«Desertification and Drought Monitoring in Arid Tunisia based on Remote Sensing Imagery» Research Undertaken & Case-Studies.

Transcription

1 «Desertification and Drought Monitoring in Arid Tunisia based on Remote Sensing Imagery» Research Undertaken & Case-Studies EU COST Action September 2015, Antalya Turkey Bouajila ESSIFI INSTITUT DES REGIONS ARIDES (IRA), TUNISIA Bouajila ESSIFI Environmental Remote Sensing, Ph.D. Candidate INSTITUT DES REGIONS ARIDES (IRA) TUNISIA

2 RSDTGBA T U N I S I A i n N O R T H A F R I C A TUNISIA Arid and Semiarid regions: The dry prone areas cover almost more than 4/5 the total area where desertification related problems are of major importance.

3 G E O G R A P H I C & C L I M AT I C C H A R A C T E R I S T I C S Longitude: 7 and 12 E Latitude: 32 and 38 N Area: km² Climate Heterogeneity: 2 opposite climate domains: Mediterranean (temperate humid), Sahara (arid tropical) Coastline spans: 1300 km, 75% suffers from aridity and drought, Annual rainfall: Northwest: mm. South:150 mm. A strong variability: After 1900: 20 Droughts and 14 Floods,

4 G E O - I N F O R M AT I C R E L AT E D A C T I V I T I E S O F I R A The INSTITUT DES RÉGIONS ARIDES (IRA), created in 1976, has been assigned the main mandates of: Conducting research on natural resources management and combating desertification Contributing to capacity building in drylands related topics Providing expertise and assistance for development agencies operating in the dry areas.

5 G E O - I N F O R M AT I C R E L AT E D A C T I V I T I E S O F I R A A specific program on desertification surveillance by combining RS tools to field investigation. Natural resources and desertification surveillance at different spatial and resolution scales Socioeconomic interactions between local population and their environmental landscapes Monitoring of wildlife and endangered animal species Geomaticbased tools for decision making in drylands assessment and development

6 I R A I N T E R N AT I O N A L C O O P E R AT I O N P R O J E C T S : Desertification Observatories funded by the Swiss Cooperation in collaboration with OSS and ROSELT

7 I R A I N T E R N AT I O N A L C O O P E R AT I O N P R O J E C T S : A Surveillance System for Assessing and Monitoring of Desertification (DeSURVEY) funded by the EU

8 I R A I N T E R N AT I O N A L C O O P E R AT I O N P R O J E C T S : LADA Land Degradation in Drylands funded by FAO

9 I R A I N T E R N AT I O N A L C O O P E R AT I O N P R O J E C T S : Desertification Mitigation and Remediation of Land (DESIRE) funded by the EU

10 N AT I O N A L C E N T E R S F O R S PA C E T E C H N O L O G Y 1988: CNCT, The National Remote Sensing Center Develeop capacities at national level, Coordinate and execute national programs on space technology, Provide technical advisory services related to space infromation, training and education opportunities in Space technology, Enhance the regional and internatinal cooperation. 1990: CRTEAN, The North African States Regional Center for Remote Sensing Promote RS, GIS, mapping and their applied activities, Ensure a useful and efficient complementarity in the above fields for the benfit of its member statesand associated members.

11 D R O U G H T M O N I T O R I N G : A H I G H P R I O R I T Y F O R T U N I S I A Drought is a complex natural phenomenon of climate (Wilhite, 2005): A period of lower than average rainfall, Linked to a deficit of water resources availability covering a large geographic area and which extends over a relatively significant period (Rossi, 2000). Droughts impacts depend on meteorological conditions, land surface and ecosystem type, and social and economic circumstances. Preparedness for drought forms an important part of national environmental policies. TUNISIA, has limited institutional and technical capacity to prepare for a drought and to mitigate its impacts. Insufficient readily available information on drought onset and development for agencies and for the general public.

12 P R O B L E M AT I C R AT I O N A L E Edaphic / Climatic Contrainsts Droughts / Erosion Anthropogenic Impact Croplands / Overgrazing ARID & SEMIARID TUNISIA Quantitative Degradation Reduction of Area Qualitative Degradation Biodiversity Loss

13 ARID TUNISIA: B I O P H Y S I C A L A S P E C T S Precarious climate tightly linked to aridity. Degraded soil resources and water resources. Steppic rangelands with sparse vegetation

14 ARID TUNISIA: B I O P H Y S I C A L A S P E C T S Overexploitation Favorising Desertification Processes Dry Farming Desertification Overgrazing Extensive Livestock

15 E A R T H O B S E R VAT I O N S : A N A S S E T Environmental Change is defined by its landscape consequences, and it is these consequences that have to be detected and quantified using space data. Environmental Change can only be inferred from remote measurements of the spatial and temporal dynamics of landscape attributes. -R.D. Graetz (1996) Detection and Monitoring must be based on Landscape Functions that are Associated with Land Degradation Status Biological Productivity, Soil Resources, Efficiency of Water & Energy Use

