When It Comes To Sea Level Changing Glaciers, New NASA Technique Measures Up

When It Comes To Sea Level Changing Glaciers, New NASA Technique Measures Up

ScienceDaily (Nov. 10, 2008) — A NASA-led research team has used satellite data to make the most precise measurements to date of changes in the mass of mountain glaciers in the Gulf of Alaska, a region expected to be a significant contributor to global sea level rise over the next 50-100 years.

Geophysicist Scott Luthcke of NASA's Goddard Space Flight Center, Greenbelt, Md., and colleagues knew from well-documented research that changes in the cryosphere – glaciers, ice caps, and other parts of the globe covered year-round by ice -- are a key source of most global sea level rise. Melting ice will also bring changes to freshwater resources and wildlife habitat. Knowing that such ice-covered areas are difficult to observe consistently, the team worked to develop a satellite-based method that could accurately quantify glacial mass changes across seasons and years, and even discern whether individual glacier regions are growing or shrinking.

The study's authors found that the annual ice mass lost from glaciers in the Gulf of Alaska has been 84 gigatons annually, about five times the average annual flow of the Colorado River through the Grand Canyon and equal to the entire amount of water in the Chesapeake Bay.

"The Gulf of Alaska region is 20 times smaller than the ice-covered area of Greenland, yet it contributes nearly half as much freshwater melt as Greenland and accounts for about 15 percent of present-day global sea level rise stemming from melting ice," said Luthcke, lead author of the study which will appear this week in the Journal of Glaciology. "Considering that the Gulf of Alaska makes such a disproportionate contribution, it is vital that we know more about the nature of glacial change there."

Luthcke and colleagues found a way to remotely measure the "mass balance" of a glacier; that is, the net annual difference between ice accumulation and ice loss. Past measurements of glacial mass balance in remote mountain ranges have been sparse or imprecise. Ground-based sensors can provide long-term data, but such data points are scattered due to the inaccessibility of many remote mountain ranges. Altimeters aboard aircraft can measure changes in the height of glaciers, but the sampling is sporadic because flights are relatively infrequent.

Glaciers in the coastal environments on the edge of the Arctic or Antarctic shed and gain mass rapidly, a high mass turnover that is particularly sensitive to climate change. Warming seas can accelerate the motion of tidewater glaciers, and melt water on glacial surfaces can flow to the floors of glaciers and serve as a lubricant as the ice slides toward the sea. The subsequent addition of freshwater to the ocean contributes to one of two sources of global sea level rise; "eustatic" rise resulting from melted ice in the form of freshwater, with the other source set off by "thermal expansion," sea level rise that occurs due to warming ocean temperatures.

The Goddard-led research team developed a new data analysis technique for NASA's Gravity Recovery and Climate Experiment (GRACE) mission. GRACE is made up of twin satellites that orbit Earth about 137 miles apart and 300 miles above Earth's surface. The positions of the two satellites change in response to variations in Earth's gravity field, which is stronger or weaker depending on the land or ice mass that they are flying over. Microwave ranging systems measure the distance between the two satellites down to the width of a human hair, so by measuring the change in the distance between the satellites over time, researchers can essentially "weigh" the changes in Gulf of Alaska glaciers.

Using data collected by the GRACE satellites from 2003-2007, as well as unique processing and analysis techniques, Luthcke and colleagues were able to measure the mass of the glaciers every 10 days across an area spanning 18,919 square miles, about the equivalent of Vermont and New Hampshire combined.

The team found the largest ice mass losses occurring in the Yakutat, Glacier Bay, and St. Elias regions. Those observations are consistent with recent studies from aircraft-based altimeters and other satellites.

"The consistent and direct measurement of ice-mass change made possible by the GRACE data and the analysis techniques applied in this study provide unprecedented observations that further our knowledge of the region's complex ice evolution," said Luthcke.

