Integrated system for monitoring and drought risk analysis in Romania.

Poenaru, Violeta Domnica ; Savin, Elena ; Mihailescu, Denis 等

1. INTRODUCTION

The enormous damage caused by drought has determined international organizations to act on various levels: political, research, management activities and humanitarian aid. The UN has prepared the United Nations Convention to Combat Desertification (UNCCD) and adopted a global action plan in 1997. FAO supplies information, expert advice and assistance, in particular to developing countries, in order to help them ensure the necessary food for their populations. Joint Research Center prepares agro-meteorological forecasts and derivative products based on satellite images at high spatial resolution, covering the entire Europe. Scientific research has shown that various land surface states (i.e surface soil moisture, land surface temperature, albedo) can efficiently be monitored from space platforms.

At an international level, drought monitoring systems are still based on classical methods of processing field data and culture models, supplying information for irrigation planning. By atmospheric forcings and land surface parametrization, macroscale hydrological and atmospheric circulation models have the ability to simulate soil moisture in the root zone (Liang et al., 1994), which could be used as drought indicators.

At a national level, the Romanian Ministry of Environment and Sustainable Development and the Romanian Ministry of Agriculture and Rural Development have initiated the preparation of a national management strategy in case of drought.

In this context, it is necessary to create an integrated system for early warning, monitoring and analysis of the drought risk (SIAT) on the Romanian territory, combining satellite products and modelling approaches so that the reliability of hydrological and weather forecasts can be increased and more accurate prediction information can be made.

2. METHODOLOGY

Based on the Romanian experience gained from the Arges River basin studies which combined temperature indicators with vegetation condition indices for the drought monitoring (Kianicka et al., 2007), an integrated system for early warning, monitoring and drought risk analysis is developed as an interactive system which provides information in real time on the basis of meteorological, hydrological and agricultural drought research features and of the Romanian users requirements.

The first stage is to establish system's architecture. The user's interface showed in Fig. 1 is acquired through WMS (Web Map Service) system comprising client and server application components integrating in-situ and satellite data with numerical modelling for thematic map products able to produce complex mapping, either for basic or for assessment user procedures. This system would allow using the existing databases which respect to the INSPIRE European Directive.

The system designing and implementation involve a distributed architecture using the newest Web technologies so that the information flows between the various types of data (maps, analysis, charts and synthesis). The front end graphical interface is determined by the interaction between users and their requests (De Bernardinis, 2007) (Fig. 2). The functional decomposition of the system foresees:

* access gateway, which allow the users to know and chose available services, to select possible alternative and to obtain the service;

* end users (decision- making factors);

* the basic component, maps, delivered to users together with an interpretation report, prepared by experts;

* quality control service component.

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The research is focused on operational system achiving which integrates early warning, monitoring and drought risk analysis in the Romania's regions by access to real time and archive in-situ data and information, access to data and information produced by other European services and value added products. For the added products have been identified reference maps and drought damage assessment maps.

Reference maps are maps derived from pre-existent data or obtained by pre-event simulations containing cartographic information as well information about climate change, agricultural practices, surface soil moisture, main infrastructure and networks, completed with DEM information and combined in a GIS environment by moving from the 1:100.000 to the 1:25.000 scale.

Assesment maps are maps directly derived from in-situ data and satellite images acquired during the crisis or indirectly obtained through numerical modeling and comparation between post crisis and drought archive information, provind information about location, level of hazard and damage in a scaling moving from detailed scales (1:10.000-1:25.000) and overview scales (1:50.000- 1:25.000).

The second stage of research activity is focusing on the satellite techniques, climate numerical modeling, agrometeorology, plants physiology and drought risk mapping for early warning drought (Fig. 3).

The main requirements for based-space observation are range resolution (from medium to VHR) and spectral resolution (visible and IR). Satellite data (NOAA AVHRR, MODIS, MERIS, LANDSAT, MSG, SPOT, ENVISAT and TerraSAR), received in near-real time or downloaded from international databases (EOS NASA Gateway, KALIDEOS, European Space data base) are geometrically and radiometrically corrected, integrated in a GIS environment and processed together with land use/land cover information and with climate numerical models results.

NOAA images are used for computing the Normalized Difference Vegetation Index (NDVI), the Water Supplying Vegetation Index (WSVI) and the brightness temperature (BT) which is converted to the Vegetation Condition Index (VCI) and the Temperature Condition Index (TCI). The differences in TCI values and their spatial distribution give information where and when the drought is started and how intensive it is (Jain et al., 2009; Wan et al., 2004). The research also demonstrated that backscattering coefficient extracted from ERS2 / RADARSAT1 data characterises surface soil moisture condition and can be used for drought detection and mapping (Prevot et al., 2003).

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In-situ data can play a crucial role in the emergency situations allowing a global collection of high precision ground control points and ad hoc collected information to support the analysis of imagery.

Thus, the early warning is acquired from satellite data processing and analysis, regional climate modeling and in-situ data. The regional climate model provides estimates of the rainfall and thermal regimes, one season, one month and 3 days in advance.

Actually, the system is in implementation phase; it was developed the user's interface, the strategy and technical coordination. The future researches consist in algorithms elaboration, processing methods, statistical analysis of satellite images, the regional climate model, system application, implementation and verification.

3. CONCLUSION

The system allows forecasting meteorological drought with one year/season, based on regional climate simulations and agricultural drought with 3-6 weeks in advance and on the statistical analysis of the multi-temporal series of satellite images.

Also, the system allows the assessment of drought risk and early warning, the rapid, regular and very low cost assesment of the areas impacted by drought, the intensity, spatial dynamics and evolution in time. Immediate access to information of decision-making factors and of a high number of users represents a permanent benefit, due to the fact that the impact of drought varies throughout the year and will allow taking measures for rapid management actions and consequence mitigation.

4. REFERENCES

De Bernardinis, B. (2007). GMES Fast Track Emergency Response Core Service. Strategic Implementation Plan, final version, 2007

Jain, S.K.; Keshri, R.; Goswami, A.; Sarkar, A. & Chaudhry, A. (2009). Identification of drought- vulnerable areas using NOAA AVHRR data, International Journal of Remote Sensing, vol 30, pp 2653-2668, ISSN: 0143-1161, January 2009

Kianicka, J.; Savin, E.; Flueraru, C. & Craciunescu, V. (2007).Remote Sensing Data Analyses for the Study of Drought, Proceedings of GIS Ostrava 2007, ISSN 1213 239x, 8 pp, Ostrava 2007

Liang, X.; Lettenmaier, D.; Wood, E. & Burges, S.J. (1994). A simple hydrologically based model of land surface water and energyfluxes for general circulation models, Journal of Geophysical Research, pp 14415-14428

Prevot, L.; Poenaru, V. D. ; Voicu, P. ; Vintila, R.; DeBoissezon H. & Pourthie, N. (2003). Surface soil moisture estimation from SAR data over wheat fields during the ADAM project, Geoscience and Remote Sensing Symposium, 2003. IGARSS '03. IEEE International, 21-25, Volume: 4, pp 2885- 2887; July 2003

Wan, Z.; Wang, P. & Li, X. (2004). Using MODIS Land Surface Temperature and Normalized Difference Vegetation Index products for monitoring drought in the southern Great Plains, USA International Journal of Remote Sensing, vol 25, ISSN: 0143-1161, pp 61-72, January 2004