In simple terms, the drizzle problem refers to the tendency of large-scale climate models to overlook smaller-scale atmospheric factors that cause routine storms to deliver less or more precipitation than average. These models more often underestimate precipitation intensity. For instance, they might anticipate light drizzles instead of actual torrential downpours. This reduces their usefulness, especially as extreme precipitation occurs ever more frequently with climate change.

The solution to the drizzle problem, contends new research from Columbia University (New York) climatologists, relies on accounting for how clouds move and interact with one another to affect rainfall. However, this is difficult for two reasons. For one, the interplay between cloud organization and precipitation during a storm occurs on scales too small for most climate models to capture. For another, it requires something that has not existed until now: a quantitative measure that can accurately represent cloud organization.

A recent study published in the Proceedings of the National Academy of Sciences describes how a combination of machine learning and artificial intelligence can help solve the drizzle problem by addressing both issues.

“Our findings are especially exciting because, for many years, the scientific community has debated whether to include cloud organization in climate models,” Pierre Gentine, study co-author and Director of Columbia University’s LEAP Center, said in a statement. “Our work provides an answer to the debate and a novel solution for including organization, showing that including this information can significantly improve our prediction of precipitation intensity and variability.”

Dissecting the ‘Drizzle Problem’

Cloud organization is an important variable to consider when attempting to understand how the same storm might deliver more precipitation to one area than another. When clouds cluster together, the surrounding atmosphere becomes more humid, which generally correlates with higher rainfall volumes within a narrow water column. These movements are poorly captured by global climate models, which typically have a resolution no finer than 100 km (62 mi).

To compensate for clouds and other phenomena that occur at smaller scales, climate models rely on a technique called stochastic parameterization — using historical data as well as other observable factors to infer such conditions as cloud organization based on probability. However, since light drizzles tend to occur far more often than heavy deluges in most of the world, parameterization by climate models often assumes deviations from normal rainfall will be sprinkles rather than inundations.

The proper metric to quantify cloud organization could eliminate the need for parameterization and make predictions by climate models more actionable at local scales. During the past few decades, at least 20 such metrics have been proposed in scientific literature, according to the study. However, these existing metrics were designed to either measure cloud movement and organization over areas too expansive to be actionable for predicting rainfall or sought to represent only specific aspects of cloud behavior that are irrelevant to precipitation.

Mimicking the Human Brain

Existing metrics for cloud organization were developed according to certain assumptions or foundations. For example, they might describe cloud clustering as a function of other climatological variables, or adapt existing formulas and measures originally intended to characterize other phenomena. In fundamental contrast to existing metrics, the Columbia study describes tasking an advanced artificial intelligence with developing an optimal way to measure cloud behavior based solely on the patterns it observes elsewhere in the climate model.

Researchers began this process by training a neural network algorithm — an artificial intelligence designed to recognize patterns in a manner that mimics the human brain — on data from a high-resolution series of simulated storm clouds provided by a publicly available climate model. The neural network delved into the patterns between when clouds began to form and when the accompanying storm dissipated. By studying the network’s observations of these patterns, researchers managed to interpret and isolate the numbers the algorithm assigned to cloud organization.

When the researchers modified global climate models to use the new metric, the models managed to predict extreme rainfall events with roughly double their usual accuracy, study results illustrate. This new metric not only offers the potential to improve how large-scale climate models predict precipitation, but also several other small-scale factors currently missed by these models, according to the researchers.

“We discovered that our organization metric explains precipitation variability almost entirely and could replace a stochastic parameterization in climate models,” said Sarah Shamekh, Columbia Ph.D. student and lead study author, in a statement. “Including this information significantly improved precipitation prediction at the scale relevant to climate models, accurately predicting precipitation extremes and spatial variability.”

Read the full study, “Implicit Learning of Convective Organization Explains Precipitation Stochasticity,” in the Proceedings of the National Academy of Sciences.

Top image courtesy of U.S. Department of Energy

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ABOUT THE AUTHOR
Justin Jacques is editor of Stormwater Report and a staff member of the Water Environment Federation (WEF). In addition to writing for WEF’s online publications, he also contributes to Water Environment & Technology magazine. Contact him at jjacques@wef.org.

The post New Metric Solves ‘Drizzle Problem’ in Global Climate Models appeared first on Stormwater Report.

These sneaker wave events — often described as “mini-tsunamis” — occur periodically at beaches around the world. However, unlike tsunamis, scientists have concluded that sneaker waves do not result from mid-ocean earthquakes or landslides. The specific factors that drive sneaker waves are poorly understood, which hampers efforts to predict and prepare for them.

New research published in the journal Natural Hazards and Earth System Sciences suggests that large-scale storm systems may have a major effect on sneaker wave formation. The study team, which includes researchers from Oregon State University (OSU; Corvallis), Pacific Northwest National Laboratory (Richland, Washington), and the U.S. National Weather Service (Portland, Oregon), describes that sneaker waves are the result of a complex interplay between topography, weather, and climate. The influence of storm systems hundreds of kilometers away from shore can make sneaker waves more likely to occur. Tuba Özkan-Haller, study co-author and OSU Oceanographer, expressed hope that her team’s findings can help protect people and property.

“The more we learn, the closer we get to our ultimate goal, which would be to develop a warning system that is specific, accurate, and localized,” Özkan-Haller said in a release.

Searching for a Signal

The spate of Northwest U.S. sneaker waves in 2016 was unique because of how thoroughly it was documented, researchers say. It occurred in the early afternoon on a clear day and was widely observed by locals who posted video footage of the sneaker waves online. Several local news outlets reported from affected beaches.

Researchers examined these videos closely, compiling subtle details of how the waves behaved alongside firsthand accounts from witnesses. The footage confirmed that while the number and strength of different sneaker waves varied based on their location, each wave surged inland and then retreated into the ocean abruptly.

