Nature: Scientific Reports: A 5‑km‑thick reservoir with > 380,000 km3 of magma within the ancient Earth’s crust

Rais Latypov, Sofya Chistyakova, Richard A. Hornsey, Gelu Costin & Mauritz van der Merwe



Several recent studies have argued that large, long-lived and molten magma chambers may not occur in the shallow Earth’s crust. Here we present, however, field-based observations from the Bushveld Complex that provide evidence to the contrary. In the eastern part of the complex, the magmatic layering continuously drapes across a ~ 4-km-high sloping step in the chamber floor. Such deposition of magmatic layering implies that the resident melt column was thicker than the stepped relief of the chamber floor. Prolonged internal differentiation within this thick magma column is further supported by evolutionary trends in crystallization sequence and mineral compositions through the sequence. The resident melt column in the Bushveld chamber during this period is estimated at > 5-km in thickness and > 380,000 km3 in volume. This volume of magma is three orders of magnitude larger than any known super-eruption in the Earth’s history and is only comparable to the extrusive volumes of some of Earth’s large igneous provinces. This suggests that super-large, entirely molten, and long-lived magma chambers occur, at least occasionally, in the geological history of our planet. Therefore, the classical view of magma chambers as ‘big magma tanks’ remains a viable research concept for some of Earth’s magmatic provinces.

Latypov, R., Chistyakova, S., Hornsey, R. A. & Costin, G. (2022). A 5 ‑ km ‑ thick reservoir km 3 of magma within the ancient Earth ’ s crust. Scientific Reports. Nature Publishing Group UK 1–12.

Most but not all Texas coaches say they’ll plan for climate change

Mike Williams, Rice News – Aug. 1, 2022

Rice University survey suggests some aren’t considering dangerous conditions to come

A survey of coaches and athletic officials in Texas indicates many of them would be wise to think harder about the risks their students face as the climate changes, according to Rice University researchers who conducted the statewide study.

Rice climate scientist Sylvia Dee led a survey of Texas coaches, trainers and athletic directors showing that while many are aware of the risks of outdoor workouts during the height of summer, not all are on board with adjusting for hotter weather. Dee said that’s concerning in light of recent warnings that climate change is already making Texas’ summers hotter. For example, a 2021 report from the Texas State Climatologist’s office said Texans should expect the number of 100-degree days each summer to nearly double by 2036 compared to the average numbers from 2001-2020.

A survey of Texas college and high school coaches, trainers and athletic directors suggests many are not taking climate change into account as they plan their programs’ futures. (Credit:

“It’s one thing to send out a survey, but we need to think ahead and have the tough conversations about what to do if it’s too hot to play football in the summer in the near future (or even now),” said Dee, an assistant professor of Earth, environmental and planetary sciences. “I want to hope that just receiving this survey got these athletic staff thinking about the problem.”

The survey of hundreds of coaches and athletic directors at Texas high schools, colleges and universities found that most are aware of the dangers of intensive workouts and strenuous events when temperatures above 95 degrees Fahrenheit can put athletes at risk of heat-related illnesses.

They indicated they’re keeping a close eye on damaging heat, humidity and wet bulb temperatures and will adjust schedules as necessary. But surprisingly, some indicated they don’t acknowledge climate change or its implications for the health of athletes and their programs.

The results appear in an open-access paper in the American Geophysical Union journal GeoHealth.

The 22-question survey, organized and carried out by students starting during the COVID-19 pandemic in 2020, went to 4,701 email contacts, with complete responses from 224 Texas coaches and officials, 51% of whom coach football.

The study relied on state-of-the-art simulations developed at the National Center for Atmospheric Research to compare temperature, heat index, humidity and wet bulb temperature in Texas over two key periods: 1976-2000 and 2076-2100. The projections incorporated estimates for high- and low-carbon emissions scenarios through the end of the century.

