Okay, Thanks Intertonic

About the size of a small pickup truck, Sentinel-6 Michael Freilich will extend a nearly 30-year continuous dataset on sea level collected by an ongoing collaboration of U.S. and European satellites while enhancing weather forecasts and providing detailed information on large-scale ocean currents to support ship navigation near coastlines. The ocean-observing Sentinel-6 Michael Freilich satellite launched from Vandenberg Air Force Base in California aboard a SpaceX Falcon 9 rocket on Nov. 21, 2020 at 12:17 p.m. EST (9:17 a.m. PST, 5:17 p.m. UTC). Credit: NASA-JPL/Caltech "The Earth is changing, and this satellite will help deepen our understanding of how," said Karen St. Germain, director of NASA's Earth Science Division. "The changing Earth processes are affecting sea level globally, but the impact on local communities varies widely. International collaboration is critical to both understanding these changes and informing coastal communities around the world." After arriving in orbit, the spacecraft separated from the rocket's second stage and unfolded its twin sets of solar arrays. Ground controllers successfully acquired the satellite's signal, and initial telemetry reports showed the spacecraft in good health. Sentinel-6 Michael Freilich will now undergo a series of exhaustive checks and calibrations before it starts collecting science data in a few months' time. Continuing the Legacy The spacecraft is named in honor of Michael Freilich, the former director of NASA's Earth Science Division, who was a leading figure in advancing ocean observations from space. Freilich passed away Aug. 5, 2020. His close family and friends attended the launch of the satellite that now carries his name. "Michael was a tireless force in Earth sciences. Climate change and sea level rise know no national borders, and he championed international collaboration to confront the challenge," said ESA (European Space Agency) Director of Earth Observation Programmes Josef Aschbacher. "It's fitting that a satellite in his name will continue the 'gold standard' of sea level measurements for the next half-decade. This European-U.S. cooperation is exemplary and will pave the way for more cooperation opportunities in Earth observation." "Mike helped ensure NASA was a steadfast partner with scientists and space agencies worldwide, and his love of oceanography and Earth science helped us improve understanding of our beautiful planet," added Thomas Zurbuchen, NASA associate administrator for science at the agency's headquarters. "This satellite so graciously named for him by our European partners will carry out the critical work Mike so believed in -- adding to a legacy of crucial data about our oceans and paying it forward for the benefit of future generations." Sentinel-6 Michael Freilich will continue the sea level record that began in 1992 with the TOPEX/Poseidon satellite and continued with Jason-1 (2001), OSTM/Jason-2 (2008), and eventually Jason-3, which has been observing the oceans since 2016. Together, these satellites have provided a nearly 30-year record ofprecise measurements of sea level height while tracking the rate at which our oceans are rising in response to our warming climate. Sentinel-6 Michael Freilich will pass the baton to its twin, Sentinel-6B, in 2025, extending the current climate record at least another 10 years between the two satellites. Global Science Impact This latest mission marks the first international involvement in Copernicus, the European Union's Earth Observation Programme. Along with measuring sea levels for almost the entire globe, Sentinel-6 Michael Freilich's suite of scientific instruments will also make atmospheric measurements that can be used to complement climate models and help meteorologists make better weather forecasts. "NASA is but one of several partners involved in Sentinel-6 Michael Freilich, but this satellite speaks to the very core of our mission," said NASA Administrator Jim Bridenstine. "Whether 800 miles above Earth with this remarkable spacecraft or traveling to Mars to look for signs of life, whether providing farmers with agricultural data or aiding first responders with our Disasters program, we are tirelessly committed not just to learning and exploring, but to having an impact where it's needed." The initial orbit of Sentinel-6 Michael Freilich is about 12.5 miles (20.1 kilometers) lower than its ultimate operational orbit of 830 miles (1,336 kilometers). In less than a month, the satellite will receive commands to raise its orbit, trailing Jason-3 by about 30 seconds. Mission scientists and engineers will then spend about a year cross-calibrating data collected by the two satellites to ensure the continuity of sea level measurements from one satellite to the next. Sentinel-6 Michael Freilich will then take over as the primary sea level satellite and Jason-3 will provide a supporting role until the end of its mission. "This mission is the very essence of partnership, precision, and incredible long-term focus," said Michael Watkins, director of NASA's Jet Propulsion Laboratory in Southern California, which manages the mission. "Sentinel-6 Michael Freilich not only provides a critical measurement,it is essential for continuing this historic multi-decadal sea level record." Sentinel-6 Michael Freilich and Sentinel-6B compose the Sentinel-6/Jason-CS (Continuity of Service) mission developed in partnership with ESA. ESA is developing the new Sentinel family of missions to support the operational needs of the Copernicus program, managed by the European Commission. Other partners include the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), and National Oceanic and Atmospheric Administration, with funding support from the European Commission and technical support from France's National Centre for Space Studies. "The data from this satellite, which is so critical for climate monitoring and weather forecasting, will be of unprecedented accuracy," said EUMETSAT Director-General Alain Ratier. "These data, which can only be obtained by measurements from space, will bring a wide range of benefits to people around the globe, from safer ocean travel to more precise prediction of hurricane paths, from greater understanding of sea level rise to more accurate seasonal weather forecasts, and so much more." JPL, a division of Caltech in Pasadena, California, is contributing three science instruments to each Sentinel-6 satellite: the Advanced Microwave Radiometer for Climate, the Global Navigation Satellite System -- Radio Occultation, and the Laser Retroreflector Array. NASA is also contributing launch services, ground systems supporting operation of the NASA science instruments, the science data processors for two of these instruments, and support for the U.S. component of the international Ocean Surface Topography Science Team. The launch is managed by NASA's Launch Services Program, based at the agency's Kennedy Space Center in Florida. source: https://www.sciencedaily.com/releases/2020/11/201122094039.htm

