Friday, April 19, 2024

What are China’s long- term Antarctic ambitions?

Russia and China repeatedly rejected new marine protection areas in Antarctica
Main image courtesy of Unsplash user Derek Oyen.

From The Interpreter by Benjamin J. Sacks & Peter Dortmans

The recent opening of China’s Qinling base, its third permanent Antarctic station, has worried some Australian and American observers.
Their concerns suggest it may be time for Australia to delineate China’s Antarctic ambitions more clearly and better organise its response.

Qinling station
Image Credit : China News Service - CC BY 3.0
 
Qinling is China’s first base located adjacent to the Ross Sea, south of Australia and New Zealand and near the US McMurdo base.
Its satellite monitoring facility has raised Western apprehensions.
Qinling could become another node in China’s People’s Liberation Army-affiliated BeiDou navigation network and be used to monitor Australian and New Zealand communications.
Antarctica’s sheer remoteness and extreme climate limit its potential for Chinese military activities, at least with existing technology.

Some of Beijing’s own statements have supported these concerns, with China’s National Defense University’s Science of Military Strategy (2020) stating that “the polar regions have become an important direction for our country’s interests to expand overseas and far frontiers, and it has also proposed new issues and tasks for the use of our country’s military power”.
Elizabeth Buchanan notes that the Chinese government’s civil-military fusion law requires “all civilian research activities…to have military application or utility for China.
This extends to China’s Antarctic footprint”.

Qinling is China’s newest station to begin operations in Antarctica.
Concerns raised about China’s new research station in Antarctica : 
Qinling research station in Antarctica could intercept signals from Australia 
(ABC News: Erwin Renaldi)

While experts should be concerned, they might be worried for the wrong reasons.
Claire Young has stressed that Antarctica’s sheer remoteness and extreme climate limit its potential for Chinese military activities, at least with existing technology.
She argues that Qinling is simply too distant from Australia and New Zealand to effectively monitor their communications.
China could more easily monitor from neighbouring states or its disputed South China Sea artificial islands.

A 2023 RAND study, while acknowledging the potential military risks posed by China’s Antarctic activities, added that Chinese officials have affirmed their respect for the 1959 Antarctic Treaty and subsequent protocols, collectively known as the Antarctic Treaty System.
The Madrid Protocol, for instance, banned Antarctic mining.
China is a signatory.
 
 
The Ross Sea Marine Protected Area includes a (1) General Protection Zone; (2) Special Research Zone; and (3) Krill Research Zone (Wikimedia Commons)

What, then, are China’s long-term ambitions? Buchanan has argued that, in the Antarctic semi-regulated global commons, “presence equals power”.
RAND, through an examination of both English- and Chinese-language sources, concluded that Beijing seeks a “right to speak” in Antarctic regional affairs and that this could be part of China’s efforts to shift the balance of Antarctic influence in its favour ahead of any future Antarctic Territory renegotiation.

These efforts appear to be driven primarily by economics, especially in regard to krill fishing and mining, both of which fall under China’s vague goal of Antarctic “utilisation”.
Along with Russia, China’s long-distance fishing fleet – the world’s largest – is rapidly expanding its krill industry, deploying super trawlers in the name of scientific research (in krill research zones) that will eventually collect more krill than is allowed under the Antarctic Territory System.

Both Russia and China have repeatedly rejected new marine protection areas and are likely to continue growing their lucrative fishing industries.
China has so far resisted other signatories’ efforts to rein in its fishing ambitions.
While other signatories are willing to abide by the limits imposed by the Antarctic Territory System, China and Russia appear to want to ignore them.
Australia and its allies and partners should publicly “name-and-shame” China’s activities when and if they violate the Antarctic Territory System.
 
People attend the launch ceremony of China's first domestically built polar icebreaker, Xuelong 2, or Snow Dragon 2, at a shipyard in Shanghai, Sept. 10, 2018.

Similarly, China is eager to undertake onshore and offshore mineral extraction in Antarctica, despite being a signatory to the 1991 Madrid Protocol, which bans such activities.
Some experts posit that in the future, China may be able to develop advanced mining technologies in anticipation of the Protocol’s potential 2048 renegotiation where it may seek to legalise some forms of mining.
As the Antarctic Territory System currently has no enforcement mechanism, RAND added that Chinese Antarctic mining activities could consequently open “the floodgates for similar activities”.

Given that any signatory can call for the Antarctic Treaty’s renegotiation at any time – a privilege China has yet to invoke – it appears Beijing is biding its time while diversifying its Antarctic presence.
Under this reasoning, China’s recent actions, including the opening of Qinling base, constitute long-term shaping activities to place itself in the strongest position possible ahead of any changes to the Treaty.

How should Australia and its allies and partners respond? Some observers have highlighted the Antarctic Territory System’s provision for unannounced inspections as key to mitigating Chinese ambitions.
However, Russia has demonstrated that it can block inspections by making “station runways inaccessible” and switching off station radios “to block parties landing”.

Nengye Liu has suggested that Australia update its 2009 Australia–China Joint Statement to explicitly ensure the peaceful stability of bilateral Antarctic relations, given China’s significant Australian Antarctic Territory presence.
Australia and its allies and partners should publicly “name-and-shame” China’s activities when and if they violate the Antarctic Territory System.
Australia should consider sanctions against relevant Chinese individuals, state-owned enterprises, and the Polar Research Institute of China.

Given the uncertainties of Antarctica’s geopolitical future, as evidenced by growing concerns over China’s regional activities and ambitions, it may be time for the Australian Department of Foreign Affairs and Trade to establish its own Antarctic Affairs office.
Such an office could be charged with establishing Australia’s future strategy and contingencies, working across government to implement its official position, and negotiating and building an international consensus with allies and partners.

Links :

Thursday, April 18, 2024

NASA’s PACE data on Ocean, Atmosphere, Climate now available


NASA’s PACE satellite’s Ocean Color Instrument (OCI) detects light across a hyperspectral range, which gives scientists new information to differentiate communities of phytoplankton – a unique ability of NASA’s newest Earth-observing satellite.
This first image released from OCI identifies two different communities of these microscopic marine organisms in the ocean off the coast of South Africa on Feb. 28, 2024.
The central panel of this image shows Synechococcus in pink and picoeukaryotes in green.
The left panel of this image shows a natural color view of the ocean, and the right panel displays the concentration of chlorophyll-a, a photosynthetic pigment used to identify the presence of phytoplankton.
Credit: NASA 

From NASA by Erica McNamee

NASA is now publicly distributing science-quality data from its newest Earth-observing satellite, providing first-of-their-kind measurements of ocean health, air quality, and the effects of a changing climate.

