<div>Introducing Open-Source Tool for Near-Real-Time Global Flash Drought
Monitoring with SMAP</div><div>Vinit Sehgal, Nandita Gaur, Binayak P. Mohanty</div><div>Session:
H126Earth
System Science Results Based on NASA Soil Moisture Active Passive (SMAP)
Satellite Mission Measurements</div><div>The increasing frequency and severity of flash droughts pose a threat to
global food and water security and seasonal climate forecasts. We
introduce a new tool for near-real-time global flash drought monitoring
with SMAP leveraging the footprint-scale thresholds of soil hydrologic
regimes (energy-limited wet phase, moisture limited transitional, and
dry phase) and land-atmospheric coupling strength. We define two
complementary indices based on SMAP soil moisture for measuring
the <i>severity</i>  and the <i>rate of intensification</i>  of drought,
namely, Soil Moisture Stress (SMS) and Relative Rate of Drydown (RRD),
respectively. SMS and RRD are non-linearly combined to provide FDSI
(Flash Drought Stress Index) ─ a composite indicator used for global
flash drought monitoring. Several advantages of FDSI include
non-reliance on long-term soil moisture records, sensitivity to changing
land-surface heterogeneity, land-atmospheric interactions, and evolving
meteorological anomalies. FDSI is extensively validated globally across
multiple timescales (daily, weekly, and monthly) using a suite of
vegetation and meteorological drought indices. We demonstrate the
application of FDSI in the mechanistic evaluation of select recent flash
droughts across the globe (Northern Great Plains in 2017, South Africa
in 2015-2016, and Eastern Australia in 2019-2020), and the onset of the
ongoing (since 2020) heatwave induced drought in the western U.S.
Through this presentation, we introduce the viewers to the open-source
web-based resources for accessing global FDSI estimates and related
geospatial parameters.</div>