They projected average air temperatures, heat index values and wet bulb temperatures will all rise substantially in the future with heat index values regularly exceeding 113 degrees Fahrenheit in Houston, Austin and San Antonio, and exceeding 110 degrees in Dallas, even in the lower-emissions scenario. In West and North Texas cities, including Lubbock, El Paso, Midland/Odessa and Abilene, maximum heat index values could be 30 degrees higher than they are now.

Wet bulb temperature is the temperature of a parcel of air at 100% humidity, basically the point at which athletes — and everyone else — can no longer sweat to cool their bodies. According to one study, even the healthiest people would not survive a wet bulb temperature of 95 degrees for more than several hours in the shade.

Researchers at Rice University and elsewhere polled thousands of coaches and athletic directors at Texas high schools and colleges about how rising temperatures will affect their summer practices. From left: top row, Selena Guo, Beck Miguel Saunders-Shultz, Gargi Samarth and Emily Gurwitz; second row, Chelsea Li, Lizzy Gaviria, Karen Lu and Ebrahim Nabizadeh; bottom row, Kate Weinberger, Sylvia Dee, Jane Baldwin and Christine Nittrouer. Photos courtesy of The Climate and Water Lab/Rice University

“It’s quite rare that you would see the wet bulb temperatures on a newscast,” Dee said. “Although a weather forecast usually reports the heat index (the “feels-like” number that combines temperature and humidity), the wet bulb temperature is the one that matters for heat exhaustion, heat stroke and exertional heat illness.”

All of those responding to the survey reported they were aware of heat warnings issued by the National Weather Service, and 88% indicated they factor those warnings into decisions on whether to cancel practice. However, only 54% indicated they take humidity into account when making decisions.

“This discrepancy suggests that there may be a lack of understanding among athletic staff in how humidity affects the perceived temperature,” the researchers wrote.

They noted “athletic staff placed heavier emphasis on and were more concerned about the impact of temperature rather than climate change.” Fully 30% of those who responded were “not concerned at all” about the effects of climate change.

Dee noted there are state-level guidelines that discuss the risks of heat illness for various athletic activities. “But there’s certainly no acknowledgement of increasing risk in the future in any of these documents,” she said.

Dee said the Rice athletes among her intro-level students inspired the project. “I asked them what they do when it’s 100 degrees and humid outside. Where do you go? How do you handle that?” she said. “That got me thinking it would be a neat to start them thinking about the impacts of climate change on student athletes.”

The first pandemic summer of 2020 provided an opportunity to set them to work through online internships, gathering contact data for Texas coaches and officials. Along with designing the survey itself, she said that took nearly two years.

To better understand the responses, Dee and her Rice team collaborated with Christine Nittrouer, formerly a Ph.D. student of Mikki Hebl in Rice’s Department of Psychological Sciences and now a colleague at Texas Tech University who is accustomed to analyzing survey data, as well as colleagues who study extreme weather and epidemiology.

“It’s not surprising that it’s going to get really hot,” Dee said. “But it was a little frightening that, in relation to the physiological limit, there’s a lot of evidence that it’s already too hot for student athletes to safely play sports outdoors.”

She and co-author Nittrouer are interested in a follow-up collaboration that goes beyond the athletic field.

“There’s some interesting work to be done in this field,” she said. “A lot will rely heavily on our colleagues in the social sciences and humanities to think about how we communicate the risks to people in a way that will help them change their minds.”

Co-authors of the paper are Rice Ph.D. student Ebrahim Nabizadeh and undergraduates Chelsea Li, Lizzy Gaviria, Selena Guo, Karen Lu, Beck Miguel Saunders-Shultz and Gargi Samarth; Stanford undergraduate Emily Gurwitz; Jane Baldwin, an assistant professor of Earth system science at the University of California, Irvine, and an adjunct associate research scientist at the Lamont-Doherty Earth Observatory at Columbia University; and Kate Weinberger, an environmental epidemiologist at the University of British Columbia. Nittrouer is an assistant professor of management at Texas Tech.

The Rice Office of Undergraduate Research and Inquiry supported the research.

