scholarly journals Temperature history and accumulation timing for the snowpack at GISP2, central Greenland

1998 ◽  
Vol 44 (146) ◽  
pp. 21-30 ◽  
Author(s):  
C. A. Shuman ◽  
R. B. Alley ◽  
M. A. Fahnestock ◽  
R. A. Bindschadler ◽  
J. W. C. White ◽  
...  
Keyword(s):  
High Resolution ◽  
Stable Isotope ◽  
Annual Variation ◽  
Close Association ◽  
Snow Accumulation ◽  
Temperature History ◽  
Near Surface ◽  
Brightness Temperatures ◽  
Isotope Record ◽  
Temperature Proxy

AbstractPrevious research has documented a close association between high-resolution snow-pit profiles of hydrogen and oxygen stable-isotope ratios and multi-year Special Sensor Microwave/lmager (SSM/I) 37 GHz brightness temperature data in central Greenland. Comparison of the SSM/I data to profiles obtained during the 1989-91 field seasons indicated thatδD andδ18O data from the near-surface snow at the Greenland summit are a reliable, high-resolution temperature proxy. To test this new technique further, additional stable-isotope data were obtained from a 2 m snow pit constructed during late-June 1995 near the GISP2 site.This new profile, supported by pit stratigraphy and chemistry data, confirms the utility of comparing stable-isotope records with SSM/I brightness temperatures. The sub-annual variation of theδDrecord at the GISP2 site was determined using 15 match points, from approximately December 1991 through June 1995 and was guided in part by time-constrained hoar layers. The close association of these temperature proxies supports the assertion that snow accumulation occurs frequently through the year and that the isotope record initially contains temperature information from many times of the year. This is also independently confirmed by analysis of H2O2data. The slope of the multi-yearTvsδcorrelation was evaluated along with the sub-annual variation in the amount, rate and timing of accumulation. These new results are consistent with those from the previous study and they also demonstrate that the snow in this area initially contains temperature and chemical records with sub-annual resolution. This encourages confident interpretation of the paleoclimatic signal variations in the GISP2 and GRIP deep cores.

scholarly journals Temperature history and accumulation timing for the snowpack at GISP2, central Greenland

1998 ◽  
Vol 44 (146) ◽  
pp. 21-30
Author(s):  
C. A. Shuman ◽  
R. B. Alley ◽  
M. A. Fahnestock ◽  
R. A. Bindschadler ◽  
J. W. C. White ◽  
...  
Keyword(s):  
High Resolution ◽  
Stable Isotope ◽  
Annual Variation ◽  
Close Association ◽  
Snow Accumulation ◽  
Temperature History ◽  
Near Surface ◽  
Brightness Temperatures ◽  
Isotope Record ◽  
Temperature Proxy

AbstractPrevious research has documented a close association between high-resolution snow-pit profiles of hydrogen and oxygen stable-isotope ratios and multi-year Special Sensor Microwave/lmager (SSM/I) 37 GHz brightness temperature data in central Greenland. Comparison of the SSM/I data to profiles obtained during the 1989-91 field seasons indicated that δD and δ18O data from the near-surface snow at the Greenland summit are a reliable, high-resolution temperature proxy. To test this new technique further, additional stable-isotope data were obtained from a 2 m snow pit constructed during late-June 1995 near the GISP2 site.This new profile, supported by pit stratigraphy and chemistry data, confirms the utility of comparing stable-isotope records with SSM/I brightness temperatures. The sub-annual variation of the δD record at the GISP2 site was determined using 15 match points, from approximately December 1991 through June 1995 and was guided in part by time-constrained hoar layers. The close association of these temperature proxies supports the assertion that snow accumulation occurs frequently through the year and that the isotope record initially contains temperature information from many times of the year. This is also independently confirmed by analysis of H2O2 data. The slope of the multi-year T vs δ correlation was evaluated along with the sub-annual variation in the amount, rate and timing of accumulation. These new results are consistent with those from the previous study and they also demonstrate that the snow in this area initially contains temperature and chemical records with sub-annual resolution. This encourages confident interpretation of the paleoclimatic signal variations in the GISP2 and GRIP deep cores.

scholarly journals High-resolution ammonite, belemnite and stable isotope record from the most complete Upper Jurassic section of the Bakony Mts (Transdanubian Range, Hungary)

2011 ◽  
Vol 62 (5) ◽  
pp. 413-433 ◽  
Author(s):  
István Főzy ◽  
Nico Janssen ◽  
Gregory Price
Keyword(s):  
High Resolution ◽  
Stable Isotope ◽  
Carbon Isotope ◽  
Isotopic Analysis ◽  
Upper Jurassic ◽  
Western Tethys ◽  
Isotope Record ◽  
Transdanubian Range ◽  
The Rich ◽  
Stable Isotope Record

