Impacto de los cambios climáticos y demográficos en la vegetación del Geoparque M’goun de la UNESCO en Marruecos (1984-2021)

The primary goal of this study is to identify changes in the vegetation cover of the geopark M’goun region of Morocco, as a sample area to track the Moroccan vegetation status, and the crucial factors that influenced its evolution between 1984 and 2021. The NDVI (Normalized Difference Vegetation Index) method has been used, combined with supervised classification manipulated with the Google Earth Engine and through statistical analysis using R, together with field trips and Google Earth records for supervised classification. The percentage of vegetation density, made up of oak groves, Matorrals, red juniper, and thuja, in addition to a highly biodiverse cover, displays a declining trend. Medium-cover vegetation decreased by 29.5%, dense vegetation decreased considerably by 70.9%, and low-cover vegetation saw a minimal decline of 0.02%. As a result, dense and medium vegetation are being replaced by bare lands or poor-quality cover formed by sparse plants and solitary trees. In addition, precipitation increased slightly, showing an irregular trend, with average minimum and maximum temperatures rising by +1.7°C and +1.4°C, respectively. Furthermore, the population increased by 84.47%. Statistical analysis showed that the most important parameters affecting medium and dense vegetation cover are temperatures (Tmin and Tmax) and population density, as evidenced by the strong correlation between them. In contrast, sparse vegetation cover showed less correlation due to its heterogeneity. However, precipitation played a minimal role in vegetation evolution. Change detection maps revealed a significant negative impact on vegetation cover. This degradation was localized in the southern part of the area of study, where, according to the demographic density map, the majority of the population resides. Deforestation continues due to the lifestyle and economic activities of the local population. These factors, combined with climate change, are exerting large-scale pressure on the forest throughout the geopark.El objetivo principal de este estudio es identificar los cambios en la cobertura vegetal de la región del geoparque M’goun en Marruecos, como área de muestra para monitorear el estado de la vegetación marroquí, y los factores cruciales que influyen en su evolución entre 1984 y 2021. Se utilizó el método del Índice de Vegetación de Diferencia Normalizada (NDVI, por sus siglas en inglés), combinado con clasificación supervisada manipulada mediante Google Earth Engine y análisis estadístico utilizando R, junto con visitas de campo y registros de Google Earth para la clasificación supervisada. El porcentaje de densidad de vegetación, que incluye bosques de roble, matorrales, enebro rojo y tuya, junto con una cubierta altamente biodiversa, tiende a disminuir. La vegetación de cobertura media disminuyó en un 29,5%, la vegetación densa disminuyó considerablemente en un 70,9% y la vegetación de cobertura baja experimentó una disminución mínima del 0,02%. Como resultado, la vegetación densa y de cobertura media está siendo reemplazada por tierras desnudas o coberturas de mala calidad formadas por plantas dispersas y árboles solitarios. Además, las precipitaciones aumentaron ligeramente y tendieron a ser irregulares, con un aumento promedio de las temperaturas mínimas y máximas de +1,7 °C y +1,4 °C, respectivamente. Además, la población aumentó en un 84,47%. El análisis estadístico mostró que los parámetros más importantes que afectan la cobertura de vegetación de cobertura media y densa son las temperaturas (Tmin y Tmax) y la densidad de población, como se evidencia por la fuerte correlación entre ellos. En contraste, la cobertura vegetal dispersa mostró una menor correlación debido a su heterogeneidad. Sin embargo, las precipitaciones jugaron un papel mínimo en la evolución de la vegetación. El mapa de detección de cambios reveló un impacto negativo significativo en la cobertura vegetal. Esta degradación se localizó en la parte sur del área estudiada, donde, según el mapa de densidad demográfica, reside la mayoría de la población. La deforestación continúa debido al estilo de vida y las actividades económicas de la población local. Estos factores, combinados con el cambio climático, están ejerciendo una presión a gran escala sobre el bosque en todo el geoparque

Spatial patterns of Moroccan transhumance: Geoarchaeological field work & spatial analysis of herder sites in the High Atlas Mountains of Morocco

