long way in using space technology to mitigate environmental problems and promote sustainable development
The important role of space science and technology for mankind as well as its immediate and continuous impact on sustainable development of various aspects of societies cannot be denied. In recent decades the Islamic Republic of Iran has followed intensive activities on space science and technology and its applications including establishment of research centers and several aerospace institutions at academic level, however, more increasing demand in this respect was felt by the Iranian authorities which led to the final approval of the establishment of new set up for space affairs, on 10th December 2003. It is believed a long and practical step forward not only towards concentrating the efforts in advancing relevant science and technology in effective use of space peacefully but also to enhance cooperation at the international level for this very well deserved goal. Iranian Space Agency covers and supports all the activities in country concerning the peaceful applications of space science and technology under leadership of a Supreme Council of Space chaired by the President of the I. R. Iran. To follow and implement the strategies set by the Supreme Council of Space, Iranian Space Agency affiliated to the Ministry of Communications and Information Technology has the straightforward responsibility.
Nowadays space technology emerges as a vital and important mean for the development in the national and international levels. It has led to advance in various fields of human activities, from management and control of natural disasters to navigation and from monitoring of the natural resources and the environment to tele-health and tele-education. Some examples among of the wealth of the practical activities in using space technology to mitigate environmental problems and promote sustainable development in Iran are given below.
Due to its negative impacts on the country’s economy, people’s life and relevant losses, droughts are considered as the natural disasters that strike the country as well as the neighboring regions frequently. Accordingly the planners and the authorities pay high attention to the studies in this connection leading to promising results for mitigation or control of droughts.
From 1998 to 2002, the country experienced a drought period. Remote sensing as the effective tool in drought studies was applied broadly. A team of specialists in Iranian Space Agency then the Iranian Remote Sensing Center has begun a research program. To assess the Impact of those dry years NOAA data and NDVI method were used to detect the change in vegetation cover of the whole country which the periodical results of the program has been forwarded to related authorities for their use as a tool for informed decision making. According to the findings of the program the annual NDVI decrement from 1998 to 1999 and from 1999 to 2000 is about 14% and 18% respectively.
Secondary impact of this drought period was observed in many wetlands of the country. These wetlands and marshlands which were covered by a considerable amount of waters were completely dried with a very important effects not only on the life of the people living in their peripheral areas but also associated with a serious environmental, social, and economic changes in their nearby areas. The largest of these wetland are two vast marshlands in Iran-Iraq southeastern border which studied by the United Nations Development Program (UNDP). To carry out these studies Landsat data including MSS, TM and ETM+ imageries were used. These data assists to collect valuable multi-temporal information on different parameters involved and to extract information required to establish a GIS-based databank. Generation of DEM by integrating of collected data is part of the approach.
DEM and DSM Generation
Digital Elevation Models (DEMs) and Digital Surface Models (DSMs) are considered as comprehensive and efficient tools for studies using geo-referenced data and information. There are some approaches for DEM and DSM generation. The conventional method applies optical satellite data and maps for DEM and DSM generation.
In a national project supported by the Radio-Communication Office of the Ministry of Communications and Information Technology, a team of specialists from the Technology Application Department of Iranian Space Agency commissioned to generate DEM and DSM of the whole country. Radio-Communication Office needs these DEMs and DSMs for its countrywide project to find and locate the convenient and suitable locations and sites for mounting telecommunication installations and antennas to provide a full coverage of the country for radio communications. The project aiming to set up a position based dataset for telecommunication link design comprised of 3 operational phases as follows.
- DEM and DSM generation using either 1/25,000-scale topographic maps or SPOT stereo pairs,
- Providing clutter/land use- morphological maps using Landsat TM and ETM through interpretation method,
- DEM generation of the whole country and 400 km beyond the borders by using the 1/250,000 scale topographic maps.
Generating the mosaic of the 1/250,000-scale maps of the whole country and the mosaic of the 1/25,000 scale maps of the cities were the supplements to the project that is reportedly carried out with success.