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EEPS joint faculty and Clever Planets scientist Pedram Hassanzadeh wins NSF CAREER Award

– APRIL 21, 2021

Grant will push study of atmospheric ‘blocking events’ that cause extreme weather

Remember Hurricane Harvey? Look west and there was an atmospheric block. Remember the Great Freeze of 2021? Look north and there was a block.

Atmospheric blocking is known to cause or exacerbate extreme weather events, but much about them remains a mystery. Rice University fluid dynamicist Pedram Hassanzadeh has won a prestigious National Science Foundation CAREER Award to study these events with an eye toward better understanding the physics behind their complex mechanics.

Pedram Hassanzadeh

Pedram Hassanzadeh

CAREER grants are awarded to fewer than 400 early career engineers and scientists each year who are expected to make significant impact in their disciplines.

The five-year, $735,000 award will allow Hassanzadeh and his lab to study blocks, which are large-scale, quasi-stationary, high-pressure systems that persist from five days to a few weeks in the middle latitudes between 40 and 60 degrees. In the northern hemisphere, this includes most of the United States and Canada.

“The main component of the middle latitude atmosphere is the jet stream of strong, turbulent winds in the first 10 kilometers of the atmosphere that generally go from west to east,” said Hassanzadeh, an assistant professor of mechanical engineering at Rice’s Brown School of Engineering. “They can be pretty fast, about 100 miles per hour on average, and you see them as wavy lines on the weather.

“The news also shows you high- and low-pressure systems, and generally these systems move and local weather changes daily,” he said. “But sometimes these high-pressure systems stop moving. They get stuck. And when that happens for more than five days, they’re called blocking events.”

They can wreak havoc, prompting heat waves and cold spells. “In 2010, there was a heatwave over Russia that lasted for a month and killed thousands,” Hassanzadeh said. “In 2003, there was one in France. And specifically for Houston, one reason Harvey didn’t move was because a blocking event over the western U.S., with clockwise circulation, prevented it from moving up. This year, during the cold snap, there was a blocking event over Canada.

“These events show up a lot in association with extreme weather but their dynamics are still not well-understood, even though people have been looking at them since the 1940s,” Hassanzadeh said. Poor understanding of the dynamics of blocks has hindered decades of effort focused on improving the prediction of extreme events and projecting how these events might change in the future, he said.

Blocks are thought to involve complex interactions between small and large turbulent swirling flows, and understanding them requires novel methods and approaches, Hassanzadeh said. His group has been developing such methods for atmospheric turbulence and extreme events.

An earlier study from his group used climate models to suggest blocking events in the northern hemisphere will become as much as 17% larger due to anthropogenic climate change.

Hassanzadeh also won one of 26 grants from the Office of Naval Research Young Investigator Program in 2020 to pursue improved weather/climate modeling capabilities using deep learning.

The CAREER grant includes funds for a Research Experiences for Teachers program with research positions and workshops for high-school science teachers. The grant will also facilitate the development of materials to teach climate science and a course to introduce college students to climate science and applications of math, advanced computing and artificial intelligence to climate research.

Perserverance has Landed! Mars 2020 scientist Kirsten Siebach led EEPS landing party


EEPS assistant professor and Mars 2020 scientist Kirsten Siebach answers questions about the mission during EEPS virtual landing party.

Thursday February thee 18th was a big day.  From her office in the Keith Wiess Geological Laboratories, EEPS planetary scientist Kirsten Siebach led a Mars 2020 mission virtual landing party. More than 120 participants were treated to a first-hand account of the upcoming landing from one of only 13 scientists chosen to operate the rover and help select samples.


Siebach answered numerous questions about the Mars 2020 mission, the Perseverance Rover and its analytical instrument payload, and the sample collection activities that she will be helping to direct. You can watch both the Q&A and entire landing party zoom meeting HERE.

About 5 minutes before Perseverance lands, Kirsten Siebach joins undergraduate Madison Morris in the Chevron Visualization Lab to watch the landing on the large projection screen.


