– 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.
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.
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.
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.
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!!!
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.
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.
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.
“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.
– 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.
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.
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.
“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.
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.
– 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.
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.
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.
“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.
“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.”
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.
“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.
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.
“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.