“The videos showed important general characteristics of the [sneaker wave] events on this day — in particular that they were roughly 5 minutes from beginning to end,” said lead author Chuan Li, who participated in the study as an OSU doctoral student. “This information helped us identify their signals from tide gauges and also helped narrow down possible causes.”

The next phase of the team’s investigation relied on three distinct types of U.S. National Ocean and Atmospheric Administration (NOAA) ocean sensors.

• Tide gauges, which are located along shallow coastlines, provide minute-by-minute data on water level, wind speed, and atmospheric pressure.
• Data buoys take hourly wave height, wave speed, and wave energy readings in deeper waters, approximately 30 to 85 km (18 to 53 mi) offshore.
• Bottom sensors are used to detect tsunamis and measure water-column height, located as low as 4,319 m (14,169 ft) beneath the waterline and as far as 556 km (345 mi) into the ocean.

Comparing this data alongside video footage and eyewitness reports from different locations along the coast helped researchers understand how and where sneaker waves form and travel, as well as identify signals that a sneaker wave might be on its way inland. 

New Insights on Sneaker Waves

The investigation confirmed that winter conditions in the Pacific Northwest make the region particularly susceptible to sneaker waves.

In their study, researchers distinguish between two types of wave systems: surface gravity waves, which are those typically seen by beachgoers, and infragravity waves, which are larger, stronger wave regimes that lurk deeper beneath the waterline. The intensity of these infragravity waves dictates the behavior of the surface gravity waves above them, including their frequency, height, and strength.

When large storm systems form in far-off ocean waters, such as those near Alaska or the South Pacific, stronger winds add energy to infragravity wave systems. In turn, this influx of energy causes surface gravity waves to space out, becoming less frequent but reach greater heights and faster movement speeds. During the winter storm season, nearshore waves tend to reach approximately twice the average height that they reach in summer, the researchers write.

These taller waves are more likely to become sneaker waves when they encounter beaches in areas where the continental shelf is narrow — in other words, flat, low-sloping beaches that offer less resistance to the inland flow of water. These types of beaches make up the majority of those located along the Pacific Northwest coastline, according to the study. With sufficient energy granted by storm systems with sufficient intensity, tall surface gravity waves become long and strong enough to avoid breaking against the beachfront.

“The longer the wave is, the less likely it is to break,” Özkan-Haller said. “Instead, it sloshes up, like the water would if you’re getting into a bathtub.”

However, researchers also found that weather along the coast is just as important as storm systems in far-off ocean waters. Evidence suggests that winter storms near beachfronts tend to dampen the energy of incoming waves, discouraging strong waves from surging into sneaker waves, Özkan-Haller explained. The clear conditions along the Northwest U.S. on January 16, 2016 — which contrasted with a strong storm system near Alaska’s Aleutian Islands — made the region highly susceptible to sneaker waves.

“If these long waves are forming out in the ocean, but there is also a local storm, the wave field is jumbled, and sneaker waves won’t occur,” Özkan-Haller said. “When the wind is calm, the local weather is mild – a beautiful day on the beach – sneaker waves are more likely.”

Read the full study, “Observations of extreme Wave Runup Events on the US Pacific Northwest Coast,” in Natural Hazards and Earth System Sciences.

Top image courtesy of StockSnap/Pixabay

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ABOUT THE AUTHOR
Justin Jacques is editor of Stormwater Report and a staff member of the Water Environment Federation (WEF). In addition to writing for WEF’s online publications, he also contributes to Water Environment & Technology magazine. Contact him at jjacques@wef.org.

The post Researchers Decipher Relationship Between Storms and ‘Sneaker Waves’ appeared first on Stormwater Report.

In humans, evolution is a process that occurs gradually over millions of years. For plants, the process is much faster. Just a few decades can provide ample time for plants to develop and proliferate new traits within a single species.

In the wetlands lining Chesapeake Bay, researchers have discovered major changes in the below-ground behavior of the common grass known as chairmaker’s bulrush. The change — shallower root systems — has evolved over less than a century. Researchers contend that this trend could have serious implications for the ability of wetlands in the Chesapeake Bay to keep pace with projected sea-level rise.

“Now that we’ve shown that evolutionary change can be fast enough and large enough to affect ecosystem resilience, we hope other researchers will consider this component of biological response to global environmental change,” said Jason McLachlan, University of Notre Dame Biologist and study co-author, in a release.

An Exercise in ‘Resurrection Ecology’

Coastal vegetation interacts with sea-level rise in two main ways: carbon sequestration and soil-surface accretion. Through photosynthesis, plants help to mitigate the effects of climate change by transferring carbon dioxide from the atmosphere into soil, inhibiting the greenhouse effect, and discouraging sea-level rise. On a more localized level, deeper root systems promote the gradual upward movement of the soil surface — a process called accretion — which helps coastal ecosystems keep up with rising waterlines.

Chairmaker’s bulrush is one of the most abundant plant species in the Chesapeake Bay ecosystem, and through carbon sequestration and soil-surface accretion, it plays a crucial role in the resilience of coastal wetlands. The Smithsonian Environmental Research Center in Edgewater, Maryland, maintains preserved core-sediment samples that contain dormant chairmaker’s bulrush seeds from as early as 1931.

By planting these “resurrected” seeds alongside modern specimens, researchers were able to directly compare physiological differences between generations. Additionally, carrying out computer simulations enabled the team to project generational differences in long-term effects on carbon sequestration and soil-surface accretion rates in local marshes. The researchers, representing the University of Notre Dame, University of Tennessee (Knoxville), and University of Florida (Gainesville), published findings from their experiments in the February 2023 issue of the journal Science.

This type of study — known as resurrection ecology — is a time-tested approach to help assess long-term genealogical changes in plants and animals. What makes this study different, describes Megan Vahsen, lead study author and Notre Dame doctoral student, is that it focused specifically on underground characteristics.