At about 5 minutes from Mars 2020 atmospheric entry, Kirsten moved to the EEPS Chevron Visualization Laboratory where she watched the final countdown—known as Entry Descent and Landing or EDL, with Rice undergraduate Madison Morris.  Morris is working with Siebach on research related to the upcoming rover activities.

The final 7-10 minutes, known as the ‘seven minutes of terror’, is the period during which the spacecraft must operate on its own, with no eyes to see and a 14 minute data delay back to Earth.

During those seven minutes, the spacecraft enters Mars atmosphere at almost 12,000 miles per hour (19,000 kmh).  Facing towards the planet, a heat shield is the only protection the rover has as it descends down to an altitude of about 1 mile (1.5 km).  The descent module then fires its engines to slow the spacecraft while JPL’s new terrain relative navigation system (TRN) identifies a place to land. The TRN scans the surface and compares it with maps of a landing ellipse that are already loaded into its database. A signal from the TRN triggers the deployment of a 70-foot (21-meter) diameter parachute that slows the craft further, bringing its descent down to a few meters per second. Finally, the hovering-landing sky crane system lowers the rover the rest of the way to the ground.

The flight engineers at the Jet Propulsion Laboratory create a graphic that tracks Mars 2020 spacecraft milestones. Siebach and Morris watch intently the final steps of the deployment of the rover by the sky crane.

Siebach sits in silence, listening to the engineers mark each step in the process.  At the final minute she stands, looking intently at the screen.  As the flight engineers signal a successful deployment of the sky crane, cheers erupt on screen and in the Viz Lab.  Perseverance has landed!!!

Clenched fists and happy exclamations instead of hugs in celebration of a successful landing!


And the first picture from Jezero crater arrives.

Perseverance is proceeded by four other rovers, Sojourner in 1997, Spirt and Opportunity in 2004, and Curiosity in 2012. Perseverance is the largest, most advanced rover NASA has sent to another world. It traveled 293 million miles (472 million km) – over 203 days – to get to Mars. It will look directly for signs of past life on Mars, test ISRU tools, and collect samples from one of Mars oldest regions—what scientists believe is a river delta. The rocks in this region could tell us about Mars earliest wet history of the Red Planet and thus is a good target for signatures of past life.


Mars Perseverance rover scientist Kirsten Siebach is excited to see the first image from Jezero crater sent by Perseverance’s hazard camera.

Postdoc Sahand Hajimirza’s collaborative research on Yellowstone’s Steamboat Geyser highlighted

Steamboat Geyser in Yellowstone National Park is active again!

Considered the worlds tallest active geyser, the 400 foot jet of water can be tough for the average tourist to witness, with quiescent periods lasting as long as 50 years.  Yet since 2018, Steamboat has erupted more times than it has in the last half century.

Image and caption from Berkeley News: A 2019 eruption of Steamboat Geyser in the Norris Geyser Basin of Yellowstone National Park. The geyser’s first documented activity was in 1878, and it has turned off and on sporadically since, once going for 50 years without erupting. In 2018 it reactivated after a three-and-a-half-year hiatus, for reasons that are still unclear. (UC Berkeley photo by Mara Reed)

Sahand Hajimirza is on the team (with lead author Dr. Mara Reed and senior author Professor Michael Manga from University of California at Berkeley) that wanted to know why.

Geysers, from the name describing water that erupts from the ground, have some thermodynamic similarities to volcanic eruptions.  Yet geyser eruptions, which range in size from bubbling pools to extraordinary skyward jets such as Steamboat, are much rarer than volcanoes, and according to the U.S. Geological survey, number less than a thousand in the world, with most of them found in Yellowstone National Park.

During the 2019 CIDER (Cooperative Institute of Dynamic Earth Research hosted by UC Berkeley), which focused on volcanic and hydrothermal eruptions, a group of researchers set out to study the reawakening of Steamboat. Sahand’s expertise in the dynamics of volcanic eruption helped the group to address what makes Steamboat the tallest active geyser in the world.

