Witwatersrand / Sue Webb /
Okavango Research Centre, Botswana / Piotr Wolski /
GFZ Potsdam (Germany) / Juergen Neumeyer *
Pieter Schwintzer
Tilo Schoene
Ludwig Grunwald /
Alfred Wegener Institute (Germany) / Hans Werner Schenke
Daniel Schulte

Total for the 5-year duration project beginning in 2004: Euros 1 260 000

Requested Funding

Year 1

/

Year 2

/

Year 3

/

Year 4

/

Year 5

South Africa

/

114 000

/

137 000

/

143 750

/

139 000

/

96 250

Germany

/

114 000

/

137 000

/

143 750

/

139 000

/

96 250

Totals

/

228000

/

274000

/

287500

/

278000

/

192500

Summary

The geodetic infrastructure of most countries in Africa is based on a variety of outdated co-ordinate reference frames and systems. In order to achieve most of the objectives set out by the Southern African Development Community (SADC) development programmes, it is essential that a reliable and sound geospatial information framework or Geographic Information System (GIS) be in place in a country, region or continent. The establishment of a geodetic network will facilitate the establishment of modern and accurate reference systems, geographical information systems, and will provide the required infrastructure for numerous scientific applications. This project will lead to the establishment of a SADC reference frame (in effect the southern part of the African Reference Frame), and will both facilitate and stimulate numerous applications and local research groups with subsequent infrastructure and social advantages to poorly developed countries of the region. Funding is solicited for initial equipment and travel only.
Manpower, training, maintenance and sustainability of the projects will primarily be supported by the National Research Foundation of South Africa, in collaboration with other stakeholders, to ensure a sustainable, long-term programme in the SADC region. It is envisaged that successful initiation of the project will lead to the establishment of a Geodetic Institute, located within South Africa, that will serve the needs of the SADC region in terms of research capacity development, student training and sustainability of the project SADC Earth and Ocean Monitoring Network.

Introduction

Following on from the fruitful discussions at the Germany/RSA workshops in 2002 and 2003, and after subsequent communications to colleagues local and abroad, it was obvious that with a bit of thought, South Africa collaboration with GFZ/AWI can successfully support a multitude of international and local earth science projects. Furthermore, and very importantly, it can directly benefit local development and capacity building on the southern African continent.

In his speech on the African Renaissance to the United Nations University on 9 April 1998, President Thabo Mbeki spoke of, amongst other things, the eradication of hunger and curable diseases, overcoming the disadvantages of operating small economies through the establishment of regional economic associations such as the Southern African Development Community, the establishment of instruments to address regional security, peace and stability. “These economic objectives, which must result in the elimination of poverty, the establishment of modern multi-sector economies, and the growth of Africa’s share of world economic activity, are an essential part of the African Renaissance.”

One of the many infrastructure initiatives that is common to all initiatives within the southern Africa development programmes are the science and technology platforms which include among other things;

  • To promote cross-border co-operation and connectivity by ultilising knowledge currently available in existing centres of excellence in the continent;
  • To develop and adapt information collection and analysis capacity to support productive activities as well as for exports outside of Africa;
  • To generate a critical mass of technology expertise in targeted areas that offer high growth potential, especially in biotechnology and geoscience.
  • To develop and expand scientific collaborations with international partners to ensure global participation and continuous exposure to global scientific projects.

In order to achieve most of these objectives it is essential that a reliable and sound geospatial information framework or Geographic Information System (GIS) be in place in a country, region or continent. Such a framework is essential for the effective and economical spatial planning and execution of all land related projects, be they for agriculture and land reform programmes or the development of infrastructure such as roads, railways, electricity and water supply etc.

Such a framework, if properly planned, will also provide scientific data for a multitude of projects within the fields of geodesy, geology, geophysics, oceanography, meteorology, ionospheric/atmospheric sciences and earth sciences in general.

The fundamental infrastructure on which all geospatial information is based is, in turn, a sound geodetic reference system. It is within this context that we would propose a multi-disciplinary earth science approach, which is based on Space Geodetic techniques, collocated with other instrumentation (gravimeters, seismometers, magnetometers, tide gauges, automatic weather stations etc.).

The geodetic infrastructure in most countries in Africa is based on a variety of outdated co-ordinate reference frames and systems. Many of the original trigonometrical beacons and marks have either been destroyed or are difficult or impossible to recover in order to carry out new surveys. Neighbouring countries have different and, in many instances, unrelated co-ordinate systems, which make the planning and execution of regional geospatially related projects very difficult indeed.

The determination of the relationship between adjacent co-ordinate systems is a difficult and complex task. Many environmental issues transcend international boundaries requiring cross-border management of river catchment basins, spread of diseases etc. This requires the integration of trans-national spatial information, which will only be possible if all the information is standardised on the same geodetic reference system.

In summary, the establishment of a geodetic network will facilitate the establishment of modern and accurate reference systems, geographical information systems, and will provide the required infrastructure for numerous scientific applications. In the sections following this introduction, we will discuss a GPS network for the SADC region (collocated with other advanced space geodetic systems in certain cases), multidisciplinary scientific applications, as well as student and training opportunities that will enable capacity building and local expertise to ensure sustainability.


