Friday, March 5, 2021

Sailor survives for 14 hours in Pacific Ocean by clinging to abandoned buoy

Vidam Perevetilov was rescued 14 hours after falling overboard from the Pitcairn Island Silver Supporter supply ship. He clung to an abandoned fishing buoy to stay afloat.
Photograph: Supplied

From The Guardian by Ben Doherty

Vidam Perevertilov, a supply ship engineer, fell overboard between New Zealand and the isolated British territory of Pitcairn

Vidam Perevetilov was rescued 14 hours after falling overboard from the Pitcairn Island Silver Supporter supply ship.
He clung to an abandoned fishing buoy to stay afloat. Photograph: Supplied

A sailor who fell overboard from a supply ship in the Pacific Ocean at 4am spent more than 14 hours clinging to an old fishing buoy before being rescued.

Alone in the middle of the ocean, and without a lifejacket, at dawn he chose to swim towards a black speck on the horizon, a decision that would ultimately save his life.

Vidam Perevertilov, the chief engineer on board the Silver Supporter, was hauled back on deck nearly a full day after falling overboard on 16 February as his freighter made a supply run between New Zealand’s Tauranga port on the country’s North Island and the isolated British territory of Pitcairn.

He later told his son he had been feeling dizzy after finishing a night shift in the engine room, and had walked out on to the deck to recover, before falling.
“He doesn’t remember falling overboard. He may have fainted,” Perevetilov’s son Marat told New Zealand’s Stuff.

Perevetilov remembers gaining consciousness, seeing his ship sailing away into the dark.
The crew did not notice he was missing for six hours. 
Vidam Perevetilov fell into the ocean from the Pitcairn Island Silver Supporter supply ship.
Photograph: Pitcairn Islands Tourism

The ship radioed a distress call and French navy aircraft joined the search from Polynesia, while France’s meteorological service examined winds and currents to determine probable drift patterns.

Crew onboard were able to determine Perevertilov had been on board at 4am because he had filed a log report at that time.
At the time he went overboard, the Silver Supporter was about 400 nautical miles south of French Polynesia’s southernmost Austral Islands.

In the middle of the ocean, with his ship out of sight over the horizon, 52-year-old Perevertilov made a decision at dawn that would – ultimately – save his life.

He saw a black speck on the horizon and, unsure what it was, swam towards it.
“His will to survive was strong, but he told me until the sun came up he was struggling to stay afloat,” Marat told Stuff from Lithuania.

The dot on the horizon turned out to be an abandoned fishing buoy.
Perevertilov clung to it until he was found at about 6pm.
His ship was in a set search pattern when a crew member heard a faint voice, and a lookout saw a hand raised from the ocean.
Perevertilov was pulled from the water exhausted but unhurt.

Vidam Perevertilov fell overboard about 400 nautical miles south of the Austral Islands.
He was rescued after 14 hours, clinging to an old fishing buoy.

The British high commissioner to New Zealand Laura Clarke, who also serves as the governor of Pitcairn Island, told the New Zealand Herald everyone was “hugely relieved” to hear of the rescue.
“We all feared for the worst, given the sheer scale of the Pacific Ocean, and its strong currents,” she said.
“So the fact that the Silver Supporter found him, and he survived is just amazing: a story of survival that even Captain Bligh … would have applauded.”
William Bligh was cast adrift by mutineers on his ship the Bounty 1789, and successfully navigated more than 6,000km in an open launch to the island of Timor, then called the Dutch East Indies.
The mutineers would become the first inhabitants of Pitcairn Island, and their descendants still live there.
The remote volcanic island remains a British territory.

Perevetilov’s son Marat, told Stuff, his father had left the fishing buoy in the sea, rather than taking it as a souvenir.
“It’s funny. He said he wanted to leave it there, so it could save another person’s life.”

Links :

The Guardian : Missing sailors stranded on Pacific island saved by giant SOS in the sand

Thursday, March 4, 2021

How fast are oceans rising? The answer may be in century-old shipping logs

Shipping workers recorded the tide levels beginning in 1854 at St. George's Dock in Liverpool, England, creating valuable records for future scientists.Heritage Images/Getty Images

From NPR by Lauren Sommer

Off the coast of England, there's a tiny, wind-swept island with the remains of a lifeboat rescue station from the mid-1800s.
The workers who once ran the station on Hilbre Island did something that, unbeknownst to them, has become crucial for understanding the future of a hotter climate: They recorded the tides.