Six members of the science team assembled around a table in McCone Hall at UC Berkeley in the summer of 2019, at work on the Steamboat Geyser project. Clockwise from lower left, Carolina Munoz-Saez, Anna Barth, Sahand Hajimirza, Tarsilo Girona, Sin-Mei Wu and Majid Rasht-Behesht. The three questions and hypotheses the team analyzed are on the greenboard, while the fluid dynamics equations that describe a geyser eruption are on the whiteboard. (UC Berkeley photo by Michael Manga)

Sahand builds thermodynamical models that show how the thermal energy of water and steam drives geyser eruptions. His model, published in December in the Proceedings of the National Academy of Sciences, suggests geysers with a deeper water reservoir, that directly feeds the eruption have taller plumes.  The model hypothesis was verified when tested against a worldwide database of geyser plume height and reservoir depth, and then compared with data collected from Steamboat.

Sahand says the work is not finished; there are several questions that are left unanswered. Scientists still don’t know what initiated the current eruption phase that started in 2018. The other is more basic- why do geysers erupt?

“We know geysers need water, heat and a proper plumbing system. But we still do not know how the combination of these three factors lead to an eruption, “ says Sahand.

While the study rules out processes such as recent earthquakes or significant external water source (such as snowmelt) as factors for the sudden increase in activity, the mystery will keep scientists and Sahand looking for the answers.

For more information about the paper and other press coverage, go to the following links:


Biochar helps hold water, saves money

– OCTOBER 19, 2020

The abstract benefits of biochar for long-term storage of carbon and nitrogen on American farms are clear, and now new research from Rice University shows a short-term, concrete bonus for farmers as well.

That would be money. To be precise, money not spent on irrigation.

In the best-case scenarios for some regions, extensive use of biochar could save farmers a little more than 50% of the water they now use to grow crops. That represents a significant immediate savings to go with the established environmental benefits of biochar.

Biochar’s benefits for the long-term sequestration of carbon and nitrogen on American farms are clear, but new research from Rice University shows it can help farmers save money on irrigation as well. The study showed that sandy soil, in particular, gains ability to retain more water when amended with biochar. Courtesy of the Masiello Lab

The open-access study appears in the journal GCB-Bioenergy.

Biochar is basically charcoal produced through pyrolysis, the high-temperature decomposition of biomass, including straw, wood, shells, grass and other materials. It has been the subject of extensive study at Rice and elsewhere as the agriculture industry seeks ways to enhance productivity, sequester carbon and preserve soil.

The new model built by Rice researchers explores a different benefit, using less water.

“There’s a lot of biochar research that focuses mostly on its carbon benefits, but there’s fairly little on how it could help stakeholders on a more commercial level,” said lead author and Rice alumna Jennifer Kroeger, now a fellow at the Science and Technology Policy Institute in Washington, D.C. “It’s still an emerging field.”

The study co-led by Rice biogeochemist Caroline Masiello and economist Kenneth Medlock provides formulas to help farmers estimate irrigation cost savings from increased water-holding capacity (WHC) with biochar amendment.

Jennifer Kroeger

Jennifer Kroeger

The researchers used their formulas to reveal that regions of the country with sandy soils would see the most benefit, and thus the most potential irrigation savings, with biochar amendment, areas primarily in the southeast, far north, northeast and western United States.

The study analyzes the relationship between biochar properties, application rates and changes in WHC for various soils detailed in 16 existing studies to judge their ability to curtail irrigation.

The researchers defined WHC as the amount of water that remains after allowing saturated soil to drain for a set period, typically 30 minutes. Clay soils have a higher WHC than sandy soils, but sandy soils combined with biochar open more pore space for water, making them more efficient.

WHC is also determined by pore space in the biochar particles themselves, with the best results from grassy feedstocks, according to their analysis.

In one comprehensively studied plot of sandy soil operated by the University of Nebraska-Lincoln’s Agricultural Water Management Network, Kroeger calculated a specific water savings of 37.9% for soil amended with biochar. Her figures included average rainfall and irrigation levels for the summer of 2019.

