scholarly journals The Swedish Time Scale: A Potential Calibration Tool for the Radiocarbon Time Scale During the Late Weichselian

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 347-359 ◽  
Author(s):  
Barbara Wohlfarth ◽  
Svante Björck ◽  
Göran Possnert
Keyword(s):  
Time Scale ◽  
East Coast ◽  
Short Term ◽  
Data Set ◽  
Varve Chronology ◽  
Data Points ◽  
The Difference ◽  
Late Weichselian ◽  
Calibration Program ◽  
Calibration Tool

The Swedish Time Scale (STS) is a ca. 13,300-yr-long varve chronology that has been established for the Swedish east coast from >1000 overlapping clay-varve diagrams. We describe the present state of the STS and illustrate the application of this worldwide unique varve chronology for AMS radiocarbon measurements. The results are compared to other 14C-dated calendar-year chronologies: dendrochronology, laminated lake sediments and U/Th. Our data set agrees with the oldest part of the dendrochronological calibration curve, and with AMS 14C-dated lake lamination data and U/Th on corals down to ca. 12 ka calendar years bp. Further back in time, the AMS-dated part of the STS partly compares well with lake lamination chronologies and shows that the difference between 14C and calendar years decreases rapidly between 12,600 and 12,800 calendar years bp. Such a development seems to contrast with U/Th measurements on corals. We suggest that the cause for the divergence among three supposed calendar-year chronologies lies in the fact that the data points on the marine 14C-U/Th curve are more widely spaced in time than the tightly grouped set of terrestrial AMS 14C dates, and thus are not able to reflect short-term changes in atmospheric 14C. Therefore, we argue that the use of the pre-Holocene part of the calibration program is premature and inadvisable.

scholarly journals Re-analysis of ground-based microwave ClO measurements from Mauna Kea, 1992 to early 2012

2013 ◽  
Vol 13 (17) ◽  
pp. 8643-8650 ◽  
Author(s):  
B. J. Connor ◽  
T. Mooney ◽  
G. E. Nedoluha ◽  
J. W. Barrett ◽  
A. Parrish ◽  
...  
Keyword(s):  
Atmospheric Composition ◽  
Composition Change ◽  
Major Focus ◽  
Short Term ◽  
Data Set ◽  
Long Term Changes ◽  
The Difference ◽  
Long Term Trend ◽  
Linear Decline

Abstract. We present a re-analysis of upper stratospheric ClO measurements from the ground-based millimeter-wave instrument from January 1992 to February 2012. These measurements are made as part of the Network for the Detection of Atmospheric Composition Change (NDACC) from Mauna Kea, Hawaii, (19.8° N, 204.5° E). Here, we use daytime and nighttime measurements together to form a day–night spectrum, from which the difference in the day and night profiles is retrieved. These results are then compared to the day–night difference profiles from the Upper Atmosphere Research Satellite (UARS) and Aura Microwave Limb Sounder (MLS) instruments. We also compare them to our previous analyses of the same data, in which we retrieved the daytime ClO profile. The major focus will be on comparing the year-to-year and long-term changes in ClO derived by the two analysis methods, and comparing these results to the long-term changes reported by others. We conclude that the re-analyzed data set has less short-term variability and exhibits a more constant long-term trend that is more consistent with other observations. Data from 1995 to 2012 indicate a linear decline of mid-stratospheric ClO of 0.64 ± 0.15% yr−1 (2σ).

scholarly journals Variability of seasonal and annual rainfall in the River Nile riparian countries and possible linkages to ocean–atmosphere interactions

2015 ◽  
Vol 47 (1) ◽  
pp. 171-184 ◽  
Author(s):  
Charles Onyutha
Keyword(s):  
Large Scale ◽  
Equatorial Region ◽  
Annual Rainfall ◽  
River Nile ◽  
Short Term ◽  
Ocean Atmosphere ◽  
Data Points ◽  
The Difference ◽  
Term Data

Variability analyses for the rainfall over the Nile Basin have been confined mostly to sub-basins and the annual mean of the hydroclimatic variable based on observed short-term data from a few meteorological stations. In this paper, long-term country-wide rainfall over the period 1901–2011 was used to assess variability in the seasonal and annual rainfall volumes in all the River Nile countries in Africa. Temporal variability was determined through temporal aggregation of series rescaled nonparametrically in terms of the difference between the exceedance and non-exceedance counts of data points such that the long-term average (taken as the reference) was zero. The co-occurrence of the variability of rainfall with those of the large-scale ocean–atmosphere interactions was analyzed. Between 2000 and 2012, while the rainfall in the equatorial region was increasing, that for the countries in the northern part of the River Nile was below the reference. Generally, the variability in the rainfall of the countries in the equatorial (northern) part of the River Nile was found to be significantly linked to occurrences in the Indian and Atlantic (Pacific and Atlantic) Oceans. Significant linkages to Niño 4 regarding the variability of both the seasonal and annual rainfall of some countries were also evident.

