Radar absorption due to impurities in Antarctic ice

first_imgMeasurements of radar echo strength have been carried out on Ronne and George VI Ice Shelves, Antarctica. The differences in ice-column absorption between the two sites cannot be resolved by considering ice temperatures alone. We present an absorption model that resolves the discrepancy by considering both the ice temperature and the ice impurity concentrations. In Antarctic coastal sites the concentrations of acid and sea salt impurities, both of which affect absorption, have a marked spatial variability and can dominate the absorption budget. Using the absorption model, impurity levels in the ice column at the George VI site are deduced from the radar strength measurements and found to be typical of levels measured in Antarctic ice at similar elevations and distances from the sea. In particular the measurements suggest that the concentrations of biogenically-derived acids are much lower than the unusually high levels found on the east coast of the Antarctic Peninsula.last_img read more

An overview of snow photochemistry: evidence, mechanisms and impacts

first_imgIt has been shown that sunlit snow and ice plays an important role in processing atmospheric species. Photochemical production of a variety of chemicals has recently been reported to occur in snow/ice and the release of these photochemically generated species may significantly impact the chemistry of the overlying atmosphere. Nitrogen oxide and oxidant precursor fluxes have been measured in a number of snow covered environments, where in some cases the emissions significantly impact the overlying boundary layer. For example, photochemical ozone production (such as that occurring in polluted mid-latitudes) of 3–4 ppbv/day has been observed at South Pole, due to high OH and NO levels present in a relatively shallow boundary layer. Field and laboratory experiments have determined that the origin of the observed NOx flux is the photochemistry of nitrate within the snowpack, however some details of the mechanism have not yet been elucidated. A variety of low molecular weight organic compounds have been shown to be emitted from sunlit snowpacks, the source of which has been proposed to be either direct or indirect photo-oxidation of natural organic materials present in the snow. Although myriad studies have observed active processing of species within irradiated snowpacks, the fundamental chemistry occurring remains poorly understood. Here we consider the nature of snow at a fundamental, physical level; photochemical processes within snow and the caveats needed for comparison to atmospheric photochemistry; our current understanding of nitrogen, oxidant, halogen and organic photochemistry within snow; the current limitations faced by the field and implications for the future.last_img read more

Extended ecophysiologicalanalysis of Gomphiocephalus hodgsoni (Collembola) : flexibility in life history strategy and population response

first_imgThe springtail Gomphiocephalus hodgsoni (Arthropoda: Collembola) has been the focus of extensive ecophysiological and molecular genetic work and is now arguably the most well-studied of the continental Antarctic springtails. Here, we further the ecophysiological catalogue of this species. First, we provide experimental data on G. hodgsoni from one summer season at Cape Bird (Ross Sea Region) examining dispersal ability and desiccation tolerance. Next, we expand an existing metabolic rate dataset that encompasses individual metabolic rate measurements across both temporal and spatial scales in southern Victoria Land, adding an additional season of metabolic rate measurements taken at a cooler, drier continental location (Garwood Valley). Our data show that some G. hodgsoni individuals can survive at least ten days of suspension on the surface of both fresh and sea water. This, coupled with the presence of G. hodgsoni specimens in air and pitfall traps suggests that dispersal over local scales (i.e. metres) is possible for this species. Our metabolic data show that different populations within the same Antarctic region have different average metabolic rates at both temporal and spatial scales, indicating that distinct populations may respond differently to environmental variables. We suggest that G. hodgsoni maintains a flexible life history strategy that allows its ecophysiological response(s) to be dependent on local environmental conditions. Accordingly, there may be no ‘typical’ response to environmental changes—a factor that should be considered in both future ecophysiological work and conservation approaches.last_img read more