16 S AT E L L I T E O B S E R VAT I O N S Consistency with Desertification Process Sufficiently large time window for observation steps (i.e. 5 year integration periods) to avoid impact of exceptional situations Sufficiently long time intervals between assessment steps (i.e., 10 years) to allow for recordable changes in landscape functions applicable to both natural and agricultural landscapes (annual averages vs. seasonal peaks of landscape functions) Forecasting Capacities

17 S AT E L L I T E O B S E R VAT I O N S

18 A S P E C T S O F T H E A D O P T E D A P P R A O C H RS Times-Series Synoptic - Repetitive - Selective Socioeconomic Data GIS Fieldwork Inventory Assessment Surveillance Knowledge Modelling Management LU/LC Classification Discriminate Hotspots of Change Synthesis in terms of Tendencies DEGRADATION STABILITY AMELIORATION

19 O V E R A L L O B J E C T I V E S To assess land degradation in Southern Tunisia natural regions (1984 to 2010) using RS timesseries (Landsat, AVHRR, MODIS ) and higher resolution for hotspots (SPOT, GEOEYE, IKONOS...), To develop a surveillance system that can de used to monitor and diagnose desertification, vulnerability of eco-agricultural systems relative to desertification ( vulnerability is land degradation). To contribute to strengthen the necessary scientific knowledge for the future orientation of the sustainable Development Strategy at national level. To establish the relationships between degradation processes, natural dynamics ecosystem, and human activities.

20 M E T H O D O L O G Y & S T U D Y F L O W C H A R T Bibliographical Review Data Preprocessing: Radiometric & Atmospheric Calibrations of LANDSAT - MODIS - AVHRR Image Enhancement: Photo-interpretation Decadal Image Classification: LANDSAT Geostatistics: TimeStats Accuracy Assessment Land Cover / Land Use Maps GIS Integration: Change Detection Ancillary Data Ground Truth Analysis & Discussion of Results Conclusion

21 M E T H O D O L O G Y & S T U D Y F L O W C H A R T ( C o n t i n u e d ) LANDSAT TIME-SERIES Assessment / SPACE Geostatistics Landcover Classification Modelling / TIME Map of ASSESSMENT Change-maps of Land Processes Map of MONITORING CHARACTERIZATION OF DEGRADATION/DESERTIFICATION HOTSPOTS DESERTIFICATION SYNDROME: DESCRIPTION OF ARCHETYPICAL, CO-EVOLUTIONNARY PATTERNS OF HUMAN NATURE INTERACTIONS

22 L A N D C O N D I T I O N I N T H E M A G H R E B ( ) DEL BARRIO et al. (2010) 2dRUE APPLICATION, (DeSurvey Project) Input Data: NDVI monthly images ( ) Source: SPOT VEGETATION NDVI data, (VITO, 2005): Dekadal NDVI data is obtained in a geographic projection with spatial resolution of degrees

23 L A N D C O N D I T I O N I N T H E M A G H R E B ( ) DEL BARRIO et al. (2010) 2dRUE APPLICATION, (DeSurvey Project) Land actively degrading along the last 10 years is very scarce: 7000 sq.km. Land static with no trend in long or short term is very abundant: sq.km. Hypothesis: Active degradation took place before the analysis period, and a reason for so much static land is that it is already very degraded,

24 L C L U I N S O U T H E R N T U N I S I A ( ) Typology of hydrological years from 1969 to 2012 (Beni-Khedache Station): MOURTALA et al. (2013) - AFROMAISON PROJECT Pourcentage of normality (mm): PN = (Pi/Pm)*100 With Pi (mm): annual rainfall et Pm: average rainfall of years (1969 à 2012), Based on year classification: Humid: PN [ 110;+ ], Normal: PN [ 80;110], Moderately Dry: PN [ 55;80], Very Dry: PN [0;55]

25 L C L U I N S O U T H E R N T U N I S I A ( ) MOURTALA et al. (2013) - AFROMAISON PROJECT

26 L C L U I N S O U T H E R N T U N I S I A ( ) MOURTALA et al. (2013) - AFROMAISON PROJECT

27 L C L U I N S O U T H E R N T U N I S I A ( ) MOURTALA et al. (2013) - AFROMAISON PROJECT

28 L C L U I N S O U T H E R N T U N I S I A ( ) MOURTALA et al. (2013) - AFROMAISON PROJECT

29 L C L U I N S O U T H E R N T U N I S I A ( ) MOURTALA et al. (2013) - AFROMAISON PROJECT

30 L C L U I N S O U T H E R N T U N I S I A ( ) MOURTALA et al. (2013) - AFROMAISON PROJECT

31 D R O U G H T M O N I T O R I N G : O N G O I N G Q U E S T Perspectives: Data acquisition and processing, Statistical modelling, LC-LU mapping. Bring out results that may explain: Desertification syndrome concept: Exploitation - Regional/Local Analysis, Retrospective evaluation of the effects of changing socioeconomic boundary conditions on development and current state of natural resources in Southern Tunisia.

32 Bouajila Essifi Eremology & Combating Desertification Lab. Institut des Regions Arides (IRA) Medenine 4119 Tunisia THANK YOU