Extreme rainfall events are connected across the world

Posted: January 30, 2019 by oldbrew in climate, Forecasting, modelling, research, waves, weather
Tags: ,


We’re told there are patterns which ‘appear to be created by Rossby waves – wiggles in fast-flowing currents of air high in the atmosphere, known as the jet streams.’

An analysis of satellite data has revealed global patterns of extreme rainfall, which could lead to better forecasts and more accurate climate models, reports Phys.org.

Extreme rainfall—defined as the top five percent of rainy days—often forms a pattern at the local level, for example tracking across Europe.

But new research, published today in Nature, reveals that there are also larger-scale global patterns to extreme rainfall events.

These patterns connect through the atmosphere rather than over land—for example, extreme rainfall in Europe can precede extreme rainfall in India by around five days, without extreme rain in the countries in between.

The research, led by a team at Imperial College London and the Potsdam Institute for Climate Impact Research in Germany, could help better predict when and where extreme rainfall events will occur around the world. The insights can be used to test and improve global climate models, leading to better predictions.

The study additionally provides a ‘baseline’ for climate change studies. By knowing how the atmosphere behaves to create patterns of extreme rainfall events, scientists will be able to gain new insights into changes that may be caused by global warming.

Lead author Dr. Niklas Boers, from Potsdam Institute for Climate Impact Research and the Grantham Institute—Climate Change and Environment at Imperial, said: “Uncovering this global pattern of connections in the data can improve weather and climate models.

This is especially true for the emerging picture of couplings between the tropics and the European and North American regions and their consequences for extreme rainfall.

“This finding could also help us understand the connections between different monsoon systems and extreme events within them. I hope that our results will, in the long term, help to predict extreme rainfall and associated flash floods and landslides in northeast Pakistan, north India and Nepal. There have been several such hazards in recent years, with devastating consequences in these regions, such as the 2010 Pakistan flood.”

To find patterns in extreme rainfall events, the team developed a new method rooted in complex system theory to study high-resolution satellite data of rainfall.

Continued here.

Comments
  1. MrGrimNasty says:

    Potsdam and Grantham, haha hahah ha ha ha hahah ah………

  2. oldbrew says:

    a new method rooted in complex system theory

    Or was it the jet stream?

    The results from this ‘complex network’ model, analysed using our understanding of the motion of the atmosphere, revealed a possible mechanism for how the events were connected. The patterns appear to be created by Rossby waves—wiggles in fast-flowing currents of air high in the atmosphere, known as the jet streams.

    Read more at: https://phys.org/news/2019-01-extreme-rainfall-events-world.html
    – – –
    Extreme 2010 Russian Fires and Pakistan Floods Linked Meteorologically 08.30.11

    Two of the most destructive natural disasters of 2010 were closely linked by a single meteorological event, even though they occurred 1,500 miles (2,414 km) apart and were of completely different natures, a new NASA study suggests.
    . . .
    A Rossby Connection

    The atmosphere, gaseous and transparent, may not seem like a fluid, but that’s precisely how the thin layer of air encasing the planet behaves. As Earth spins on its axis, huge rivers of air — scientists call them Rossby waves — meander around the globe in a westerly direction. Currents in the center of these waves form the jet streams, fast-moving columns of air that push weather systems from west to east.

    https://www.nasa.gov/topics/earth/features/asia-fire.html
    – – –
    Frozen jet stream links Pakistan floods, Russian fires [2010]

    https://www.newscientist.com/article/mg20727730-101-frozen-jet-stream-links-pakistan-floods-russian-fires/

  3. Curious George says:

    Did they find any predictable patterns, or are they stuck with unpredictable patterns?

  4. oldbrew says:

    From the abstract:

    We find that the distance distribution of significant connections (P < 0.005) around the globe decays according to a power law up to distances of about 2,500 kilometres.
    . . .
    We show that extreme-rainfall events in the monsoon systems of south-central Asia, east Asia and Africa are significantly synchronized. Moreover, we uncover concise links between south-central Asia and the European and North American extratropics, as well as the Southern Hemisphere extratropics.
    . . .
    Our results provide insights into the function of Rossby waves in creating stable, global-scale dependencies of extreme-rainfall events, and into the potential predictability of associated natural hazards.

    https://www.nature.com/articles/s41586-018-0872-x

  5. hunter says:

    Two extremely disreputable institutions claiming that they have uncovered evidence supporting what they have been found wrong about many times.

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