 
The data from PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) will help us better understand how the ocean and atmosphere exchange carbon dioxide. In addition, it will reveal how aerosols might fuel phytoplankton growth in the surface ocean. Novel uses of PACE data will benefit our economy and society. For example, it will help identify the extent and duration of harmful algal blooms. PACE will extend and expand NASA's long-term observations of our living planet. By doing so, it will take Earth's pulse in new ways for decades to come.
 
The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite was launched on Feb. 8, and has been put through several weeks of in-orbit testing of the spacecraft and instruments to ensure proper functioning and data quality.
The mission is gathering data that the public now can access at
 https://pace.oceansciences.org/access_pace_data.htm.

PACE data will allow researchers to study microscopic life in the ocean and particles in the air, advancing the understanding of issues including fisheries health, harmful algal blooms, air pollution, and wildfire smoke.
With PACE, scientists also can investigate how the ocean and atmosphere interact with each other and are affected by a changing climate.

“These stunning images are furthering NASA’s commitment to protect our home planet,” said NASA Administrator Bill Nelson.
“PACE’s observations will give us a better understanding of how our oceans and waterways, and the tiny organisms that call them home, impact Earth.
From coastal communities to fisheries, NASA is gathering critical climate data for all people.”

“First light from the PACE mission is a major milestone in our ongoing efforts to better understand our changing planet.
Earth is a water planet, and yet we know more about the surface of the moon than we do our own oceans.
PACE is one of several key missions – including SWOT and our upcoming NISAR mission – that are opening a new age of Earth science,” said Karen St. Germain, NASA Earth Science Division director.


PACE’s OCI instrument also collects data that can be used to study atmospheric conditions.
The top three panels of this OCI image depicting dust from Northern Africa carried into the Mediterranean Sea, show data that scientists have been able to collect in the past using satellite instruments – true color images, aerosol optical depth, and the UV aerosol index.
The bottom two images visualize novel pieces of data that will help scientists create more accurate climate models.
Single-Scattering Albedo (SSA) tells the fraction of light scattered or absorbed, which will be used to improve climate models.
Aerosol Layer Height tells how low to the ground or high in the atmosphere aerosols are, which aids in understanding air quality.
Credit: NASA/UMBC


The satellite’s Ocean Color Instrument, which was built and managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, observes the ocean, land, and atmosphere across a spectrum of ultraviolet, visible, and near infrared light.
While previous ocean color satellites could only detect a handful of wavelengths, PACE is detecting more than 200 wavelengths.
With this extensive spectral range, scientists can identify specific communities of phytoplankton.
Different species play different roles in the ecosystem and carbon cycle — most are benign, but some are harmful to human health — so distinguishing phytoplankton communities is a key mission of the satellite.

PACE’s two multi-angle polarimeters, HARP2 and SPEXone, measure polarized light that has reflected off clouds and tiny particles in the atmosphere.
These particles, known as aerosols, can range from dust to smoke to sea spray and more.
The two polarimeters are complementary in their capabilities.
SPEXone, built at the Netherlands Institute for Space Research (SRON) and Airbus Netherlands B.V., will view Earth in hyperspectral resolution – detecting all the colors of the rainbow – at five different viewing angles.
HARP2, built at the University of Maryland, Baltimore County (UMBC), will observe four wavelengths of light, with 60 different viewing angles.


Early data from the SPEXone polarimeter instrument aboard PACE show aerosols in a diagonal swath over Japan on Mar. 16, 2024, and Ethiopia on Mar. 6, 2024.
In the top two panels, lighter colors represent a higher fraction of polarized light.
In the bottom panels, SPEXone data has been used to differentiate between fine aerosols, like smoke, and coarse aerosols, like dust and sea spray.
SPEXone data can also measure how much aerosols are absorbing light from the Sun.
Above Ethiopia, the data show mostly fine particles absorbing sunlight, which is typical for smoke from biomass burning.
In Japan, there are also fine aerosols, but without the same absorption.
This indicates urban pollution from Tokyo, blown toward the ocean and mixed with sea salt.
The SPEXone polarization observations are displayed on a background true color image from another of PACE’s instruments, OCI.
Credit: SRON


With these data, scientists will be able to measure cloud properties — which are important for understanding climate — and monitor, analyze, and identify atmospheric aerosols to better inform the public about air quality.
Scientists will also be able to learn how aerosols interact with clouds and influence cloud formation, which is essential to creating accurate climate models.


Early images from PACE’s HARP2 polarimeter captured data on clouds over the west coast of South America on Mar. 11, 2024.
The polarimetry data can be used to determine information about the cloud droplets that make up the cloudbow – a rainbow produced by sunlight reflected by cloud droplets instead of rain droplets.
Scientists can learn how the clouds respond to man-made pollution and other aerosols and can measure the size of the cloud droplets with this polarimetry data.
Credit: UMBC


“We’ve been dreaming of PACE-like imagery for over two decades.
It’s surreal to finally see the real thing,” said Jeremy Werdell, PACE project scientist at NASA Goddard.
“The data from all three instruments are of such high quality that we can start distributing it publicly two months from launch, and I’m proud of our team for making that happen.
These data will not only positively impact our everyday lives by informing on air quality and the health of aquatic ecosystems, but also change how we view our home planet over time.”

The PACE mission is managed by NASA Goddard, which also built and tested the spacecraft and the ocean color instrument.
The Hyper-Angular Rainbow Polarimeter #2 (HARP2) was designed and built by the University of Maryland, Baltimore County, and the Spectro-polarimeter for Planetary Exploration (SPEXone) was developed and built by a Dutch consortium led by Netherlands Institute for Space Research, Airbus Defence, and Space Netherlands.
 
Links :

Wednesday, April 17, 2024

How NASA spotted El Niño changing the saltiness of coastal waters


Rivers can flush rainwater over hundreds of miles to the sea, changing the makeup of coastal waters in ways that scientists are still discovering.
In this satellite image from December 2023, a large, sediment-rich plume from the Mississippi River spreads down the Gulf Coast of Louisiana and Texas following winter rains.
NASA/OB.DAAC 

From NASA by Sally Younger

New findings have revealed a coastal realm highly sensitive to changes in runoff and rainfall on land.