Seit geraumer Zeit, nicht zuletzt unter dem Einfluss des Klimawandels, nimmt das Interesse der Ethnologie an den Methoden einiger Nachbardisziplinen im Sinne der interdisziplinären Zusammenarbeit zu. Hierbei spielen die Geographie und in besonderem Maße fernerkundliche Methoden sowie räumliche Analysen eine herausragende Rolle. Ebenso wie, im Kontext diachroner Analysen, die Methoden der Geoarchäologie zur Erfassung der lokalen Historie. Um diese Forschungsansatze den Studierenden der Ethnologie nahezubringen habe ich Frau Mirijam Zickel gebeten mir ihre Masterarbeit, die von Herrn Prof. Dr. Georg Bareth und Frau Dr. Astrid Röpke betreut und mit dem zweiten Platz des Dr. Prill Preises 2020 der Gesellschaft für Erdkunde ausgezeichnet wurde, in leicht veränderter Form, für meine Reihe zur Verfügung zu stellen. Nach einer allgemeinen Darstellung der Methoden der Fernerkundung zeigt Frau Zickel am Beispiel transhumanter Ait Atta auf deren Sommerweiden im Hohen Atlas, wie durch die räumliche Analyse von Fernerkundungsdaten und unter Einbezug von geoarchäologischen Informationen, Erkenntnisse uber die Aufenthaltsplätze der Nomaden im Sommerlager gewonnen werden können. Hierbei zeigt sich, dass die Viehpferche der Nomaden eine zentrale Rolle für die räumliche und zeitliche Erfassung von Transhumanz im Untersuchungsgebiet spielen können. Weiterhin ist es ihr gelungen, mit unterschiedlichen, einander ergänzenden Methoden der Fernerkundung die ökologische Situation des Gebietes und insbesondere der Pferchstandorte zu beleuchten. Ihre Arbeit eröffnet eine neue Perspektive, um die Mensch-Umweltbeziehung im semiariden Bergland von Marokko zu erfassen

Development of a satellite-based dynamic regional vegetation model for the Drâa catchment

Analysing and modelling land cover dynamic of the vegetation under a changing hydrological cycle inside the semi-arid area resulting from the global climate change are a difficult task. It is important to be able to understand and predict the characteristics and availability of vegetation as result of the global climate. This study was carried out inside the upper and middle Drâa catchment in south Morocco, focusing on the natural vegetation outside rural and agricultural areas. Development of a dynamic regional land cover model is traditionally driven by site specific plant growing parameters or by spatial information from remote sensing (e.g. NDVI). By scaling both approaches to a regional level plant activity can be analysed with the MODIS sensor and interpreted by local measurements. By using signal processing techniques, a double regression approach was developed and tested under the conditions of temporal trends and performance parameters. Completed by a regional adopted vegetation model, important productivity parameters could be extracted. This semi-automatic approach is realized in the conceptual model MOVEG Drâa, bringing together remote sensing, meteorological and other data and techniques. An extensive phenological database was built up by integrating Terra MODIS NDVI time series (2000 until 2008), a vegetation monitoring network and 10 years of meteorological measurements. In order to validate the method a comprehensive field measurement along a North-South transect was established. The results show that a robust point conclusion on vegetation trends and parameters on a statistical significant level is possible. Based on these findings a spatial explicit output was realized by a spatial extrapolation technique considering the annual and intra-annual vegetation trends. Based on the IPCC Scenarios (A1B and B1) a forecast of vegetation activity and productivity was implemented until 2050. MOVEG DRAA is an improvement to the hitherto state of unknown atmospheric-vegetation-relationship for the semi-arid area of southern Morocco. The study reveals that the semi automatic modular model approach is capable of handling the highly variable vegetation signal and projecting further scenarios of environmental changes. The model output will help to refine all models using land cover information (e.g. pastoral modelling), hydrological modelling (e.g. SWAT) and meteorological parameterisations (e.g. FOOD3DK). The output of the MOVEG DRAA model can also built a valuable information source for all kind of land users

Characterisation of snowfall events in the northern Iberian Peninsula and the synoptic classification of heavy episodes (1988-2018)

