Modelling Pliocene warmth: contribution of atmosphere, oceans and cryosphere

first_imgThe relative role of the atmosphere, oceans and cryosphere in contributing towards middle Pliocene warmth (ca 3 Ma BP) is investigated using the HadCM3 coupled ocean-atmosphere general circulation model. The model was initialised with boundary conditions from the USGS PRISM2 data set and a Pliocene atmospheric CO2 level of 400 ppmv and run for 300 simulated years. The simulation resulted in a global surface temperature warming of 3degreesC compared to present-day. In contrast to earlier modelling experiments for the Pliocene, surface temperatures warmed in most areas including the tropics (1-5degreesC). Compared with present-day, the model predicts a general pattern of ocean warming (1-5degreesC) in both hemispheres to a depth of 2000 m, below which no significant differences are noted. Sea ice coverage is massively reduced (up to 90%). The flow of the Gulf Stream/North Atlantic Drift is up to 100 mm s(-1) greater in the Pliocene case. Analysis of the model-predicted meridional streamfunction suggests a global pattern of reduced outflow of Antarctic bottom water (AABW; up to 5 Sv), a shallower depth for North Atlantic deep water formation and weaker thermohaline circulation (3 Sv). The decrease in AABW occurs mainly in the Pacific rather than Atlantic Ocean. Model diagnostics for heat transports indicate that neither the oceans nor the atmosphere are transporting significantly more heat in the Pliocene scenario. Rather, these results indicate that the major contributing mechanism to global Pliocene warmth was the reduced extent of high-latitude terrestrial ice sheets (50% reduction on Greenland, 33% reduction on Antarctica) and sea ice cover resulting in a strong ice-albedo feedback. These results highlight the need for further studies designed to improve our knowledge regarding Pliocene terrestrial ice configurations.last_img read more

A positive trend in western Antarctic Peninsula precipitation over the last 50 years reflecting regional and Antarctic-wide atmospheric circulation changes

first_imgIn situ observations of precipitation days (days when snow or rain was reported in routine synoptic observations) from Faraday/Vernadsky station on the western side of the Antarctic Peninsula, and fields from the 40 year European Centre for Medium-Range Weather Forecasts re-analysis (ERA-40) project are used to investigate precipitation and atmospheric circulation changes around the Antarctic Peninsula. It is shown that the number of precipitation days is a good proxy for mean sea-level pressure (MSLP) over the Amundsen-Bellingshausen Sea. The annual total of precipitation days at the station has been increasing at a statistically significant rate of +12.4 days decade−1 since the early 1950s, with the greatest increase taking place during the summer and autumn. This is the time of year when the Southern Annular Mode (SAM) has experienced its greatest shift to a positive phase, with MSLP values decreasing in the Antarctic coastal zone. The lower pressures in the circumpolar trough have resulted in greater ascent and increased precipitation at Faraday/Vernadsky.last_img read more

Antarctic sea ice losses drive gains in benthic carbon drawdown

first_imgClimate forcing of sea-ice losses from the Arctic and West Antarctic are blueing the poles. These losses are accelerating, reducing Earth’s albedo and increasing heat absorption [1]. Subarctic forest (area expansion and increased growth) and ice-shelf losses (resulting in new phytoplankton blooms which are eaten by benthos) are the only significant described negative feedbacks acting to counteract the effects of increasing CO2 on a warming planet, together accounting for uptake of ∼107 tonnes of carbon per year [2]. Most sea-ice loss to date has occurred over polar continental shelves, which are richly, but patchily, colonised by benthic animals. Most polar benthos feeds on microscopic algae (phytoplankton), which has shown increased blooms coincident with sea-ice losses [3]. Here, growth responses of Antarctic shelf benthos to sea-ice losses and phytoplankton increases were investigated. Analysis of two decades of benthic collections showed strong increases in annual production of shelf seabed carbon in West Antarctic bryozoans. These were calculated to have nearly doubled to >2×105 tonnes of carbon per year since the 1980s. Annual production of bryozoans is median within wider Antarctic benthos [4], so upscaling to include other benthos (combined study species typically constitute ∼3% benthic biomass) suggests an increased drawdown of ∼2.9×106 tonnes of carbon per year. This drawdown could become sequestration because polar continental shelves are typically deeper than most modern iceberg scouring, bacterial breakdown rates are slow, and benthos is easily buried. To date, most sea-ice losses have been Arctic, so, if hyperboreal benthos shows a similar increase in drawdown, polar continental shelves would represent Earth’s largest negative feedback to climate change.last_img read more