The data, scrawled in long, handwritten ledgers, is just one example of the tens of thousands of pages of tidal measurements stored in archives around the world.
Now, scientists and historians are racing to digitize them in an effort to understand how fast oceans are rising.
The aging notebooks establish a historical baseline to compare with today's changing world.

Sea level rise is accelerating around the globe, likely to displace millions of people who live in coastal communities.
Forecasts show between 3 and 6 feet of rise by the end of the century, or potentially more, depending on how much heat-trapping pollution humans emit.

Knowing exactly how much inundation to expect and how fast it's happening in each city can be tricky. Sea levels rise at different rates in different places due to the movement of the Earth's crust and ocean currents.

Long-term historical data, diligently tallied when the shipping industry was king, provide a window into these geologic processes and help improve the complex computer models scientists use to forecast the future.
Those forecasts are crucial for helping cities prepare, whether it's building infrastructure to protect themselves or moving people out of harm's way.

Still, the vast majority of these historical records come from Europe and the U.S., leaving a glaring data gap in the Southern Hemisphere.
That has researchers scouring archives of the Global South, including the ledgers of former colonial powers.
"If we really know what happened in the past, it can really help us to help people with better projections," says Thomas Frederikse, climate scientist at NASA's Jet Propulsion Laboratory. 
"Even one single record can really help us out in understanding what's going on."

"Srawl-y" historical records

The tidal logs gathered at Hilbre Island, just off the coast of Liverpool, weren't just a snapshot of the daily high and low tides.
Beginning in the mid-1800s, water heights were logged every 15 minutes, producing granular timelines of the ebb and flow.
Nearby, workers at the port of Liverpool kept the same detailed records beginning in the 1850s.
"You needed tide gauge records to know when it was safe to enter and exit the ports" says Andy Matthews, data scientist at the Permanent Service for Mean Sea Level, an organization that gathers ocean data worldwide and is also home to archival tidal records.

Tidal heights were recorded every 15 minutes, like in this ledger from Hilbre Island in 1903. Scientists are hoping volunteers will help digitize the data.
Andrew Matthews

The data collection was often done with automatic tide recorders, which used a float, sitting on the surface of the water, that relayed information to a recorder.
Dock workers or other maritime staff would then transcribe the numbers into huge tables.

"You can see some of them have very intricate handwriting and others are pretty scrawl-y," Matthews says.
"There's one record where at one point there's a little hand-scrolled note that says: no data this week because the tide gauge operator was off sick."

Matthews and his colleagues have scanned more than 16,000 images of the tidal ledgers.
But the data are still locked on the pages, because they haven't been extracted and digitized.
Using computers to read the data with character recognition can be hit-or-miss, based on the old handwriting.

So, Matthews posted the documents on Zooniverse, where anyone can help transcribe the information, in the hope that volunteers will chip in from home.
"The world is going crazy out there but you can just focus on this sheet of numbers and type them and it lets you take your mind off that for a while," he says.

Sea level rise is local

Global sea levels have already risen about 8 inches since 1900 on average, but in some locations, the water has risen substantially higher.

"One of the really difficult things of sea level rise is that it happens everywhere on a different pace," Frederikse says. 
"Sea level rise is not rising everywhere with the same speed. Like for example, the U.S. East Coast has seen a lot of sea level rise.

Since the Industrial Revolution, melting glaciers have caused a large part of the rise, but there are other causes scientists have had to tease out.
Massive ice sheets on Greenland and Antarctica are also melting at an increasingly rapid pace.
Oceans are warming, which causes the water itself to expand and take up more space. Around the 1960s and 70s, humans actually built so many dams that the rate of sea level rise slowed, because reservoirs held water back and prevented it from reaching the oceans.

Even after scientists calculate how much water comes from all those sources, the Earth's oceans don't fill evenly like giant bathtub.
The planet's crust is slowly moving, essentially re-forming the shape of the bathtub itself. Heavy objects on land, like ice sheets, make depressions in the Earth. Then, when they melt, the crust slowly rebounds, a lot like what happens to a couch cushion when someone gets up.

