I am pleased to report that Adam Sobel and Mingfang Ting have been elected Fellows of the American Meteorological Society. According to AMS, Fellows “shall have made outstanding contributions to the atmospheric or related oceanic or hydrologic sciences or their applications during a substantial period of years,” and no more than “two-tenths of 1 percent of all AMS members” may be elected Fellow in a given year. Congratulations, Adam and Mingfang!
The Geochemistry Division this week welcomed Visiting Associate Research Scientist Ewa Slowik-Opoka, an Assistant Professor at the University of Agriculture in Krakow, Poland. During a visit to Lamont that will extend to late September, Prof. Slowik-Opoka will work with Sid Hemming, Mike Kaplan, and Steve Goldstein on terrestrial sedimentary processes.
The R/V Marcus Langseth this week is conducting a three-dimensional seismic velocity survey of the crust beneath Axial Seamount on the Juan de Fuca Ridge. The expedition is led by Adrian Arnulf from the Institute for Geophysics at the University of Texas, Austin. The team is maintaining a blog from the ship, and science party member Michelle Lee penned an entry on Sunday (https://www.axial3dexpedition.com/?m=1). Sean Higgins wrote on Wednesday, “The project is going pretty well. We’ve managed to collect ~one-third of the 3D box so far. At the completion of the 3D box, the Langseth will convert from a 4x6 km array to a 15-km-long offset streamer to collect some 2D lines near the 3D box. The cruise is scheduled to be completed by August 12 with a return into Seattle.”
Journal of Geophysical Research: Oceans last week posted to Early View a paper by David Porter, Kirsty Tinto, Robin Bell, and their colleagues on the ROSETTA-Ice team reporting the first multiyear time-series measurements of ocean temperature and salinity in the Ross Sea, Antarctica. The measurements were made by six Air-Launched Autonomous Micro Observer (ALAMO) floats deployed in late 2016, mostly near the outer edge of the Ross Ice Shelf, and seven Apex floats deployed in 2013 on the midcontinental shelf. As expected, annual changes to temperature and salinity in the upper ocean were closely related to seasonal changes in sea ice. However, the salinity in the upper ocean continued to decrease even after the sea ice had all melted, particularly in the eastern Ross Sea and along the front of the ice shelf, indicating inflow of fresh water from melting ice in the Amundsen Sea and along the shelf front. The importance of these observations is that changes in upper-ocean fresh water and heat content along the shelf front in summer affect cross-front advection, ice shelf melting, and calving processes, all of which influence mass loss from the adjacent grounded ice sheet and its contribution to rising sea level. A Nicole deRoberts press release was posted on Monday (https://www.ldeo.columbia.edu/news-events/robots-roaming-antarctic-waters-reveal-why-ross-ice-shelf-melts-rapidly-summer).
On Monday, Nature Geoscience published online a paper by Pratigya Polissar, Cassaundra Rose, Kevin Uno, Sam Phelps, and Peter deMenocal on the expansion of C4 grasslands in Africa over the past 10 million years. Pratigya and his colleagues focused in particular on the question of whether that expansion was driven by aridity or changes in atmospheric carbon dioxide. From carbon isotope measurements on leaf-wax molecules recovered from deep-sea drill cores off equatorial west Africa, northwestern Africa, and east Africa, the group measured the rise in C4 ecosystems in those portions of the continent. From leaf-wax hydrogen isotope measurements and dust deposition rates in those same cores, the team reconstructed paleohydroclimate change. They showed that C4-dominated ecosystems expanded synchronously across northwestern and east Africa, and the expansion was not accompanied by substantial changes in paleohydrology or dust deposition. The latter result rules out aridification as a causal agent, and a coincidence in timing among grassland expansion, marked high-latitude cooling, and increased pole-to-equator temperature gradients points to declining atmospheric carbon dioxide levels as the probable cause of all of these phenomena. A Kevin Krajick interview of Cassaundra Rose (now Climate Coordinator for the state of Maine) on the findings of the paper (https://www.ldeo.columbia.edu/news-events/how-did-africas-grasslands-get-started) was posted to our web site on Monday.
Also on Monday, the Indian Space Research Organization launched the Chandrayaan-2 spacecraft to the Moon (https://www.nytimes.com/2019/07/22/world/asia/chandrayaan-india-moon-launch.html). After more than three weeks in Earth orbit and a trans-lunar injection, the mission is scheduled to send a lander (Vikram) and a rover (Pragyan) to the Moon’s surface at a site near the lunar south pole.