“For reasons of inconvenience, science has often ignored what happens below ground,” Vahsen said in a release. “But we have learned so much in this study; there are so many secrets happening below ground.”

Seeking Answers Underground

From aboveground, modern bulrush specimens did not display substantial differences from their resurrected ancestors, according to the study. But underground, bulrush root systems steadily shrunk, with the bulk of their biomass on a clear trend upward toward the marsh surface over the decades. This trend remained stable in bulrush specimens gathered from different parts of the Chesapeake Bay shoreline.

“We think this surprising reduction in below-ground growth might be a response to increased pollution in Chesapeake Bay,” McLachlan said. “Decades of pollution have resulted in higher levels of nitrogen and phosphorus in the waters, and since these are plant nutrients, evolution might now favor plants that ‘invest’ less in expensive roots.”

Computational marsh models showed that these smaller root systems entailed significant weaknesses in accumulating carbon in soils and supporting soil-surface accretion. Compared to plants from the previous century, modern bulrushes sequestered atmospheric carbon an average of 18% slower. Likewise, soil-surface accretion rates in marshes featuring modern bulrushes were an average of 8% lower than those in marshes containing the same concentration of ancestral specimens.

Assuming this evolutionary shrinkage continues, by 2100, Chesapeake Bay marshes dominated by chairmaker’s bulrush could rise by about 5 cm (2 in.) less than static projections based on the size of today’s average bulrush root system, the researchers write. Simulations based on sea-level rise scenarios of varying intensity also showed that changes in carbon capture due to shrinking root systems could account for an average of 4 cm (1.5 in.) of local sea-level rise by 2100. 

Importantly, the researchers caution that their results explore the long-term changes of only species in one location. As many types of vegetation work in concert to affect an ecosystem’s climate change resilience, study authors call for a more holistic approach to research into the relationship between plants and sea-level rise adaptation.

“Evolutionary change over almost a century played a destabilizing role for coastal ecosystems,” McLachlan said. “Other species in other ecosystems might have responded differently to human environmental impact, perhaps providing more resilience to ecosystems, or perhaps having no impact at all.”

Read the full study, “Rapid Plant Trait Evolution Can Alter Coastal Wetland Resilience to Sea Level Rise,” in the journal Science.

Top image courtesy of James DeMers/Pixabay

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ABOUT THE AUTHOR
Justin Jacques is editor of Stormwater Report and a staff member of the Water Environment Federation (WEF). In addition to writing for WEF’s online publications, he also contributes to Water Environment & Technology magazine. Contact him at jjacques@wef.org.

The post Fast-Evolving Plants Undermine Flood Resilience in Chesapeake Bay appeared first on Stormwater Report.

For example, the 2018 monsoon generated a series of severe convective storms across Colorado, Wyoming, Nebraska, and South Dakota. In addition to baseball-sized hail and winds as high as 90 miles per hour, the storms brought record-breaking rainfall volumes, which combined to incur millions in property damages .

Researchers at Pacific Northwest National Laboratory (PNNL; Richland, Washington) have discovered that a phenomenon occurring simultaneously hundreds of miles away — a series of historically destructive wildfires in California and Oregon — likely contributed to the 2018 monsoon’s severity. By increasing temperatures and generating plumes of smoke across an enormous area, the researchers contend, the wildfires affected weather patterns on an unprecedented scale.

“The more we understand about the contributing factors behind storms like this, which cause massive property loss, the better we’ll be able to prepare for them,” said Jiwen Fan, PNNL earth scientist and co-author of a new study about the discovery in the journal Proceedings of the National Academy of Sciences, in a release. “And, as we look at the future climate, we know wildfires will increase, particularly in the west.”

The 2018 Anomaly

When a major storm broke out above the central U.S. on July 26, 2018, three severe wildfires — California’s Carr and Cranston Fires and Oregon’s Long Hollow Fire — already were raging. As the fires continued to scour acres of land over the following weeks, consecutive storms of similar intensity would occur in the central U.S. each day through July 29.

This timing, in itself, was an anomaly, PNNL researchers describe. A period where West Coast wildfires and central U.S. monsoons overlapped for more than three consecutive days had not been observed in at least 20 years, the authors write. When those summer storms turned out far more severe than any in recent history, Fan and her team began investigating whether a link existed between the historic wildfires and the historic storms.

“I thought, maybe there’s some kind of connection there,” Fan said.

Using a sophisticated weather systems model developed by the National Center for Atmospheric Research (Boulder, Colorado), the team carried out high-resolution simulations to explore how abnormalities resulting from the wildfires might affect broader weather systems, including the North American Monsoon.

The model detailed that the 2018 wildfires increased air temperatures in their immediate vicinities by as much as 40 times the resting average for July. This additional heat caused local air pressure to skyrocket. As wind from the West Coast already tends to move east, this ultra-pressurized air traveled to the low-pressure monsoon system forming above the central U.S. at a higher-than-usual speed — bringing with it high concentrations of aerosolized particles generated by massive plumes of smoke.

When the warm West Coast air mingled with the budding storm clouds above the central U.S., the influx of aerosolized particles provided extra surface area onto which water vapor in the clouds could attach and condense into precipitation. The added heat also provided more energy — and thus, more mobility — for this water vapor, which ascended to greater (and colder) atmospheric heights and fell further after they condensed. This increased movement, the model found, generated large hailstones large enough to cause damage even despite their occurrence in the middle of summer. 

“The cost of the storms we studied exceeded $100 million in damage,” said Yuwei Zhang, PNNL atmospheric scientist and first author of the study, in a release. “If we know that distant wildfires contribute to stronger storms, that information could bring about better projections, which might help avoid some degree of destruction.”