During the last ice age, Greenland and Canada were heavily loaded with ice, so the crust there is still slowly rebounding after it melted away.
As it rises, the southern part of the North American tectonic plate is sinking, like the opposite end of a seesaw.
As a result, the East Coast, especially around the mid-Atlantic, has the fastest-rising sea levels in the country.

Ocean conditions like currents also dramatically affect sea level rise in any given place.
The water on one side of a current can be many inches higher than the other side.
As a result, the ocean itself is somewhat lumpy with its own varying topography.

The old tide gauge at Hilbre Island's lifeboat station.
Joanne Williams

For all those reasons, every coastal city faces a different level of risk. Having historical tidal records from many different locations helps scientists understand how these local conditions work. Once digitized, the records can be quickly added to the historical ocean data set that scientists use in climate computer models.

"If we don't have that information, it's easy to be like a few feet off if we don't have local records of sea level," Frederikse says. 
"And it's decisions we have to make now. If you build a neighborhood in a floodplain and then you miscalculate the risk, then the people who live there in 50 years might pay the price."

Gap in the Southern Hemisphere

As historical tidal records have been uncovered and digitized from Europe and the U.S., a glaring lack of data exists for the rest of the globe.

"The Southern Hemisphere — it's not really well covered," says Capt. Ariel Troisi, technical secretary of Argentina's Naval Hydrographic Service.
Troisi says it's a common problem across many forms of climate data, whether it's temperature records or weather stations.
His department is currently working on recovering tidal records that began in 1905 at the port of Buenos Aires, taken to support shipping operations.

To rescue even older records, researchers are looking in the archives of former colonial powers.
As countries like France, Great Britain and Germany took control of other countries and extracted their resources, many gathered detailed maritime records.
Some assisted with geographic mapping, while others helped with port or shipping infrastructure projects.

In France, the country's national hydrographic and oceanographic service, known as SHOM, has digitized records from dozens of overseas ports where they once held power, ranging from West Africa to Vietnam.
"There are so many projects that are initiated right now to rescue these data, because with time, these documents can be lost again and again," says Alexa Latapy, a historical reconstruction expert at SHOM.

In some locations, the work involves piecing together records across the various governments that held power.
In Cameroon, doctoral student Yannick Fossi Fotsi has found tidal records from Germany, which was in power in the late 1800s.
After that, France took control until Cameroon won independence in 1960.

Tidal data like this 1930 chart provides a valuable baseline for understanding how fast oceans are rising around the globe today.
Andrew Matthews

While there are other short-term historical tidal records for the African continent, only one other multi-decade tidal record exists in Senegal, which Fossi Fotsi says makes it challenging for scientists to refine their global predictions for sea level rise.
"This can't be done only with stations in Europe, America and Asia, without stations in Africa," Fossi Fotsi says. "It's very important."

He's also hoping the historical records will lead to better information for Cameroon itself.
The country's economic capital, Douala, is extremely susceptible to sea level rise.
The coastal city, home to millions, is located in an estuary on the Atlantic Ocean and was hit by a damaging flood last year.
Says Fossi Fotsi: "The effects of climate change are going to have an enormous impact on the coast and will have a huge effect in terms of coastal vulnerability."

Wednesday, March 3, 2021

The history of pursuing hydrographic measurement accuracy

Leadline sounding operation.
(Photo: 1928 and 1931, Hydrographic Manual)

From Hydro

The profession of hydrographer is built upon measurement accuracy.
Ever since Lucas Janszoon Waghenaer produced the first true nautical charts in 1584, hydrographers have been working to improve the accuracy of their measurements.
For anyone fortunate enough to have reviewed Waghenaer’s atlas, the 'Spieghel der Zeevaert' (The Mariner’s Mirror), one of the first questions that comes to mind is how accurate are these charts?
As the technology of the times was crude at best, it would be difficult to evaluate his charts by modern standards.
However, two soundings stand out as indicative of both the relative accuracy of his data and Waghenaer’s integrity.