High-resolution ammonite, belemnite and stable isotope record from the most complete Upper Jurassic section of the Bakony Mts (Transdanubian Range, Hungary)This research focuses on the cephalopod fauna and biostratigraphy of the latest Jurassic succession of the Lókút Hill (Bakony Mts, Transdanubia, Hungary). Fossils were collected bed-by-bed from Ammonitico Rosso facies and from the subsequent Biancone type rock. The poorly preserved cephalopods from the lowermost part of the profile, immediately above the radiolarite, may represent a part of the Oxfordian stage. The rich Kimmeridgian ammonite fauna is published for the first time while the formerly illustrated Tithonian fauna is revised. All the successive Kimmeridgian and Early Tithonian Mediterranean ammonite zones can be traced. The highest documented ammonite zone is the Late Tithonian Microcanthum Zone. The beds above yielded no cephalopods. Particular attention was paid to the belemnite fauna of over 120 specimens collected under strict ammonite control. Among the belemnite faunas an Early Tithonian, an early middle Tithonian, a late middle Tithonian, and a latest Tithonian assemblage can be distinguished. Thereby, an association is distinguished in the middle Late Kimmeridgian and one that characterizes the Oxfordian-Kimmeridgian boundary beds. The main difference from previously published belemnite data appears to be that the Hungarian assemblages are impoverished with respect to contemporary faunas from Italy and Spain (Mediterranean Province). An isotopic analysis of the belemnites show that the carbon-isotope data are consistent with carbon-isotope stratigraphies of the Western Tethys and show a decrease in values towards the Jurassic-Cretaceous boundary.

A HIGH-RESOLUTION BENTHIC STABLE ISOTOPE RECORD OF THE MIDDLE EOCENE CLIMATIC OPTIMUM FROM THE NEWFOUNDLAND DRIFTS

2016 ◽  
Author(s):  
Donald Penman ◽  
◽  
Richard D. Norris ◽  
Steve Bohaty ◽  
Maximilan Vahlenkamp ◽  
...  
Keyword(s):  
High Resolution ◽  
Stable Isotope ◽  
Middle Eocene ◽  
Isotope Record ◽  
Climatic Optimum ◽  
Stable Isotope Record

scholarly journals High-Resolution Regional Climate Simulations over Iceland Using Polar MM5*

2005 ◽  
Vol 133 (12) ◽  
pp. 3527-3547 ◽  
Author(s):  
David H. Bromwich ◽  
Lesheng Bai ◽  
Gudmundur G. Bjarnason
Keyword(s):  
High Resolution ◽  
Regional Climate ◽  
Sea Breeze ◽  
Winter Precipitation ◽  
Snow Accumulation ◽  
Northern Coast ◽  
Near Surface ◽  
Surface Climate ◽  
Climate Simulations ◽  
Precipitation Decrease

Abstract High-resolution regional climate simulations of Iceland for 1991–2000 have been performed using the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesocale Model (MM5) modified for use in polar regions (Polar MM5) with three nested domains and short-duration integrations. The simulated results are compared with monthly mean surface observations from Iceland for 1991–2000 to demonstrate the high level of model performance; correlation coefficients exceed 0.9 for most variables considered. The simulation results are used to analyze the near-surface climate over Iceland. The simulated near-surface winds in winter are primarily katabatic. The land–sea-breeze circulation is clearly evident in summer. The land is colder than the ocean during winter, with a strong (weak) temperature gradient along the southern (northern) coast. This temperature pattern over the sloping terrain forces the katabatic wind. The diurnal cycle of near-surface air temperature is marked in summer over the land areas, which drives the land–sea breeze. The near-surface climate variations for extremes of the North Atlantic Oscillation (NAO) index during winter and summer result from the large-scale atmospheric advection conditions. The time-averaged mesoscale precipitation distribution over Iceland is reasonably well simulated by Polar MM5. Winter precipitation rates are double those during the summer, reflecting the much greater winter cyclonic activity. The simulated interannual precipitation variations during winter for 1991–2000 agree with those observed from snow accumulation measurements on the Vatnajökull ice cap. The winter precipitation decrease for 1991–2000 dominates the annual signal for all of Iceland except the northeastern and eastern parts where the precipitation increases. The large precipitation trends (decadal decrease of up to 50%) are caused by the eastward shift and weakening of the Icelandic low during the 1990s, as a result of changes in the NAO modulation of regional climate.

scholarly journals The changes in isotope composition and accumulation of snow at Vostok station, East Antarctica, over the past 200 years

2004 ◽  
Vol 39 ◽  
pp. 569-575 ◽  
Author(s):  
Alexei A. Ekaykin ◽  
Vladimir Ya. Lipenkov ◽  
Irina N. Kuzmina ◽  
Jean Robert Petit ◽  
Valérie MASSON-Delmotte ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Accumulation Rate ◽  
Surface Air Temperature ◽  
Snow Accumulation ◽  
General Tendency ◽  
Near Surface ◽  
The Past ◽  
The Pacific ◽  
Isotope Record ◽  
Vostok Station

AbstractHigh-resolution records of isotope composition (δD) and accumulation of snow have been obtained from 10–12m deep snow pits dug in the vicinity of Vostok station during the 1979/80 and 1999/2000 Antarctic field seasons. We employ meteorological, balloon-sounding and snow-stake data to interpret the isotope record in terms of past temperature changes. Our reconstruction suggests that snow accumulation rate and the near-surface air temperature at Vostok have varied during the past 200 years between 15 and 30 kg m–2 a–1, and between –56 and –55˚C, respectively, with a slight general tendency to increase from the past to the present. Both parameters reveal a 50 year periodicity that correlates with the Pacific Decadal Oscillation index, implying a climatic teleconnection between central Antarctica and the tropical Pacific.

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