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Johannes Gutenberg Universität Mainz (2005)

Climate change in Libya and desertification of Jifara Plain : using geographical information system and remote sensing techniques

Tantawi, Attia Mahmoud Mohamed el-

Titre : Climate change in Libya and desertification of Jifara Plain : using geographical information system and remote sensing techniques

Auteur : Tantawi, Attia Mahmoud Mohamed el-

Université de soutenance : Johannes Gutenberg Universität Mainz

Grade : Doktorgrade 2005

Résumé partiel
The study was arranged to manifest its objectives through preceding it with an introduction. Particular attention was paid in the second part to detect the physical settings of the study area, together with an attempt to show the climatic characteristics in Libya. In the third part, observed temporal and spatial climate change in Libya was investigated through the trends of temperature, precipitation, relative humidity and cloud amount over the periods (1946-2000), (1946-1975), and (1976-2000), comparing the results with the global scales. The forth part detected the natural and human causes of climate change concentrating on the greenhouse effect. The potential impacts of climate change on Libya were examined in the fifth chapter. As a case study, desertification of Jifara Plain was studied in the sixth part. In the seventh chapter, projections and mitigations of climate change and desertification were discussed. Ultimately, the main results and recommendations of the study were summarized. In order to carry through the objectives outlined above, the following methods and approaches were used : a simple linear regression analysis was computed to detect the trends of climatic parameters over time ; a trend test based on a trend-to-noise-ratio was applied for detecting linear or non-linear trends ; the non-parametric Mann-Kendall test for trend was used to reveal the behavior of the trends and their significance ; PCA was applied to construct the all-Libya climatic parameters trends ; aridity index after Walter-Lieth was shown for computing humid respectively arid months in Libya ; correlation coefficient, (after Pearson) for detecting the teleconnection between sun spot numbers, NAOI, SOI, GHGs, and global warming, climate changes in Libya ; aridity index, after De Martonne, to elaborate the trends of aridity in Jifara Plain ; Geographical Information System and Remote Sensing techniques were applied to clarify the illustrations and to monitor desertification of Jifara Plain using the available satellite images MSS, TM, ETM+ and Shuttle Radar Topography Mission (SRTM). The results are explained by 88 tables, 96 figures and 10 photos. Temporal and spatial temperature changes in Libya indicated remarkably different annual and seasonal trends over the long observation period 1946-2000 and the short observation periods 1946-1975 and 1976-2000. Trends of mean annual temperature were positive at all study stations except at one from 1946-2000, negative trends prevailed at most stations from 1946-1975, while strongly positive trends were computed at all study stations from 1976-2000 corresponding with the global warming trend. Positive trends of mean minimum temperatures were observed at all reference stations from 1946-2000 and 1976- 2000, while negative trends prevailed at most stations over the period 1946-1975. For mean maximum temperature, positive trends were shown from 1946-2000 and from 1976- 2000 at most stations, while most trends were negative from 1946-1975. Minimum temperatures increased at nearly more than twice the rate of maximum temperatures at most stations. In respect of seasonal temperature, warming mostly occurred in summer and autumn in contrast to the global observations identifying warming mostly in winter and spring in both study periods. Precipitation across Libya is characterized by scanty and sporadically totals, as well as high intensities and very high spatial and temporal variabilities. From 1946-2000, large inter-annual and intra-annual variabilities were observed. Positive trends of annual precipitation totals have been observed from 1946-2000, negative trends from 1976-2000 at most stations. Variabilities of seasonal precipitation over Libya are more strikingly experienced from 1976-2000 than from 1951-1975 indicating a growing magnitude of climate change in more recent times.

Mots clés : Libyen ; Klimaänderung ; Jifarah ; Desertifikation ;

Annonce (WorldCat)

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Page publiée le 12 mars 2006, mise à jour le 11 janvier 2019