Historic snowfall events in the northern Iberian Peninsula recorded between 1988 and 2018 are presented and analysed. This study makes use of data collected over a course of 31 years from 105 observation stations. These weather reports describe the temporal and spatial characteristics of five Spanish provinces facing the Cantabrian Sea. The average number of snow events observed per year (as recorded by all 105 stations) was 133, where a maximum of 421 snow events was recorded in 2010 and a minimum of 24 events were recorded in 2002. In addition, the monthly distribution of snow events per day had a maximum of 630 events, (February), with a mean monthly value of 170 snow events. Other features like the distribution of snow events depending on the altitude of each province studied and the corresponding spatial patterns are also shown. Furthermore, the circulation patterns responsible for heavy snowfall in the region were also examined. To carry out this study, we considered the daily patterns at 1200 UTC of the geopotential height at 500 and 850 hPa pressure levels and sea‐level pressure and temperature at 500 and 850 hPa respectively. The synoptic situations were classified based on a principal component analysis coupled with a K‐means clustering, and four groups associated with heavy snowfall events were subsequently identified. The analysis of the daily synoptic patterns showed that a trough was present over the Iberian Peninsula, or close by, and a low appeared over the Mediterranean Sea or Central Europe. The low‐level flow was from the north (N) or northeast (NE) in ~ 85% of the cases and the temperature at 850 hPa pressure level was lower than ‐3°C in ~ 70% of the cases

Mapping the Desertification Process in Southern Morocco Using Remote Sensing Data

Desertification is a problem occurring in arid and semiarid zones all over the world. It is a consequence of mismanagement of the land. Human activities and livestock pressure on such fragile ecosystems lead to a deterioration of the soil by increasing its salinity, lessening its moisture, and covering it with sand and dust. Aerial photographs and satellite images constitute a tool for mapping and monitoring the desertification process. Multispectral data can assist in detecting the indicators of desertification in early stages in order to plan adequate action. The improvement of the resolution of satellite images and the fact that they are available on a periodic basis make the use of these data suitable for mapping the evolution of desert patches at large scales. The green band of Landsat MSS is used in this study. Two images taken, respectively, in 1976 and 1985 and covering the province of Ouarzazate in southern Morocco are used to map the desertification process and its evolution in the region. At the scale used and given the ground resolution of the MSS (80 meters), significant changes were found between the two images. However, changes occurring at scale smaller than 80 meter square were impossible to detect by visual interpretation of this band

Modeling hydrological processes in a semi-arid mountainous catchment at the regional scale