After helping stoke record heat in 2023 and drenching major swaths of the United States this winter, the current El Niño is losing steam this spring.
Scientists have observed another way that the climate phenomenon can leave its mark on the planet: altering the chemistry of coastal waters.

A team at NASA’s Jet Propulsion Laboratory in Southern California used satellite observations to track the dissolved salt content, or salinity, of the global ocean surface for a decade, from 2011 to 2022.
At the sea surface, salinity patterns can tell us a lot about how freshwater falls, flows, and evaporates between the land, ocean, and atmosphere – a process known as the water cycle.

The JPL team showed that year-to-year-variations in salinity near coastlines strongly correlate with El Niño Southern Oscillation (ENSO), the collective term for El Niño and its counterpart, La Niña.
ENSO affects weather around the world in contrasting ways.
El Niño, linked to warmer-than-average ocean temperatures in the equatorial Pacific, can lead to more rain and snowfall than normal in the southwestern U.S., as well as drought in Indonesia.
These patterns are somewhat reversed during La Niña.

During the exceptional El Niño event of 2015, for example, the scientists traced a particularly distinct global water cycle effect: Less precipitation over land led to a decrease in river discharge on average, which in turn led to notably higher salinity levels in areas as far as 125 miles (200 kilometers) from shore.

At other times, the opposite was found: Areas with higher-than-normal rainfall over land saw increased river discharge, reducing salinity near those coasts.
“We’re able to show coastal salinity responding to ENSO on a global scale,” said lead author Severine Fournier, an ocean physicist at JPL.

The team found that salinity is at least 30 times more variable in these dynamic zones near coasts than in the open ocean.
The link between rain, rivers, and salt is especially pronounced at the mouths of large river systems such as the Mississippi and Amazon, where freshwater plumes can be mapped from space as they gush into the ocean. 

Salt as Signal

With global warming, researchers have been observing changes in the water cycle, including increases in extreme precipitation events and runoff.
At the intersection of land and sea, coastal waters may be where the impacts are most detectable.

“Given the sensitivity to rainfall and runoff, coastal salinity could serve as a kind of bellwether, indicating other changes unfolding in the water cycle,” Fournier said.

She noted that some of the world’s coastal waters are not well studied, despite the fact that about 40% of the human population lives within about 60 miles (100 kilometers) of a coastline.
One reason is that river gauges and other on-sitemonitors can be costly to maintain and cannot provide coverage of the whole planet, especially in more remote regions.

That’s where satellite instruments come in. Launched in 2011, the Aquarius mission made some of the first space-based global observations of sea surface salinity using extremely sensitive radiometers to detect subtle changes in the ocean’s microwave radiation emissions.
Aquarius was a collaboration between NASA and Argentina’s space agency, CONAE (Comisión Nacional de Actividades Espaciales).

Today, two higher-resolution tools – the ESA (European Space Agency) Soil Moisture and Ocean Salinity (SMOS) mission and NASA’s Soil Moisture Active Passive (SMAP) mission – allow scientists to zoom to within 25 miles (40 kilometers) of coastlines.

Using data from all three missions, the researchers found that surface salinity in coastal waters reached a maximum global average (34.50 practical salinity units, or PSU) each March and fell to a minimum global average (34.34 PSU) around September.
(PSU is roughly equal to parts per thousand grams of water.) River discharge, especially from the Amazon, drives this timing.

In the open ocean, the cycle is different, with surface salinity reaching a global average minimum (34.95 PSU) from February to April and a global average maximum (34.97 PSU) from July to October. The open ocean does not show as much variability between seasons or years because it contains a significantly larger volume of water and is less sensitive to river discharge and ENSO.
Instead, changes are governed by planet-scale precipitation minus total global evaporation, plus other factors like large-scale ocean circulation. 
 
Links : 

Tuesday, April 16, 2024

Rogue waves in the ocean are much more common than anyone suspected, says new study


From The Conversation by Alessandro Toffoli


We used three-dimensional imaging of ocean waves to capture freakish seas that produce a notorious phenomenon known as rogue waves.
Our results are now published in Physical Review Letters*.

Rogue waves are giant colossi of the sea – twice as high as neighbouring waves – that appear seemingly out of nowhere.
Stories of unimaginable mountains of water as tall as ten-storey buildings have populated maritime folklore and literature for centuries.

Recent technology has allowed scientists to spot rogue waves out at sea, making legend become reality.
The first and most famous measurement was of the Draupner wave, a 25.6-metre monster recorded in the North Sea on January 1 1995.

Despite observations, we still don’t know how often rogue waves occur, or if we can predict them.
A record of a rogue wave doesn’t include specific features that distinguish the sea around it, so we can’t make comparisons or predict the conditions needed.

Our team set sail on the South African icebreaker S.A. Agulhas-II to chase rogue waves across the Southern Ocean, where mighty winds shape Earth’s fiercest waves.


Ocean surface during a storm somewhere in the Southern Ocean.
Alessandro Toffoli

What creates rogue waves?


In the random environment of ocean waves, several mechanisms give rise to rogue ones.
One primary source involves the overlap of multiple waves at the same location and time.
This results in concentrated energy, leading to tall waves.

Under consistent ocean conditions, rogue waves generated this way may occur once every two days at a set location.
But the ocean is dynamic, so conditions are rarely consistent for long – making it less likely for rogue waves to occur.
The overlap of waves may be minimal or non-existent even during prolonged and intense storms.

Numerical and laboratory studies suggest strong winds also contribute to the development of rogue waves, because they push harder on some already tall wave forms.
But wind has seldom been considered in rogue wave analysis.
 

A simplified anatomy of ocean waves.

Wind prompts ocean waves to grow progressively higher, longer and faster.
During this stage, waves are “young” and hungry for wind input.
When waves go faster than wind, they stop being accelerated by it and reach a “mature” stage of full development.

Through this process, the wind creates a chaotic situation where waves of different dimensions and directions coexist.

Our recent observations show that unique sea conditions with rogue waves can arise during the “young” stage – when waves are particularly responsive to the wind.
This suggests wind parameters could be the missing link.
However, there’s even more to consider.
 
Powerful waves amplify each other

Ocean waves are one of the most powerful natural forces on Earth and could become even more powerful in the future due to climate change.
If the wave field possesses an extreme amount of energy – when waves are steep and most of them have a similar amplitude, length and direction – another mechanism can trigger the formation of rogue waves.