Figure 1: Proposed SADC GPS Network. This network will form the southern part of the African Reference Frame (AFREF) and will provide necessary data for surveys and mapping purposes as well as a multitude of scientific applications.

State of the Art: SADC GPS Network

The Southern African Development Community (SADC) is a sub-regional organisation whose member countries are Angola, Botswana, Democratic Republic of Congo, Lesotho, Malawi, Mozambique, Mauritius, Namibia, Seychelles, South Africa, Swaziland, Tanzania, Zambia and Zimbabwe. This project will however extend to include Madagascar. The objectives of SADC cover sectors such as:

  • Trade, Finance and Industry
  • Food, Agriculture and Natural Resources
  • Social and Human Development as well as Special Programmes

These objectives all have direct impact on the SADC macro-and microeconomic health. Most

of these objectives cannot be reached in an optimal way without due care being given to issues of land, where a national surveying and mapping capability is of paramount importance.

Furthermore, the promotion and development of science and technology to enhance competitiveness within the SADC region can only benefit the peoples of Africa if a strong, multidisciplinary scientific component is embedded in the SADC GPS Network. Currently, only South Africa has a network of permanent GPS stations, the other SADC countries rely on antiquated datums and systems, which are not compatible with modern satellite imagery, GIS or land management practice.

State of the Art: Densification of the ITRF

The International Terrestrial Reference Frame (ITRF) consists of the tracking stations and related monuments which constitute the IERS network (Figure 2), together with the station coordinates and their variations in time. This set of points (3-dimensional Cartesian coordinates) realises an ideal reference system, the ITRS. HartRAO is depicted on the worldmap as one of only six global Fiducial sites, where at least three major space geodetic systems are collocated (HartRAO is collocated with VLBI, GPS, SLR and DORIS). It is quite clear that Africa is sparsely populated with geodetic systems. GPS is the most cost effective technique to densify the ITRF in Africa.


Figure 2: The IERS network consists of a set of reference points, determined by space geodetic techniques (VLBI, LLR, GPS, SLR and DORIS). HartRAO has 4 of these techniques collocated on site. The IERS provides reference values for Earth orientation parameters and reference realisations of internationally accepted celestial and terrestrial reference systems.

How can we densify the ITRF in Africa?

  • Installing at least one IGS GPS station in each SADC country. HartRAO, in collaboration with JPL, NOAA, CNES and NRCan has installed 7 permanent GPS stations to date. Five of these are located in South Africa (two of these collocated with tide gauges) and two in other SADC countries; Zambia (2002) and Botswana (2003). During 2003, the HartRAO station in Windhoek (Namibia) will be upgraded in collaboration with GFZ. Two additional IGS stations (collocated with a tide gauge, part of the TIGA network) will be installed at Port Nolloth and East London, on the west and east coast of South Africa respectively, in collaboration with JPL. We need at least another 25 GPS stations in addition to the existing stations.
  • As part of the SADC GPS Network, HartRAO and its collaborators intend to install a tide gauge and GPS system on MarionIsland, which will fill a huge gap in necessary scientific data in the southern ocean area. This will also be a TIGA station, as are SIMO (Simonstown) and RBAY (Richardsbay). High quality tide gauges located at the coast of SADC countries should be equipped with TIGA GPS stations. Where tide gauges are absent, a tide gauge and GPS will be collocated.
  • Conversion of MOBLAS6 to a SLR/LLR station. There is no southern hemisphere lunar laser ranging capability. NASA has indicated that MOBLAS6 will be replaced with an eye-safe, automated SLR2000 system within the next 3-4 years. MOBLAS6 as a NASA asset will then be transferred to South Africa for conversion to an SLR/LLR system. This is very important for fundamental physics and lunar science research. An international working group has been established to support the transformation of MOBLAS6.
  • Collocation of GPS and other geodetic stations with other geophysical and meteorological instrumentation. It is envisaged that each GPS system be collocated with a MET unit to enhance its use for integrated water vapour studies and consequent improved weather prediction and climatological studies.