Can't find a way to update my post from Jul 30. The link to follow has moved to here

there is also a new tool in arcgis pro called "Pixel Editor" if you need to correct the values for this tool you need the Image analyst license.  https://pro.arcgis.com/en/pro-app/help/analysis/image-analyst/editing-elevation-pixels.htm depending on your task or your licence you can also use the "Raster Calculator" (needs spatial analysis). For example if you have a polygon with the elevation data and you want to substitute the values on your raster (polygon to raster, then use the conditional function > con() https://desktop.arcgis.com/en/arcmap/10.3/tools/spatial-analyst-toolbox/con-.htm

In some ways, drilling into Antarctica’s ancient ice is easier than interpreting it. Today, more than 2 years after presenting the discovery of the world’s oldest ice core, scientists have published an analysis of the 2.7-million-year-old sample. One surprising finding: Air bubbles from 1.5 million years ago—from a time before the planet’s ice age cycles suddenly doubled in length—contain lower than expected levels of carbon dioxide (CO2), a possible clue to the shift in the ice age cycle. The CO2 levels are “amazingly low,” says Yige Zhang, a paleoclimatologist at Texas A&M University in College Station. He adds that the study, published today in Nature, is “quite interesting” because it reports the first direct measurements of atmospheric gases from that mysterious time. Some 2.6 million years ago, Earth entered a time known as the Pleistocene, which saw the planet swing in and out of deep periods of glaciation at regular 40,000-year intervals. About 1 million years ago, during what’s called the Mid-Pleistocene transition, these ice age cycles went from occurring every 40,000 years to 100,000 years. (The most recent ice age ended 11,000 years ago.) Scientists have long known that tiny changes in Earth’s orbit, called Milankovitch cycles, drive the planet in and out of these ice ages. But nothing changed in orbital patterns 1 million years ago that would have driven the “flip.” Some scientists suspect that overall CO2 levels were higher in the 40,000-year world, but declined over time and cooled the planet, eventually reaching a point where Earth transitioned into deeper, longer freezes every 100,000 years. One way to check that theory would be to examine samples of Earth’s atmosphere from before the flip. But before the discovery of the new ice core, the oldest greenhouse gases one could measure were in trapped bubbles in ice dating to about 800,000 years ago. To reach further back in time, a team of scientists targeted so-called “blue ice” near Antarctica’s surface in the Allan Hills. Here, ancient ice flows have exhumed the oldest ice from the deep. Old ice layers are driven up from below, while wind strips away snow and younger ice. Paul Mayewski, a glaciologist at the University of Maine in Orono, suspected such ice could be ancient, and Michael Bender, a geochemist at Princeton University, developed a way to date chunks of ice directly from trace amounts of argon and potassium gases they contain. In 2015, a team led by John Higgins, a Princeton geochemist, excavated the record-setting core. At first, the oldest ice seemed to contain startling levels of CO2, several times the 407 parts per million (ppm) we see today, says Yuzhen Yan, the Princeton geochemist who led the new study. Further analysis, however, revealed the bubbles had been contaminated by CO2 percolating from beneath the ice, likely released by microbes. That meant the team had to toss out data from many of the oldest samples—a reflection of their conscientiousness, says Bärbel Hönisch, a geochemist at Columbia University. “The authors had to do a lot of work to convince themselves of what they’re actually seeing.” When the team looked at CO2 levels from 1.5 million years ago, they found them on average quite similar to the postflip world, swinging between 204 and 289 ppm, depending on whether the world was in an ice age or not. “It’s surprising,” Yan says, given broad evidence that the world was warmer in the early Pleistocene, before the ice ages grew deeper. “The educated guess is you’d have higher CO2 to achieve that. But that’s not something we see.” That means that something other than a long-term CO2 decline was likely driving the cooling, says Peter Clark, a glaciologist at Oregon State University in Corvallis. One such driver could be the cumulative buildup of ice across the Northern Hemisphere; more ice would leave the world more arid, for example, allowing iron-rich dust to fertilize ocean microbes, encouraging them to absorb more CO2 from the atmosphere during glacial times. Clark has long advanced a hypothesis that repeated glaciations gradually scoured away soil and other loose grit that would have prevented ice from “sticking” to bedrock. Once that grit was gone, the anchored ice sheets could thicken and grow to a tipping point, sending the planet into 100,000-year cycles. Other subtleties in the ice’s CO2 levels point to other possible mechanisms. When the planet transitioned to 100,000-year ice ages, for example, levels of CO2 dropped on average 24 ppm lower during glacial periods compared with similar events in the previous era. That suggests the world was quite sensitive to CO2 and could have “flipped” thanks to something like a small disruption in the currents that drive carbon storage in the ocean—perhaps caused by ice sheet growth or something else, Hönisch says. Given its limitations, including a small amount of material collected by a narrow drill, the Allan Hills core is unlikely to settle debate on the ice age transition. However, its data are helping calibrate other, indirect methods of measuring ancient CO2, like using isotopic shifts in single-celled foraminifera fossils. As those methods have improved, their estimates have lined up with the new findings. “It’s a wonderful confirmation that the proxies are really working,” Hönisch says. Meanwhile, the team hasn’t stopped its exploration of the blue ice. “It’s conceivable that there’s ice as old, or even older, out there,” Yan says. Next month, a team led by Higgins will arrive in Antarctica to hunt for it. And this time, they’re bringing a bigger drill.   source: https://www.sciencemag.org/news/2019/10/world-s-oldest-ice-core-could-solve-mystery-flipped-ice-age-cycles