This mechanism involves an exchange of energy between waves that produces a “self-amplification”, where one wave grows disproportionately at the expense of its neighbours.
Theoretically, studies show this could increase the likelihood of rogue waves ten-fold.

While self-amplification manifests as whitecaps – frothy, aerated crests of choppy waves – until now there has been no evidence it can make rogue waves more likely in the ocean.

Recent experiments suggest wind can make extreme events like rogue waves more common.
But this aspect has not been thoroughly explored.

The most extreme 'rogue wave' on record has just been confirmed in the North Pacific Ocean. 
Picture: AP
 
 What did we find in the Southern Ocean?

We used a new three-dimensional imaging method for scanning the ocean surface throughout the expedition.
It mimics human vision: closely located sensors record sequences of simultaneous images.
Computer algorithms then match pairs of them to reconstruct the three-dimensional depths – the wavy surface.

Example of the three-dimensional ocean surface reconstructed from synchronised images.
Hans Clarke

As our ship passed through several storms, the sensors captured data during various phases of wave growth – from the early stages of young waves fuelled by the wind, to mature waves that aren’t influenced by it.

Our results show young waves display signs of self-amplification and an increased likelihood of rogue waves.
We recorded waves twice as high as their neighbours once every six hours.

This mirrors what lab models have reported: sea conditions theoretically more prone to self-amplification would produce more rogue waves.

In contrast, mature seas don’t show an increased probability of rogue waves.
We detected none under those conditions.

Our findings challenge previous thinking: that self-amplification doesn’t change the likelihood of rogue waves in the ocean.
We have also shown that when developing tools for predicting rogue waves, we need to take wind into thorough consideration.
After all, it’s a natural feature of the open sea.
 
Links :

Monday, April 15, 2024

Illuminating the 'Shadows of the Sea' - How Theia exposes Russian maneuvers amidst global sanctions

URSA MAJOR (IMO 9538892) at Tartus Port, Syria.

From Pulse by SynMax
 
SynMax will use its artificial intelligence technology combined with Planet’s satellite data to support maritime tracking of illegal fishing, illicit ship-to-ship transfers, and vessel spoofing via a new vessel tracking product called Project Theia.
 
Since November 2023, SynMax’s maritime domain awareness platform, Theia, has detected, attributed, and tracked the locations of three Russian-flagged vessels: the general cargo ships URSA MAJOR (IMO 9538892) and SPARTA IV (IMO 9743033) and the oil/ chemical tanker YAZ (IMO 9735323).
The SPARTA IV is owned by SC South LLC, a Russian Ministry of Defense shipping company subsidiary.
The UK, Ukraine, and the US have sanctioned the vessels for “delivering maritime goods on behalf of the Russian Ministry of Defence.”

As a result of Russia’s involvement in the Syrian civil war, a significant quantity of Russian heavy military equipment is located in Syria.
As the Ukrainian war drags on, Russia’s equipment shortfalls have necessitated the mass transportation of military equipment from Syria to Sevastopol, Crimea, which is the closest port to the frontlines under Russian control.

Unfortunately for Russia, at the request of Ukraine, Turkey exercised the 1936 Montreux Convention on the 28th of February, 2022, banning Russian warships from entering the Black Sea via the Bosphorus and Dardanelles straits.
This was later revised to allow Russian warships access if they were returning to a home port in the Black Sea, but it left a significant shortfall between Russia’s transport capabilities and its requirements.

As a result, Russia has utilized vessels in its civilian fleet to transport military equipment, including the URSA MAJOR, SPARTA IV, and YAZ.
A Royal United Services Institute (RUSI Europe) report has claimed that the SPARTA IV “serves as an auxiliary vessel for the Russian military.” As such, it could be argued that Russia is acting in contravention of the Montreux Convention.
Ukraine is confident that the SPARTA IV is a Russian military transport, so much so that they unsuccessfully attempted to attack the ship with an uncrewed surface vessel (USV) on the 4th of August, 2023.

Theia collected imagery of the vessels transiting from Novorossiysk Port, Russia, to Tartus military port, Syria, through the Bosphorus and Dardanelles straits.

Theia detected and attributed the URSA MAJOR AIS dark at a military berth in Novorossiysk Port on the 10th of November, 2023.
The URSA MAJOR remained dark, transiting across the Black Sea until the 3rd of December 2023, when she began emitting AIS transmissions at the mouth of the Bosphorus Strait.
The URSA MAJOR continued to transmit while transiting through the Bosphorus and Dardanelles Straits, turning off her AIS before entering the Mediterranean.
She remained AIS dark for a further three months.



The SPARTA IV was sighted at the same military berth at Novorossiysk Port on the 24th of December, 2023, before she carried out the same AIS dark journey across the Black Sea to reappear at the mouth of the Bosphorus Strait on the 28th of December, 2023.
It is assessed that the vessels turned off their AIS to avoid the Ukrainian drone threat faced by Russian ships in the Black Sea, and again in the Mediterranean to hide their destination- Tartus Port.
Theia observed the URSA MAJOR and SPARTA IV AIS dark, transferring cargo in Tartus Port.

On the 24th of February, 2024, the YAZ and the SPARTA IV transited north with AIS on for what appeared to be the return journey to Novorossiysk.
On the 26th of February, both vessels approached the entrance to the Bosphorus Strait, pausing for 13 hours before unexpectedly returning south.
It has been suggested that the vessels were deterred by the threat of Ukrainian USVs, which have been responsible for the destruction of multiple Russian warships, including the SERGEY KOTOV on the 4th of March, and resulted in the dismissal of Adm Nikolai Yevmenov, ex-Commander of the Russian Navy.



On the 3rd of March, the AIS dark URSA MAJOR and SPARTA IV were detected at Tartus Port, imaged alongside one another.
The URSA MAJOR was assessed to have concluded her cargo transfer.
On the 5th of March, the URSA MAJOR, SPARTA IV, and YAZ resumed AIS transmissions, making their way across the Mediterranean, transiting through the Strait of Gibraltar before continuing through the English Channel, North Sea, and Baltic Sea.



The SPARTA IV arrived in Baltiysk, Russia, on the 22nd of March.
At 19:50 UTC, she came alongside a civilian cargo berth before turning off her AIS at 21:30 UTC.
Despite this being the apparent conclusion to her journey, Theia detected the SPARTA IV engaging in loading/ unloading activity at a military berth on the 29th of March.

