Aridity influence on vegetation patterns in the middle Ebro Valley (Spain): Evaluation by means of AVHRR images and climate interpolation techniques

Abstract

This paper analyses the role of climatic aridity on the spatial differences of vegetation activity and its inter-annual variability in a semi-arid region of the North East of the Iberian Peninsula. The vegetation activity was quantified by means of a monthly Normalized Difference Vegetation Index (NDVI) database from NOAA-AVHRR satellite images (1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000) at 1 km 2 of spatial resolution. Coefficients of variation (CoV) from temporal NDVI series were also calculated. The greater temporal variability of NDVI was recorded in areas with low vegetation cover (steppe and dry farming lands), whereas the lowest temporal variability of NDVI was recorded in the irrigated lands and forests located in the most humid areas. There is a strong and negative relationship between the CoV and the NDVI distribution, but we recorded important differences among land uses. Using maps of annual precipitation and temperature obtained by means of a regression-based method, we studied the influence of aridity on spatial patterns of NDVI and CoV values. The results show the high influence of aridity on the spatial distribution of vegetation activity in the Middle Ebro Valley. Aridity causes a general decrease of NDVI and an increase of CoV. Nevertheless, non-linear ARTICLE IN PRESS www.elsevier.com/locate/jnlabr/yjare 0140-1963/$ -see front matter r (S.M. Vicente-Serrano).relationships between aridity and NDVI and CoV were recorded for the whole of the study area and for the different land uses. The relationships between aridity and vegetation patterns in the semi-arid region studied are discussed in depth. r

An improvement of the Ts-NDVI space drought monitoring method and its applications in the Mongolian plateau with MODIS, 2000–2012

“…Soil moisture could be used to monitor the region drought with water characteristics of strong absorption in shortwave infrared band (Gao et al 2011). Since the 1980s, a number of remote sensing indices (vegetation index, VI), such as, the normalized difference vegetation index (NDVI), the vegetation condition index (VCI) (Kogan 1995), the normalized difference water index (NDWI) (Mcffters 1996), etc., have been developed to investigation vegetation condition and amount or soil moisture for drought monitoring (Tucker et al 1981;Malo and Nicholson 1990;Anyamba and Tucker 2005;Vicente-Serrano et al 2006;Sun et al 2013;Chandrasekar and Sai 2015). However, one single vegetation index could not reflect the surface condition comprehensive.…”

Spatial Statistical Analyses of Global Trends of Ultraviolet B Fluxes in the Continental United States

“…In statistics, the CoV is computed as the standard deviation (σ) divided by the mean (μ) of the time series data (Milich and Weiss, 2000;Vicente-Serrano et al, 2006;Sun et al, 2010) as follows:…”

Comparison of different procedures to map reference evapotranspiration using geographical information systems and regression‐based techniques

“…In addition, aridity is high in this area and extreme droughts are relatively common (Vicente-Serrano and Beguería-Portugués, 2003). The area has recorded a general increase in the severity and temporal variability of droughts (Vicente-Serrano and Cuadrat, 2006a), and this leads to greater uncertainty concerning future water availability and possible negative consequences in terms of the local ecology, social well-being, and economy (Herrero and Aragüés, 1988;Lasanta et al, 2001;Embid, 2003;Vicente-Serrano et al, 2006). For these reasons, it is necessary to obtain good spatial knowledge of the different processes that influence the availability of water resources.…”