Monitoring polar ice melting by combining data from different satellites

Scientists develop a combinational approach to more accurately estimate changes in elevation in the Antarctic ice sheet

Peer-Reviewed Publication

SPIE--INTERNATIONAL SOCIETY FOR OPTICS AND PHOTONICS

 

IMAGE: (A) BOUNDARIES OF SENTINEL-3 (BLUE CIRCLE) AND CRYOSAT-2 (YELLOW LOOP). THE STUDY REGION IS INDICATED IN LIGHT BLUE. (B) COMPARISON BETWEEN THE ELEVATION CHANGES IN THE STUDY REGION EXTRACTED WITHOUT FILTERING (LEFT) AND WITH FILTERING (RIGHT). FILTERING REMOVES OUTLIERS VIA DATA CLUSTERING, IMPROVING THE ACCURACY OF THE RESULTS. view more 

CREDIT: THE AUTHORS, DOI 10.1117/1.JRS.16.034514.

The Antarctic region is particularly vulnerable to climate change, and studies have shown that the melting of Antarctic ice sheets has accelerated considerably in recent years. As a result, sea levels continue to rise globally, threatening the lives of coastal inhabitants.

Given the potentially devastating effects of the melting ice sheets in Antarctica, scientists have been closely monitoring their topography and height for decades. This is usually done using satellites equipped with special altimeter radars, which provide a nearly continuous coverage of most of the Antarctic region. In many cases, data from multiple satellite missions are combined to achieve higher accuracy and precision as well as to compare data from different periods. However, combining these data is not a straightforward process because of the different instrumentation and processing techniques involved.

In a recent study, researchers led by Professor Jingjuan Liao from the Chinese Academy of Sciences tested a new approach that combined elevation data of the Antarctic ice sheet from two different satellites. As explained in their paper published in SPIE’s Journal of Applied Remote Sensing, their goal was to obtain a more accurate map of the latest elevation changes in the Antarctic ice sheet as well as validate their data analysis methods.

The data used in the study came from radar altimeters installed in CryoSat-2 and Sentinel-3, and corresponded to surface elevation changes in the ice sheet between 2016 and 2019. CryoSat-2, which was launched in 2010, provides greater coverage of the Antarctic ice sheet and has better accuracy in complex edge regions of ice sheets. In contrast, Sentinel-3, launched in 2016, offers higher resolution under most conditions and performs better in large flat areas.

To improve the accuracy of the results, the team first filtered the data using a clustering algorithm. Essentially, the algorithm divided up the input data points into clusters according to their value and rejected clusters containing outliers (which likely represented large measurement errors).

Additionally, the team employed a fitting model designed to extract elevation changes from the combined satellite data while correcting for measurement biases. To validate the results of this model, they compared them with reliable elevation data gathered using other altimeters.

Their analyses showed that the average elevation of the ice sheets had decreased at a rate of 4.3 ± 0.9 cm/year during 2016-2019. However, the inner continental ice sheet, where the terrain is mostly flat, had shown a milder decrease of only 1.1 ± 0.3 cm per year. “We derived a correlation between elevation changes and the surface slope, with rapid elevation changes occurring more often in areas with large terrain undulations, such as mountainous and marginal ice shelves,” Liao said.

With these results, the researchers are hopeful that their approach would find applications in future investigations of Antarctic ice sheets. “Our study presents an effective method for improving the measurement accuracy by combining elevation information from new radar altimeters. This could enable a long-term monitoring of global climate change in the Antarctic region,” Liao said.

Continued efforts on this front could help mitigate the adverse effects of global warming in the poles.

Read the Gold Open Access article by S. Li, J. Liao, and L. Zhang, “Extraction and analysis of elevation changes in Antarctic ice sheet from CryoSat-2 and Sentinel-3 radar altimeters,” J. Applied Remote Sensing 16(3) 034514 (2022), doi 10.1117/1.JRS.16.034514.