Improvements in Circumpolar Southern Hemisphere Extratropical Atmospheric Circulation in CMIP6 Compared to CMIP5

first_imgOne of the major globally relevant systematic biases in previous generations of climate models has been an equatorward bias in the latitude of the Southern Hemisphere (SH) mid‐latitude tropospheric eddy driven westerly jet. The far reaching implications of this for Southern Ocean heat and carbon uptake and Antarctic land and sea ice are key reasons why addressing this bias is a high priority. It is therefore of primary importance to evaluate the representation of the SH westerly jet in the latest generation of global climate and earth‐system models that comprise the Coupled Model Intercomparison Project Phase 6 (CMIP6). In this paper we assess the representation of major indices of SH extratropical atmospheric circulation in CMIP6 by comparison against both observations and the previous generation of CMIP5 models. Indices assessed are the latitude and speed of the westerly jet, variability of the Southern Annular Mode (SAM) and representation of the Amundsen Sea Low (ASL). These are calculated from the historical forcing simulations of both CMIP5 and CMIP6 for time periods matching available observational and reanalysis datasets. From the 39 CMIP6 models available at the time of writing there is an overall reduction in the equatorward bias of the annual mean westerly jet from 1.9° in CMIP5 to 0.4° in CMIP6 and from a seasonal perspective the reduction is clearest in austral spring and summer. This is accompanied by a halving of the bias of SAM decorrelation timescales compared to CMIP5. However, no such overall improvements are evident for the ASL.last_img read more

Orndorff and Bastian Place at UWW Cadet & U-23 Nationals

first_imgJune 6, 2018 /Sports News – Local Orndorff and Bastian Place at UWW Cadet & U-23 Nationals Written by Tags: David McFadden/Joe Smith/Mapleton/Oklahoma State Wrestling/Spokane/UVU Wrestling FacebookTwitterLinkedInEmailAKRON, Ohio-This past weekend, a pair of Utah Valley wrestlers excelled at the 2018 UWW Cadet and U-23 nationals. Both placing on the podium for the Wolverines were Tate Orndorff and Kimball Bastian.Orndorff, a freshman out of Spokane, Wash., led the way by wrestling his way to a pair of podium finishes, earning the runner-up finish at 130 kilos and placed fourth at 125 kilos in the U-23 freestyle event.Orndorff was 3-1 in the U-23 Greco-Roman tournament, earning a second-place finish as well.Bastian, a sophomore from Mapleton, Utah, earned a place on the podium in the U-23 freestyle competition with a third place finish at 79 kilos. His sole loss in the tournament came at the hands of David McFadden of Virginia Tech, suffering a 6-2 defeat in the semifinals to the Hokies’ standout.Among Bastian’s attainments at this tournament were a pair of victories over Oklahoma State’s Joe Smith, a multiple times All-American for the Cowboys. Brad Jameslast_img read more

Just released from Raiders, Bruce Irvin heads to hometown Falcons

first_imgNovember 7, 2018 /Sports News – National Just released from Raiders, Bruce Irvin heads to hometown Falcons Man it’s time! You can’t put a price on the chance for me to play for my people and city! It’s bigger than money!— Bruce Irvin (@BIrvin_WVU11) November 7, 2018Irvin’s deal with Atlanta also reunites him with his former Seahawks defensive coordinator Dan Quinn, who now leads the Falcons as head coach. The hope, according to the Falcons’ website, is that Irvin can help improve Atlanta’s struggling pass rush.“We know exactly how Bruce with fit into our team on the field, and just as importantly into our locker room,” Quinn told the Falcons’ website.  He added, “He will add to our rotation along the defensive line, while adding to our pass rush.”Quinn said he looks forward to “getting [Quinn] on the field as soon as possible.”Copyright © 2018, ABC Radio. All rights reserved. Written by Beau Lund FacebookTwitterLinkedInEmailiStock/Thinkstock(ATLANTA) — The Oakland Raiders released Bruce Irvin less than one week ago, and now he’s confirmed his decision to head home to Atlanta. On Wednesday, Irvin, 31, signed a one-year contract with the Atlanta Falcons.Neither the team nor Irvin revealed the financial details of the deal, but Irvin told ESPN he passed up more lucrative offers for the chance to play for Atlanta.“This was a dream [come] true. The Patriots and Steelers offered more money, but being able to play for my city and my people — just can’t put a price on that,” Irvin told ESPN’s Vaughn McClure.The former first-round draft pick posted a similar statement on his Twitter account.last_img read more