The URSA MAJOR arrived at an anchorage 50km from St Petersburg, Russia, on the 23rd of March before transiting to Mpp Bol’shoy customs port, St Petersburg, where she remains.
The YAZ arrived at the same anchorage as the URSA MAJOR, 50km from St Petersburg, on the 27th of March at 10:28 before turning off her AIS at 15:46 UTC.

During the same reporting period, Theia identified two other vessels engaging in similar activity.
Russian flagged Ro-Ro vessels, the BALTIC LEADER (IMO: 9220639) and the LADY MARIIA (IMO: 9220641), were captured at Novorossiysk alongside the SPARTA IV on the 3rd of February 2024.
The LADY MARIIA was detected again as she came alongside the URSA MAJOR and SPARTA IV at Tartus military port on 18th February.
The LADY MARIIA was AIS dark at the time of detection, although she didn’t adopt the same AIS tactics as the URSA MAJOR and SPARTA IV during their voyages to Tartus.


Unlike the URSA MAJOR and SPARTA IV, both vessels sailed to Unye Port, Turkey, where they remain.

Theia specializes in data fusion.
Ingesting Automatic Identification System (AIS) data and 20,000,000 km2 of electro-optical imagery daily, Theia’s proprietary AI extracts actionable intelligence from the terabytes of data, producing genuinely scalable, automatic maritime surveillance.

Theia’s extensive imagery archives mean that regardless of when a vessel raises red flags or suspicions, its past activity can be proven conclusively.
Imagery ties a ship to a specific time and a place with a certainty that synthetic dots on a map cannot replicate.

Without AI analysis of millions of square kilometers of satellite imagery, these detections would not have been possible without a significant expenditure of person-hours.
Instead, SynMax's analysts spend minutes verifying.
Data fusion is the key to understanding big intelligence problems.
AI is a powerful tool for investigators to make sense of big data, significantly scaling up analysts' reach and understanding.

Links :

Sunday, April 14, 2024

Illuminating the seafloor


Teamwork between a deep-sea robot and a human occupied submarine recently led to the discovery of five new hydrothermal vents on the seafloor of the eastern Tropical Pacific Ocean.
Scientists mapped the area at night using the undersea robot Sentry, an autonomous underwater vehicle (AUV) operated by WHOI and the National Deep Submergence Facility (NDSF) and funded by NSF.
After Sentry was recovered each morning, high-resolution maps from the vehicle’s sensors were then used to plan the day’s dive by the human-occupied vehicle Alvin also operated by WHOI-NDSF, which enables scientists to view firsthand the complex and constantly changing environment of a place like the East Pacific Rise.
Footage description: HOV Alvin navigates the around hydrothermal vents at the YBW-Sentry Field during a recent expedition to the eastern Tropical Pacific Ocean.
HOV Alvin lands on seafloor lava flows in the eastern Tropical Pacific Ocean, prepared for imaging and sample collection.
Shots of the hydrothermal vent field, Biovent, including Riftia pachyptila - giant tubeworms.
Towering colonies of these giant tubeworms grow adjacent to where hot, mineral-laden water jets out of hydrothermal vents the deep seafloor.
Also present are Cyanagraea crabs, a dominant predator in this ecosystem.
They can only be found on hydrothermal vents.
Footage of tubeworms, muscles, and a zoarcid fish that call this field of hydrothermal vents home.
A downward look at the hydrothermal vent field, Biovent.
A look at hydrothermal vent chimneys in the YBW-Sentry Vent Field.
The white areas are microbial mats.
A panorama of the YBW-Sentry Vent Field, including large anemones.
Hydrothermal chimneys in the YBW-Sentry Vent Field.
A vulcan - or vent - octopus thriving in the ecosystem created by hydrothermal vents.
A lone stalked crinoid sways in the current.
Crinoids are marine invertebrates.
Crinoids that are attached to the sea bottom by a stalk in their juvenile form are commonly called sea lilies.
HOV Alvin approaches a hydrothermal vent.
Its manipulator arm can be seen taking a sample of the hydrothermal fluids and gasses for scientists to analyze.
A WHOI-MISO self-recording high-temperature logger has been inserted into one of the active vent chimneys.
It records temperatures inside the vent orifice every 10 minutes, providing researchers with invaluable data about hydrothermal system behavior and activity over 1-2 years between the site visits to the study area.
The next time the researchers will go back to this site is in about 12-18 months.
A close-up of one of the newly discovered chimneys.
This one is roughly 9-10 meters tall.
This is a curtain folded whorl of lava, quickly frozen into the beautiful shape within minutes after it erupted.
The wrap around feature gives scientists information about how fluid the lava was when it erupted and the rate at which the lava flowed over the seafloor.

Saturday, April 13, 2024

Revealing secrets of the Pacific seafloor with bathymetry


This flythrough shows some of the complex bathymetric maps generated on our current expedition in and around the Johnston Atoll Unit of the Pacific Remote Islands Marine National Monument (PRIMNM) and how we use those maps to identify potential ROV dive targets for our next expedition.
 Watch and learn more from our Corps of Exploration about the importance of multibeam data to understanding the unique geological features of this mostly unsurveyed region of the Central Pacific.


 How exactly do we map the seafloor?
Onboard E/V Nautilus, our Corps of Exploration uses the Kongsberg EM302 multibeam echosounder to create detailed seafloor maps.
By generating sound beams and collecting returning data, this technology allows us to piece together the topography of the deep sea.
Seafloor mapping began over a century ago, yet less than 25 percent of the world’s ocean has been charted at high resolutions.
Our seafloor maps contribute to the Seabed 2030 initiative, an international collaborative project to combine all bathymetric data to create a comprehensive map of the ocean floor.
Having 3D maps of the seafloor also leads our ocean exploration goals.
When exploring little-known ocean regions, we often need to create our own maps to plan efficient and safe operations.
Whether focused on a canyon, seamount, or shipwreck, creating a map allows us to identify potential targets, cutting down exploration time and boosting our mission efficiency.
Before ROVs are deployed, our team must first map the area to understand the region's characteristics and identify potential benthic habitats, seeps, and other environments and resources worthy of exploration.

Friday, April 12, 2024

Cruising the Northwest Passage

Trapped by pack ice, the Stevens 47 Polar Sun spent nine days moving from floe to floe in Pasley Bay in Nunavut, Northern Canada, to avoid being dragged aground.
Ben Zartman 

From Cruising World by Ben Zartman 

We expected iceblink during our arduous journey through the Northwest Passage. The typhoon, not so much. 