The researchers noted that lab experiments typically pack more biochar into a soil sample than would be used in the field, so farmers’ results may vary. But they hope their formula will be a worthy guide to those looking to structure future research or maximize their use of biochar.

More comprehensive data for clay soils, along with better characterization of a range of biochar types, will help the researchers build models for use in other parts of the country, they wrote.

A map shows low, mid-range and high estimates for theoretical water-holding capacity changes in soil with the addition of biochar. A study by Rice University scientists showed how biochar can help curtail excess irrigation in agriculture, depending on the type of soil and biochar characteristics. Courtesy of the Masiello Lab

“This study draws attention to the value of biochar amendment especially in sandy soils, but it’s important to note that the reason we are calling out sandy soils here is because of a lack of data on finer-textured soils,” Masiello said. “It’s possible that there are also significant financial benefits on other soil types as well; the data just weren’t available to constrain our model under those conditions.”

“Nature-based solutions are gaining traction at federal, state and international levels,” Medlock added, noting the recently introduced Growing Climate Solutions Act as one example. “Biochar soil amendment can enhance soil carbon sequestration while providing significant co-benefits, such as nitrogen remediation, improved water retention and higher agricultural productivity. The suite of potential benefits raises the attractiveness for commercial action in the agriculture sector as well as supportive policy frameworks.”

Rice alumna Ghasideh Pourhashem, a nonresident faculty scholar at the Center for Energy Studies (CES) at Rice’s Baker Institute for Public Policy, is co-author of the paper. Masiello is the W. Maurice Ewing Professor, a professor of Earth, environmental and planetary sciences and a faculty scholar at the CES. Medlock is the James A. Baker, III, and Susan G. Baker Fellow in Energy and Resource Economics at the Baker Institute, senior director of the CES and an adjunct assistant professor of economics.

The Rice Department of Earth, Environmental and Planetary Sciences and the Rice Shell Center for Sustainability supported the research.

JGR Planets: Constraining Ancient Magmatic Evolution on Mars Using Crystal Chemistry of Detrital Igneous Minerals in the Sedimentary Bradbury Group, Gale Crater, Mars

V. Payré, K. L. Siebach, R. Dasgupta, A. Udry, E. B. Rampe, S. M. Morrison


Understanding magmatic processes is critical to understanding Mars as a system, but Curiosity’s investigation of dominantly sedimentary rocks has made it difficult to constrain igneous processes. Igneous classification of float rocks is challenging because of the following: (1) the possibility that they have been affected by sedimentary processes or weathering, and (2) grain size heterogeneity in the observed rock textures makes the small‐scale compositions measured by rover instruments unreliable for bulk classification. We avoid these ambiguities by using detrital igneous mineral chemistry to constrain models of magmatic processes in the source region for the fluvio‐deltaic Bradbury group. Mineral chemistry is obtained from X‐ray diffraction of three collected samples and a new stoichiometric and visual filtering of ~5,000 laser induced breakdown spectroscopy (LIBS) spots to identify compositions of individual igneous minerals. Observed mineral chemistries are compared to those produced by MELTS thermodynamic modeling to constrain possible magmatic conditions. Fractionation of two starting primary melts derived from different extent of adiabatic decompression melting of a primitive mantle composition could result in the crystallization of all minerals observed. Crystal fractionation of a subalkaline and an alkaline magma is required to form the observed minerals. These results are consistent with the collection of alkaline and subalkaline rocks from Gale as well as clasts from the Martian meteorite Northwest Africa 7034 and paired stones. This new method for constraining magmatic processes will be of significant interest for the Mars 2020 mission, which will also investigate an ancient volcaniclastic‐sedimentary environment and will include a LIBS instrument.

Future Texas hurricanes: Fast like Ike or slow like Harvey?