---

JOURNAL

Journal of Applied Remote Sensing

DOI

10.1117/1.JRS.16.034514 

ARTICLE TITLE

Extraction and analysis of elevation changes in Antarctic ice sheet from CryoSat-2 and Sentinel-3 radar altimeters

ARTICLE PUBLICATION DATE

2-Aug-2022

Persistent low wages linked to faster memory decline in later life

Peer-Reviewed Publication

COLUMBIA UNIVERSITY'S MAILMAN SCHOOL OF PUBLIC HEALTH

Sustained low wages are associated with significantly faster memory decline, according to a new study by Columbia University Mailman School of Public Health. While low-wage jobs have been associated with health outcomes such as depressive symptoms, obesity, and hypertension, which are risk factors for cognitive aging, until now no prior studies had examined the specific relationship between low wages during working years and later-life cognitive functioning. The findings are published in the American Journal of Epidemiology and were reported today at the 2022 Alzheimer’s Association International Conference® (AAIC®) 2022 Promoting Diverse Perspectives: Addressing Health Disparities Related to Alzheimer’s and All Dementias.

“Our research provides new evidence that sustained exposure to low wages during peak earning years is associated with accelerated memory decline later in life,” said Katrina Kezios, PhD, postdoctoral researcher in the Department of Epidemiology at Columbia University Mailman School of Public Health and first author. “This association was observed in our primary sample as well as in a validation cohort.”

Research into the effects of lower income on health is rapidly expanding. Using records from the national Health and Retirement Study (HRS) of adults for the years 1992-2016, the researchers analyzed data from 2,879 individuals born between 1936 and 1941.  Low-wage was defined as hourly wage lower than two-thirds of the federal median wage for the corresponding year. Kezios and colleagues categorized study participants’ history of low wages into those who never earned low wages, intermittently earned low wages, or always earned low wages based on wages earned from 1992 to 2004 and then examined the relationship with memory decline over the next 12 years from 2004-2016

The researchers found that, compared with workers never earning low wages, sustained low-wage earners experienced significantly faster memory decline in older age. They experienced approximately one excess year of cognitive aging per a 10-year period; in other words, the level of cognitive aging experienced over a 10-year period by sustained low-wage earners would be what those who never earned low wages experienced in 11 years.

In the U.S., the federal minimum wage has remained $7.25 per hour since 2009. While economic growth has increased since then, wage and salary growth for employees - particularly those in low-wage jobs - have slowed over time, and the minimum wage has not kept up with inflation.

“Increasing the federal minimum wage, for example to $15 per hour, remains a gridlock issue in Congress, “said Kezios. 

“Our findings suggest that social policies that enhance the financial well-being of low-wage workers may be especially beneficial for cognitive health,” said senior author Adina Zeki Al Hazzouri, PhD, assistant professor of epidemiology at Columbia Mailman School and the Columbia Butler Aging Center. “Future work should rigorously examine the number of dementia cases and excess years of cognitive aging that could be prevented under different hypothetical scenarios that would increase the minimum hourly wage.”

Columbia University Mailman School of Public Health

Founded in 1922, the Columbia University Mailman School of Public Health pursues an agenda of research, education, and service to address the critical and complex public health issues affecting New Yorkers, the nation and the world. The Columbia Mailman School is the fourth largest recipient of NIH grants among schools of public health. Its nearly 300 multi-disciplinary faculty members work in more than 100 countries around the world, addressing such issues as preventing infectious and chronic diseases, environmental health, maternal and child health, health policy, climate change and health, and public health preparedness. It is a leader in public health education with more than 1,300 graduate students from 55 nations pursuing a variety of master’s and doctoral degree programs. The Columbia Mailman School is also home to numerous world-renowned research centers, including ICAP and the Center for Infection and Immunity. For more information, please visit www.mailman.columbia.edu.

JOURNAL

American Journal of Epidemiology

James Webb Space Telescope depicts Cartwheel Galaxy in stunning detail


Kris Holt
·Contributing Reporter
Tue, August 2, 2022 

NASA, ESA, CSA, STScI and Webb ERO Production Team

NASA and its partners on the James Webb Space Telescope have shared more spectacular images from the observatory. This time around, they provided a fresh look at the Cartwheel Galaxy, which Hubble and other telescopes previously observed. NASA said JWST has been able to reveal new details about both star formation and the black hole at the center of the galaxy, which is around 500 million light years from Earth.

Using infrared light detection, JWST was able to peer through the dust that obscured the Cartwheel Galaxy from view when other telescopes observed it. The above image is a composite from JWST's Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI). The JWST website has higher-resolution versions.