Study of Waghenaer’s charts reveals that there are few soundings deeper than 30 fathoms: one 60-fathom sounding, and one anomalous nearshore sounding of 200 fathoms.
This 200-fathom sounding was the final sounding of a line of soundings that ended with 7, 50, and then 200 fathoms.
Was this a blunder on Waghenaer’s part, an error on the part of the engraver, or indicative of the real configuration of the seafloor?

Comparison with a modern bathymetric map gave the answer.
These two soundings were made at the head of Subetal Canyon – a large canyon incising the Portuguese continental shelf and slope.
The soundings are convincing evidence of Waghenaer’s integrity as a hydrographer and also his commitment to producing charts that were as accurate as the technology of the times permitted.

Waghenaer's Chart No. 17.
It is oriented with North to left.
200 fathom sounding on north wall of Subetal Canyon is to east of Cape Spichel.
Cape Spichel with the GeoGarage platform (UKHO nautical chart)
For the next 340 years, little was done to improve the accuracy of depth sounding instrumentation.
The hydrographer was constrained to using the lead line.
However, positioning technology began improving in the eighteenth century with the invention of octant, sextant, chronometer and station pointer.
These inventions, coupled with the evolving understanding that depth information had to be placed in the same geographic framework as the shoreline and landmarks shown on charts, led to a quantum leap in the accuracy of charts.
This new understanding was driven by the work of such British hydrographers as Murdoch Mackenzie Senior, Murdoch Mackenzie Junior, Graeme Spence and the incomparable James Cook.

Triangulation Network

In 1747, Mackenzie Senior was the first hydrographer to develop a local triangulation scheme during his survey of the Orkney Islands.
In 1750, he wrote, “The lives and fortunes of sea-faring persons, in great measure, depend on their charts.
Whoever, therefore, publishes any draughts of the sea-coast is bound in conscience, to give a faithful account of the manner and grounds of performance, impartially pointing out what parts are perfect, what are defective, and in what respects each are so….”
He then went on to describe his methodology of measuring a baseline, developing a triangulation network, building “beacons, or landmarks” over prominent points in the network, and then positioning his sounding boat by taking intersecting compass bearings to these points during sounding operations.
The weakest link in this methodology was the use of compass bearings to position the sounding boat.
Murdoch Mackenzie rectified this situation in 1775 with the invention of the station pointer, or as it is known in the United States, the three-arm protractor.
This instrument allowed hydrographers to plot three-point sextant fixes which resulted in horizontal accuracies of less than ten metres within the bounds of the triangulation scheme.
By 1785, George Vancouver was able to report regarding his survey of the Kingston, Jamaica harbour that, “The positive situation of every point and near landmarks as well as the situation and extent of every Shoal has been fixed by intersecting Angles, taken by a sextant and protracted on the Spot, the Compasses only used to determine the Meridian, and observe its Variation.”

Swiss Precision

The United States began making contributions to the sciences of geodesy and hydrography in 1807 with the beginnings of the Survey of the Coast of the United States.
The Swiss immigrant, Ferdinand Hassler, was chosen to head this embryonic organization.
He combined the talents of mathematician, geodesist, metrologist, instrument-maker, linguist, and even legal expert.
Not only had he worked on the trigonometric survey of Switzerland, he had also served as its attorney general in 1798.
Hassler procured books and instruments for the Coast Survey between 1811 and 1815 and then started the field work in 1816.
In 1818, a law was passed forbidding civilians from working on the survey.
Hassler retired to a home in western New York for the next 14 years until recalled to head the survey again.
In 1825, he published Papers on Various Subjects connected with the Survey of the Coast of the United States in the Transactions of the American Philosophical Society.
This document served as the philosophic underpinning of the work and role of the Coast Survey.