On Wednesday, Science Advances published a paper by Nathan Steiger, Jason Smerdon, Ben Cook, Richard Seager, Park Williams, and Ed Cook on the causes of medieval megadroughts in the American southwest. From a global grid of hydroclimate and sea-surface temperature (SST) over the past two millennia reconstructed from a global climate model and a global collection of proxy time series, as well as a radiative forcing model, Nathan and his colleagues showed that past megadroughts in the American southwest – all before about the year 1600 – were driven by a combination of cold SST excursions in the central tropical Pacific, anomalously warm SSTs in the Atlantic, and locally positive radiative forcing. Their results provide support for the prediction that the risk of prolonged droughts in the American southwest will increase with global warming. A press release by Nicole deRoberts can be found on our web site (https://www.ldeo.columbia.edu/news-events/climate-change-could-revive-medieval-megadroughts-us-southwest), and the story was carried by National Geographic (https://www.nationalgeographic.com/environment/2019/07/megadroughts-could-return-southwestern-us/) and other media.
Nathan also coauthored a paper in Nature this week reporting analyses of warm and cold periods during the preindustrial Common era. The study, led by Raphael Neukom at the Oeschger Centre for Climate Change Research and the Institute of Geography at the University of Bern, showed from global paleoclimate reconstructions that no cold or warm epochs before the industrial revolution displayed temporal coherence at a global scale, beyond that of stochastic climate variability. The team concluded that the modern period of anthropogenic warming is unprecedented over the last two millennia not only in terms of absolute temperature but also in terms of spatial consistency. A Kevin Krajick interview of Nathan was posted to our web site on Wednesday (https://www.ldeo.columbia.edu/news-events/climate-epochs-werent), and media coverage was widespread (https://www.nbcnews.com/mach/science/climate-scientists-drive-stake-through-heart-skeptics-argument-ncna1033646).
Congress and the White House reached a budget agreement this week that would increase limits on the federal debt, increase spending caps for defense and non-defense spending for federal fiscal years 2020 and 2021, and enable timely passage of appropriations bills for fiscal year 2020 (https://www.nytimes.com/2019/07/25/us/politics/budget-spending-deal.html). The agreement – brokered by Speaker of the House Nancy Pelosi and Treasury Secretary Steven Mnuchin – would budget non-defense spending at $624 billion for fiscal year 2020 and $625.5 billion for fiscal year 2021, levels substantially higher than the administration’s 2020 request. Columbia University’s federal lobbyists, Federal Science Partners, estimate that the new budget levels “will mean that agencies will see an average increase of approximately 4% above their FY 2019 level instead of the 10% reduction they would have been forced to take if the FY 2020 spending caps had not been amended by this agreement.” The House passed the budget agreement yesterday, and the Senate is expected to take up the measure next week. Both chambers will be in recess for August.
Our blog pages were enriched this week with entries from two field groups. Julia Gottschalk reported from Lamont’s team on International Ocean Discovery Program Expedition 383 on the JOIDES Resolution in the Southern Ocean with a blog entry devoted to the mechanics of deep-sea drilling (https://www.ldeo.columbia.edu/news-events/how-drilling-ship-pulls-cores-25-miles-below-sea). And Mike Steckler posted two blogs from Bangladesh, where he is leading a multi-institutional project to measure subsidence, sedimentation rate, and shifting river patterns in an area where rebuilding of river embankments is planned to protect coastal areas from severe flooding; a post Tuesday discussed field logistics (and included two photos of tables filled with food) (https://www.ldeo.columbia.edu/news-events/delays-dhaka), and a second post Wednesday described the geodetic measurement systems and their installation (https://www.ldeo.columbia.edu/news-events/sonatola-sundarbans).
Kai Kornhuber was quoted in a Xinhua story Saturday about the role of climate change in last week’s heat wave over much of the U.S. (http://www.xinhuanet.com/english/2019-07/20/c_138242851.htm). Scientific American’s Science Talk on Sunday was given by Elizabeth Case, in the second of her two-part podcast on her fieldwork last summer on an icefield near Juneau, Alaska (https://www.scientificamerican.com/podcast/episode/its-melting-science-on-ice/); as with the first podcast, Jonny Kingslake also participated. On Monday, Anders Levermann was interviewed by Live Science about a paper he and colleagues published last week in Science Advances on the use of artificial snow to strengthen ice sheets in Antarctica (https://www.livescience.com/65992-antarctica-snow-cannons.html). And on Wednesday, the Jackson Hole News & Guide ran a story on a local science school program on “Raising Strong Female Scientists” that featured a conversation between students (of all ages) and Terry Plank (https://www.jhnewsandguide.com/scene/events/volcanologist-terry-plank-encourages-young-women-to-get-in-the/article_868c286c-c85a-5517-b685-85dd0462e856.html).
This week the news on heat waves and new high-temperature records has been focused on western Europe (https://www.washingtonpost.com/weather/2019/07/25/record-temperatures-europe/?utm_term=.f4cc6c04dcb7). May New York City’s above-normal high temperatures this weekend seem mild by comparison.