McDermott, Turner lead Pacers to 121-88 rout of Jazz

first_img Written by FacebookTwitterLinkedInEmailSALT LAKE CITY (AP) — Doug McDermott scored a season-high 21 points and the Indiana Pacers rolled to an easy victory without their leading scorer, beating the Utah Jazz 121-88 on Monday night.Victor Oladipo, averaging 21.4 points, missed his fourth game with a sore right knee, so his teammates turned up their defensive intensity and spread the ball.Myles Turner set the tone with 16 points, all in the first three quarters, and seven Pacers reached double figures. Tyreke Evans scored 14 points and Cory Joseph and Domantas Sabonis each had 13.The Pacers shot a season-best 58.3 percent and made half of their 18 3-point attempts.Donovan Mitchell, who scores 20.6 per game, sat out his second game with bruised ribs and Utah was playing a back-to-back, but it was 19 turnovers and poor shooting that buried the Jazz and dropped their usually stellar home record to 2-6.The Jazz repeatedly tried to dribble through the Pacers’ tenacious defense or pass over their outstretched hands. Even Utah’s traditionally supportive crowd booed at times as Utah’s turnovers led to 25 Indiana points.Turner drew Rudy Gobert outside and made his first five shots, mostly on mid-range jumpers off pick-and-pop actions.Turner signed a four-year, $72 million extension in the offseason and the big man from Texas went to work earning it, dropping fat, gaining muscle and improving his shot during the summer.After a four-game stretch where he didn’t score more than nine points, Turner has reached double figures in five consecutive games.He missed Friday’s loss to San Antonio with an ankle injury but was active from the start against Utah. Led by his 11 points in the first half, the Pacers were ahead by as many as 14 before settling for a 58-47 advantage at the break.The Jazz have lost six of eight.TIP-INSPacers: The Pacers beat the Jazz 121-94 last Monday. … Indiana is 8-0 when making at least half its 3-pointers. … The Pacers had their largest margin of victory this season and their first 30-point-plus win on the road in 22 years.Jazz: Rubio had 23 points on 10-of-13 shooting on Sunday against Sacramento but just three points on 1-of-6 shooting against the Pacers, typical of his up-and-down season. … Thabo Sefolosha and Joe Ingles both got technical fouls. … Utah went 8 for 31 on 3s.UP NEXTPacers: Continue their road trip at Phoenix on Tuesday night.Jazz: Visit the Brooklyn Nets on Wednesday night. Tags: Basketball/NBA/Utah Jazz November 26, 2018 /Sports News – Local McDermott, Turner lead Pacers to 121-88 rout of Jazz Associated Presslast_img read more

Serena Williams talks Australian Open loss, what she is still learning after maternity leave