NOAA's Ferdinand R.Hassler (S 250) is a coastal mapping vessel.
(Photo: NOAA)

The twin themes of standards and accuracy permeate the ‘Papers’.
The word ‘standard’ is used as either noun or verb over 60 times.
The word ‘accurate’ or its derivative forms have over 120 occurrences throughout the document.
These simple words, combined with the inherent integrity of Ferdinand Hassler, were the foundation of the Survey of the Coast.
Hassler addressed the concept of accuracy in the ‘Papers’ with many practical examples of means to eliminate or reduce error and thus increase the accuracy of the final results of observation and measurement.
But he made a philosophical leap when he stated: “Absolute mathematical accuracy exists only in the mind of man.
All practical applications are mere approximations, more or less successful.
And when all has been done that science and art can unite in practice, the supposition of some defects in the instruments will always be prudent.
It becomes therefore the duty of an observer to combine and invent, upon theoretical principals, methods of systematical observations, by which the influence of any error of his instruments may be neutralized, either by direct means, or more generally by compensation.”
The observer must also counteract those errors “to which he himself is liable in making his observations.
Without such a method, and a regular system in his observations, his mean results will be under the influence of hazard, and may even be rendered useless by adding an observation, which would repeat an error already included in another observation.”

The Law of Human Error

Two surprisingly modern concepts that Hassler addressed were personal bias in the observation of physical phenomena and the effect of personal comfort, in other words ergonomics, upon the observer’s results.
He was among the first to take steps to mitigate various systematic errors and analyse their causes.
Further advances in understanding were made by Benjamin Peirce, head of Coast Survey longitude operations in the 1850s, and Charles Schott, the chief mathematician and geodesist of the Coast Survey.
Their work, like Hassler’s, was related to terrestrial positioning problems but ultimately this led to more accurate nautical charts.

The three-point sextant fix was the most accurate positioning technique for inshore hydrographic surveying for nearly 200 years.
Plotting a three-point sextant fix.

Peirce began with the supposition that with only one observation of a physical quantity, that observation must be adopted as the true value of the constant.
However, “A second observation gives a second determination, which is always found to differ from the first.
The difference of the observations is an indication of the accuracy of each, while the mean of the two determinations is a new determination which may be regarded as more accurate than either.”

As more and more observations are acquired: “The comparison of the mean with the individual determinations has shown, in all cases in which such comparison has been instituted, that the errors of … observation are subject to law, and are not distributed in an arbitrary and capricious manner.
They are the symmetrical and concentrated groupings of a skillful marksman aiming at a target, and not the random scatterings of a blind man, nor even the designed irregularities of the stars in the firmament.
This law of human error is the more remarkable, and worthy of philosophic examination, that it is precisely that which is required to render the arithmetical mean of observations the most probable approach to the exact result.
It has been made the foundation of the method of least squares, and its introduction into astronomy by the illustrious Gauss is the last great era of this science.”

Peirce continued: “If the law of error embodied in the method of least squares were the sole law to which human error is subject, it would happen that by a sufficient accumulation of observations any imagined degree of accuracy would be attainable in the determination of a constant; and the evanescent influence of minute increments of error would have the effect of exalting man’s power of exact observation to an unlimited extent.
I believe that the careful examination of observations reveals another law of error, which is involved in the popular statement that ‘man cannot measure what he cannot see’.
The small errors which are beyond the limits of human perception, are not distributed according to the mode recognized by the method of least squares, but either with the uniformity which is the ordinary characteristic of matters of chance, or more frequently in some arbitrary form dependent upon individual peculiarities – such, for instance, as an habitual inclination to the use of certain numbers.
On this account it is in vain to attempt the comparison of the distribution of errors with the law of least squares to too great a degree of minuteness; and on this account there is in every species of observation an ultimate limit of accuracy beyond which no mass of accumulated observations can ever penetrate.”
Improving the Methods

“A wise observer, when he perceives that he is approaching this limit, will apply his powers to improving the methods, rather than to increasing the number of observations.
This principle will thus serve to stimulate, and not to paralyse effort; and its vivifying influence will prevent science from stagnating into mere mechanical drudgery....”

Peirce’s words are at the heart of modern hydrographic surveying.
With the coming of electronic systems, the need to analyse and understand sources of error and the limits of accuracy of those various systems has been of paramount importance.
From the early twentieth century onward, generations of hydrographers have studied the limitations of and made improvements to their navigation systems and sounding systems.
They have not ‘stagnated’, but instead have concentrated their efforts on ‘improving of methods’.
One wonders what our future ‘ultimate limit of accuracy’ will be.