More Common With Climate Change

According to the study, influence from the West Coast wildfires was directly responsible for a 19% increase in total rainfall to affect the central U.S. between July 26 and 29. The study also suggests that the wildfires significantly enhanced the occurrence of intense precipitation capable of causing flash flooding — falling at more than 10 mm per hour — while discouraging less severe rainfall. Air-pressure differentials were found to increase maximum updraft speeds in the storm system by about 30%.

The researchers acknowledge that their findings may only be applicable to a small subset of weather phenomena, when larger-than-average wildfires and storms occur simultaneously within a relatively restrained distance of each other. However, evidence from the last few years suggests that climate change is causing wildfire season in the western U.S. to begin earlier in the summer, placing its onset increasingly within the range where it would overlap with the North American Monsoon.

“Severe storms in the central U.S. are also projected to increase,” Fan said. “Therefore, it is reasonable to expect that these co-occurring events would happen more frequently, and the impact of western wildfires on central storms may become increasingly important in the future.”

Read the full, open-access study, “Notable impact of wildfires in the western United States on weather hazards in the central United States,” in the journal Proceedings of the National Academy of Sciences.

Top image courtesy of Dave Ritchey/U.S. National Weather Service

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ABOUT THE AUTHOR
Justin Jacques is editor of Stormwater Report and a staff member of the Water Environment Federation (WEF). In addition to writing for WEF’s online publications, he also contributes to Water Environment & Technology magazine. Contact him at jjacques@wef.org.

The post West Coast Wildfires Intensify Storms Hundreds of Miles Away appeared first on Stormwater Report.

Authors behind the new study, representing Stockholm University (Sweden) and ETH Zurich (Switzerland), suggest that PFAS contamination represents a previously unrecognized “planetary boundary” — a global, quantitative threshold which compromises humanity’s rate of development if surpassed.

“Due to the global spread of PFAS, environmental media everywhere will exceed environmental quality guidelines designed to protect human health and we can do very little to reduce the PFAS contamination,” said Martin Scheringer, study co-author and ETH Zurich environmental chemist, in a release. “In other words, it makes sense to define a planetary boundary specifically for PFAS and, as we conclude in the paper, this boundary has now been exceeded.”

Contamination Outpaces Regulation

The research team compiled findings from several studies published since 2010 that examined the occurrence of four of the most common PFAS — perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) — in rainfall, covering both urban and rural environments as well as Antarctica and the Tibetan Plateau, among Earth’s most remote biomes. They then compared these PFAS levels with advisory contaminant limits for drinking water specified by EPA, the Dutch and Danish governments, as well as the European Union.

Each of these limits has grown increasingly stringent in recent years as the body of research about PFAS exposure risks expands. In June, for example, EPA lowered advisory limits for PFOA and PFOS in drinking water from 70 ng/L for the sum of both substances to 20 pg/L and 4 pg/L respectively. Last year, the Danish Environmental Protection Agency announced that drinking water must not contain more than a total of 2 ng/L of PFOS, PFOA, PFHxS, and PFNA.

“There has been an astounding decline in guideline values for PFAS in drinking water in the last 20 years,” said Stockholm University environmental scientist Ian Cousins, lead author of the study, in a release. “For example, the drinking water guideline value for one well-known substance in the PFAS class, namely the cancer-causing PFOA, has declined by 37.5 million times in the U.S. Based on the latest U.S. guidelines for PFOA in drinking water, rainwater everywhere would be judged unsafe to drink.”

The team’s review found that the levels of PFOA detected in rainfall by all studies in all regions far exceeded EPA’s advisory limits. The lowest recorded concentration of PFOA was in the Tibetan Plateau, with a median contamination level of 55 pg/L — approximately 14 times higher than EPA guidelines. PFOS, too, exceeded limits set by EPA, the Environmental Quality Standard for Inland European Union Surface Water, and other measures, in all but two studies conducted in Antarctica and the Tibetan Plateau.

A Threat to Human Development

Originally prized by industry for their durability and longevity, as an environmental pollutant, PFAS have proven especially persistent in the hydrosphere. After discharge from industrial facilities, PFAS eventually reach waterways and oceans, where instead of dissolving, they commonly enter the atmosphere via sea-spray aerosols. Rainfall, in turn, returns the chemicals to the surface, perpetuating their environmental threats even decades after their initial release. Although the world’s largest PFAS manufacturers had phased out their use by the early 2000s, the chemicals continue to accumulate even within the most remote corners of the world.

Because of the ubiquity of PFAS contamination in rainfall, soil, and surface water and the inability to reverse this contamination on a global scale with existing technology, the researchers argue that conservationists should regard PFAS as a tenth planetary boundary.

The concept of planetary boundaries was first proposed in 2009 by a group of 28 scientists coordinated by the Stockholm University Resilience Centre. They include nine measurable processes, such as stratospheric ozone depletion, ocean acidification, biosphere integrity, and climate change, each underlined by a series of metrics and indicators. Among these metrics are a threshold for each boundary, which if surpassed signal the threat has become irreversible using existing tactics. To varying degrees, several of these thresholds have already been exceeded, including climate change, land-use change, and nutrient pollution.  

Read the full, open-access study, “Outside the Safe Operating Space of a New Planetary Boundary for Per- and Polyfluoroalkyl Substances (PFAS),” in the journal Environmental Science & Technology.

Top image courtesy of Roman Grac/Pixabay

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ABOUT THE AUTHOR
Justin Jacques is editor of Stormwater Report and a staff member of the Water Environment Federation (WEF). In addition to writing for WEF’s online publications, he also contributes to Water Environment & Technology magazine. Contact him at jjacques@wef.org.

The post Scientists Contend PFAS in Rainfall Represents Global Crisis appeared first on Stormwater Report.