Where does the fabled Northwest Passage—that ­tenuous, long-sought sea route between the Atlantic and Pacific oceans—­properly begin?

For the keepers of official records, jealously counting how many of each sort of boat makes the transit each year, the answer is the Arctic Circle, at 66°30′ N.
It begins when you cross into the Arctic going northward, and it ends when you cross out of it again southbound, 100 degrees of longitude away. 

Only in the past 15 years or so has enough sea ice given way to allow pleasure boats to complete the Northwest Passage.
 Manuel Mata/stock.adobe.com

Others—often those attempting to kayak, paddleboard, kitesurf or dinghy across—count it from Pond Inlet at northern Baffin Island to the hamlet of Tuktoyaktuk, which is nearly on the US-Canada border. That’s a far shorter distance, and it cuts out nearly 1,000 miles of the difficult coast of Alaska, not to mention about 500 miles on the Atlantic side.

Surely, we can forgive those with the audacity to try it in any sort of open craft.
With our Stevens 47, Polar Sun, however, although we had crossed the Arctic Circle halfway through a cruise of Greenland’s coast from Nuuk to Ilulissat, we didn’t feel like our bid for the passage had properly begun until we wriggled out of the untidy raft-up of sailboats at the fish wharf in the inner harbor at Ilulissat.
It was midafternoon and raining lightly as we dodged past icebergs at the harbor mouth, but neither time nor atmospheric moisture matters a whole lot in a place where the sun doesn’t set and you’re bundled head to toe against the cold anyway.

Having been going hard for weeks on end, with uncertainty and ice and everlasting cold, it was the longest sailing leg of my life.

We were bound across Baffin Bay for Pond Inlet, a four-day leg that took us closer to seven, and taught us that just because we’d gotten to Ilulissat ahead of schedule didn’t mean we were always going to get easy sailing. 

Baffin Island basks in the midnight sun. The spectacular, wild landscape is an accessible Arctic playground for the adventurous. Jillian/stock.adobe.com

We were used to icebergs by then.
They’re mostly huge and visible.
They’re easy to sail around, and their dangers are predictable and avoidable.
But halfway across Baffin Bay, we encountered pack ice for the first time.
We found it a far more chilling prospect.
Being mostly flat and close to the surface, it doesn’t show up well on radar or forward-looking sonar, and it tends to hang tight.
If you see one floe, there’s probably a whole bunch of them nearby, drifting amiably around together.

By the time we beat our way against a 20-knot breeze close to the craggy Baffin Island shore, we were hardly surprised to find icebergs drifting amid the barrier of pack ice that blocked the shore.
Who says you can’t have it all? 

Polar Sun, tied to a floe with ice screws in Pasley Bay.
Ben Zartman

When we had finally worked our way through the ice and up along the coast for another day, we were in for several surprises.
The first was that a brand-new harbor with breakwalls and docks had just been built at Pond Inlet, so we didn’t have to anchor in a rolly roadstead like we had expected.
The second was that although the town there was relatively close to Greenland, it couldn’t have been more different than the ones we’d just left.
Lacking the warm current that Greenland enjoys, this area stays locked up in ice most of the year.
There isn’t a whole lot to do in one place, and it’s easy to see why the native Inuit were once nomadic.
It makes sense in a place where nature is so savage. 

 
A warm pot of lentil stew in the galley.
Ben Zartman

Pond Inlet was the first of only four settlements we visited in the next 2,000 miles.
Between them lie mind-numbingly vast stretches of barren, cliff-filled islands where even lichens struggle to grow in the whorls and rings of frost-heaved gravel.

We didn’t linger too long in any one place—at least, not by choice—but ­hastened always, feeling the shortness of the navigable season, and knowing that the later we got to the Bering Sea, the ­better chance we had of getting clobbered by something nasty.
After an iceberg-­fraught, lumpy, breezy passage of the Navy Board Inlet, we had an ­exceedingly pleasant sail diagonally up Lancaster Sound to Beechey Island.

Between the Beechey and King William islands is where the most pack ice can be expected. Some years, it’s so abiding that no small boats get through.
We were lucky.
A violent south wind flushed all the ice out of Peel Sound, our projected route.
After a day anchored in Erebus and Terror Bay, a band of pack ice that had barred the way opened up just enough for Polar Sun to get through.
A view from the spreaders, where we climbed often to spot a path through the ice.
Ben Zartman

I had always heard of iceblink, a ­phenomenon where distant pack ice throws a glow along the horizon, making it impossible to judge how far off it is.
I had thought I wanted to see it someday, but I realized as we raced toward the rapidly shrinking opening to Peel Sound that I could have done without it, at least when a fogbound island, a foul current and a whole lot of ice coming out of the blink were converging on Polar Sun.

It wasn’t the last time we would squeak through a narrow gap at the last minute.
The next 500 miles saw us often in and out of ice.
Twice, we were denied passage out of a bay where we ultimately spent nine days trapped in the pack, shifting from one ice floe to another.
We almost didn’t make it out of there at all, and when we did, it was to find the way nearly shut farther along.

At last, though, we made it to Gjoa Haven on the south side of King William Island.
We sighed with relief that the ice, at least, would trouble us no more—but given the trouble we did see for the next several thousand miles, perhaps a little ice would have been the least of it. 

 
a typical shack the Canadian government supplied to the Inuit once upon a time.
Evan/stock.adobe.com;

What we hadn’t accounted for was that Gjoa is barely halfway across the Northwest Passage.
There was still such a long way to go, and now, each night was dark for a little longer than the prior.

Given the lateness of the season—those nine days in the ice had really set us back—we considered leaving the boat in Cambridge Bay for the winter, but the crane that had once hauled the occasional stray sailboat was no longer there. To leave the boat in the water would be to lose it. We had already lost two crew, who had to return home for work, and couldn’t lose the time to find more.

So, Mark Synnott, the expedition leader, and I doublehanded the six weary days to Tuktoyaktuk. It’s not that doublehanding is normally that bad, but having been going hard for weeks on end, with hopes raised and dashed, with uncertainty and ice and everlasting cold, it was the longest sailing leg of my life. Before we finally rounded Cape Bathurst and raced with a strong following wind into Tuk, we had spent eight hours hove-to in a midnight blow, overheated the engine, sailed the wrong direction with a lee shore wherever we could point the bows, and did I mention the cold?
Crewmember Eric Howes catches a camera drone while underway.
Ben Zartman

Tuktoyaktuk is on the shallow, oil-rich shelf of the Beaufort Sea.
The channel barely carries 2 fathoms into the harbor at the best of times.
This was not one of those times; the strong wind that rushes unopposed over the featureless peninsula tends to blow water out of the harbor.
Polar Sun grounded gently just abeam of the half-wrecked public wharf.
We got lines ashore to take in when the tide should float her again, and we went ashore to eat with the relief crew, who had flown out to meet us.