Mollusc species richness and abundance from shelf to abyssal depths in the Ross Sea (Antarctica): the importance of fine-mesh-towed gears and implications for future sampling

first_imgIn polar areas, where benthic sampling is constrained by a series of limitations imposed by climate and logistic challenges, knowledge about the key elements required to plan a successful survey is fundamental. During the International Polar Year (IPY, 2007/2008), under the Census of Antarctic Marine Life (CAML), new sampling campaigns were undertaken in several Antarctic areas comprising the Ross Sea. In this region, the 2008 NIWA IPY-CAML voyage obtained benthos samples from shelf to abyssal depths. In the present study, we focus on the Mollusca from this expedition and on the possible variations in their richness and composition with latitude and depth. Given the use of sampling gears selective for different size fractions of the macrofauna, we also assess which size fraction contained the highest biodiversity. Differences were detected in species composition with latitude (averaged across depth groups) but not for depth (averaged across latitudinal groups). Richness varied locally and showed a variety of patterns depending on the areas and depths considered. The greatest diversity of molluscs was found in the fine fraction (i.e., <4.1 mm) where a considerable number of species corresponded to new species or new regional records. Rarity was high with up to ~41% of species represented by single individuals and ~63% occurring at one station only. Fine-mesh trawling appears to be of fundamental importance in accelerating the census of the fine fraction, which is the one containing the highest diversity, and is recommended for future sampling in Antarctica and in polar areas in general.last_img read more

The potential of gypsum speleothems for paleoclimatology: application to the Iberian Roman Human Period.

first_imgCarbonate cave deposits (speleothems) have been used widely for paleoclimate reconstructions; however, few studies have examined the utility of other speleothem-forming minerals for this purpose. Here we demonstrate for the first time that stable isotopes (delta O-17, delta O-18 and delta D) of structurally-bound gypsum (CaSO(4)2H(2)O) hydration water (GHW) can be used to infer paleoclimate. Specifically, we used a 63 cm-long gypsum stalactite from Sima Blanca Cave to reconstruct the climate history of SE Spain from similar to 800 BCE to similar to 800 CE. The gypsum stalactite indicates wet conditions in the cave and humid climate from similar to 200 BCE to 100 CE, at the time of the Roman Empire apogee in Hispania. From similar to 100 CE to similar to 600 CE, evaporation in the cave increased in response to regional aridification that peaked at similar to 500-600 CE, roughly coinciding with the transition between the Iberian Roman Humid Period and the Migration Period. Our record agrees with most Mediterranean and Iberian paleoclimate archives, demonstrating that stable isotopes of GHW in subaerial gypsum speleothems are a useful tool for paleoclimate reconstructions.last_img read more

Report: Bryce Harper turned down ‘aggressive offer’ from Nationals

first_imgNovember 7, 2018 /Sports News – National Report: Bryce Harper turned down ‘aggressive offer’ from Nationals FacebookTwitterLinkedInEmailDustin Bradford/Getty Images(NEW YORK) — The Washington Nationals made an offer to Bryce Harper late in the season in an attempt to reach a deal before he became a free agent.At the general managers’ meetings on Tuesday, Nationals general manager Mike Rizzo disclosed the team’s talks with Harper’s agent, Scott Boras.The team made Harper an “aggressive offer” in September that included no opt-outs and was less than the $400 million Harper was speculated to receive, according to Washington Post reports. Harper, who turned 26 last month, is expected to receive the largest contract among the 164 free agents. He is a six-time All-Star with 184 homers, 521 RBIs and a .900 OPS.Boras is known for extending talks with his free agents past the holiday break. His clients include Nationals pitchers Max Scherzer and Stephen Strasburg, and former Nats outfielder Jayson Werth.According to soruces, Boras is floating the notion that Harper could shift from outfield to first base which could open up negotiations with other teams. Copyright © 2018, ABC Radio. All rights reserved. Written bycenter_img Beau Lundlast_img read more