– JULY 6, 2020

Climate change will make fast-moving storms more likely in late 21st-century Texas

Climate change will intensify winds that steer hurricanes north over Texas in the final 25 years of this century, increasing the odds for fast-moving storms like 2008’s Ike compared with slow-movers like 2017’s Harvey, according to new research.

Hurricane Harvey as seen from the International Space Station on Aug. 28, 2017

Hurricane Harvey as seen from the International Space Station on Aug. 28, 2017. (Photo courtesy of Randy Bresnik/NASA)

The study published online July 3 in Nature Communications examined regional atmospheric wind patterns that are likely to exist over Texas from 2075-2100 as Earth’s climate changes due to increased greenhouse emissions.

The research began in Houston as Harvey deluged the city with 30-40 inches of rain over five days. Rice University researchers riding out the storm began collaborating with colleagues from Columbia University’s Lamont-Doherty Earth Observatory (LDEO) and Harvard University to explore whether climate change would increase the likelihood of slow-moving rainmakers like Harvey.

“We find that the probability of having strong northward steering winds will increase with climate change, meaning hurricanes over Texas will be more likely to move like Ike than Harvey,” said study lead author Pedram Hassanzadeh of Rice.

Pedram Hassanzadeh

Pedram Hassanzadeh

Harvey caused an estimated $125 billion in damage, matching 2005’s Katrina as the costliest hurricane in U.S. history. Ike was marked by coastal flooding and high winds that caused $38 billion damage across several states. It was the second-costliest U.S. hurricane at the time and has since moved to sixth. Ike struck Galveston around 2 a.m. Sept. 13, 2008, crossed Texas in less than one day and caused record power outages from Arkansas to Ohio on Sept. 14.

Hassanzadeh, a fluid dynamicist, atmospheric modeler and assistant professor of both mechanical engineering and Earth, environmental and planetary sciences, said the findings don’t suggest that slow-moving storms like Harvey won’t happen in late 21st century. Rather, they suggest that storms during the period will be more likely to be fast-moving than slow-moving. The study found the chances that a Texas hurricane will be fast-moving as opposed to slow-moving will rise by about 50% in the last quarter of the 21st century compared with the final quarter of the 20th century.

Suzana Camargo

Suzana Camargo

“These results are very interesting, given that a previous study that considered the Atlantic basin as a whole noticed a trend for slower-moving storms in the past 30 years,” said study co-author Suzana Camargo, LDEO’s Marie Tharp Lamont Research Professor. “By contrast, our study focused on changes at the end of the 21st century and shows that we need to consider much smaller regional scales, as their trends might differ from the average across much larger regions.”

Hassanzadeh said the researchers used more than a dozen different computer models to produce several hundred simulations and found that “all of them agreed on an increase in northward steering winds over Texas.”

Steering winds are strong currents in the lower 10 kilometers of the atmosphere that move hurricanes.

Map depicting total rainfall from 2017's Hurricane Harvey

Map depicting total rainfall from 2017’s Hurricane Harvey. (Image courtesy of NOAA)

“It doesn’t happen a lot, in studying the climate system, that you get such a robust regional signal in wind patterns,” he said.

Harvey was the first hurricane Hassanzadeh experienced. He’d moved to Houston the previous year and was stunned by the slow-motion destruction that played out as bayous, creeks and rivers in and around the city topped their banks.

“I was sitting at home watching, just looking at the rain when (study co-author) Laurence (Yeung) emailed a bunch of us, asking ‘What’s going on? Why is this thing not moving?’” Hassanzadeh recalled. “That got things going. People started replying. That’s the good thing about being surrounded by smart people. Laurence got us started, and things took off.”

Laurence Yeung

Laurence Yeung

Ebrahim Nabizadeh

Ebrahim Nabizadeh

Yeung, an atmospheric chemist, Hassanzadeh and two other Rice professors on the original email, atmospheric scientist Dan Cohan and flooding expert Phil Bedient, won one of the first grants from Rice’s Houston Engagement and Recovery Effort (HERE), a research fund Rice established in response to Harvey.