Data from NIRCam, which is the JWST's primary imager, is colored in blue, orange, and yellow, while MIRI's data is in red. NASA says the blue dots that appear in the red swirls of dust are individual stars or pockets of star formation. "NIRCam also reveals the difference between the smooth distribution or shape of the older star populations and dense dust in the core compared to the clumpy shapes associated with the younger star populations outside of it," the agency noted.

MIRI, meanwhile, was able to unearth more details about the galaxy's dust. It detected regions that are rich in hydrocarbons and other chemical compounds, along with silicate dust, which is similar to a lot of the dust present on Earth. Those regions form several spiraling spokes that led to the naming of the Cartwheel Galaxy. Hubble was previously able to image the spokes, but they're much clearer in the JWST observations. NASA also provided a MIRI-only image of the galaxy:

This image from Webb’s Mid-Infrared Instrument (MIRI) shows a group of galaxies, including a large distorted ring-shaped galaxy known as the Cartwheel. The Cartwheel Galaxy, located 500 million light-years away in the Sculptor constellation, is composed of a bright inner ring and an active outer ring. While this outer ring has a lot of star formation, the dusty area in between reveals many stars and star clusters.

The Cartwheel Galaxy formed following a collision between a large spiral galaxy and a smaller one. It has two rings, a bright inner ring and a colorful outer one. The outer ring has been expanding from the center of the collision for around 440 million years.

The interior ring contains "a tremendous amount of hot dust," NASA said. The brightest areas host gigantic young star clusters. The outer ring, meanwhile, features star formation and supernovas. When it expands and hits surrounding gas, star formation occurs.

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NASA, the European Space Agency, Canadian Space Agency and the Space Telescope Science Institute last month revealed the first stunning full-color images from JWST. They included one that showed the "Cosmic Cliffs" of the Carina Nebula and a peek at stars in the early stages of formation. The telescope has also caught sight of Earendel, the most distant star that we know of in the universe. While it's still very early days for the JWST's science operations, it's already helping scientists develop a deeper understanding of the cosmos — as well as providing some incredible images for the rest of us to admire.

Green Hydrogen Can Help Latin America’s Energy Transition

By Oxford Business Group - Jul 30, 2022, 

• Amid the energy transition, Latin American countries are investing in hydrogen.
• 
  
• The fuel is seen as a potential solution for energy, food, and environmental crises.
• 
  
• With abundant natural resources, Latin America is eyeing exports to Europe and Asia.
• 
  
• While investment is ramping up, most mega-projects target 2030 for completion.

With countries and energy companies around the world looking to accelerate their transitions towards cleaner energy resources, Latin American nations are developing plans to scale up the production, consumption and export of so-called green hydrogen, which is generated from clean energy resources.

One of the most recent, high-profile developments came in June, when the Argentine province of Tierra del Fuego – located at the southernmost tip of South America – outlined plans to develop a hydrogen and ammonium industry.

The province is attempting to utilise the region’s ample wind resources to attract $6bn in investment in technologies to produce the fuel. This includes investment in wind farms to generate electricity that can be used to power electrolysers, which remove oxygen atoms from water to produce hydrogen.

Once established, some of the project’s hydrogen will be used to make ammonium, which in addition to being used to create fertiliser, can also serve as a carrier fuel for transporting hydrogen through pipelines to downstream markets.

Along with renewable sources like solar and wind, hydrogen is seen as a potential low-carbon or zero-carbon fuel that is key to the transition away from fossil fuels.

While countries across Latin America and the Caribbean are focused on green hydrogen, hydrocarbons-producing countries like Argentina, Colombia, and Trinidad and Tobago can use carbon-capture utilisation and storage technologies to remove carbon emissions from their production process and generate so-called blue hydrogen.

The Tierra del Fuego announcement comes as appetite for hydrogen – and its economic and environmental benefits – continues to grow.

While there were just three hydrogen pilot projects in Latin America in 2019 – in Argentina, Chile and Costa Rica – by 2021 the region had a pipeline of more than 25 projects, according to the International Energy Agency, with many of them GW-scale mega-projects that intend to export hydrogen to Europe and Asia.

Economic benefits

Hydrogen has significant potential as a clean energy substitute for fossil fuels in power generation, most notably in the energy-intensive industrial sector, but also as a transport fuel across numerous sectors.

Argentina and Brazil have the most expansive hydrogen plans on the continent and are also looking to become major export hubs to feed markets in Europe, the centre of the world’s hydrogen demand, and Asia.