Gobert leads Jazz to 114-83 romp over Bulls

first_imgBulls: Chicago made just 2 of 16 3-pointers. … Shaquille Harrison set a career high with nine rebounds. … Markkanen has 32 straight double-digit scoring games. Lauri Markkanen had 18 points and 10 rebounds, but made just 6 of 20 shots. Associated Press March 23, 2019 /Sports News – Local Gobert leads Jazz to 114-83 romp over Bulls “Tough one in Atlanta but we bounced back tonight,” Mitchell said. “It really shows who we are and what we’re capable of.” Gobert dominated inside, making 9 of 11 shots and blocking four. BANGED UP “That loss kinda was a good slap in the face,” Gobert said. “I think our urgency was great tonight. We started the game the right way defensively and it just (carried to) the offense.” UP NEXT “It would be great to have the homecourt,” Gobert said. “But at the same time, like I said, if we don’t, I like our chances … on the road against anyone.” Gobert had another neat block on Kris Dunn’s fastbreak layup, setting up a break that Mitchell punctuated with a soaring dunk. Porter missed his third straight game and LaVine missed his second in a row. They led 33-18 through the first quarter and continued to pour it on in the second, heading to the locker room up by 34. The Jazz’s most lopsided victory this season was a 139-105 romp over San Antonio on Dec. 4. And it looked like they might surpass that. Things were so bad for the Bulls that fans cheered sarcastically when Dunn hit a 16-foot jumper with just under five minutes left in the half to stop a 17-0 run. The 31-point margin of victory was just three shy of the Jazz’s season high. They raced out to a 70-36 halftime lead on the way to their sixth win in seven games, and bounced back quite nicely from a three-point loss at Atlanta on Thursday. TIP-INS He blocked a layup by Markkanen in the second quarter and converted one on the other end off of a no-look pass from Ricky Rubio driving the baseline. The Bulls also ruled out injured rookies Wendell Carter Jr. (left thumb surgery) and Chandler Hutchison (right toe injury) for the remainder of the season. Carter and Hutchison each appeared in 44 games. The No. 7 pick, Carter averaged 10.3 points and 7 rebounds, while Hutchison averaged 5.2 points and 4.2 rebounds after getting drafted 22nd overall. There was no shortage of highlights along the way. And Gobert was in on several of them. The Bulls delivered one of their worst performances of the season coming off back-to-back victories and lost for the sixth time in eight games. Dunn was slowed by back pain that he said limited his mobility and made it difficult to fight through screens. He finished with just four points on 1-of-8 shooting and five assists. Rudy Gobert had 21 points and 14 rebounds, and Utah rolled to one of its most lopsided wins of the season, beating the Chicago Bulls 114-83 Saturday night. Donovan Mitchell added 16 points and eight rebounds. Derrick Favors and Joe Ingles each scored 13. And the Jazz made about half of their shots, with Chicago offering little resistance, particularly in the early going. “We’re not using that as an excuse, that we’re short with guys,” Markkanen said. “We’re just trying to focus on winning the second half and playing hard and together and get better. A 36-point hole or whatever it was — it’s kind of hard to come back from that.” Written by Jazz: Host Phoenix on Monday. Utah is in a crowd of six teams jockeying for position behind Golden State and Denver in the Western Conference. The Jazz would love to land home-court advantage in the first round of the playoffs. Bulls: Visit Toronto on Tuesday. Otto Porter Jr. (strained right rotator cuff) and leading scorer Zach LaVine (bruised right thigh, right knee tendinitis) remained sidelined, leaving the Bulls without two of their best players. But even so, Chicago seemed disinterested right from the start while the Jazz sure were locked in. Tags: NBA/Rudy Gobert/Utah Jazz FacebookTwitterLinkedInEmailCHICAGO (AP) — The Jazz got a slap in the face a couple nights earlier and answered with quite a punch. Jazz: Utah’s highest scoring half was 81 points against Golden State on Oct. 17. … The Jazz had 13 players score, with seven reaching double digits.last_img read more