In the third quarter of the 20th century, several evolutionary concepts were advanced that fundamentally changed the way we map the seafloor.
(Courtesy: NOAA)

Links :

Tuesday, March 2, 2021

ClimaCell, an ambitious private weather firm, plans to launch its own satellites

 Artistic rendering of a ClimaCell satellite. (ClimaCell)
From WP by Andrew Fredman

The company would be the first to operate a satellite fleet to improve its own forecasts, rather than selling the data to others

ClimaCell, a growing private weather company based in Boston whose customers include airlines, maritime shipping firms and everyday consumers, plans to spend $150 million during the next few years to launch its own satellite radar constellation.
The goal, company leaders said in an interview, is to make its own forecasts more reliable, thereby benefiting its clients, the public through its weather app and policymakers.

This aim contrasts with the business of most, if not all, space companies today that are pursuing weather applications. 
These firms, such as GeoOptics and Spire, have business models based on selling the data for others to use in forecasting the weather, with customers that include federal agencies.
However, ClimaCell would use its own technology, which already includes proprietary weather modeling, to take advantage of the data it gathers from space.

The end result, if all goes well, would be a vertically integrated weather company whose operations range from generating its own data to sifting through that information using computer models and turning that into products aimed at improving how businesses operate.

According to ClimaCell co-founder and chief executive Shimon Elkabetz, ClimaCell has several dozen scientists and engineers now dedicated to developing and eventually deploying a fleet of small space-based weather radars that could gather real-time data of every location on the globe at any time.
This would be a major leap forward for radar coverage over data-sparse regions, he said, such as Africa, South America and the oceans.

The satellites would carry a Ka-band radar instrument, Elkabetz said, which he compared to a research mission that NASA has carried out known as the Global Precipitation Measurement (GPM) satellite.

GPM consists of a dual-frequency radar that allows it to get a three-dimensional view of precipitation falling within a storm, including by seeing the distribution of different droplet sizes within the clouds, according to Dalia Kirschbaum, who heads NASA’s hydrological sciences lab at the Goddard Space Flight Center in Greenbelt, Md.

The downside to GPM is that it is just one satellite. 
“When you have a single orbiting spacecraft, if you don’t get a good [pass over] a storm, then you just miss it,” she said.

The space agency has also launched small satellites, such as rainCube, which was deployed from the International Space Station, to help solve the challenge of building powerful radars in small boxes, Kirschbaum said.
“The instrument will offer similar capabilities” to the radar aboard GPM, Elkabetz said, “in terms of both resolution and sensitivity, but exceed the swath,” or scan footprint, by a factor of more than two.

To accomplish this, the company is planning to use its own technologies to develop a new radar and antenna. ClimaCell is seeking to lower the costs per satellite by at least half compared with the NASA satellite, which scans a location on Earth only every three days.
The cost savings, Elkabetz said, “will allow us to scale this from a single-satellite mission to a constellation of dozens of satellites that enables global coverage with high revisit rates.”

Rei Goffer, co-founder and chief strategy officer at ClimaCell, said revisit times, the interval between instances when the satellite passes over the same location on Earth, would be one hour in the company’s planned satellite constellation.
“We are not going to space just because it’s cool,” Goffer said in an interview, but instead are trying to solve a data gap that could allow the company to make far more accurate forecasts.

Outside experts, such as Brian Weeden of the Secure World Foundation, questioned whether the new satellites would interfere with other spacecraft also operating within the Ka band of spectrum, including planned 5G satellites and other weather satellites already in low Earth orbit.

Elkabetz said he expects to encounter skepticism from those who may not believe that ClimaCell has solved some of the technical challenges in developing and deploying these satellites.
If he were not involved in the project already, he would not believe it, either, he said.

“I respect anyone who thinks it’s difficult, and as we are able to reveal in the future how it works, hopefully people will be able to witness it themselves,” he said in an interview.

Marshall Shepherd, director of the University of Georgia’s atmospheric sciences program, said he sees this project as a way to better predict weather extremes.
“Precipitation is at the heart of many weather-related extremes ranging from flooding to hurricanes, yet is very difficult to measure on global scales,” Shepherd said in an email.

Estimates of rainfall rates on July 8, 2019, a day that brought flooding to the D.C. region, from NASA's Global Precipitation Measurement Core Observatory. (NASA)

“I am not surprised that scholars are exploring new ways to provide measurements with the accuracy and resolution useful for applications.”

