Record-breaking Texas drought more severe than previously thought
New study improves method for tracking drought severity and impact

Date:
October 6, 2021
Source:
University of Texas at Austin
Summary:
In 2011, Texas experienced one of its worst droughts ever. The dry,
parched conditions caused over $7 billion in crop and livestock
losses, sparked wildfires, pushed power grids to the limit, and
reduced reservoirs to dangerously low levels. And according to
a recent study led by geoscientists, the drought was worse than
previously thought.



FULL STORY ==========================================================================
In 2011, Texas experienced one of its worst droughts ever. The dry,
parched conditions caused over $7 billion in crop and livestock losses,
sparked wildfires, pushed power grids to the limit, and reduced reservoirs
to dangerously low levels.


==========================================================================
And according to a recent study led by geoscientists at The University
of Texas at Austin, the drought was worse than previously thought.

The study, published in the Journal of Hydrology,incorporated additional
soil moisture-related data from gravity and microwave sensors on
satellites into a land surface model used by scientists to determine
the severity of droughts.

According to the updated model simulation, severe drought was more
widespread and longer lasting than judged by the U.S. Drought Monitor
(USDM), which is the current standard for designating drought across
the United States.

"The development of technology has allowed us to gain more real-time observation, and this observation can more accurately reflect the ground conditions," said Weijing Chen, the study's lead author and a postdoctoral researcher at the UT Jackson School of Geosciences.

Even though the 2011 drought is now a decade gone, the study results
are important because they show that incorporating new sources of data
related to soil moisture into an existing land surface model can more accurately predict the severity and impact of droughts.

Soil moisture is a key indicator of drought and one of the most important factors when it comes to a drought's impact on agricultural production.



==========================================================================
The USDM incorporates a number of indexes, expertise and data sources
to make its findings, including a hydrological model that gives an
estimate of an area's soil moisture. The UT researchers took their model
a step further by using data assimilation technology to incorporate a combination of real-time satellite measurements related to soil moisture
into their model. The microwave satellite data gave measurements of the
top 2 inches of soil moisture. Adding in the gravity satellite data
gave them soil moisture measurements in the rest of the root zone --
down to about 40 inches.

"Soil moisture in the root zone is very important because it determines
the water supply for vegetation," Chen said.

The USDM releases a map every week that shows what parts of the U.S. are
in drought. It is produced by the National Drought Mitigation Center at
the University of Nebraska-Lincoln, the National Oceanic and Atmospheric Administration and the U.S. Department of Agriculture. Its results
are used to trigger disaster declarations and other federal, state and
local responses.

Chen and her team incorporated the satellite data into an existing land
surface model used by researchers around the world. They then zeroed in
on what that meant for Texas drought from 2010 to 2013.

The updated model simulation and the USDM were in agreement when it
came to the geographical extent of the drought. But the updated model simulation showed that more areas were experiencing more severe drought
than determined by the USDM, particularly in the western half of the
state. The new model also found that widespread drought started in 2010,
much earlier than the USDM.

The results also differ in what was the worst week of the historic
drought. For the USDM it was the week of Oct. 4, 2011, with the most
severe category of drought gripping 87.99% of the state. For the
new model, it was the week of April 5, 2011, with 95.1% of the state experiencing the most severe category of drought.

The researchers said that developing methods for better understanding
droughts is important to Texas as policymakers try to determine how
the state's water resources will be affected by climate change and
population growth.

"Using measurement from space is a clever way to be able to more
realistically detect and monitor droughts," said co-author Zong-Liang
Yang, a professor at the Jackson School.

The study was also co-authored by Chunlin Huang of the Chinese Academy
of Sciences. The research was funded by the Chinese Academy of Sciences
and the UT Austin-Portugal MAGAL Constellation Project.

========================================================================== Story Source: Materials provided by University_of_Texas_at_Austin. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Weijing Chen, Chunlin Huang, Zong-Liang Yang. More severe drought
detected by the assimilation of brightness temperature
and terrestrial water storage anomalies in Texas during
2010-2013. Journal of Hydrology, 2021; 603: 126802 DOI:
10.1016/j.jhydrol.2021.126802 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/10/211006160058.htm

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