“Without that, we couldn’t have done this work,” Hassanzadeh said. The HERE grant allowed Rice co-author Ebrahim Nabizadeh, a graduate student in mechanical engineering, to work for several months, analyzing the first of hundreds of computer simulations based on large-scale climate models.

The day Harvey made landfall, Hassanzadeh also had reached out to Columbia’s Chia-Ying Lee, an expert in both tropical storms and climate downscaling, procedures that use known information at large scales to make projections at local scales. Lee and Camargo used information from the large-scale simulations to make a regional model that simulated storms’ tracks over Texas in a warming climate.

Chia-Ying Lee

Chia-Ying Lee

“One challenge of studying the impact of climate change on hurricanes at a regional level is the lack of data,” said Lee, a Lamont Assistant Research Professor at LDEO. “At Columbia University, we have developed a downscaling model that uses physics-based statistics to connect large-scale atmospheric conditions to the formation, movement and intensity of hurricanes. The model’s physical basis allowed us to account for the impact of climate change, and its statistical features allowed us to simulate a sufficient number of Texas storms.”

Hassanzadeh said, “Once we found that robust signal, where all the models agreed, we thought, ‘There should be a robust mechanism that’s causing this.’”

He reached out to tropical climate dynamicist Ding Ma of Harvard to get another perspective.

“We were able to show that changes in two important processes were joining forces and resulting in the strong signal from the models,” said Ma, a postdoctoral researcher in Earth and planetary sciences.

Ding Ma

Ding Ma

One of the processes was the Atlantic subtropical high, or Bermuda high, a semipermanent area of high pressure that forms over the Atlantic Ocean during the summer, and the other was the North American monsoon, an uptick in rainfall and thunderstorms over the southwestern U.S. and northwestern Mexico that typically occurs between July and September. Hassanzadeh said recent studies have shown that each of these are projected to change as Earth’s climate warms.

“The subtropical high is a clockwise circulation to the east that is projected to intensify and shift westward, producing more northward winds over Texas,” he said. “The North American monsoon, to the west, produces a clockwise circulation high in the troposphere. That circulation is expected to weaken, resulting in increased, high-level northward winds over Texas.”

Hassanzadeh said the increased northward winds from both east and west “gives you a strong reinforcing effect over the whole troposphere, up to about 10 kilometers, over Texas. This has important implications for the movement of future Texas hurricanes.”

Models showed that the effect extended into western Louisiana, but the picture became murkier as the researchers looked further east, he said.

Map depicting total rainfall from 2008's Hurricane Ike

Map depicting total rainfall from 2008’s Hurricane Ike. (Image by Hal Pierce/SSAI/NASA

“You don’t have the robust signal like you do over Texas,” Hassanzadeh said. “If you look at Florida, for instance, there’s a lot of variation in the models. This shows how important it is to conduct studies that focus on climate impacts in specific regions. If we had looked at all of North America, for example, and tried to average over the whole region, we would have missed this localized mechanism over Texas.”

Bedient is the Herman Brown Professor of Engineering and department chair of civil and environmental engineering and director of Rice’s Severe Storm Prediction, Education and Evacuation from Disasters Center. Cohan is an associate professor of civil and environmental engineering. Yeung is the Maurice Ewing Career Development Assistant Professor in Earth Systems Science in the Department of Earth, Environmental and Planetary Sciences.

The research was supported by the National Science Foundation, NASA, the Gulf Research Program of the National Academies of Sciences, Engineering and Medicine’s Early-Career Research Fellowship Program, Rice’s Houston Engagement and Recovery Effort Fund, Columbia’s Center for Climate and Life Fellows Program, the National Oceanic and Atmospheric Administration and the New York State Energy Research and Development Authority. Computational resources were provided by the National Science Foundation’s Extreme Science and Engineering Discovery Environment, the National Center for Atmospheric Research’s Computational and Information Systems Lab and Rice’s Center for Research Computing.

EEPS’s Stand Against Systemic Racism