Without that extra crew, that last leg across the north coast of Alaska and down to the Bering Sea would have been not just exhausting, but also dangerous.
Even with the new life that David Thoresen and Ben Spiess breathed into our souls, the strong following wind and seas required constant watchfulness.
We rounded Point Barrow, the northernmost point in Alaska, in a welter of muddy, breaking waves, with sleet whitening the weather side of every shroud and halyard.
We had thought of stopping in Barrow for a rest, but the seas were too rowdy along the shore.
Besides, the wind was fair to sail south, and south is where we wanted to go. 

 
The crew on the aft deck, with expedition leader Mark Synnott in the foreground.
Ben Zartman

South, that is, until Point Hope, where we needed to tuck in and hide from a typhoon—yes, a typhoon. It had strayed beyond its reasonable bounds into the Bering Sea, not only bringing record flooding to the coastal communities, but also having the audacity to pass through the Bering Strait into the Chukchi Sea, where Polar Sun sheltered in the tenuous lee of a permafrost-topped sandbar.

The eye of the storm, still well-defined although weakening, came abeam of our anchorage and made it untenable.
We weighed anchor for the last time and sailed deep-reefed straight toward the center of it.
Tacking some hours later to claw across Kotzebue Sound, we had occasion to wish that Cambridge Bay had worked out.
The wind drove Polar Sun farther from the Bering Strait, toward a shoreline guarded by poorly charted shallow sandbars and lagoons.

It was nearly dark when the wind relented enough that we could make a run toward Cape Prince of Wales.
That was the last obstacle, and we hand-steered around it in pitch-blackness, hugging the shore as close as we dared to avoid a current offshore.
With the lights of Wales close abeam, and with Polar Sun surfing at 9 knots down-sea, we were grateful that we couldn’t see.

Once properly in the Bering Sea, all the jumble of the strait settled down, as if turned off with a switch.
We motored sedately into Nome, Alaska, in the late afternoon, just hours ahead of the next southerly gale that pounded that ­unforgiving coast. 

Bright, radiant ice and glassy calm water as far as the eye can see are typical of any Greenland scene around Pond Inlet. Colin/stock.adobe.com

For the record-keepers, the Northwest Passage was officially completed halfway across Kotzebue Sound, when Polar Sun crossed the Arctic Circle just north of the Bering Strait.
For Mark and me, the only two of the 12 people on the trip to sail every mile, it wasn’t fully over even in Nome.
There were sails to unbend and stow, halyards to messenger out.
A whole winterization had to be done, and there were long flights, which undid in 12 hours the distance we had taken 112 days to sail, to endure.

Where does the Northwest Passage end?
For me, at least, it ends when you get home.

Thursday, April 11, 2024

Rare sponge reefs and new corals discovered in Ireland


Sampling a coral thanks to SeaRover.
(Image credit: Marine Institute)
When scientists launched the EU funded SeaRover project to explore the depths of Ireland’s oceans, no one expected them to make groundbreaking discoveries.

The goal of the project was safeguarding Ireland’s delicate ecosystems and habitats from the impact of increased fishing activities.
The project was divided into three phases. In phase one, researchers assessed sensitive ecosystems using a remote operated vehicle (ROV) to explore the reef, hence the name SeaRover. In the second and third phases of the project, they analyzed the survey findings and made them publicly available through an online platform.
 

Rare coral has been found in a past deep sea research mission off the west coast of Ireland in 2018
 
During the deep-sea expedition, in the initial phase of the SeaRover survey, scientists identified new coral species and sponge reefs.
Using advanced technology, the team was able to unveil rich biodiversity, uncovering rare deep-sea black corals and even identified a shark nursery—a remarkable find off the coast of Ireland.

Brisingids and sponges on a rock.
 (Image credit: Marine Institute)
 
Supported by the European Maritime and Fisheries Fund (EMFF), the SeaRover project contributed to conservation efforts and helped Ireland fulfil its national obligation to map vulnerable fisheries resources.
 
 
The project not only shed light on Ireland's offshore ecosystems, but it also emphasized the significance of international collaboration in marine research.
The project’s extensive and publicly available datasets are invaluable for informing future policies on marine management and conservation.
“We must acknowledge that this work would not have been possible without the support of EMFF, and we hope to further our efforts with the support of its successor, the EMFAF. The challenge going forward is to engage the public, policy makers and researchers, and to make them aware of the unique habitats that exist in Ireland’s waters,” said Fergal McGrath, SeaRover Project Manager.

Glass sponge.
(Image credit: Marine Institute)
 
One of the ways the project has been engaging with the public is through outreach programs with schools.
SeaRover's discoveries have been shared and used in educational materials, fostering a greater understanding of Ireland's marine biodiversity.
 
The project has also provided invaluable training opportunities for young scientists, ensuring the continuity of ocean exploration, conservation efforts, and new discoveries for years to come.
“Revealing the hidden wealth of the deep seas of Ireland will lead to increased knowledge of, and appreciation for, the rich biodiversity that exists offshore. These delicate habitats will require monitoring and protection to ensure their preservation for current and future generations.” underlined Fergal McGrath.
 
Links :

Wednesday, April 10, 2024

Cities aren’t prepared for a crucial part of sea-level rise: they’re also sinking


Photo : Darwin Fan / Getty Images
 
From Wired by Matt Simon

Coastal land is dropping, known as subsidence.
That could expose hundreds of thousands of additional Americans to inundation by 2050.

 
Fighting off rising seas without reducing humanity’s carbon emissions is like trying to drain a bathtub without turning off the tap.
But increasingly, scientists are sounding the alarm on yet another problem compounding the crisis for coastal cities: Their land is also sinking, a phenomenon known as subsidence.
The metaphorical tap is still on—as rapid warming turns more and more polar ice into ocean water—and at the same time the tub is sinking into the floor.

An alarming new study in the journal Nature shows how bad the problem could get in 32 coastal cities in the United States.
Previous projections have studied geocentric sea-level rise, or how much the ocean is coming up along a given coastline.
This new research considers relative sea-level rise, which also includes the vertical motion of the land.
That’s possible thanks to new data from satellites that can measure elevation changes on very fine scales along coastlines.