ClimaCell has raised a substantial amount of money for a recent entrant into the weather forecasting business: about $112 million in venture capital funding, with the most recent round closing in July 2020.

Elkabetz noted that most of the world still does not have radar coverage, including in Latin America, Africa, the Middle East and Asia.
“The system’s capabilities will enable new modeling and analytics with precision never before available in the developing world,” he said.

“The data will power applications such as monitoring the conditions favorable for locust reproduction and migrations, as well as conditions that lead to devastating infectious diseases such as malaria, which put millions of lives and livelihoods at risk,” Elkabetz said in a statement.

The satellites could significantly help hurricane forecasts, he said, since they would provide details about the structure and evolution of such storms.
The National Hurricane Center has utilized data from the GPM mission and previous weather satellites for forecasting purposes.

The chief engineer for the program is John Springmann, who has worked with private sector space firms including SpaceFlight industries, which launched the BlackSky constellation.
The team has also been working with Kerri Cahoy, co-director of the small-satellite center at MIT.

ClimaCell is aiming to launch its first radar satellite in the third quarter of 2022.

Through the company’s nonprofit arm known as, the satellite data could flow to areas where improved forecasts are desperately needed, mainly in the developing world, Goffer and Elkabetz said.

Links :

Monday, March 1, 2021

Brunt Ice Shelf in Antarctica calves

First imageFirst image of the newly calved Brunt Ice Shelf from Sentinel 2!
Taken (26th Feb) at 09:40:19 UTC.

From BAS

A huge iceberg (1270 km²) the size of the county of Bedfordshire has broken off the 150-m thick Brunt Ice Shelf, almost a decade after scientists at British Antarctic Survey (BAS) first detected growth of vast cracks in the ice.

The Brunt Ice Shelf is the location of British Antarctic Survey’s (BAS) Halley Research Station.
BAS glaciologists, who have been expecting a big calving event for at least a decade, say that the research station is unlikely to be affected by the current calving.
The 12-person team working at the station left mid-February by BAS Twin Otter aircraft.
The station is now closed for the Antarctic winter.

North Rift crack photographed by Halley team in January 2021

The first indication that a calving event was imminent came in November 2020 when a new chasm – called North Rift – headed towards another large chasm near the Stancomb-Wills Glacier Tongue 35 km away.
North Rift is the third major crack through the ice shelf to become active in the last decade.

During January, this rift pushed northeast at up to 1 km per day, cutting through the 150-m thick floating ice shelf.
The iceberg was formed when the crack widened several hundred metres in a few hours on the morning of 26th Feb, releasing it from the rest of floating ice shelf.
Map of Brunt ice shelf and Halley Research Station

The glaciological structure of this vast floating ice shelf is complex, and the impact of ‘calving’ events is unpredictable.
In 2016, BAS took the precaution of relocating Halley Research Station 32 km inland to avoid the paths of ‘Chasm 1’ and ‘Halloween Crack’.

Since 2017, staff have been deployed to the station only during the Antarctic summer, because during the dark winter months evacuation would be difficult.
‘Chasm 1’ and ‘Halloween Crack’ have not grown in the last 18 months.

Professor Dame Jane Francis, Director of British Antarctic Survey says:
“Our teams at BAS have been prepared for the calving of an iceberg from Brunt Ice Shelf for years.
We monitor the ice shelf daily using an automated network of high-precision GPS instruments that surround the station, these measure how the ice shelf is deforming and moving.
We also use satellite images from ESA, NASA and the German satellite TerraSAR-X.
All the data are sent back to Cambridge for analysis, so we know what’s happening even in the Antarctic winter, when there are no staff on the station, it’s pitch black, and the temperature falls below minus 50 degrees C (or -58F).

“Over coming weeks or months, the iceberg may move away; or it could run aground and remain close to Brunt Ice Shelf.
Halley Station is located inland of all the active chasms, on the part of the ice shelf that remains connected to the continent.
Our network of GPS instruments will give us early warning if the calving of this iceberg causes changes in the ice around our station.”