The most rapid glacial melt, according to Luthcke and colleagues, came in response to the summer heat wave of 2004, when the region's glaciers shed 374 gigatons of ice, or about 98 cubic miles of ice. In comparison, the record for Greenland ice melt was 500 gigatons, or about 131 cubic miles, during the summer of 2007.

"With such rapid change taking place in such a critical area, we need to be able to more reliably observe how these glaciers are responding," said Luthcke. "The direct measurement of ice-mass variation is important for improving our modeling capability and for ultimately predicting future changes."

WEATHER NOTE

Colors of the ocean make their way into a book

The compositions are simple: cresting waves, a stretch of sand, a field of sky. In some, glimmering sunlight highlights the ocean’s surface. In others, a protected cove is defined by water that ebbs and flows over sand. Gray cloudscapes sometimes threaten; the water might be rough.

Regardless, all the watercolor paintings seem serene, and project an air of solitude. No one inhabits these beaches—the viewer is one with the vista, alone, looking out to sea.

And this is exactly what artist Mike Solomon intended. It’s how he experiences the ocean while scanning sea conditions, waiting to surf. Waiting for the perfect time to put away his paints, grab his board and see how the shoreline view meshes with surfing reality.

The paintings can easily stand on their own. But closer examination brings a subtle surprise—there is writing across the bottom of the composition. At first, it seems like some sort of code: a numerical date, an actual time or time of day, a location. Notations on swell heights, air temperature, water temperature and weather-related information follow. The words are clinical, factual: a straight reporting of conditions. Then, unexpectedly, the personal.

A single sentence punctuates the text, changing the whole experience. The words can be simple like “(Michele’s Birthday)” or “A couple of guys out.” Sometimes the reference leans toward the poetic: “Strong offshores and shoulder high swell at low tide—all the elements baking in the sun.”

In some works, an unexpected twist concludes the text: “I sat and watched for a couple of hours but saw nothing worth enduring that cold for.” Or, “Claudia took her expensive sunglasses off and hid them in a crevice, never to be found again…” or “Xavier, the owner, offers me a beer.”

Yet other comments are more reflective: “They say Mike Diffenderfer used to surf the wave off the island. I would.” Or, “small surf can change on the tide—got it on the high a few days later—surprisingly good sometimes,” or “…No one out yet, just me with a few birds…” The cumulative effect changes the art and renders it more personal. Reading the small writing beneath the composition requires moving closer to the work, which the artist hopes will evoke the experience of feeling connected to the seascape and help viewers experience the artwork more intensely. These effects are of a piece with Mr. Solomon’s intentions.

“The paintings are deceptively simple,” he said. “They are memories of a specific time and place. The diaristic aspect is my way of bringing people closer to experiencing the ocean and the day the way that I did.”

Viewing a painting from close range also creates the sensation of “seeing” the view that lies beyond the 
parameters of the painting, Mr. Solomon explained.

“How we look at these paintings is important,” he said. “It’s not just what’s in the painting and what we see there. The work is about how we look at something.”

There’s no doubt the series of watercolor paintings is personal. The diaristic entries are part of it—but so are seascapes painted so that the emotional resonance of his experience radiates from the multi-layered composition.

The watercolor paintings take center stage in two manifestations. A series of 12 paintings is currently being shown in a solo show at John McWhinnie @ Glenn Horowitz Bookseller at 36 Newtown Lane in East Hampton. And 36 paintings are the substance of Mr. Solomon’s new book, “Meterological Watercolors,” with the title a nod to the weather and water notations that accompany each painting.

The 80-page book is self-created and will be available through the publisher, Blurb.com, in December, for $60. A foreword was written by Alicia G. Longwell, chief curator at the Parrish Art Museum. Signed copies are available now at Glenn Horowitz Bookseller, 87 Newtown Lane, East Hampton, for $75, and copies are also available through the artist’s website, www.mikesolomon.com.