As the world’s second-largest producer of hydroelectric power and home to substantial wind and solar resources, Brazil has significant potential to produce hydrogen. Some estimates suggest the country could earn $4bn-6bn by 2040 through the export of hydrogen to the EU and the US alone.

In the country’s north-east, the $5.4bn Base One green hydrogen project will be the world’s largest when completed, capable of producing 600,000 tonnes per year from 3.4 GW of combined solar and wind power generation capacity.

Beyond energy, hydrogen has important applications for the food sector, among others, highlighting the positive effects that developing hydrogen can have in addressing global challenges.

“Hydrogen has multiple applications, not only for the energy sector but in the manufacturing of fertilisers, which is of an increasingly critical concern for countries around the world,” Rodrigo Rodriguez Tornquist, Secretary of Climate Change, Sustainable Development and Innovation at Argentina’s Ministry of Environment and Sustainable Development, told OBG.

“Globally, three major crises are being discussed: the energy, food and environmental crises. Hydrogen is a key component in all three, as it generates a more sustainable energy solution, enables food production and accelerates the decarbonisation of the economy.”

Reaching export markets

To fulfil their hydrogen ambitions, Latin American countries need to consider the most challenging and expensive part of the energy industry: transport.

This will likely involve both internal pipelines for intracontinental markets and seaborne export terminals to reach Europe and Asia.

One of hydrogen’s most appealing aspects is that hydrocarbon pipelines can be repurposed to transport it. Latin America and the Caribbean already has strong pipeline networks in both the north, starting from Venezuela and T&T, and the south, from Bolivia, which feed into Argentina and Brazil and could serve these export ambitions.

In Tierra del Fuego’s case, the province’s location at the tip of South America means that it is also eyeing potential exports to Asia.

Aside from supplying export markets, the production of hydrogen could also result in the use of more cost-effective and environmentally friendly fuels domestically.

“Latin America not only has the potential to supply high-demand international markets like Europe, which has been more aggressive in its clean energy adoption, but also to displace imported fuels,” Alfonso Blanco, executive director of the Latin American Energy Organization, told OBG. “The large natural advantages of countries like Argentina and Chile to produce renewable energy enables the low-cost and large-scale production of green hydrogen.”

Development timelines

Hydrogen’s uptake in the global energy system will be decades-long, with most mega-projects in Latin America looking to 2030 as a target date for completion. This timeline gives governments more time to establish the regulatory, institutional, legal and commercial frameworks that will allow hydrogen to penetrate the global energy system in a meaningful way.

For instance, one of the largest projects in Latin America is the $8.4bn Pampas facility in Argentina’s Río Negro province, which seeks to generate 15 GW in power that will produce 2.2m tonnes of green hydrogen by 2030.

Similarly, Uruguay has crafted a roadmap for hydrogen that aims to build 10 GW of renewable energy to power electrolysers as part of plans to become a net-exporter in the 2030s.

Ultimately, the key to developing such capital-intensive, low-carbon hydrogen projects will be cooperation between government and business, which industry figures say must continue to include incentives for renewable energy.

“On a global level, hydrogen will allow for the decarbonisation of many sectors – in terms of not only electricity generation, but also energy consumption, especially in the industrial and transport sectors,” Rodriguez Tornquist told OBG. “However, this transition requires a long-term roadmap and significant resources, which will require all stakeholders in the public and private sector to align their needs and expectations.”

By Oxford Business Group

THE NEW FRONTIER

More Oil Discoveries Boost Guyana’s Offshore Boom

By Matthew Smith - Jul 30, 2022

• Guyana has seen a string of oil discoveries, quickly positioning it as one of the world’s hottest offshore drilling locations.
• 
  
• ExxonMobil has led the charge, along with its partners Hess Corporation and CNOOC.
• 
  
• Guyana’s gross domestic product grew by just under 20% in 2021, and is on track to expand even further.

