Abstract
Northeast Brazil (NEB) has recently experienced one of its worst droughts in the last decades, with large losses on rainfed agriculture. Soil moisture is the main variable to monitor agricultural drought. The remote sensing approach for drought monitoring has been enriched with the launch of the Soil Moisture and Ocean Salinity (SMOS) in November 2009 by European Space Agency (ESA). In this work, the Soil Water Deficit Index (SWDI) was calculated using the SMOS L2 soil moisture in the NEB. The SMOS-derived SWDI data (SWDIS) were evaluated against the atmospheric water deficit (AWD) calculated from in situ observations. Comparisons were made at seven-day and 0.25° scales, over the time-span of June 2010 to December 2013. It was found that the SWDIS has a reasonably good overall performance in terms of the drought-weeks detection (skill = 0.986) and capture of the upper soil moisture temporal dynamic (r = 0.652), implying that the SWDIS could be used to track agricultural droughts. Furthermore, SWDIS shows poor performance at sites located in mountains regions affected by severe droughts (−0.10 ≤ r ≤ 0.10). It is also noted that the vegetal cover/use, climate regime, and soil texture have little influence on the AWD-SWDIS coupling.
Highlights
Climate variability and extreme weather events threaten many populations throughout the world [1]
A decoupling very evident was found for values of k from 0 to 6 weeks at Correntina and Fazendas do Piauí. These results reveal an important disconection between the dynamics of the atmospheric system and the soil system at Correntina and Fazendas do Piauí, which seems to be driven by environmental conditions
The agricultural drought index (SWDI), based on soil moisture content derived from the Soil Moisture and Ocean Salinity (SMOS) satellite (SWDIS) for a weekly scale, has been assessed for the first time as a proxy of the superficial soil moisture deficit in Northeast Brazil (NEB)
Summary
Climate variability and extreme weather events threaten many populations throughout the world [1]. Most regions of Brazil have suffered extreme droughts, their impacts are significantly more complex in the semiarid region of Northeast Brazil (NEB) due to its high variability of precipitation in both time and space [8,9,10] It is the world’s most densely populous dry land region [11,12,13]. The 2012/2015 drought was one of the most severe in the recent decades with more than 10 million people affected in the semi-arid region [14] This extreme condition in the northeast was linked to the deficit of rainfall and drying conditions that contributed to reduced soil water availability [15,16]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