Existing methods to measure precipitation are generally reliable, according to USBR — however, particularly in remote environments where manual maintenance is a challenge, each conventional method has its weaknesses. For example, traditional rain gauges based on graduated cylinders often require someone on hand to empty them after each rain event and struggle to capture solid precipitation, while weight-based instruments often rely on antifreeze, which must be manually hauled away after use, to melt solid precipitation. Ground-based weather radars can circumvent many of these issues and can measure precipitation even over long distances, but they require a line of sight that may be hard to maintain in mountainous regions. Each of these weaknesses affect the critical data water managers require to plan for irrigation needs, control flooding, predict water supplies, and more.

“Accurately measuring rain and snow is critical for water managers to understand how much water is available and for predicting floods and droughts,” said USBR Senior Advisor for Research and Development Levi Brekke in a statement. “The goal of this prize competition is to develop new devices that increase accuracy and reliability while reducing maintenance so they can operate cost-effectively in extremely remote areas.”

Enter by Oct. 24

The Counting Every Drop Challenge, run by USBR alongside the U.S. Department of Agriculture Natural Resources Conservation Service (NRCS), U.S. National Aeronautics and Space Administration Tournament Lab, Geonor Inc. (Branchville, New Jersey), and Freelancer (Sydney, Australia), consists of two phases.

In the first phase, entrants will submit technical papers describing their proposed solution by October 24, 2022. These submissions should describe how the planned device will accurately measure both liquid and solid precipitation on only a 12V DC power supply without discharging any substances besides water. Solutions should also output data compatible with common dataloggers and provide measurements at least once per hour. Perhaps most importantly, as the challenge intends to develop solutions specifically for remote areas, proposed devices should only require manual maintenance at a maximum of once per year, contest rules describe. Judges will select the top eight proposals by November 18, 2022, which will each receive USD $10,000.

After a series of preliminary reviews in which competition representatives will meet with each of the eight frontrunners to discuss their idea and their ability to develop it, five finalists will receive USD $15,000 each to transform their proposal into a prototype device. In May 2023, they will ship their prototypes to NRCS, which will carry out field testing alongside a benchmark precipitation measurement device in remote conditions over an eight-month period. The five teams will receive an extra USD $3,000 each for shipping their devices for testing.

The top-performing solution will receive the grand prize of USD $100,000, while the other four solutions will share USD $30,000 based on their device’s performance. USBR will announce the winners in August 2024.

See full rules and submission guidelines for the Counting Every Drop Challenge on Freelancer.com. 

Casting a Wider Net

Through its Water Prize Competition Center, USBR has been hosting public competitions to accelerate innovation in all corners of the water sector since 2015. Earlier this year, for example, USBR announced the winners of its Streamflow Forecast Rodeo competition, which tasked participants with predicting short-term streamflow in the western U.S. more accurately than conventional methods.

Other recent competitions orchestrated by the USBR Water Prize Competition Center include

• the Imperfection Detection competition, seeking portable tools to identify defects in polymer-based pipelines and other structures;
• the Water America’s Crops challenge, focusing on controlling seepage in irrigation pipelines;
• the Guardians of the Reservoir challenge, accelerating technologies to collect and transport sediment from reservoirs; and
• the More Water, Less Concentrate challenge, aiming to devise new ways to generate more usable water from inland desalination facilities.

Learn more about USBR’s innovation competitions at its website.

Top image courtesy of Rebecca Matthews/Pixabay

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ABOUT THE AUTHOR
Justin Jacques is editor of Stormwater Report and a staff member of the Water Environment Federation (WEF). In addition to writing for WEF’s online publications, he also contributes to Water Environment & Technology magazine. Contact him at jjacques@wef.org.

The post ‘Counting Every Drop Challenge’ Offers $300K For New Precipitation Measurement Solutions appeared first on Stormwater Report.

The plan joins a growing collection of adaptation measures the city has introduced in recent years in light of expected increases in storm frequency and severity. The New York City Department of City Planning estimates that an event considered a 100-year storm in 2015 will become up to three times more likely in New York by 2050. Local sea levels also are expected to rise by as much as 20 to 75 cm (8 to 30 in.) over the same period, intensifying the destructive potential of storm surge in addition to spurring more extensive coastal flooding.

“Being prepared for extreme weather emergencies is a shared responsibility, and Rainfall Ready NYC is a blueprint that will guide us throughout all phases of the disaster cycle,” said New York City Emergency Management Commissioner Zach Iscol in a statement. “While the city has made several improvements to its operations — from mitigation to preparedness, response, and recovery — Rainfall Rescue NYC captures how we will continue to safeguard our city and the public.”

Infrastructure and Information

For the city government, Rainfall Ready NYC prescribes a combination of short-term infrastructure projects, outreach efforts, and initiatives to provide residents with more actionable information during heavy storms.

By June 2023, the city plans to complete nine upgrade and retrofit projects targeting storm sewers in the city’s most flood-prone neighborhoods, in addition to installing more than 1,300 green infrastructure measures within city limits. The New York City Department of Parks and Recreation will also consider permanently lowering water levels in lakes and basins located in eight city parks, expanding their capacity to detain and channel stormwater, according to the plan.

Additionally, the plan taps the New York City Department of Environmental Protection to offer free sandbags and flood barriers to residents living in the city’s most flood-prone areas in advance of anticipated storms. These residents also can attend a series of new, hands-on workshops on household-scale flood resilience measures.

As such services as Uber Eats, GrubHub, and DoorDash each day make tens of thousands of deliveries throughout New York City, Rainfall Ready NYC also contains outreach provisions targeting delivery drivers. The city has formed a working group with representatives from major delivery services to incorporate extreme weather warnings into the drivers’ app interfaces as well as considering other protocols, such as restricting deliveries during particularly severe storms, the plan describes.

Lastly, the city plans to bolster two existing resources to help New Yorkers manage their flood exposure: FloodHelpNY and FloodNet.