The book contains artwork made from 1999 to August 2008, printed in chronological order. The paintings occupy the right-hand page with the text set on the opposite page. The foreword is the only introduction and explanation for the artwork. Some of the art is already part of collections held by private individuals or museums.

Watercolors are not Mr. Solomon’s primary method of expression. He is known more for abstract expressionist paintings and minimalist sculptures. His subject matter is often inspired by waves and the ocean, reflecting his lifelong love of surfing and the sea. He decided to create a series of watercolor paintings after uncovering a sketchbook from his 20s when he lived and surfed on the California coast.

Like the current series of paintings, his notebook artwork was rendered in watercolors while on site. After examining the combination of words and images, Mr. Solomon decided there was something that still spoke to him in the work. So he set out to create a new series of paintings.

Most of the compositions are painted on site. The painting is then developed and completed in his studio using multiple layers of watercolors. Sometimes the views are local; other times they capture foreign locales. The local site names were changed to protect beloved surfing spots.

Mr. Solomon’s aim is to conjure the mood and experience of watching a specific stretch of ocean at a specific time while gauging the surf conditions. Sometimes the mood is based on a two-hour span; other times a full day of observation is synthesized.

“It’s not a photograph,” Mr. Solomon said. “It’s not an exact replica—it’s a painting. I’m capturing a memory of that moment and that particular place.”

The exhibition, “Mike Solomon/Meteorological Watercolors,” remains on view through November 29 at John McWhinnie @ Glenn Horowitz Bookseller, 36 Newtown Lane, East Hampton. The gallery is open weekends. For information, call 324-5561 or visit Johnmcwhinne.com .

Further information on Mr. Solomon’s art can be found at www.mikesolomon.com. He is represented by Salomon Contemporary (no relation). The book can be ordered in December through blurb.com.

Have You Seen Our Hourly Weather Graphs?

Have you ever wanted to know what the forecast temperature is for 2 PM the next day? Or what the chance of rain is at 7 AM Friday morning? Did you know you can get hourly forecasts out to seven days on our website? You can! Weather forecast graphs, just like the one below, can be created and custom tailored to your location with just a few mouse clicks on our website!

MARITIME NOTE

PhilNaRe's profit falls after paying for marine accident claims

MANILA, Philippines - The National Reinsurance Corp. of the Philippines (PhilNaRe) said profit fell by more than half as it paid claims to beneficiaries of marine accident victims, including those in the Princess of the Stars tragedy.

Net income for the third quarter of 2008 plunged 52 percent to P45.8 million from P95.6 million during the same period last year, the company said in a disclosure to the Philippine Stock Exchange (PSE).

Claims and losses from July to September reached P236.2 million, 73.4 percent more than last year’s P136.2 million, said PhilNaRe, which helps other firms share their insurance risks.

“Claims incurred in the current quarter include large marine losses including, among others, Princess of the Stars, Sea Bass Carriers, and Oceanic Container Line," the company said.

However, the company earned from foreign currency gains as its investments and other income reached P119.4 million during the three-month period, higher than the P82.1 million reported from July to September last year.

During the period, expenses climbed to P43 million, 45.67 percent more than the P30 million it spent last year. The company hiked employee benefits and salaries and paid taxes, licenses, and professional fees.

Earnings for the first nine months declined due to the fall in underwriting and investment income.

“Net income for the first three quarters was P238 million, P179 million or 43 percent lower than last year’s performance," the company said.

Meanwhile, expenses for the nine-month period went up by 37.5 percent to P123.6 million as against last year’s P89.9 million.

On the other hand, investment and other income declined by 6.6 percent to P350.4 million in the first nine months of 2007, the company said.

“The decline was largely due to the absence of trading opportunities during the period owing to the steep drop in the Philippine stock market," the company said. “Higher interest rates also negatively affected the valuation of the company’s investment portfolio, which is concentrated largely in fixed-income investments." - GMANews.TV

RS