Water Availability of São Francisco River Basin Based on a Space-Borne Geodetic Sensor

Abstract

Brazil has recently experienced one of its worst droughts in the last 80 years, with wide-ranging consequences for water supply restrictions, energy rationing, and agricultural losses. Northeast and Southeast Brazil, which share the São Francisco River basin (SFRB), have experienced serious precipitation reduction since 2011. We used terrestrial water-storage (TWS) fields, inverted from the Gravity Recovery and Climate Experiment (GRACE) mission measurements, to assess and quantify the ongoing drought over the SFRB. We found a water loss rate of 3.30 km 3 /year over the time-span of April 2002 to March 2015. In addition, the TWS drought index (TWSDI) showed the extension of the recent drought that has jeopardized the SFRB since January 2012, and which reached its maximum in July 2015 (the end of TWS time series). In this sense there seems to be a linkage between the TWSDI (wetness/dryness) and the El Niño Southern Oscillation (ENSO), in terms of the wavelet coherence, at the semi-annual and biennial bands, suggesting a relationship between the two. While acknowledging that further investigation is needed, we believe that our findings should contribute to the water management policies by quantifying the impact of this drought event over the SFRB.

Evaluation of the SMOS-Derived Soil Water Deficit Index as Agricultural Drought Index in Northeast of Brazil

“…Results revealed that during the 2012-2015 drought the central Sertão region was exposed to drought conditions more severe than other regions of the NEB, which is consistent with find by [13][14][15]45]. It is interesting to indicate that the Sertão region showed high radio frequency interference (RFI) during the analyzed period, leading to SWDIS time series with high proportion of gaps.…”

“…However, 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].…”

“…Severe droughts have caused serious impacts on water supply and agriculture of the NEB, especially during the rainy season [8,15,45]. The main goal of this work is to compare the series of the SWDI calculated with SMOS L2 data with those of the Atmospheric Water Deficit derived from in situ observations, which is used as a reference index.…”

Characterizing Drought and Flood Events over the Yangtze River Basin Using the HUST-Grace2016 Solution and Ancillary Data

“…responsible for the observed TWS variations [7,16,48,49], a cross-comparison was also implemented between GRACE-derived TWS, TRMM-derived precipitation and NCEP/NCAR-derived vertical velocity. As shown in Figure 11, the consistency between the non-seasonal values can also be seen during the 'universal' drought and flood events.…”

Land Water-Storage Variability over West Africa: Inferences from Space-Borne Sensors

“…Studies such as Sun et al [25] and Thomas et al [24] have confirmed TWS as a more dependable means for drought analysis, since it reflects all the combined factors of hydrological changes including human effects. However, the GRACE-derived TWS time series did not cover the desired 30-year period.…”