CORDIS provides links to public deliverables and publications of HORIZON projects.
Links to deliverables and publications from FP7 projects, as well as links to some specific result types such as dataset and software, are dynamically retrieved from OpenAIRE .
Deliverables
The correct description of the land surface, current, past and possible futures, is at the core of the CLD programme. For the present land cover we are quite well served, with both satellite images and processed data sets (such as CORINE for Europe and IGBP_DIS worldwide). To use these data base in climate and atmospheric models they must be mapped onto the land cover classifications within the land surface schemes within these models. Almost universally the land cover schemes have less land cover categories than the land cover databases and there is rarely a simple linkage between the two. The assessment of past changes in land cover and degradation are more difficult that assessing the present. Although there are many local reports of land cover changes the challenge is to provide these in a quantified and regional way. In the Iberian peninsula we have agriculture and land use maps dating back to at least the 1960s. These have been analysed and show small but quantifiable changes. The most dramatic of which has been a large percentage rise in the area of irrigated land (although this remains a small percentage of the overall land surface).
On the regional scale it is demonstrated that the impact of land degradation on the climate of the Iberian Peninsula depends on many factors, the most important being the scale and amount of land degradation, the location of the degraded region and the large-scale atmospheric variations in climate. On this scale we found that there is a positive feedback between the summer precipitation and land degradation.
The strength of this feedback is largest in the northern and central regions where land degradation leads to a reduction of both evaporation and precipitation during the summer. It also leads to an increase in the near-surface minimum temperature. The magnitude of these changes is also determined by the amount of soil moisture produced by the rains of the previous winter - leading to lower evaporation and rainfall in the spring (this is especially marked in the SE region. On the smaller scale, land degradation leads to an increased strength of the sea breeze circulation: both the wind speed and the inland penetration of the sea breeze front increase in a degraded land cover situation. The onset of the sea breeze is earlier in the day and the end of it is later than when no degradation has taken place.
A number of important links between the land surface and Sahelian rainfall have been found. Vegetation has a pronounced effect on precipitation at short time scales; notably sparse vegetation may reduce the amplitude of the diurnal cycle and enhance synoptic activity. On the annual time scale, the seasonality of vegetation appears to delay the onset of the West African monsoon.
The HAPEX_Sahel measurements have been distilled down to provide time series of fluxes and driving data suitable for use in model calibration.
These include:
- Measurements of the energy balance over the main land cover types, both natural and agricultural, in each region were made.
- Detailed measurements of the bare soil patches within the vegetation covers were made. The energy balance of the bare soil turned out to be crucial to the response of the overall landscape.
- Upgraded rain-gauge networks yielded considerable insight into spatial rainfall and soil moisture patterns, especially in the Sahel.
- Extensive site and spatial data sets, often using remote sensing, have been produced which provide an important basis for further research.
The work has illustrated a number of important links between the land surface and rainfall in semi-arid. Vegetation has a pronounced effect on precipitation at short time scales; notably sparse vegetation may reduce the amplitude of the diurnal cycle and enhance synoptic activity. On the annual time scale, the seasonality of vegetation appears to delay the onset of the West African monsoon. These mechanisms highlight the importance of the land surface description in the simulation of current climate by atmospheric models.
A number of important links between the land surface and Sahelian rainfall have been. Vegetation has a pronounced effect on precipitation at short time scales; notably sparse vegetation may reduce the amplitude of the diurnal cycle and enhance synoptic activity. On the annual time scale, the seasonality of vegetation appears to delay the onset of the West African monsoon. These mechanisms highlight the importance of the land surface description in the simulation of current climate by atmospheric models.
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