Scientific and Technical Goals

  • Densification of the International Terrestrial Reference Frame.
  • Crustal Dynamics, e.g. separation of Africa into Nubian and Somalian plates, studies of the East African Rifting zone.
  • Participation in global GPS (International GPS Service) network. This will allow establishment of an ITRF reference point in each SADC country, which will be vital for updating geodetic datums. Adding these stations will in turn improve the products of the IGS and IERS.
  • Monitoring of Tide Gauges as part of the TIGA pilot project of the IGS. This is important as it plays a vital role in determining ocean level and global warming parameters.
  • Collocation with Satellite Laser Ranging (ILRS) and Geodetic VLBI (IVS). This provides technique dependent tests, reference frame ties between the reference systems and enhances IERS products, with consequent global benefits.
  • This project will support the conversion of an existing SLR system (MOBLAS6) to an SLR/LLR capable system. NASA has indicated that it will make MOBLAS6 available for this purpose when they replace it with an automated SLR2000 system. There is no other LLR capable system in the southern hemisphere. New opportunities in fundamental physics and lunar science will be available to the global and SADC scientific community, and will provide a multitude of engineering and scientific spin-offs to the SADC region in terms of research, training, software development, high-tech electronics and student projects. A feasibility study is currently in process to evaluate the conversion and integration of the 0.75 m telescope (located at the South African Astronomical Observatory, Sutherland) and MOBLAS6. This will collocate the GFZ (Potsdam) Superconducting gravimeter with a state of the art SLR/LLR, which will be a crucial aid in determining parameters such as vertical motion due to earth tide, a source of data contamination in SG data. Several SADC universities will be involved in this project, leading to a strengthening of academic cross-border collaboration and technological development.
  • Seismic event and hazard monitoring. A denser network will facilitate monitoring of local crustal dynamics.
  • Assimilation of GPS derived meteorological data into numerical weather prediction models. This will enhance prediction capability and add additional parameters into climatology models.
  • Collocation with other geophysical instruments, e.g. Superconducting Gravimeter at Sutherland. This leads to additional applications; HartRAO/GFZ has an existing project, which determines vertical crustal motion (sub-diurnal and longer term), which can be used to model long wave gravity parameters, which will be useful for the Champ satellite and other future projects.
  • Creation of research groups and users in SADC countries. Once there is an established network providing data, it becomes feasible to initiate (or it will stimulate) the creation of research groups at universities and research institutions in SADC countries. This will in turn have societal, capacity building and local expertise benefits.
  • Contribution towards the Global Velocity Synthesis Working Group (GPSVEL) that will synthesize velocity vectors from international GPS campaigns into a consistent global reference frame. This effort depends on the densification of the ITRF. GPSVEL will provide a benchmark against which geophysical models such as NUVEL1-A can be compared. It will also be a primary input into the Global Strain Rate Map Project initiated in 1998 by the International Lithosphere Program.
  • Monitoring of water levels in the Okavango Delta, a huge wetland in north-eastern Botswana. HartRAO, in collaboration with NRCan, WITS and the Okavango Research Centre (University of Botswana) has installed a permanent GPS station at Maun, on the edge of the Okavango Delta. This station is a prerequisite for successful monitoring of the Okavango water level. Additional permanent or campaign type measurements will provide data about a suspected tilting towards the west of the delta. The Okavango system plays an essential economic role locally, nationally and regionally. The ORC’s main objective is to support the development of sustainable resource use by local communities in the whole river basin in order to promote its long-term conservation.

ILRS: International Laser Ranging Service, IVS: International VLBI Service, TIGA:
GPS at Tide Gauge (pilot project of the IGS)

Existing Infrastructure to Perform Project

  • Global Positioning System (GPS)

HartRAO, in collaboration with JPL, NOAA, CNES and NRCan has installed 7 permanent (International GPS Service (IGS) GPS stations to date. Five of these are located in South Africa (two of these collocated with tide gauges) and two in other SADC countries; Zambia (2002) and Botswana (2003).

  • Tide Gauges (TIGA)

Two of the above mentioned permanent GPS stations, SIMO (Simonstown) and RBAY (Richardsbay), are collocated with tide gauges to form TIGA stations. These stations are part of the Global Sea Level Observing System (GLOSS) network.

  • Very Long Baseline Interferometry (VLBI)

15% of all observing time on the 26m radio telescope at the Hartebeesthoek Radio Astronomy Observatory is currently allocated for international geodetic VLBI experiments.

  • Satellite Laser Ranging (SLR)

The MOBLAS 6 satellite laser ranger at Hartebeesthoek has been operational for three years as part of the IVS network and achieved superior performance level only a year after operational status.

The Hartebeesthoek Radio Astronomy Observatory, a National Facility of the National Research Foundation (NRF) resorts under the Department of Science and Technology. HartRAO, in co-operation and collaboration with its international and local partners, has the capacity and in-house expertise to install, maintain, upgrade, process, archive, administrate and disseminate the components and products of this proposed project.

The facility has ample workshops (mechanical and electronic) to manufacture necessary geodetic monumentation, adjustable self-locating antenna mounts, instrumentation housing, make up cabling, backup power systems etc.

This proposed project is in fact an extension of an existing international effort to bring space geodesy, geology and geophysics to the region in a more meaningful and sustainable way, so as to create benefits and impact of adequate level. We will make available whatever resources are required to meet the implementation and successful continuation of this project as we see it as vital to the region.

The required funds for initial instrumentation, development of the projects, training and implementation should lead to a committed budget from the NRF to ensure sustainability for the whole project in the long-term. Therefore, even though a 50-50 share in funding is sought, the manpower and long-term commitment from the NRF/South African component will be the greater of the shares; additionally the SADC countries will contribute infrastructure and manpower as they can afford.

Furthermore, the objectives and impact of this project will aid sustainable development and supports the NEPAD and SADC initiatives, which in turn is supported by relevant government departments. We feel confident therefore that future resources in terms of manpower, training, student training and exchange initiatives and sustainability will be supported and funded locally.