Evaluation of aridity indices using SPOT Normalized Difference Vegetation Index values calculated over different time frames on Iberian rain-fed arable land

The objective of this study was to find the best-performing aridity index and time-frame in the Iberian Peninsula characterizing the effect of dryness on agricultural production. To achieve this goal time-series of 5 aridity indices for 1998 October - 2009 December time-period were calculated on a 25x25 km grid, and the closest relationship with plant biomass was determined. Plant biomass was represented by the SPOT-VEGETATION Normalized Difference Vegetation Index (NDVI) satellite data masked out for rain-fed arable land for the period between 1998 and 2009, and also by official yield statistics of Spain and Portugal between 1999 and 2009. Aridity indices calculated for time- frames matching the entire vegetative period resulted in the highest correlation coefficients with NDVI and with the crop yield. There was a difference between the two time frames covering twelve months. In contrast with the calendar year, using the hydrological year (1st October-30th September) ensured a very strong correlation between NDVI data and most aridity indices, with UNEP and Water Deficit aridity indices outperforming the others. Among the shorter time frames of April-October, January-October, and October-June, the latter provided very strong correlation between vegetation, UNEP and Water Deficit indices surpassing Budyko, De Martonne and Thornthwaite aridity indices.

BUSSAY Attila;  TOTH Tibor;  JUSKEVICIUS Valentinas;  SEGUINI Lorenzo; 

2012-12-13

TAYLOR & FRANCIS INC

JRC71040

1532-4982,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC71040,   

10.1080/15324982.2012.694398,