In the Upper Drâa Valley (14,988 km2) on the southern slopes of the Moroccan High Atlas Mountains, a highly variable precipitation and large evaporation losses cause major water availability problems. The combined effect of projected increase in water demand and temperature and a decrease in precipitation poses a major challenge for water managers in the region. To assess the actual state of the hydrological system (1978-2007), but also the impacts of future changes (2000-2049) a conceptual model, adapted to the characteristics of a semi-arid mountainous environment, has been applied. A spatially explicit altitudinal representation, an oasis-irrigation routine, a second linear storage aquifer and a reservoir management module have been implemented in the SWAT model, extending it to SWAT-MAROC (SWAT-Mountainous and Arid Regions Oriented Concept). During the validation period the model performs well on a monthly timescale at the basin outlet (CME: 0.89) and satisfactorily at the two main tributaries Oued Ouarzazate (CME: 0.69) and Oued Dades (CME: 0.62). Furthermore model results are in line with validation data obtained from groundwater, snow and irrigation studies. Nevertheless the model exhibits flaws in representing water availability in groundwater-fed oases and soil water dynamics. Considering the variable sources of uncertainty, especially in arid and mountainous regions, a wide-ranging uncertainty assessment scheme, quantifying and comparing uncertainties with a signal-to-noise ratio, has been developed and applied. Uncertainties from the hydrological model are highest, followed by divergent signals from climate change ensembles, while the downscaling method has only minor effects on model results. It has been shown that climate change effects for the period 2000-2029 are subject to considerable uncertainties and no clear trends could be identified. For the period 2020-2049 the following developments are “likely” according to the IPCC terminology. Despite a decrease in precipitation (-11%) and especially snowfall (-31%), irrigation water availability in the surface water dependent oasis remains high enough (-5%) to sustain agriculture to the current extent. In contrast, water availability at the reservoir is decreasing disproportionately high (-17%). Therefore the potential for riparian conflicts between the Upper Drâa and the Middle Drâa might augment. A further finding is that the reservoir Mansour-Eddahbi is likely to become inoperable due to siltation in the period 2030-2042, dependent on the assumed pathways of socio-economic development.Modellierung hydrologischer Prozesse eines semi-ariden, gebirgigen Einzugsgebietes auf der regionalen Skala Das südmarokkanische Obere Drâatal (14.988 km2), an der Südabdachung des Hohen Atlas gelegen, ist durch eine hohe Niederschlagsvariabilität und starke Verdunstung gekennzeichnet, die bereits heute die Wasserverfügbarkeit beeinträchtigen. Die kombinierte Wirkung des prognostizierten Anstiegs der Wassernachfrage und der Temperatur sowie des Rückgangs der Niederschläge stellen eine große Herausforderung für das Wassermanagement dar. Um den aktuellen Zustand des hydrologischen Systems (1978-2007) zu beurteilen und die Auswirkungen von zukünftigen Veränderungen (2000-2049) zu erfassen, wird ein konzeptionelles Modell verwendet, das an die Eigenschaften der semi-ariden gebirgigen Region angepasst wurde. Dafür ist das SWAT-Modell um eine räumlich explizite Darstellung der Höhengliederung, ein Oasen-Bewässerungs-Modul, einen zweiten Grundwasserleiter und ein Stausee-Management-Modul zu SWAT-MAROC (SWAT – Mountainous and Arid Regions Oriented Concept) erweitert worden. Während der Validierungsphase erzielte das Modell auf monatlicher Zeitskala am Gebietsauslass (CME: 0,89) sowie an den beiden wichtigsten Zuflüssen Oued Ouarzazate (CME: 0,69) und Oued Dades (CME: 0,62) gute bis zufriedenstellende Ergebnisse. Darüber hinaus stehen Modellergebnisse im Einklang mit Validierungsdaten aus Grundwasser-, Schnee- und Bewässerungsstudien. Mängel zeigt das Modell bei der Simulation des Wasserdargebots in grundwassergespeisten Oasen und der Bodenwasserdynamik. Um diversen Unsicherheitsquellen, vor allem in ariden und bergigen Regionen, gerecht zu werden, sind im Rahmen eines umfassenden Bewertungsschemas quantifizierbare Unsicherheiten mit einer Signal-to-Noise-Ratio verglichen worden. Unsicherheiten aus dem hydrologischen Modell sind am höchsten, gefolgt von divergenten Signalen aus den Klimaensembles, während das Downscaling nur geringe Auswirkungen auf die Trends zeigt. Die Auswirkungen des Klimawandels für den Zeitraum 2000-2029 sind mit erheblichen Unsicherheiten behaftet und weisen keine eindeutigen Trends auf. Für den Zeitraum 2020-2049 sind folgende Entwicklungen „wahrscheinlich“ (entsprechend der IPCC Terminologie). Trotz einer Abnahme des Niederschlag (-11%) und insbesondere des Schneefalls (-31%), ist die Bewässerungswasserverfügbarkeit an den Oberflächenwasseroasen hoch genug (-5%), um die Landwirtschaft im aktuellen Umfang aufrecht zu erhalten. Die Wasserverfügbarkeit am Stausee hingegen nimmt überproportional ab (-17%). Deshalb könnte das Konfliktpotenzial zwischen den Wassernutzern des Oberen und Mittleren Drâa zunehmen. Weitere Implikationen für das mittlere Drâatal beinhaltet der Sedimenteintrag in den Stausee Mansour-Eddahbi. Dieser wird voraussichtlich in der Periode 2030-2042 versandet sein.Modélisation des processus hydrologiques dans un bassin versant montagneux semi-aride à l'échelle régional Dans la Haute V allée du Drâa ( 14.988 km2) située au sud du Haut Atlas M arocain, une précipitation très variable et de grandes pertes d' évaporation causent d es problèmes de disponibilité en eau. L'effet combiné projeté de l'augmentation de la demande e n eau et la température et une diminution des précipitations prévues constitue un défi majeur pour les gestionnaires de l'eau dans la région. Pour évaluer l'état actuel du système hydrologique (1978 - 2007), m ais aussi les impacts des changements futurs ( 2000 - 2049), un modèle conceptuel adapté aux caractéristiques d'un milieu semi - aride montagneuse, a été appliquée. Une représentation spatialement explicite d'altitude, une routine d'irrigation des oasis , un sec ond aquifère et un module de gestion des réservoirs ont été mis en œuvre dans le modèle SWAT, en l'étendant à SWAT – MAROC (SWAT – Mountainous and Arid Regions Oriented Concept) . Dans la période de validation , le modèle simule qualitativement bien sur une échelle de temps mensuelle à l'exutoire du bassin (CME: 0,89) ainsi que dans les deux principaux affluents Oued Ouarzazate (CME: 0,69) et Oued Dad e s (CME: 0,62). En outre les résultats du modèle sont en accord avec les données de validation obtenues à part ir d'études des e aux souterraines, de neige et d' irrigation. Néanmoins, le modèle présente des fai b l esse s dans la représentation de la disponibilité en eau dans les oasis alimentées par les eaux souterraines et de la dynamique de l'eau du sol. Les sources variables d'incertitude, en particulier dans les régions arides et montagneuses, ont été comparées dans le cadre d'un système d' évaluation des incertitudes, avec un Signal - to - Noise - Ratio . Les incertitudes de la modélisation hydrologique sont les plus élevé es suivi e s par des signaux divergents des ensembles de changement climatique, tandis que la méthode de downscaling n'a que des effets mineurs sur les résultats du modèle. Il a été démontré, que les effets du changement climatique pour la période 2000 - 2029 sont sujets à des incertitudes considérables et aucune tendance claire n'a pu être identifiée . Pour la période 2020 - 2049 les développements suivants sont "probables" selon la terminologie du GIEC. Malgré une diminution des précipitations ( - 11%) et surtout des chutes de neige ( - 31%), la disponibilité en eau d'irrigation dans l es oasis dépendant des eau x de surface reste assez élevé e ( - 5%) pour soutenir l'agriculture dans la mesure actuelle. En contraste, la disponibilité en eau , au niveau du réservoir est an ormalement en forte baisse ( - 17%). Par conséquent, le potentiel de conflits entre les riverains du Haute et Moyen Drâa pourrait augmenter. Une autre constatation est q ue le réservoir Mansour - Eddahbi est susceptible de devenir inutilisable en raison de l'en vasement dans la période 2030 - 2042