first_imgJanuary 31, 2019 /Sports News – National Serena Williams talks Australian Open loss, what she is still learning after maternity leave Beau Lund Written bycenter_img FacebookTwitterLinkedInEmailABC News(NEW YORK) — Serena Williams, fresh off her surprise loss in the Australian Open, said she is still putting the pieces together 10 months after her maternity leave. Williams lost in the quarterfinals of this year’s Australian Open after holding four match points. Karolina Pliskova defeated Williams in the upset, 6-4, 4-6, 7-5. “I learned that when I’m in the lead, I’m a closer, I’m really known to be a closer,” Williams, 37, said Thursday on ABC News’ Good Morning America. “It’s little moments like that, that you just don’t think about because you spend so much time away.” “I’ve learned little things that I used to do that I have to be like, ‘Oh, okay, I remember that. Oh, so now I won’t do that again,’” she added. Williams suffered life-threatening complications after she gave birth to her daughter, Alexis Olympia Ohanian Jr., more than one year ago. She described what she has accomplished in the 10 months she has been back on the pro tour as “really miraculous.” “Everything that I’ve done in 10 months has already been crazy,” she said. “It’s still little lessons that I’m learning and I’m happy for those lessons.” Williams, married to Reddit co-founder Alexis Ohanian, called having their daughter “the best thing I’ve ever done in my life.” She said she wants to teach Olympia, whose network of strong women includes her aunt, Venus Williams, to embrace being strong like the women who surround her. “I want to teach her that it’s okay to make the first move,” she said. “It’s okay to ask and to say, ‘Listen, I want a chance at being in this play. Put me in, or give me this first opportunity.’”Copyright © 2019, ABC Radio. All rights reserved.last_img read more

Dixie State Baseball Makes RMAC Debut At Adams State

first_imgFor the Grizzlies, redshirt junior outfielder Nico Nintze (9 RBI) and sophomore infielder Logan Bistrup (8 RBI, 2 home runs) are the offensive leaders on the season. Tags: Colorado Mesa/Colton Harris/David Maldonado/Dixie State Baseball/Jack Gonzales/Jake Engel/Jayden Murray/Logan Bistrup/Nico Nintze/Rocky Mountain Athletic Conference FacebookTwitterLinkedInEmailALAMOSA, Colo.-This weekend, Dixie State baseball (10-4, 0-0 in Rocky Mountain Athletic Conference play) plays its first ever series as a member of the Rocky Mountain Athletic Conference in visiting the Adams State Grizzlies at Alamosa, Colo. Senior right-handed pitcher Jayden Murray remains the Trailblazers’ ace as he is 3-1 on the mound thus far this season. Right-handed pitcher Colton Harris and sophomore left-handed pitcher Jack Gonzales are each 2-0 for the Trailblazers on the young season as well. The Trailblazers had been ranked nationally until dropping a pair of games to Colorado Mesa Sunday at Bruce Hurst Field in St. George. Junior right-handed pitcher, Mexican national David Maldonado, is the current leading hurler for the Grizzlies, sporting a record of 1-3. center_img Brad James The Grizzlies (3-11) are in search of some good vibes as conference play commences. March 7, 2019 /Sports News – Local Dixie State Baseball Makes RMAC Debut At Adams State Written by Junior infielder Jake Engel is the Trailblazers’ offensive star, having amassed five home runs and 12 RBI thus far on the season.last_img read more

Scoreboard roundup — 6/12/19

first_img FacebookTwitterLinkedInEmailiStock(NEW YORK) — Here are the scores from Wednesday’s sports events:MAJOR LEAGUE BASEBALLINTERLEAGUECincinnati 7, Cleveland 2Milwaukee 6, Houston 3, 14 InningsAMERICAN LEAGUEOakland 6, Tampa Bay 2Boston 4, Texas 3Toronto 8, Baltimore 6Seattle 9, Minnesota 6, 10 InningsDetroit 3, Kansas City 2NATIONAL LEAGUEChi Cubs 10, Colorado 1Arizona 2, Philadelphia 0Miami 9, St. Louis 0Atlanta 8, Pittsburgh 7, 11 InningsSan Francisco 4, San Diego 2NATIONAL HOCKEY LEAGUE PLAYOFFSSTANLEY CUP FINALS, GAME 7St. Louis 4, Boston 1 (St. Louis wins series)WOMEN’S NATIONAL BASKETBALL ASSOCIATIONNY Liberty 75, Minnesota 69Copyright © 2019, ABC Radio. All rights reserved. Beau Lund Written bycenter_img June 13, 2019 /Sports News – National Scoreboard roundup — 6/12/19last_img read more