FloodHelpNY is a website that acts as a directory for flood-preparedness information, including avenues for users to purchase flood insurance as well as assess and fortify the most flood-prone parts of their property. The New York City Mayor’s Office of Climate Resiliency manages FloodHelpNY and plans to translate the contents of the website into more languages as well as create a means by which property owners can estimate their flood exposure simply by looking up their address.

Meanwhile, FloodNet is a growing network of real-time, street-flooding sensors strategically deployed to advance local knowledge of long-term flooding frequency, severity, and effects. FloodNet partners plan to deploy 50 additional sensors within the next year, with goals to expand the network to 500 total sensors by 2026, according to Rainfall Ready NYC.

“Initiatives like Floodnet provide the real-time, hyperlocal flood information that we need to take immediate street-level action like road closures, travel bans, or informing residents on the need to deploy sandbags and flood barriers, as well as help us to target our efforts in the most vulnerable communities, validate existing flood models, and provide data for future drainage investments,” said Kizzy Charles-Guzman, Executive Director of the Mayor’s Office of Climate and Environmental Justice, in a release. “As the city continues to invest in longer-term projects to address these hazards, Rainfall Ready NYC is a crucial resource for residents and city government to take action now toward shared stormwater resiliency.”

Residents Have a Role

Rainfall Ready NYC’s message for New York City residents is clear: Take steps today to be prepared for tomorrow’s major storms.

The action plan urges residents to take advantage of the city government’s recently released stormwater flood maps, which can help users make a plan to reach higher ground safely in the event of severe flooding on their block, for example. It also encourages residents — particularly those in flood-prone neighborhoods — to involve themselves in local clean-up efforts to keep catch basins serving their property clear in advance of an expected storm.

To ensure residents are prepared for a worst-case scenario, the action plan also stresses the importance of attaining flood insurance and encourages policyholders to take photos of their most valuable possessions to facilitate the claims process. 

“Climate change is the city’s biggest environmental threat, and while we continue to invest in resiliency and infrastructure projects to protect us for generations to come, the Rainfall Ready NYC action plan will help every New Yorker to protect themselves, their families, and their homes,” said Mayor Adams in a release. “The city is acting now to keep New Yorkers safe as we move into hurricane season, and I encourage every New Yorker to make emergency plans for the next extreme weather event.”

Learn more about the Rainfall Ready NYC plan at the New York City Department of Environmental Protection website.

Top image courtesy of abdulla binmassam/Pixabay

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ABOUT THE AUTHOR
Justin Jacques is editor of Stormwater Report and a staff member of the Water Environment Federation (WEF). In addition to writing for WEF’s online publications, he also contributes to Water Environment & Technology magazine. Contact him at jjacques@wef.org.

The post Action Plan Prepares New Yorkers for Flooding Driven by Climate Change appeared first on Stormwater Report.

Parts of California and Nevada downhill from the Sierra Nevada depend on snowmelt from the mountains for as much as 75% of their annual water supplies. But as the atmosphere warms, winter precipitation increasingly falls as rain rather than snow. Not only does this mean less spring snowmelt, but it also means higher frequencies for winter rain-on-snow (ROS) events. ROS events that drop warm rain cause snowpack to rapidly melt. The result is higher winter peak flows with the potential to cause dangerous flooding conditions. Whether an ROS event will cause downstream flooding, however, is a complex function of minute-by-minute temperature, snowpack density, and precipitation. Predicting floods with accuracy in this situation is difficult.

In the desert regions of New Mexico and Arizona, water managers face a similar challenge each summer. Here, annual snowmelt also makes up a significant portion of the region’s water resources, but winter snowpack volumes are shrinking consistently. Capturing and using what little rainfall the perennially drought-stricken area receives each year can help offset these losses and bolster water security, but accurately predicting how much rain will fall in which catchments — especially during the late-summer monsoon season — has long eluded scientists and water managers.

Two recent studies published in the journals iScience and Geophysical Research Letters report new ways to minimize the Southwest’s unique forecasting uncertainties.

Using Soil Moisture to Assess Rain-on-Snow Risks

Not every winter storm produces dangerous ROS events. Under the right conditions, however, winter ROS events have produced as much as 80% higher peak flows downhill compared to the slow, gradual Sierra Nevada snowmelt that occurs each spring. If water managers could accurately identify conditions that increase flood risks from ROS events early enough, they could help stave off flooding by freeing up capacity in reservoirs. However, current streamflow prediction models often have trouble incorporating the complex, site-specific conditions affecting ROS events into actionable forecasts.

A team of interdisciplinary scientists from the Desert Research Institute (Reno, Nevada); the University of California, Berkeley; the U.S. National Weather Service; and the University of Nevada (Reno) describe a new statistical method to use data from existing snow monitoring stations to detect when flooding from ROS events is more likely to occur.

“We know the condition of the snowpack leading into a rain-on-snow event can either help mitigate or exacerbate flooding concerns,” said Tim Bardsley, Reno-based National Weather Service hydrologist and study co-author, in a release. “The challenge is that the simplified physics and lumped nature of our current operational river forecast models struggle to provide helpful guidance here. This research and framework aim to help fill that information gap.”

To build their decision-support tool, the researchers studied the hourly record of data on such factors as snowpack density, snowmelt volume, temperature, and precipitation. The data was collected by the University of California, Berkeley, Central Sierra Snow Laboratory (CSSL) snow monitoring network from 2006 to 2019. The researchers discovered a strong correlation between spikes in soil moisture after a storm begins and — a few hours later — significant upticks in streamflow. Specifically, the authors write, increases in soil moisture of at least 0.5% in one hour or 1% in two hours represented a strong predictor of increased flood risks.

Authors acknowledge that not every spike in winter soil moisture can be attributed to ROS events. The framework employs a strict quality control procedure that crosschecks measures of soil moisture alongside other environmental variables before performing a statistical analysis to more accurately determine whether each spike originates from an ROS event. Comparing the team’s framework to conventional streamflow models on simulations of historical ROS events, they found that their method predicted flooding associated with ROS more than 25% more accurately.

