Comparison of vegetation indices to discriminate C. imicola positive and negative sites in the Region of Calabria, Italy
|Project type:||Long Term RTD|
|Time frame:||2006 - 2007|
|Funding agency:||IZS dell Abruzzo e del Molise ‘G. Caporale’|
|Geographic keyword: Europe | Italy | Calabria|
|General keyword: Disease modeling | low resolution remote sensing|
|Specific keyword: Bluetongue|
Bluetongue is an arthropod-borne viral disease of ruminants. All ruminant species - sheep, goats, cattle, buffaloes, antelopes and deer - are susceptible. Of the domestic species, sheep are the most severely affected. Infection in cattle, although of great epidemiological (reservoir) and economical (import ban) significance, is generally sub-clinical. Whilst prior to 2006 the disease will linked to the emerging vector Culicoides imicola, which is currently invading the Mediterranean basin under influence of climate change, bluetongue virus is now also being transmitted by local Culicoides midges in northern Europe.
During the BTCalabria project Avia-GIS investigated the how NOAA and MODIS LR remote sensing data derived predictor variables at different resolutions (250m, 500m) can contribute to modeling the distribution of Culicoides imicola in Calabria. Based on the project outcome following conclusions could be drawn :
- Based on comparison between MODIS LST and meteorological stations it was concluded that for Calabria MODIS is a non-biased proxy for temperature.
- From the profiles and the Fourier harmonics, one can conclude that in all C. imicola positive sites, the vegetation peaks earlier in the year: for both NDVI and EVI the peak of the half yearly variation occurs for positive sites around day 100 (begin March) whilst this is for negative sites around day 220 (begin July).
- The difference in six monthly variation (=amplitude) of vegetation is also greater for positive sites than for negative sites when measured by EVI at the 250 m resolution.
Legend to the figures:
Figure 1: EVI profile discriminating between C. imicola positive and negative sites.
Figure 2: For all positive sites, vegetation peaks earlier than for negative sites.