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The former British colony of Guyana, a nation whose economy was hit hard by the pandemic, has emerged as the world’s hottest offshore drilling location. Since 2015 global energy major ExxonMobil as well as its partners Hess Corporation and CNOOC have made a slew of quality oil discoveries in the offshore Stabroek Block which have delivered resources in excess of 11 billion barrels of oil. This is driving a massive economic boom for Guyana, which was among the poorest nations in Lain America and the Caribbean. According to the IMF, the micro-state’s gross domestic product grew by just under 20% during 2021 and is poised for further strong expansion. The substantial surge in oil prices which sees the international Brent benchmark up by 58% over the last year to be trading for $110 per barrel coupled with the push by big oil to decarbonize its operations are adding considerable momentum to the boom. Guyana’s government is expected to bank over $1 billion in oil revenues during 2022 which according to industry consultancy Rystad Energy will soar to $7.5 billion by the end of the decade. That will deliver a tremendous economic boom which will see Guyana’s economy grow fivefold over that period. Key to this tremendous economic opportunity is the rapid ramping up of crude oil production, with Exxon estimating that its operations will have the capacity to pump 1.2 million barrels per day by 2027, which is further oil discoveries. Exxon and its partners in the 6.6-million-acre Stabroek Block have made over 25 quality discoveries with the crude found being light and sweet with an API of 32 degrees and 0.58% sulfur content. The latest discoveries were at the Seabob and Kiru-Kiru wells in the Stabroek Block to the southeast of the Payara Project. Exxon also announced that production from the Liza oilfield in the Stabroek Block has exceeded the 340,000 barrels per day initially targeted. Earlier this month it was revealed that Exxon had lodged an application with Guyana’s Environmental Protection Agency to drill 35 exploration and appraisal wells in the Stabroek Block. When the energy supermajor’s exploration success in the block is considered along with the five discoveries made in the Stabroek Block earlier this year, the drilling campaign will make additional discoveries boosting the 11 billion barrels already discovered. That crude oil is also economic to extract. Breakeven prices range from $35 per barrel Brent for Liza Phase 1, $25 a barrel for Liza Phase 2, which recently came online, and $32 per barrel for the 220,000-barrel capacity Payara Project, which is scheduled to start production during 2024. 

 

While it is the Exxon-led consortium that is key to driving Guyana’s epic oil boom, which will see the Caribbean country become a leading oil producer, other international energy companies are also engaged in exploration drilling. British driller Tullow Oil, which is the operator of the world-class Jubilee field in offshore Guyana discovered in 2007, announced 37.5% partner Repsol, with TotalEnergies holding the remaining 25%, had spud the Beebei-Potaro well in the Kanuku Block. That wildcat well, which comes on the back of the 2020 Carapa medium oil discovery in the block where 13 feet of net oil pay was identified, is targeting a prospect that Repsol estimates contain around 200 million barrels of crude oil. The Kanuku Block lies below the southeastern tip of the Stabroek Block, where Exxon has made nearly all discoveries in offshore Guyana and is believed to lie on the same petroleum fairway. To the east of the Kanuku Block lies Block 58 offshore Suriname, where TotalEnergies and partner Apache have made five quality light oil discoveries with modelling estimating the block contains 6.5 billion barrels. Those factors, notably the slew of high-quality oil discoveries made by Exxon in the Southeastern tip of the Stabroek Block, bode well for further finds by Repsol and its partners in the Kanuku Block.

Related: U.S. Refiners Haven't Seen Fuel Demand Destruction

Most of the crude oil found so far, in offshore Guyana, has been medium to light and relatively sweet, meaning it is cheaper and easier to refine into high-quality low contaminant fuels such as gasoline and diesel. That means, particularly in comparison to neighboring Venezuela, Colombia, and Ecuador which all predominantly pump heavy sour crude oil grades, the petroleum being produced in Guyana has a low carbon footprint. Those characteristics are especially important in a world where there are significant global efforts to significantly reduce carbon emissions while ratcheting up pollution restrictions and regulations. Disappointingly for Tullow, its exploration wells in the Orinduik Block, Jethro-1 and Joe-1, found high-sulfur content heavy crude oil, which compared to the light sweet crude being pumped by Exxon from the Stabroek Block is less economically viable.

Guyana is a rapidly growing offshore drilling hotspot, accounting for nearly a fifth of discovered oil and natural gas resources globally and nearly a third of solely oil discoveries. The latest discoveries, made by Exxon and Repsol, coupled with growing light oil production will see Guyana become the third largest oil producer in Latin America after Brazil and then Mexico. That will deliver a tremendous economic windfall for the deeply impoverished South American nation which will grow with Georgetown focused on attracting greater energy investment and building urgently needed industry infrastructure.

By Matthew Smith for Oilprice.com