Simon Garrod, Director of Operations at British Antarctic Survey adds:
“This is a dynamic situation. Four years ago we moved Halley Research Station inland to ensure that it would not be carried away when an iceberg eventually formed. That was a wise decision.
Our job now is to keep a close eye on the situation and assess any potential impact of the present calving on the remaining ice shelf.
We continuously review our contingency plans to ensure the safety of our staff, protect our research station, and maintain the delivery of the science we undertake at Halley.”

More information

About Halley VI 

Halley VI Research Station is an internationally important platform for, atmospheric and space weather observation in a climate-sensitive zone.
In 2013, the station attained the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Global station status, becoming the 29th in the world and 3rd in Antarctica.

Halley VI Research Station sits on Antarctica’s up to 150–m thick Brunt Ice Shelf.
This floating ice shelf flows at a rate of up to 2 km per year west towards the sea where, at irregular intervals, it calves off as icebergs.

Long-term monitoring of the natural changes that occur in the ice shelf has revealed changes, including growth of a recently-formed chasm, the North Rift.
Halley VI Research Station has been unoccupied during the last four winters because of the complex and unpredictable glaciological situation.

Change in the ice at Halley is a natural process and there is no connection to the calving events seen on Larsen C Ice Shelf, and no evidence that climate change has played a significant role.

During the 2016-17 Antarctic Summer season (Nov-March), in anticipation of calving, the eight station modules were uncoupled and transported by tractor to a safer location upstream of Chasm-1.

Over the summer 18/19, BAS installed an autonomous power generation and management system – Halley Automation project – which provides a suite of scientific instruments with power even when we have no staff at the station.
This system has proved effective in running through more than eight months of darkness, extreme cold, high winds and blowing snow and delivering important data back to UK.

There have been six Halley research stations on the Brunt Ice Shelf since 1956.

About Chasm 1

In 2012, satellite monitoring revealed the first signs of change in a chasm (Chasm 1) that had lain dormant for at least 35 years.  This change had implications for the operation of Halley VI Research Station.
In the 2015/16 field season, glaciologists used ice penetrating radar technologies to ‘ground truth’ satellite images and to calculate the most likely path and speed of Chasm 1.
Chasm 1 grew up until 2019 but has not moved for the past 18 months.
There is now 2 km of ice holding this iceberg in place.

About Halloween Crack

In October 2016, a new crack was detected some 17 km to the north of the research station across the route sometimes used to resupply Halley.  The ‘Halloween Crack’ continues to widen and a second large iceberg may calve to the north’.
The tip of Halloween Crack is also currently static.

About North Rift Crack

In November 2020, a new chasm, known as the North Rift opened and started extending towards Brunt-Stancomb Chasm.
The Brunt Ice Shelf is probably the most closely monitored ice shelf on Earth.
A network of 16 GPS instruments measure the deformation of the ice and report this back on a daily basis.
European Space Agency satellite imagery (Sentinel 2), TerraSAR-X, NASA Worldview satellite images, US Landsat 8 images, ground penetrating radar, and on-site drone footage have been critical in providing the basis for early warning of changes to the Brunt Ice Shelf.
These data have provided science teams with a number of ways to measure the width of Chasm 1 and changes to the Halloween Crack and North Rift crack, with very high precision.
In addition, scientists have used computer models and bathymetric maps to predict how close the ice shelf was to calving.

About Halley science 
Ozone measurements that have been made continuously at Halley since 1956 (which led to the discovery of the ozone hole in 1985, and since that time, its slow progress towards recovery)
Monitoring of space weather undertaken at Halley contributes to the Space Environment Impacts Expert Group that provides advice to UK Government on the impact of space weather on UK infrastructure and business.

Sunday, February 28, 2021

The Long Leg , Edward Hopper (1935)

Messing about on boats all summer is a holiday lived in the present; that’s the sense of this picture.
The boat remains still; it is the wind and water that move it along.
Hopper’s coolly beautiful painting of a sailboat off the New England shore perfectly expresses this curious fact about sailing.
And in conditions like these – a hot blue day, windless, the sun beating down on the blanched sand – the boat is lying almost motionless to one side, solitary as the characteristic Hopper lighthouse in the background.
Like the water itself, the painting is almost entirely composed in shades of blue.
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