With that subsidence in mind, the study finds that those coastal areas in the US could see 500 to 700 square miles of additional land flooded by 2050, impacting an additional 176,000 to 518,000 people and causing up to $100 billion of further property damage.
That’s on top of baseline estimates of the damage so far up to 2020, which has affected 530 to 790 square miles and 525,000 to 634,000 people, and cost between $100 billion and $123 billion.

Overall, the study finds that 24 of the 32 coastal cities studied are subsiding by more than 2 millimeters a year. (One millimeter equals 0.04 inches.)
“The combination of both the land sinking and the sea rising leads to this compounding effect of exposure for people,” says the study’s lead author, Leonard Ohenhen, an environmental security expert at Virginia Tech.
“When you combine both, you have an even greater hazard.”

The issue is that cities have been preparing for projections of geocentric sea-level rise, for instance with sea walls.
Through no fault of their own—given the infancy of satellite subsidence monitoring—they’ve been missing half the problem.
“All the adaptation strategies at the moment that we have in place are based on rising sea levels,” says Manoochehr Shirzaei, an environmental security expert at Virginia Tech and a coauthor of the paper.
“It means that the majority—if not all—of those adaptation strategies are overestimating the time that we have for those extreme consequences of sea-level rise.
Instead of having 40 years to prepare, in some cases we have only 10.”

Subsidence can happen naturally, for instance when loose sediments settle over time, or because of human activity, such as when cities extract too much groundwater and their aquifers collapse like empty water bottles.
In extreme cases, this can result in dozens of feet of subsidence.
The sheer weight of coastal cities like New York is also pushing down on the ground, leading to further sinking.


Courtesy of Leonard Ohenhen, Virginia Tech

In the map above, warmer colors show areas with higher rates of this vertical land motion, or VLM, per year.
Ohenhen and Shirzaei previously found that the East Coast is particularly prone to sinking: up to 74,000 square kilometers (28,600 square miles) are exposed to subsidence of up to 2 millimeters annually, impacting up to 14 million people and 6 million properties.
Worse still, over 3,700 square kilometers (1,400 square miles) are sinking more than 5 millimeters each year.

But also check out the deep reds of the Gulf Coast, which has high rates of subsidence but also lower coastal elevations that already make it vulnerable to sea-level rise.
The Pacific Coast, by contrast, is much greener, meaning it has lower rates of subsidence.

A few millimeters a year might sound tame, but it adds up if it’s happening year after year: If you’ve got 4 millimeters of sea-level rise along a coastline, and the land is also sinking by 4 millimeters annually, you’ve essentially doubled the problem.
That’s a challenge on longer timescales as seas gradually rise, but also ephemerally when hurricanes push storm surges of water onto land.

The sinking is especially dangerous where it’s happening at different rates in adjacent points, known as differential subsidence.
If a road, airport, or levee is sinking at 5 millimeters a year along its whole stretch, that might not be a huge deal—its elevation is just dropping.
But if the sinking is happening at 5 millimeters at one end and 1 millimeter at the other, that difference can destabilize the infrastructure.


Courtesy of Leonard Ohenhen, Virginia Tech

Here’s another way of looking at the East Coast, from the new paper.
These are inundation maps, showing areas exposed to high tide, taking subsidence into account.
Blue shows what was exposed in 2020 and red what could be in 2050.


Courtesy of Leonard Ohenhen, Virginia Tech

And here’s cities along the Gulf Coast.
Check out the current and future inundation in New Orleans in the top row, second from right.
The subsidence in Biloxi, Mississippi, is particularly extreme, the study found, with average rates exceeding 5 millimeters a year.
All across the Gulf Coast—which is already low-lying—extraction of groundwater and fossil fuels has led to subsidence that only drops elevations further, opening up more places to more inundation.


Courtesy of Leonard Ohenhen, Virginia Tech

Here’s the Pacific Coast.
Notice San Francisco International Airport (SFO), again in the top row, second from right.
In general, the Pacific Coast has higher elevations and lower rates of subsidence than the East or Gulf coasts, making it less vulnerable to inundation.

Overall, you can see how varied the inundation is within these coastal cities.
That’s due both to elevation—SFO, for instance, is a (necessarily) flat area right on the water—but also to the local geology.
Sediments, be they natural or human-made, will subside, while bedrock will not.
You can have high rates of subsidence at higher elevations and avoid inundation, but also lower rates of subsidence at lower elevations can reduce the risk as well.
“There is no single scenario that has been done where you show a whole city will be underwater at the same time,” says Ohenhen.
“It’s often very, very localized.”

So the subsidence is bad, and it’s widespread across US coastal cities.
But the problem is especially acute for lower-income Americans and people of color in disadvantaged neighborhoods, the study finds.
They lack both the funding and the governmental support to properly adapt to sea-level rise even without subsidence thrown into the mix.
In a place like the Gulf Coast, successive hurricanes and flooding create a deeper and deeper hole for people to get out of.
“You have this continuous vicious cycle of events,” says Ohenhen.
“Each time it makes them even more vulnerable and unable to recover.”

So what can be done about it? That depends on what’s driving the sinking.
If a stretch of coastline once hosted wetlands, restoring those can help replenish sediments, and they can act as natural buffers against rising seas.
That’d be especially useful where there’s differential subsidence, as this destabilizes any engineered seawalls.
In Indonesia, the government is moving its capital out of Jakarta because of subsidence so extreme, it’d make seawalls useless.
We’re talking nearly a foot of sinking a year in some places.
“We need to know, when we're addressing sea level rise, what problem we're exactly solving for,” says Kristina Dahl, principal climate scientist for the climate and energy program at the Union of Concerned Scientists, who wasn’t involved in the new paper.
“If you're getting a lot of land subsidence that's happening because you're over-extracting groundwater, you're going to address that problem very differently than you would if the problem were purely just sea-level rise.”

To that end, a city can find other water sources.
A growing number of metropolises are finding ways to capture more stormwater, for instance, which reduces pressure on aquifers.
With the right infrastructure, you can force stormwater to trickle underground, thus replenishing an exhausted aquifer and slowing subsidence.
Los Angeles is already doing this: Early last month, it captured 8.6 billion gallons of water over the course of three rainy days, enough to supply more than 100,000 households for a year.
“The solution really has to be tailored to the community,” says Shirzaei.
“One size does not fit all.”
 
Links :