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Niall Dollard

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Vapor Storms threatening people & property
« on: October 20, 2021, 08:43:10 AM »
Jennifer Francis's excellent article on the role of the global iincrease in water vapor fuelling storms/heavy rains.

https://www.scientificamerican.com/article/vapor-storms-are-threatening-people-and-property/

Juan C. García

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Re: Vapor Storms threatening people & property
« Reply #1 on: October 20, 2021, 05:00:44 PM »
Jennifer Francis's excellent article on the role of the global iincrease in water vapor fuelling storms/heavy rains.

https://www.scientificamerican.com/article/vapor-storms-are-threatening-people-and-property/

Quote
The amount of vapor in the atmosphere has increased about 4 percent globally just since the mid-1990s. That may not sound like much, but it is a big deal to the climate system.
...
Unlike most other atmospheric gases, water vapor is not evenly distributed around the globe. Vapor is abundant in the steamy tropical regions straddling the equator. From there, long tendrils of moisture can extend toward the cooler, drier poles along storm tracks, bathing mid- and high-latitude regions in bouts of intense, prolonged precipitation. These rivers of heat and moisture help to balance Earth’s atmospheric energy distribution—and they are creating strong vapor storms along their path.
...
The most worrisome consequence of increasing atmospheric water vapor may be its role in the rapid intensification of tropical storms.
...
Increasing water vapor is not the only impact of climate change on tropical storms, however. Decreasing wind shear—the difference in speed or direction between winds closer to the ground and those high in the atmosphere—also favors storm development because the towers of rising air are less likely to be torn apart. Other variables now being studied include changes in the amount of dust and pollution particles in the air, as well as differences in atmospheric warming at lower and higher altitudes, which affect how fast those bubbles of warm air rise.
...
The threat from increased water vapor extends beyond storms. It is also making summer nights intolerably steamy—more often and in more places.
...
If intense storms and sweltering nights are not troubling enough, water vapor is also making global warming worse. Even though carbon dioxide gets most of the attention, water vapor is by far the most important greenhouse gas in the atmosphere.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

kassy

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Re: Vapor Storms threatening people & property
« Reply #2 on: November 19, 2021, 08:21:47 PM »
It also has effects beyond the tropics as can be seen in the floods thread.

The base principle is simple:

Put simply, water evaporates from the land and sea, which eventually returns to Earth as rain and snow. Climate change intensifies this cycle because as air temperatures increase, more water evaporates into the air. Warmer air can hold more water vapor, which can lead to more intense rainstorms, causing major problems like extreme flooding in coastal communities around the world.

But it doesn’t end there. At the same time that some areas are experiencing stronger storms, others are experiencing more dry air and even drought. Like we mentioned above, as temperatures rise, evaporation increases and soils dry out. Then when rain does come, much of the water runs off the hard ground into rivers and streams, and the soil remains dry. The result? Still more evaporation from the soil and an increased risk of drought.

https://www.climaterealityproject.org/blog/climate-change-impacting-water-cycle

In a warming world we will not have less rainfall but it falls in different places and in different intensities. 24 hours of drizzle to moderate rainfall is ok if weather changes after a couple of days Getting your normal monthly regional rainfall in one day will damage things.
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kassy

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Re: Vapor Storms threatening people & property
« Reply #3 on: November 19, 2021, 08:42:14 PM »
On the interaction between warm and wet:

People living in British Columbia will feel like they have had more than their fair share of climate disasters in 2021. After a record-breaking heatwave in June, the state in western Canada has been inundated by intense rain storms in November. It’s also likely the long-lasting effects of the heatwave made the results of the recent rainfall worse, causing more landslides – which have destroyed highways and railroads – than would otherwise have happened.

In June 2021, temperature records across western North America were shattered. The town of Lytton in British Columbia registered 49.6°C, breaking the previous Canadian national record by 5°C. The unprecedented weather was caused by a high pressure system, a so-called “heat dome”, which sat over the region for several days.

Heat intensified within the dome as the high pressure compressed the air. Dry ground conditions forced temperatures even higher, as there was less water evaporating to cool things down. Although unconfirmed, it’s estimated that the heatwave caused over 400 deaths in British Columbia alone.

The hot and dry weather also sparked wildfires. Just days after recording the hottest national temperature ever, the town of Lytton burned to the ground. The summer’s fires and drought left the ground charred and barren, incapable of absorbing water. These conditions make landslides more likely, as damaged tree roots can no longer hold soil in place. It also ensures water flows over the soil quicker, as it cannot soak into the baked ground.

The huge rain storm which lasted from Saturday November 13 to Monday 15 was caused by an atmospheric river – a long, narrow, band of moisture in the atmosphere stretching hundreds of miles. When this band travels over land it can generate extreme rainfall, and it did: in 48 hours, over 250mm of rain fell in the town of Hope, 100km east of Vancouver.

This much rainfall on its own would probably cause extensive flooding. But combined with the parched soil, the results have been catastrophic. Landslides have destroyed many of the region’s transport links, leaving Vancouver cut off by rail and road. But the bad news doesn’t end there; sediment washed away by these floods could make future floods this winter even worse.

