Analisi di trend climatici e idrologici in Libano: implicazioni in termini di gestione delle risorse idriche

Responsabili di progetto

Luciano Telesca, Amin Shaban

Accordo

LIBANO - CNRS-L- not in force - National Council for Scientific Research of Lebanon

Bando

CNR/CNRS-L 2012-2013

Dipartimento

Terra e Ambiente

Area tematica

Scienze del sistema Terra e tecnologie per l'ambiente

Stato del progetto

Nuovo

Proposta di ricerca

The Mediterranean region, like many regions worldwide, is subjected to the impact of climate change, which is mainly reflected by remarkable decrease in water availability. It is reported that in the Mediterranean, rainfall is now 20% less than at the end of the nineteenth century (Ragab, 2005). Hence, rapid growth in population and industrialization are imposing growing demands and pressures on water sources, leading to an increase of 60% of water demand in the last 25 years. Also, in a relatively short period of time, like that corresponding to one generation, in several countries of the Mediterranean area the picture changed from the relative abundance to relative scarcity of water (Hamdy and Lacirignola 2005). Thus, water shortage is essentially resulted and refereed to as a "drought" phenomenon, which is considered as a creeping phenomenon of natural hazards, negatively reflected on significant economic, environmental, and social aspects.
Lebanon, typical of the Mediterranean region, is characterized by remarkable physical conditions, including mainly its morphological features and climatic regime. It was described as the "water tower of the Middle East" since it had a surplus of water resources. However, this status did not last much longer, thus both the increase in population size in combination with the changing climatic conditions affected the hydrologic regime. Preliminary data analysis shows an obvious turbulence in rainfall regime, whether in rainfall intensity or shifting in the seasonal intervals, as well as the observed increase in temperature by about 1.5 °C. Besides, the volume of water resources has been reduced; hence, the discharge in many issuing rivers has been declined by 60%, and several springs have been dried/ or do not last for long time, in addition to the lowering in water table levels in many boreholes.
The outcome of all these conditions is a shortage in water supply. The built scenarios by UN (1994) showed that human quota of renewable freshwater water in Lebanon will be decreased from 1,900 to 1,100 m3/year between 1990 and 2025.
Studies on this regard have been done, and most of them relied principally to old data, not available in sequential records. However, recent data, mainly on climate, are still missing to build up a comprehensive figure on climatic conditions in the region. Whereas, hydrologic data are often available for different areas. This project will investigate on the climatic and hydrologic trends in Lebanon using the most advanced statistical time series analysis. Hence, available records in combination with new data will be analyzed.
Within this context, the project intends to perform a detailed investigation of the spatial and temporal distribution of climatic and hydrological records in Lebanon, to analyse the drought phenomenon and give a contribution to the management of water resources, which has not found fully satisfactory solutions yet. To reach this aim several statistical time series analysis tools will be used, to study the statistical behaviour and the dynamical features of the Lebanese hydro-climatic time series, in order to improve the knowledge about the dynamics of physical changes in this area and contribute to the evaluation of future climatic and land-cover scenarios. In particular, the use of methods able to reveal scaling in hydrological series are helpful in model applications at different temporal resolutions, because models which are established for smaller scales may be employed at larger scales by simply rescaling the model parameters.
Recent methods, based on the concept of fractal have revealed their potential in getting into insight the time dynamics of non-stationary signals. The detrended fluctuation analysis (DFA) and the multi-fractal-DFA (Kantelhardt et al. 2001) allow to characterize a time series in terms of scaling exponents, dynamical crossovers, persistence, important for a deep understanding of the mechanisms governing such processes. Singular spectrum analysis (SSA) (Vautard et al. 1992), wavelets allow to describe as best as possible nonstationary, noisy and also short time series. Information-based measures, like Fisher Information Measure (FIM) (Vignat and Berher 2003), will be used to get further information on the type of dynamics in Lebanese climatic and hydrological records.
The available resources for the project are:
1) Data from rainfall gauges in several representative sites, which cover the entire Lebanon at different dates.
2) Hydrographs and flow-meters on rivers and springs watercourses to record water discharges measures,
3) Scale-levels to measure water level in lakes and ponds,
4) Remote sensing data (Radarsat, NOAA, MODIS, etc) to monitor snow coverage,
5) Manometers to measure groundwater level in aquiferous rock formations, and water table measures in drilled wells,
6) Equipments and laboratory testing to measure soil moisture,
7) Statistical and time series analysis tools and know-how.
The Lebanese and Italian groups will share their experience and competence in data analysis, and  will carry out the project in terms of knowledge transfer, data and methodologies  sharing for a better understanding of hydrological  processes and climatic trending, acquisition of co-operation procedures and sharing of human resources, to be exploited for a future continuation of joint research/education activities.
The expected results and deliverables of the project are:
1) Processed hydrological and climatic records,
2) Intermediate and final reports on the performed activities and obtained results,
3) Papers submitted to international journals and conferences with the acknowledgement of the CNR-CNRSL agreement,
4) Webpage dedicated to the project,
5) Seminars focused on the topics of the project.

Obiettivi della ricerca

The major goal of the projects is to attain comprehensive and precise trends of climatic and hydrologic data with a deep correlation to water resources management approaches. This can be specified as follows:
1) Investigating the dynamics of hydrological time series measured in Lebanon by means of advanced statistical time series tools and get information about the dynamics in terms of correlation structures, persistence, scaling, crossover phenomena, trends, periodicity;
 2) Identifying correlations among the analysed parameters in order to define climate, land cover/ use and hydrological response interactions;
 3) Analyzing the implications of the findings on the perspectives of water resource  availability and natural hazards occurrence (drought, extreme rainfall, floods);
4) Proposing possible adaptation measures for water resources management in the view of climate change;
 5) Dissemination of preliminary and final results of the project in international conferences, publications, and in a project-oriented internet website.

Ultimo aggiornamento: 07/05/2024