continuous record
Recently Published Documents


TOTAL DOCUMENTS

213
(FIVE YEARS 31)

H-INDEX

35
(FIVE YEARS 3)

2021 ◽  
Author(s):  
Matt Amos ◽  
Ushnish Sengupta ◽  
Paul Young ◽  
J. Hosking

Continuous historic datasets of vertically resolved stratospheric ozone, support the case for ozone recovery, are necessary for the running of offline models and increase understanding of the impacts of ozone on the wider atmospheric system. Vertically resolved ozone datasets are typically constructed from multiple satellite, sonde and ground-based measurements that do not provide continuous coverage. As a result, several methods have been used to infill these gaps, most commonly relying on regression against observed time series. However, these existing methods either provide low accuracy infilling especially over polar regions, unphysical extrapolation, or an incomplete estimation of uncertainty. To address these methodological shortcomings we used and further developed an infilling framework that fuses observations with output from an ensemble of chemistry-climate models within a Bayesian neural network. We used this deep learning framework to produce a continuous record of vertically resolved ozone with uncertainty estimates. Under rigorous testing the infilling framework extrapolated and interpolated skillfully and maintained realistic interannual variability due to the inclusion of physically and chemically realistic models. This framework and the ozone dataset it produced, enables a more thorough investigation of vertically resolved trends throughout the atmosphere.


Author(s):  
G. Bob Williams ◽  
Purabi Bora ◽  
Omprakash Sahu

This review work summarised new generation logging techniques such Tough Logging Conditions (TLC) & Logging While Fishing (LWF) and their advancement in drilling operations. The production of Oil & gas from the stage of exploration to production should need a lot of data for economic and safe operations. The conditions of the sub-surface cannot be simply predicted unless with some measured parameters under the LOGGING term. Logging is defined as a continuous record of Petro’s physical parameters of rock against time and depth. Instead of conventional logging techniques of wireline such as SP, Gamma-ray, Neutron, Calliper log, etc, logging while drilling, logging while fishing set them aside of their extended applications. Logging while Fishing is a new generation technology that allows unfailing operations of logging tool by a special installation even in cut and thread operation also aids economic and time enhancement. Tough logging conditions are a technique applied either when the hole has highly deviated or when you need to control the position of a tool. This project includes the study and interpretation of above discussed new generation logs. These tools offer all types of logging carried out on wireline except the SP logging. Logging while drilling provides real-time measurements of physical parameters while drilling operation itself which avoids an additional running of tools causing trips and sticking of drill pipe. The data is stored in the bottom assembled logging tool.


2021 ◽  
Vol 5 (8) ◽  
pp. 73-79
Author(s):  
Yifan Wang

Through teaching journals, teachers can actively conduct true and continuous record, description, reflection, and summary of experiences and teaching behaviors with reflection and research value in their own teaching activities in order to make progress in regard to their teaching skills and classroom presentations. This is an effective way and tool to improve English teachers’ reflective practice in teaching along with their own professional development as well as to promote the role transformation as reflective teachers. Given the widespread concern of the reflective practice in teaching along with the fact that teaching journals are effective in reflective teaching, this paper explores this topic and suggests several implications for teaching via documentation and a case analysis of three samples obtained from an actual teacher’s teaching journal.


2021 ◽  
Vol 15 (7) ◽  
pp. 3129-3134
Author(s):  
Malcolm McMillan ◽  
Alan Muir ◽  
Craig Donlon

Abstract. Over the coming decade, the quartet of Copernicus Sentinel-3 satellite altimeters will provide a continuous record of ice sheet elevation change. Ensuring consistency of measurement between the four satellites requires rigorous in-flight inter-comparison. To facilitate this, Sentinel-3B was initially flown in a unique tandem formation with Sentinel-3A, enabling near-instantaneous, co-located measurements of surface elevation to be acquired. Here, we analyse tandem measurements of ice sheet elevation, to show that both instruments operate with statistically equivalent accuracy and precision, even over complex ice margin terrain. This analysis demonstrates that both satellites can be used interchangeably to study ice sheet evolution.


2021 ◽  
Vol 7 (28) ◽  
pp. eabf4382
Author(s):  
Erik A. Sperling ◽  
Michael J. Melchin ◽  
Tiffani Fraser ◽  
Richard G. Stockey ◽  
Una C. Farrell ◽  
...  

The extent to which Paleozoic oceans differed from Neoproterozoic oceans and the causal relationship between biological evolution and changing environmental conditions are heavily debated. Here, we report a nearly continuous record of seafloor redox change from the deep-water upper Cambrian to Middle Devonian Road River Group of Yukon, Canada. Bottom waters were largely anoxic in the Richardson trough during the entirety of Road River Group deposition, while independent evidence from iron speciation and Mo/U ratios show that the biogeochemical nature of anoxia changed through time. Both in Yukon and globally, Ordovician through Early Devonian anoxic waters were broadly ferruginous (nonsulfidic), with a transition toward more euxinic (sulfidic) conditions in the mid–Early Devonian (Pragian), coincident with the early diversification of vascular plants and disappearance of graptolites. This ~80-million-year interval of the Paleozoic characterized by widespread ferruginous bottom waters represents a persistence of Neoproterozoic-like marine redox conditions well into the Phanerozoic.