... more

https://theconversation.com/canadas-flood-havoc-after-summer-heatwave-shows-how-climate-disasters-combine-to-do-extra-damage-172187

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morganism

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Re: Vapor Storms threatening people & property
« Reply #4 on: November 25, 2021, 12:12:41 PM »
between 2-3 atmospheric rivers again headed for BC Canada. Level 3 for the first two predicted. Snow first, then rain.

https://cw3e.ucsd.edu/cw3e-ar-update-24-november-2021-outlook/

vox_mundi

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Re: Vapor Storms threatening people & property
« Reply #5 on: February 01, 2022, 08:33:48 AM »
Measuring Climate Change: It's Not Just Heat, It's Humidity
https://phys.org/news/2022-01-climate-humidity.html

Researchers say temperature by itself isn't the best way to measure climate change's weird weather and downplays impacts in the tropics. But factoring in air moisture along with heat shows that climate change since 1980 is nearly twice as bad as previously calculated, according to their study in Monday's Proceedings of the National Academy of Sciences.

The energy generated in extreme weather, such as storms, floods and rainfall is related to the amount of water in the air. So a team of scientists in the U.S. and China decided to use an obscure weather measurement called equivalent potential temperature—or theta-e —that reflects "the moisture energy of the atmosphere," said study co-author V. "Ram" Ramanathan, a climate scientist at the University of California San Diego's Scripps Institution of Oceanography and Cornell University. It's expressed in degrees, like temperature.

"There are two drivers of climate change: temperature and humidity," Ramanathan said. "And so far we measured global warming just in terms of temperature."

But by adding the energy from humidity, "the extremes—heat waves, rainfall and other measures of extremes—correlate much better," he said.

From 1980 to 2019, the world warmed about 1.42 degrees (0.79 degrees Celsius). But taking energy from humidity into account, the world has warmed and moistened 2.66 degrees (1.48 degrees Celsius), the study said. And in the tropics, the warming was as much as 7.2 degrees (4 degrees Celsius).



When judging by temperature alone, it looks like warming is most pronounced in North America, mid-latitudes and especially the poles—and less so in the tropics, Ramanathan said.

But that's not the case, he said, because the high humidity in the tropics juices up storm activity, from regular storms to tropical cyclones and monsoons.

... By the end of the century, with unchecked global warming, the intensity of model projected extreme precipitation can increase by 40 to 60% relative to current extreme precipitation.

With increased Thetae_sfc, the atmosphere is more convectively unstable, as measured by CAPE, and the maximum altitude a convective parcel from the surface can reach, a proxy for cloud top altitudes of convective clouds, is higher.

The increase of CAPE in both observations and projected future climate can partly explain the increased rainfall extremes and severe thunderstorms

... As the global mean Thetae_sfc increases (Fig. 3A), future heat extremes become more severe. The extreme summer daily mean WBGT in different parts of the world (India, northern China, North America, and Europe) can increase by as much as 6 °C by the end of the 21st century compared with the heat extremes in the current climate.

The occurrence frequency of WBGT extremes exceeding 35 °C increases by 14-fold over India and southern China, 30-fold over northern China, 22-fold over North America, and 23-fold over Europe by 2100



Fengfei Song et al, Trends in surface equivalent potential temperature: A more comprehensive metric for global warming and weather extremes, Proceedings of the National Academy of Sciences (2022).
https://www.pnas.org/content/119/6/e2117832119
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― anonymous

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

kassy

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Re: Vapor Storms threatening people & property
« Reply #6 on: February 24, 2022, 12:46:42 AM »
Global warming is amplifying our water cycle – and it’s happening much faster than we expected...

The global water cycle – that is, the constant movement of freshwater between the clouds, land and the ocean – plays an important role in our daily lives. This delicate system transports water from the ocean to the land, helping to make our environment habitable and soil fertile.

But rising global temperatures have been making this system more extreme: water is moving away from dry regions towards wet regions, causing droughts to worsen in parts of the globe, while intensifying rainfall events and flooding in others. In other words, wet areas are getting wetter, and dry areas are getting drier.

Up until now, changes to the cycle have been difficult to directly observe, with around 80 per cent of global rainfall and evaporation happening over the ocean.

But a new UNSW-led study, published today in Nature, has used changing patterns of salt in the ocean to estimate how much ocean freshwater has moved from the equator to the poles since 1970. The findings show that between two and four times more freshwater has moved than climate models anticipated – giving us insights about how the global water cycle is amplifying as a whole.

“We already knew from previous work that the global water cycle was intensifying,” says lead author of the study Dr Taimoor Sohail, a mathematician and postdoctoral research associate at UNSW Science.  “We just didn't know by how much.

“The movement of freshwater from warm to cold areas forms the lion’s share of water transport. Our findings paint a picture of the larger changes happening in the global water cycle.”

The team reached their findings by analysing observations from three historical data sets covering the period 1970-2014.

But instead of focusing on direct rainfall observations – which can be hard to measure across the ocean – they focused on a more unusual aspect: how salty the water was in each ocean area.

"In warmer regions, evaporation removes fresh water from the ocean leaving salt behind, making the ocean saltier,” says co-author Jan Zika, an associate professor in the UNSW School of Mathematics and Statistics.

“The water cycle takes that fresh water to colder regions where it falls as rain, diluting the ocean and making it less salty.”

In other words, the water cycle leaves a signature on the ocean salt pattern – and by measuring these patterns, researchers can trace how the cycle changes over time.

The team estimate that between 1970 and 2014, an extra 46,000-77,000 cubic kilometres of freshwater was transported from the equator to the poles than expected – that’s around 18-30 centimetres of freshwater from tropical and sub-tropical regions, or roughly 123 times the water in Sydney Harbour.

“Changes to the water cycle can have a critical impact on infrastructure, agriculture, and biodiversity,” says Dr Sohail. “It’s therefore important to understand the way the climate change is impacting the water cycle now and into the future.

“This finding gives us an idea of how much this limb of the water cycle is changing, and can help us improve future climate change models.”
 
...

https://www.eurekalert.org/news-releases/944176

Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.