UVU Baseball Meets Utah Tuesday in Non-Conference Tilt

first_imgFellow junior right-hander Paxton Schultz leads Utah Valley with 57 strikeouts on the season. Written by FacebookTwitterLinkedInEmailSALT LAKE CITY-Tuesday, Utah Valley baseball (8-27, 5-7 in WAC play) meets the University of Utah (10-19, 3-12 in Pac-12 play) at Smith’s Ballpark. Senior left-handed pitcher Joshua Tedeschi (4-3 on the season) has inched over .500 and remains the ace of the Utes’ staff. He is also third on the staff in strikeouts with 26. The Wolverines are led on the season by senior outfielder Ryan Eastburn (a .352 batting average) while junior outfielder Alexander Marco (28 home runs, 6 RBI) leads Utah Valley in each of those categories. April 16, 2019 /Sports News – Local UVU Baseball Meets Utah Tuesday in Non-Conference Tilt The Utes are led by junior infielder Oliver Dunn (a .353 batting average, 16 RBI, 2 home runs), senior outfielder Erick Migueles and redshirt junior catcher Zack Moeller (symmetrically with 3 home runs and 25 RBI apiece). Tags: Alexander Marco/Erick Migueles/Jesse Schmit/Joshua Tedeschi/Oliver Dunn/Paxton Schultz/Ryan Eastburn/Smith’s Ballpark/UCCU Ballpark/Utah Baseball/UVU Baseball/Zack Moeller The Utes lead the all-time series against the Wolverines 30-23, including a 16-10 mark at Salt Lake City. The squads will meet again April 23 at UCCU Ballpark in Orem. Junior right-handed pitcher Jesse Schmit (2-5 on the season) has the Wolverines’ best record on the mound. Fellow senior left-hander Kyle Robeniol and sophomore right-handed hurler Brett Brocoff have 27 strikeouts apiece for the Utes. Brad Jameslast_img read more

Scoreboard roundup — 4/26/19

first_img FacebookTwitterLinkedInEmailiStock(NEW YORK) — Here are the scores from Friday’s sports events:INTERLEAGUEN.Y. Yankees 7, San Francisco 3AMERICAN LEAGUEToronto 4, Oakland 2Cleveland 6, Houston 3Minnesota 6, Baltimore 1Chi White Sox 12, Detroit 11L.A. Angels 5, Kansas City 1Seattle 5, Texas 4, 11 InningsNATIONAL LEAGUESan Diego 4, Washington 3Philadelphia 4, Miami 0Milwaukee 10, N.Y. Mets 2Colorado 8, Atlanta 4Cincinnati 12, St. Louis 1Arizona 8, Chicago Cubs 3L.A. Dodgers 6, Pittsburgh 2NATIONAL BASKETBALL ASSOCIATION PLAYOFFSGolden State 129, L.A. Clippers 110NATIONAL HOCKEY LEAGUE PLAYOFFSOT Carolina 1, N.Y. Islanders 0San Jose 5, Colorado 2Copyright © 2019, ABC Radio. All rights reserved. Beau Lund Written bycenter_img April 27, 2019 /Sports News – National Scoreboard roundup — 4/26/19last_img read more

UVU Men’s Basketball Brings In Canadian National Fardaws Aimaq

first_imgMay 22, 2019 /Sports News – Local UVU Men’s Basketball Brings In Canadian National Fardaws Aimaq Aimaq will have three seasons of eligibility remaining for the Wolverines and can begin playing for UVU in the 2020-21 season after sitting out next season per NCAA transfer rules. Tags: Fardaws Aimaq/Mercer Bears/NCAA Transfer rules/UVU Men’s Basketball FacebookTwitterLinkedInEmailOREM, Utah-Wednesday, Utah Valley men’s basketball confirmed the transfer into the program of former Mercer player Fardaws Aimaq. Aimaq also shot 51.7 percent from the field and netted 10 or more rebounds in three games last season.center_img Written by The native of Vancouver, British Columbia, Canada is a 6-11 245-pound center who averaged 5 points and a team-best 5.3 rebounds for the Bears of the Southern Conference last season. Brad Jameslast_img read more