The new method comes at an opportune time, authors write, as research suggests the Sierra Nevada region is entering a period of “peak ROS”. In this period of climate change in which winter precipitation is more likely to fall as rain than snow — but also in which the atmosphere is not yet warm enough to cause a persistent decline in snowpack volumes — ROS events are expected to occur far more frequently.

Read the full, open-access study, titled “Toward Snowpack Runoff Decision Support,” in iScience.

Interpreting Precipitation from Pressure

Between June and October, strong winds carry moisture from the Pacific Ocean across Arizona and New Mexico, delivering monsoon rains that typically account for approximately 60% of the desert region’s total annual precipitation.

Most major climate models can predict the larger-scale aspects of the North American Monsoon system, such as changes in wind speeds, air and water pressure, and temperature. However, climatologists from the National Center for Atmospheric Research (NCAR; Boulder, Colorado) and the U.S. Bureau of Reclamation describe that even the most sophisticated climate models often fail to accurately predict more localized effects, such as the specific amount of precipitation each Southwest community should expect to receive each monsoon season. The team contends in an April 2022 study that decreasing this annual uncertainty for local water managers — an acute challenge when planning year-round reservoir storage and water allocation decisions — may be deceptively simple.

Focusing on eight catchments in Arizona and six in New Mexico, the researchers sought to determine whether atmospheric and hydrological conditions earlier in the year could leave behind clues about how much precipitation to expect during monsoon season. They used an NCAR supercomputer to examine the nuances of more than three decades of forecasts made by several major climate models, comparing those forecasts against actual monsoon-season precipitation. According to the study, one popular global climate model managed by the European Centre for Medium-Range Weather Forecasts (ECMRWF) consistently outperformed all others in terms of its accuracy for atmospheric conditions in New Mexico and Arizona. But even that model often misreported monsoon precipitation.

However, during summers with above-average precipitation volumes, the researchers noticed a pattern: In April, the ECMRWF model would predict a significant uptick in moisture in the lowest level of the atmosphere. Comparing the size of these upticks to precipitation totals in each catchment between June and October, the researchers identified a statistically significant correlation. That correlation persisted across nearly all catchments within the study area. In their study, the team proposes a function to use data on low-level atmospheric moisture observed in April to predict summer rainfall totals months in advance.

“The method is surprisingly successful, enabling us to look at individual catchments and correctly predict months ahead of time whether they will get above or below average rainfall,” said Andreas Prein, NCAR scientist and lead author of the study, in a release. “The framework itself is very generalizable and can be applied to a variety of different regions and different seasons. This points the way to better seasonal predictions for water resource management across the United States as well as other parts of the world.”

Read the full, open-access study, titled “Sub-Seasonal Predictability of North American Monsoon Precipitation,” in the journal Geophysical Research Letters.

Top image courtesy of Brigitte Werner/Pixabay

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ABOUT THE AUTHOR
Justin Jacques is editor of Stormwater Report and a staff member of the Water Environment Federation (WEF). In addition to writing for WEF’s online publications, he also contributes to Water Environment & Technology magazine. Contact him at jjacques@wef.org.

The post Researchers Decipher Winter Floods, Summer Showers in Southwest U.S. appeared first on Stormwater Report.

Hawkins recognized that despite covering a significant breadth of time and geography, the written observation sheets each followed a standardized, 10-year format that allowed for easy comparison between them. With only basic instruction, the task of transcribing the massive number of measurements could be completed by just about anyone. And with more people at home and in need of distractions than ever before, the likelihood of finding willing transcribers was high. Hawkins established a project titled Rainfall Rescue on the popular citizen science website Zooniverse on March 26, 2020, asking volunteers to help build a searchable database of U.K. weather observations from 1677 to 1960. By April 10, more than 16,000 volunteers had helped Hawkins transcribe the entire archive.

Two years later, a recent paper by Hawkins about Rainfall Rescue published in the Geoscience Data Journal describes that approximately 3.34 million new observations had successfully passed a rigorous quality control process and become part of the U.K. Meteorological Office’s official record of historical precipitation. The additional data extends the continuous record of precipitation in the U.K., Ireland, and the Channel Islands back 26 years from 1862 to 1836 — and even earlier in some areas.

“I am still blown away by the response this project got from the public,” Hawkins said in an April 2022 statement about the campaign. “Transcribing the records required around 100 million keystrokes, yet what I thought would take several months was completed in a matter of days.”

Ensuring Quality Among Quantity

After Rainfall Rescue, the next task was to arrange, contextualize, and quality check the transcriptions, transforming raw data into chronological records for more than 6,000 locations. Part of this quality assurance process was built into the initial transcription effort, Hawkins described. Each handwritten observation was transcribed by at least four volunteers to ensure accuracy — if at least three volunteers agreed on a measurement, it would be “provisionally accepted.” These provisionally accepted values accounted for around 98% of all data, but even verifying the remaining 2% represented a significant undertaking.

Eight volunteers, listed as study co-authors, continued to work alongside Hawkins to check the accuracy and scientific integrity of the provisionally accepted values as well as reconcile differences among the remainders. This process involved, according to the study, eliminating measurements described by the original recorder as “estimated” or adapted from an unconfirmable source, such as an almanac, and ensuring that the sum of monthly precipitation values equaled recorded annual totals, among other protocols.

The verified data revealed much about locally observed rainfall patterns across the British Isles before national meteorological organizations began systematically measuring precipitation in the 1960s. For one, contemporary data maintained by the U.K. Meteorological Office suggested that May 2020 was the driest May in the country’s history. The new data indicates that May 1844 was even drier, receiving about 1.3 mm less rainfall. The driest full year in U.K. history was previously thought to be 1887; now, it is believed to have been 1855.