Earthquake and Landslide Impact Investigation
Earthquakes and landslides are the most destructive natural hazards with wide environmental, economic, social and human impacts. Regardless of on-going activities by numerous scientists and specialists around the world, presently main concentration of those involved in this subject, is to prevent the event through different approaches.
One of the basic steps in this regard, is based on mapping of active faults and using the maps prepared to define seismic-prone areas and their zones which itself are used to reduce the probable casualties and financial impacts. Based on this effective approach that is mainly carried out by the Geological Survey of Iran, different earth space data have been used to map basement and unknown faults to be added to previously mapped faults and to update the existing information. Such the information extracted by conventional interpretation techniques, was associated with a huge amount of new findings which were presented in the form of Seismic-Faulting Risk Map. This map itself was later used for production of Seismic Risk Map of Iran to be utilized in National Spatial Plan of the country.
Since commercialization of the radar remote sensing data early in 1990’s, following launch of ERS, RADARSAT and JERS and recently Envisat satellites, continued attention and care has been given in Iran on the use and exploitation of radar data in the study and monitoring of dynamic phenomena. Radar Remote Sensing Group of the Iranian Space Agency (headed by the author of this article) which was established in 1995 is a bi-disciplinary technical-application group that developed and studied different applications of radar remote sensing data thanks to the support mainly made by the European Space Research Institute (ESRIN) affiliated to European Space Agency (ESA). Production of time composites and developing SAR interferometry technique are amongst the new techniques of concern of group, whose work extent goes beyond the country almost in the international level, to complete knowledge and achieving better understanding about the dynamic phenomena of earth features and the mechanisms involved.
Flood Monitoring and Mapping
Almost all of the watershed areas of large and long rivers of Iran are threatened by flooding. Khuzestan Plain with its long and major rivers, Karun, Dez, Marun, Hendijan, Zohreh, Karkheh located in southwest of the country, are supposed to be the most flood-prone areas with numerous infrastructural plans which includes industrial, agricultural, oil and gas, urban development projects. In this regard, multi-temporal Landsat data has been used to extract and gather a considerable amount of information on the parameters required and try to delineate flood-prone areas and their respective use for preparation of flood plain zone map.
In addition to Khuzestan, other areas of Iran particularly in northwest, northeast, center and southeast of Iran face flooding frequently which origin in some cases are natural however the human activity impacts also should not be disregarded. For example deforestation in northeast of Iran and southern forests of Caspian is considered as the main reason for uncontrolled and devastating floods in the area.
A new set of data acquired in the Iranian Space Agency through Terra satellite and its MODIS sensor has added new and valuable information to the existing knowledge about flooding in different areas of Iran.
Parviz Tarikhi is a space science and technology expert, freelance journalist and technical writer based in Iran. Write to him either in care of GeoConnexion or directly at the e-mail address firstname.lastname@example.org .
The findings show that the annual NDVI decrease for Iran from 1998 to 1999 and from 1999 to 2000 is about 14% and 18% respectively. (images source: Iranian Space Agency)
3D mapping supports broadband wireless worldwide; integration of IKONOS image and 1/25,000 topo-map. Tehran dataset visualized as a 3D perspective, showing building detail and proportion information (image source: Iranian Space Agency)
Top image is the coherence image of Bosporus in Turkey generated from the SLCI ERS2-SAR images of 8th June 1995 and 24th December 1998. The middle image is the phase image generated from the same image pair. Mapping the phase image on the coherence image generates the bottom image. Time interval between the image pairs is 1291 days, while the normal baseline of the image pairs is 55.634m and their parallel baseline is 102.390m. According to the fringe number that is countable from the phase image and based on the principles of InSAR technique the tiny displacement of about 1.4-2.5 cm around the Bosporus for 1291 days is estimated that implies dynamic activity present in the area. This is part of the broad study that was made by the Radar Remote Sensing Group of the Iranian Space Agency headed by the author of this article. (images source: Iranian Space Agency)
Flood of Gorgan River in Golestan Province, north of Iran and southeast of Caspian Sea (image source: Ministry of Energy, I. R. Iran)
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