Hydrological assessment of different satellite precipitation products in semi-arid basins in Morocco

In data-sparse regions and in developing countries such as Morocco, where flooding has serious socio-economic impacts, satellite-based precipitation products open new possibilities for monitoring and modelling water resources and floods. The objective of the study is to explore the possibility of using satellite precipitation products (SPPs) with hydrological models (CREST and MISDc) over 9 basins in Morocco. This work provides a hydrological assessment of three SPPs that have demonstrated good capabilities in reproducing precipitation over different basins in Morocco (GPM IMERG – PERSIANN CDR (PERCDR) and CHIRPS). The two hydrological models are coupled with a stochastic calibration method to provide the different ranges of uncertainties. In addition, we investigate the ability of SPPs on reproducing the November 2014 flood event that affected a large part of Morocco. The results indicated that, in calibration, both hydrological models provided similar performance to reproduce river discharge with observed precipitation or PERSIANN CDR. In validation, the combination of the MISDc model with PERSIANN CDR performed the best, notably allowing a good simulation of the flood hydrographs during the November 2014 event. Future analysis of relationships between SPPs, basin properties, and hydrological modelling technique will allow to find the appropriate combination for different application purposes

Snow cover and snow albedo changes in the central Andes of Chile and Argentina from daily MODIS observations (2000-2016)

The variables of snow cover extent (SCE), snow cover duration (SCD), and snow albedo (SAL) are primary factors determining the surface energy balance and hydrological response of the cryosphere, influencing snow pack and glacier mass-balance, melt, and runoff conditions. This study examines spatiotemporal patterns and trends in SCE, SCD, and SAL (2000–2016; 16 years) for central Chilean and Argentinean Andes using the MODIS MOD10A1 C6 daily snow product. Observed changes in these variables are analyzed in relation to climatic variability by using ground truth observations (meteorological data from the El Yeso Embalse and Valle Nevado weather stations) and the Multivariate El Niño index (MEI) data. We identified significant downward trends in both SCE and SAL, especially during the onset and offset of snow seasons. SCE and SAL showed high inter-annual variability which correlate significantly with MEI applied with a one-month time-lag. SCE and SCD decreased by an average of ~13 ± 2% and 43 ± 20 days respectively, over the study period. Analysis of spatial pattern of SCE indicates a slightly greater reduction on the eastern side (~14 ± 2%) of the Andes Cordillera compared to the western side (~12 ± 3%). The downward SCE, SAL, and SCD trends identified in this study are likely to have adverse impacts on downstream water resource availability to agricultural and densely populated regions in central Chile and Argentina