“As well as being a fascinating glimpse into the past, the new data allows a longer and more detailed picture of variations in monthly rainfall, which will aid new scientific research two centuries on,” Hawkins said. “It increases our understanding of weather extremes and flood risk across the U.K. and Ireland and helps us better understand the long-term trends towards the dramatic changes we’re seeing today.”

The Original Citizen Scientists

Beyond the data itself, Rainfall Rescue yielded interesting information about the rainfall observers who perhaps served as the region’s first citizen meteorologists. The data — as well as the notes routinely left by the observers who gathered it — detail a broad range of people united by their often decades-long commitment to monitoring and documenting local precipitation.

Private rain gauges were typically located near churches and chapels, schools, reservoirs, parks, railway stations, and lighthouses, in addition to private residences. They were typically monitored and maintained by individual enthusiasts or families rather than scientific groups. Perhaps even more diverse than their settings and operators, however, were the reasons provided for why periodic rainfall measurements at a particular gauge would suddenly stop. In his recent paper, Hawkins lists some of these reasons:

• At a rectory in Kent, an observer in 1863 found their gauge “choked with a bird’s nest.”
• In Eltham, London, at the outset of World War II, an observer recorded that their gauge had been “destroyed by enemy action.”
• In 1951, an observer noted that a gauge on the grounds of a South London mental hospital had been “hidden by inmates,” interrupting recordings for three years.
• Gauge recordings suddenly stopped at a home in West Ayton, Yorkshire, after the observer reported that they were “too old to bother now.”

Read the full, open-access paper, “Millions of historical monthly rainfall observations taken in the UK and Ireland rescued by citizen scientists,” in the Geoscience Data Journal.

Top image courtesy of U.K. Meteorological Office/Rainfall Rescue

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ABOUT THE AUTHOR
Justin Jacques is editor of Stormwater Report and a staff member of the Water Environment Federation (WEF). In addition to writing for WEF’s online publications, he also contributes to Water Environment & Technology magazine. Contact him at jjacques@wef.org.

The post ‘Rainfall Rescue’ Data Verified, Enters Official Precipitation Records appeared first on Stormwater Report.

According to the results of a study recently featured on the cover of the journal Nature, economic growth rates drop significantly as extreme, episodic storms — as well as storms in general — become more common in a particular region. The study marries 40 years of economic and climatic data across 77 countries. It further probes the complex relationship between the environment and the economy in the age of climate change.

“This is about prosperity, and ultimately about people’s jobs,” said Leonie Wenz in a release. Wenz is co-author of the study and a scientist at Potsdam (Germany) Institute for Climate Impact Research. “Economies across the world are slowed by more wet days and extreme daily rainfall — an important insight that adds to our growing understanding of the true costs of climate change.”

Extra Rain Adds Up

To identify the correlation between increased precipitation and decreased economic growth, the researchers first examined historical rainfall data from 1979 to 2019 for 1,554 distinct, sub-national regions as provided by the European Centre for Medium-Range Weather Forecasts (Reading, United Kingdom). They compared this high-resolution data on detailed information about precipitation patterns in specific regions and across various timeframes with measures of each region’s gross regional product (GRP) reported by local or federal governments.

Specifically, they studied how a region’s GRP reacted in response to increases in the total number of days per year in which at least 1 mm (0.04 in.) of rainfall fell as well as extreme storms — those delivering enough rain over the course of a day to score within the region’s 99.9^th percentile for precipitation volume. Considering these factors in tandem, the researchers determined that just a few additional inches of rain above long-term averages per year strongly correlate with lags in economic development on the magnitude of 0.5% or more. This is significant, researchers write, as the economies of most countries typically only change a few percentage points each year.

Other studies have documented the link between the effects of climate change and financial liability. However, these previous efforts focused on broader timeframes or considered countries as a whole rather than specific regions. Wenz described that fewer studies have contextualized the local costs of increasingly high rainfall volume and intensity on the global scale.

“Macro-economic assessments of climate impacts have so far focused mostly on temperature and considered — if at all — changes in rainfall only across longer time scales such as years or months.  Thus, missing the complete picture,” Wenz said.

The study cautions that in most cases, increased rainfall is only one factor behind broader trends of economic decline. Their analysis describes several steps to account for and adapt to local factors with likely effects on GRP, such as notable legislation or the region’s positioning within the globalized economy. 

Varying Sensitivity

The team’s analysis proposes an additional conclusion that defies conventional wisdom.

The most significant disruptions from heightened precipitation, according to the study, occurred in local economies characterized mainly by industry and services rather than agriculture. Predominantly agricultural economies demonstrated far less sensitivity to increases in total annual rainfall. This is despite previous findings by other studies that climate change-induced rainfall intensifications make major differences for crop productivity around the world. 

The finding not only suggests that industrialized, high-income regions may be more susceptible to financial harm from climate change, but also that the number of extreme storms a region experiences makes more of a difference than the total number of rainy days it experiences. Urbanized areas may tend to have sufficiently robust stormwater infrastructure to handle common storms, but stand to lose more if that infrastructure is overwhelmed by extreme ones.

“While more annual rainfall is generally good for economies, especially agriculturally dependent ones, the question is also how the rain is distributed across the days of the year,” Wenz said. “Intensified daily rainfall turns out to be bad, especially for wealthy, industrialized countries like the U.S., Japan, or Germany.”

Read the team’s study, “The Effect of Rainfall Changes on Economic Production,” in Nature.

Top image courtesy of Arek Socha/Pixabay

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ABOUT THE AUTHOR
Justin Jacques is editor of Stormwater Report and a staff member of the Water Environment Federation (WEF). In addition to writing for WEF’s online publications, he also contributes to Water Environment & Technology magazine. Contact him at jjacques@wef.org.

The post More Precipitation Means Slower Economic Growth appeared first on Stormwater Report.