2021 ◽  
Vol 14 (5) ◽  
pp. e243349
Author(s):  
Lauren O'Connell ◽  
Alexander E P Heazell

A 31-year-old woman with a history of stillbirth due to placental abruption at 29 weeks’ gestation and one first trimester miscarriage documented a continuous record of her perceived fetal movements from 28 to 38 weeks’ gestation. Repeated ultrasound examinations confirmed a viable pregnancy, with normal growth, liquor volume and Doppler profile. She delivered a healthy male infant at 38 weeks and 3 days’ gestation. The data collected give a detailed record of fetal activity in a healthy pregnancy. Perceived fetal activity increased as pregnancy progressed and was greatest in the evenings. We also found that clusters of movements, which have previously been reported as protective against stillbirth, were felt earlier on in pregnancy.


2021 ◽  
Vol 29 ◽  
pp. 19-37
Author(s):  
Benjamin Läuchli ◽  
Paul Christian Augustinus ◽  
Leonie Peti ◽  
Jenni Louise Hopkins

Abstract. The accurate and precise reconstruction of Quaternary climate as well as the events that punctuate it is an important driver of the study of lake sediment archives. However, until recently lake sediment-based palaeoclimate reconstructions have largely concentrated on Northern Hemisphere lake sequences due to a scarcity of continuous and high-resolution lake sediment sequences from the Southern Hemisphere, especially from the southern mid-latitudes. In this context, the deep maar lakes of the Auckland Volcanic Field of northern New Zealand are significant as several contain continuous and well-laminated sediment sequences. Onepoto Basin potentially contains the longest temporal lake sediment record from the Auckland Volcanic Field (AVF), spanning from Marine Isotope Stage 6e (MIS 6e) to the early Holocene when lacustrine sedimentation was terminated by marine breach of the south-western crater tuff ring associated with post-glacial sea-level rise. The Onepoto record consists of two new, overlapping cores spanning ca. 73 m combined with archive material in a complete composite stratigraphy. Tephrochronology and 14C dating provide the fundamental chronological framework for the core, with magnetic relative palaeo-intensity variability downcore, and meteoric 10Be influx into the palaeolake to refine the chronology. The µ-XRF (micro X-ray fluorescence) downcore variability for the entirety of the lake sediment sequence has been established with measurement of a range of proxies for climate currently underway. This work will produce the first continuous record of the last 200 kyr of palaeoclimate from northern New Zealand to date.


The Holocene ◽  
2021 ◽  
pp. 095968362110032
Author(s):  
Xiaolong Zhang ◽  
Baiqing Xu ◽  
Jiule Li ◽  
Ying Xie ◽  
Gerd Gleixner

Glaciers on the Tibetan Plateau (TP) are reliable water sources for Asia. Continuously high-resolution and high-accuracy long-term glacier fluctuations have been examined to improve the reliability of predictions regarding future TP glacier behavior under global climate change. In this study, we analyzed physiochemical parameters in typical glaciolacustrine sediments to reconstruct multidecadal activities of the monsoonal Qiangyong Glacier over the past ~2500 years. The results show that the glacier advanced most strongly during 560 BC–AD 100, followed by AD 1050–1850 and AD 600–850. It retreated most severely during AD 1850–present, followed by AD 100–600 and AD 850–1050. This continuous record corresponds well with changes in the temperature and regional precipitation before the Current Warm Period, exhibiting “warm-humid-retreat” and “cold-dry-advance” patterns. This indicates that temperature changes, rather than precipitation variations, control the monsoonal glaciers at the southern TP at multidecadal to centennial scales. As global warming continues, although the precipitation on the southern TP is projected to increase, the mass loss of TP monsoonal glaciers is expected to continue.


2021 ◽  
Author(s):  
Thomas Smith ◽  
Jessica McCarty ◽  
Merritt Turetsky ◽  
Mark Parrington

<p>MODIS has provided an 18-year continuous record of global fire activity. Here we present a geospatial analysis of MODIS hotspots in the high latitudes of the northern hemisphere from 2003 through to 2020. By combining the hotspot data with multiple land-cover datasets relating to vegetation cover, permafrost, and peat, we investigate boreal and tundra wildfire regimes, including an assessment of a significant northwards shift and increase in fire activity in 2019 and 2020. We focus on the distribution of hotspots on high latitude peatlands and permafrost and the associated difficulties in confirming residual smouldering compustion of peat soils using current remote sensing technology.</p>


2021 ◽  
Vol 17 (2) ◽  
Author(s):  
Mary T. Silcox ◽  
Keegan R. Selig ◽  
Thomas M. Bown ◽  
Amy E. Chew ◽  
Kenneth D. Rose

The early Eocene of the southern Bighorn Basin, Wyoming, is notable for its nearly continuous record of mammalian fossils. Microsyopinae (?Primates) is one of several lineages that shows evidence of evolutionary change associated with an interval referred to as Biohorizon A. Arctodontomys wilsoni is replaced by a larger species, Arctodontomys nuptus , during the biohorizon interval in what is likely an immigration/emigration or immigration/local extinction event. The latter is then superseded by Microsyops angustidens after the end of the Biohorizon A interval. Although this pattern has been understood for some time, denser sampling has led to the identification of a specimen intermediate in morphology between A. nuptus and M. angustidens , located stratigraphically as the latter is appearing. Because specimens of A. nuptus have been recovered approximately 60 m above the appearance of M. angustidens , it is clear that A. nuptus did not suffer pseudoextinction. Instead, evidence suggests that M. angustidens branched off from a population of A. nuptus , but the latter species persisted. This represents possible evidence of cladogenesis, which has rarely been directly documented in the fossil record. The improved understanding of both evolutionary transitions with better sampling highlights the problem of interpreting gaps in the fossil record as punctuations.


Sign in / Sign up

Export Citation Format

Share Document