Remote sensing
The action “Remote sensing” consists of using new satellite imaging technology known as remote sensing. This technology is advanced enough today to provide and ensure that project activities have a complete overview of the Pyrenees mountain regions.
The aim of this action is to prepare and test certain methods and protocols to provide input for preselected indicators in the OPCC project and complete proposed lines of action. Of special focus is the use of satellite image based technology to further actions carried out under the ‘Water’ and ‘Forest’ sections of the project and provide new elements for reflection in actions related to ‘Climate’ and ‘Biodiversity’.
The three topics covered in this transversal section on remote sensing are:
1- specific and concrete tracking of the state of forests; identify places at-risk of decline;
2- track snow cover and water reserves;
3-characterise land cover in high resolution for a recent reference year (2009 or 2010).
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1 – During the first stage, the aim of this action is to analyse the response of forest vegetation to climate change using a series of satellite images of low resolution and high repeatability (MODIS images). These images allow vegetation indices to be mapped, thereby facilitating an indirect measurement of vegetation activity. Comparison with file images also enables a retrospective analysis to be performed of events occurring over the last 10 years. Climate anomalies occurring between 2000 and 2010, and interannual and territorial variability in the Pyrenees, are a particularly suitable base for observing the first significant changes in vegetation due to climate change. The mapping methodology that has been proposed will measure any change in the behaviour of populations, and assist in tracking the response of forest cover over time. The results shall serve as base for an assessment proposal on the vulnerability of the forests and identify risk situations in anticipation of moments when bioclimatic limits are exceeded. This assessment shall define indicators to monitor the state and evolution of vegetation cover throughout the Pyrenees mountain regions for three species of special interest: Beech, Fir, and Scots Pine. The validation of these indicators shall be performed through HF images, field observations, and especially the FORET action carried out under POCTEFA program.
2 – Snow plays an essential role in current hydrological dynamics of the Pyrenean watershed. Yet, snow may be the water cycle stage most exposed to climate change. Therefore, the spatial-temporal dynamic of snow cover, at the interface between climate and hydrology, must be observed and characterised in order to anticipate the effects of climate change on water resources in coming decades. Remote sensing is the only way to frequently observe the variability of snow cover on a scale as wide as the Pyrenean. Snow observation techniques by satellite are now well established, and it is partially possible to characterise the physical properties of surface snow (albedo, texture), estimate the water volume equivalent to snow cover, and even validate hydrological models. This data serves as a base to establish an indicator to characterise the hydrological potential of the snow in the Pyrenees and how climate change may affect its future evolution. From March-June 2012, a campaign shall be carried out combining field measurements and HF remote sensing tracking in order to validate the MF image based method.
3 – Characterisation of land occupation at the territorial level (use of naming conventions suited to the mountain context) is an essential component of an environmental and socioeconomic observatory. These layers of information, in themselves, are key pieces of information that Pyrenean stakeholders (scientists, planners, politicians, etc.) use directly. This action proposes the creation of land occupation maps for the entire expanse on both sides of the mountain range for a recent period (2009 or 2010), based on a series of Landsat (30 meters) and MODIS (250 meters) images, completed and validated in multiple areas by SPOT images (2.5-20 meters resolution).
For each of the three topics, an attempt will be made to complement HF resolution with MF resolution. In fact, MF images (Modis 500 meters…) make it possible to monitor large territories (France + Spain, for example) with great temporal precision (daily, every 10 days) which is indispensable for monitoring certain dynamics (snow, atmospheric variations…). Field data (derived from other OPCC actions, for example) and HF imaging only covers a few test areas, however, they serve to validate and calibrate MF imaging.
The three French regions of the Pyrenees, as well as Andorra and Catalonia, already possess vast expertise in remote sensing and Geographic Information Systems (GIS) in research laboratories and industry. In this respect, work carried out under the action “Remote sensing” fits perfectly into operational assessment of the new possibilities offered by satellite imaging GMES-Sentinelle from the present to 2014.
Action objective
The project intends to use remote sensing technology to better understand and characterize the effects of climate change on:
a) the evolution in the state of forest populations;
b) the evolution of snow cover and water resources;
A sub-action of the remote sensing line of action is transversal and useful for many jobs related to climate change:
c) create a land use map to use as a standardised reference throughout the French-Spanish Pyrenees.
Anticipated results
- use and interpretation of satellite images;
- enhance and assess methods to document information and indicators throughout the Pyrenees;
- enhance transversal indicators of other lines of action (thematic topics) of the OPCC;
- create synthetic maps to be made available on cartographic servers such as CESBIO and/or CTP.
Main stages
1. Establish a database of remotely sensed data for the Pyrenees.
2. Calibrate models and methodology with field data and HF images to validate MF images.
3. Establish benchmark indicators.
4. Analyse results and create a land use map, detect vulnerable areas throughout the mountain chain, and perform a space-time quantification of snow cover.
Climate change indicators (within the framework of this action)
|
Indicator |
Interest |
|
Changes in snow cover across the Pyrenees 2000-present, duration of snow, surfaces covered) |
- Direct indicators of climate change (effect of temperature, precipitation…) |
|
Changes in vegetational cover |
Establish a land use reference map |
| Changes in altitude and phenology for Beech, Scots Pine and Fir species, detect anormalities in growth and decay rates (vegetative growth period, Normalize Difference Vegetation Index) |
- Common concern: forest and biodiversity |
|
Changes in phenology for Pyrenean prairie (vegetative growth period, Normalize Difference Vegetation Index)
|
- Prairies and pastoral activities are one of the strengths of the Pyrenees |
Partners
Work associated with the action shall be carried out by CESBIO, with the collaboration of associated action partners, EI Purpan, CETE SO, IPE, DYNAFOR, GEODE, IDF.
Contact Us
• CESBIO
Jean-François DEJOUX :
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