• 'Flash droughts' coming on faster, globa

    From ScienceDaily@1:317/3 to All on Fri Apr 1 22:30:36 2022
    'Flash droughts' coming on faster, global study shows

    Date:
    April 1, 2022
    Source:
    University of Texas at Austin
    Summary:
    Just like flash floods, flash droughts come on fast -- drying
    out soil in a matter of days to weeks. These events can wipe out
    crops and cause huge economic losses. And according to scientists,
    the speed at which they dry out the landscape has increased.



    FULL STORY ==========================================================================
    Just like flash floods, flash droughts come on fast -- drying out soil
    in a matter of days to weeks. These events can wipe out crops and cause
    huge economic losses. And according to scientists, the speed at which
    they dry out the landscape has increased.


    ========================================================================== Researchers at The University of Texas at Austin, The Hong Kong
    Polytechnic University and Texas Tech University found that although the
    number of flash droughts has remained stable during the past two decades,
    more of them are coming on faster. Globally, the flash droughts that
    come on the fastest - - sending areas into drought conditions within
    just five days -- have increased by about 3%-19%. And in places that
    are especially prone to flash droughts - - such as South Asia, Southeast
    Asia and central North America -- that increase is about 22%-59%.

    Rising global temperatures are probably behind the faster onset, said
    co-author and UT Jackson School Professor Zong-Liang Yang, who added
    that the study's results underscore the importance of understanding
    flash droughts and preparing for their effects.

    "Every year, we are seeing record-breaking warming episodes, and that
    is a good precursor to these flash droughts," he said. "The hope and
    purpose [of this research] is to minimize the detrimental effects."
    The research was published in Nature Communications. The study was led
    by doctoral student Yamin Qing and Professor Shuo Wang, both of The Hong
    Kong Polytechnic University.

    Flash droughts are relatively new to science, with the advancement of
    remote sensing technology during the past couple of decades helping reveal instances of soil rapidly drying out. This serves as the telltale sign
    of the onset of a flash drought and can make drought conditions appear seemingly out of the blue.



    ==========================================================================
    As the name suggests, flash droughts are short lived, usually lasting
    only a few weeks or months. But when they occur during critical growing periods, they can cause disasters. For example, in the summer of 2012,
    a flash drought in the central United States caused the corn crop to
    wither, leading to an estimated $35.7 billion in losses.

    In this study, the scientists analyzed global hydroclimate data sets that
    use satellite soil moisture measurements to capture a global picture
    of flash drought and how it has changed during the past 21 years. The
    data showed that about 34%-46% of flash droughts came on in about five
    days. The rest emerge within a month, with more than 70% developing in
    half a month or less.

    When they examined the droughts over time, they noticed the flash droughts happening more quickly.

    The study also revealed the importance of humidity and variable weather patterns, with flash droughts becoming more likely when there's a shift
    from humid to arid conditions. That makes regions that undergo seasonal
    swings in humidity -- such as Southeast Asia, the Amazon Basin, and the
    East Coast and Gulf Coast of the United States -- flash drought hot spots.

    "We should pay close attention to the vulnerable regions with a high probability of concurrent soil drought and atmospheric aridity,"
    said Wang.

    Mark Svoboda, the director of the National Drought Mitigation Center and originator of the term "flash drought," said the advancement in drought- detecting technology and modeling tools -- such as those used in this
    study - - has led to growing awareness of the influence and impact of
    flash droughts.

    He said the next big step is translating this knowledge into on-the-ground planning.

    "You can go back and watch that drought evolve in 2012 and then
    compare it to how that tool did," said Svoboda, who was not part of the
    study. "We really have the stage well set to do a better job of tracking
    these droughts." The study was funded by the National Natural Science Foundation of China and the Hong Kong Research Grants Council.


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


    ========================================================================== Journal Reference:
    1. Yamin Qing, Shuo Wang, Brian C. Ancell, Zong-Liang
    Yang. Accelerating
    flash droughts induced by the joint influence of soil moisture
    depletion and atmospheric aridity. Nature Communications, 2022;
    13 (1) DOI: 10.1038/s41467-022-28752-4 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/04/220401160542.htm

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