Global Cryosphere Watch (GCW) Tropical Cryosphere Workshop

Transcription

1 Global Cryosphere Watch (GCW) Tropical Cryosphere Workshop Morocco specific presentation Meriem ALAOURI CNC/DMN Arusha, 4 July 2017

2 Geographical context Mountains cover more than two thirds of the Moroccan territory and reach significant heights. Several summits cross the 4000 m mark. Djebel Toubkal, the highest peak in the country, is 4,167 meters high. Morocco has four main mountain ranges, and it is the only country in the Maghreb to have a huge mountain range

3 The mountains of the Rif border the Mediterranean Sea. The highest peak of the Rif reaches 2,456 m and its name is Jebel Tidirhine. The Middle Atlas with peaks over 3,100 m such as djebel Bou Naceur or Bouiblane. These summits are experiencing heavy snowfall. The High Atlas which encircles the country from east to west and there is the highest summit the toubkal which culminates to nearly m. Seven watersheds with rainfall operation Geographical context

4 Cryosphere related challenges and concerns Morocco is located in semi-arid Mediterranean region, characterized by a strong spatiotemporal variability of precipitation, combined with a marked seasonality of evaporative demand, leading to a period of high water deficit in summer (Bolle, 2002). Flows are intermittent and river beds are dry for much of the year (Hughes 1995, Pilgrim et al 1988) For Moroccan watersheds, water production is located in the mountains and the presence of snow constitutes a major source of surface water. The water supply of the snowpack is therefore crucial for the water supply of the different consumption sectors, of which irrigated agriculture is often the most important.

5 Cryosphere related challenges and concerns In addition, the climate changes announced in the region (possible decrease in winter precipitation and an increase in drought periods in 2050) will greatly limit the role of water towers played by snow in the Moroccan atlas. There is therefore a real need for better monitoring of the snow cover in the region and a better understanding of the factors governing its variability. Projected future average precipitation change over Morocco to 2050 under scenario RCP8.5

6 Cryosphere related challenges and concerns Major challenges are facing the resource managers: In the short term, agricultural and socio-economic development exert pressure which requires the development of rules of rational use and better seasonal prediction. In order to better assess the inputs to dams throughout the snowmelt season and to distribute water reasonably, it is important to understand the processes and variables that control the hydrological cycle. In the longer term, climate change is a cause for concern not only for total precipitation, but also for solid precipitation, which represents a stockpile stored during the winter and available during low summer.

7 Cryosphere related challenges and Tourism remains marginal in the region with only two ski resorts in Oukaimden and Michlifen. concerns

8 DMN Snow observation network DMN has recently implemented a network of 156 automatic weather stations, of which 19 sites have sensors of ultrasonic transducer type for measuring snow height (Microstep and Cimel brands) Snow depth data are available since 2013 in climatological databases

9 DMN Snow observation network

10 Other Snow observation network Five automatic naval stations acquired under the SudMed project for Understanding the functioning of an ecosystem in a semi-arid region and IMPETUS project (Integrated Approach to Effective Water Resource Management in West Africa) Naval station of Oukaimeden : 3200m

11 Other Snow observation network These 5 stations are implemented in watersheds of Tensift and Draa and managed by the Center for Space Studies of the Biosphere CESBIO in collaboration with the Cadi Ayyad University in Marrakech Nom de la Station Bassins versants Altituude (m) Disponibilité Oukaimeden Tensift Tizi n Touza Draa M Goun Draa Tichki Draa Imeskar Draa

12 Remote sensing observations the monitoring of the spatial and temporal variability of the snow cover remains difficult. In fact the meteorological observation network is not sufficiently dense, particularly in the mountains, for reasons of accessibility. Remote sensing is an alternative to in situ data to extract information on snow cover. It allows regular monitoring during the season with better Time Step (Daily) and for Large Area Snow cover as seen by satellite formosat2

13 Projects / Researches Several scientific researches were conducted by the IRD and the Caddy Ayad University of Marrakech at the level of watersheds, especially the Tensift in collaboration with Moroccan institutions and in close association with Management bodies such as the Tensift Basin Agency and the Haouz Agricultural Office. They are aimed at assessing and forecasting water resources and mainly concern: Observation of snow cover, accumulation and snow melt, estimation of snow melting contribution to river flows Mapping of snow-covered areas of the entire Moroccan mountain range through a series of images from satellite snow products. Analysis of spatial and temporal variations in snow cover across the High Atlas Producing of snow resource indicators through satellite remote sensing, and analyzing the spatial and temporal variability of these indicators.

14 Current researches Evaluation of snow Product MOD10A1 in the Moroccan Atlas and snow cover variability Analysis The objective of this work is to: To understand the spatio-temporal dynamics of the snowpack using data from remote sensing. Characterize snow cover in semi-arid mountains by watershed to produce a mapping of snow surfaces in the Atlas Mountains. MODIS Raw Image Treated Image February 11, 2017

15 Current researches Interannual variation of the snow surface at the Tensift monthly snow surface Variation, Tensift watershed

16 Recommandations Strengthening naval stations network with transmission data in near real time, for better: Knowledge and monitoring of the spatio-temporal dynamics of the snowpack Estimate of the water equivalent of the snowpack Risk management and water resources planning through hydrological models

17 Many thanks