scholarly journals Re-analysis of ground-based microwave ClO measurements from Mauna Kea, 1992 to early 2012

2012 ◽  
Vol 12 (11) ◽  
pp. 30571-30588
Author(s):  
B. J. Connor ◽  
T. Mooney ◽  
G. E Nedoluha ◽  
J. W. Barrett ◽  
A. Parrish ◽  
...  
Keyword(s):  
Atmospheric Composition ◽  
Composition Change ◽  
Major Focus ◽  
Short Term ◽  
Data Set ◽  
Trend Data ◽  
The Difference ◽  
Long Term Trend ◽  
Linear Decline

Abstract. We present a re-analysis of upper stratospheric ClO measurements from the ground-based millimeter-wave instrument from January 1992 to February 2012. These measurements are made as part of the Network for the Detection of Atmospheric Composition Change (NDACC) from Mauna Kea, Hawaii, (19.8° N, 204.5° E). Here, we use daytime and nighttime measurements together to form a day-night spectrum, from which the difference in the day and night profiles is retrieved. These results are then compared to the day-night difference profiles from the UARS and Aura Microwave Limb Sounder (MLS) instruments. We also compare them to our previous analyses of the same data, in which we retrieved the daytime ClO profile. The major focus will be on comparing the year-to-year and long-term changes in ClO derived by the two analysis methods. We conclude that the re-analyzed data set has less short-term variability and exhibits a more constant long-term trend. Data from 1995–2012 indicate a linear decline of mid-stratospheric ClO of 0.64 ± 0.08% yr−1.

scholarly journals Extended 14C Data Base and Revised CALIB 3.0 14C Age Calibration Program

Radiocarbon ◽  
1993 ◽  
Vol 35 (1) ◽  
pp. 215-230 ◽  
Author(s):  
Minze Stuiver ◽  
Paula J. Reimer
Keyword(s):  
Data Base ◽  
Time Scale ◽  
Set Covering ◽  
Calibration Data ◽  
Data Set ◽  
14C Age ◽  
Scale Calibration ◽  
Calibration Data Set ◽  
Calibration Program

The age calibration program, CALIB (Stuiver & Reimer 1986), first made available in 1986 and subsequently modified in 1987 (revision 2.0 and 2.1), has been amended anew. The 1993 program (revision 3.0) incorporates further refinements and a new calibration data set covering nearly 22,000 cal yr (≈18,400 14C yr). The new data, and corrections to the previously used data set, derive from a 6-yr (1986–1992) time-scale calibration effort of several laboratories.

Leveling HEM and aeromagnetic data using differential polynomial fitting

Geophysics ◽  
2010 ◽  
Vol 75 (1) ◽  
pp. L13-L23 ◽  
Author(s):  
Majid Beiki ◽  
Mehrdad Bastani ◽  
Laust B. Pedersen
Keyword(s):  
Differential Polynomial ◽  
Average Height ◽  
Aeromagnetic Data ◽  
Polynomial Fitting ◽  
Data Set ◽  
Sliding Windows ◽  
Fitting Method ◽  
Data Points ◽  
The Difference ◽  
Fitting In

We introduce a new technique to level aerogeophysical data. Our approach is applicable to flight-line data without any need for tie-line measurements. The technique is based on polynomial fitting of data points in 1D and 2D sliding windows. A polynomial is fitted to data points in a 2D circular window that contains at least three flight lines. Then the same procedure is done inside a 1D window placed at the center of the 2D window. The leveling error is the difference between 1D and 2D polynomial fitted data at the center of the windows. To demonstrate the reliability of the method, it was tested on a synthetic aeromagnetic data set contaminated by some linear artifacts. Using the differential polynomial fitting method, we can remove the linear artifacts from the data. The method then was applied to two real airborne data sets collected in Iran. The leveling errors are removed effectively from the aeromagnetic data using the differential polynomial fitting. In the case of helicopter-towed electromagnetic (HEM) data, the polynomial fitting method is used to level the measured real (in-phase) and imaginary (quadrature) components, as well as the calculated apparent resistivity. The HEM data are sensitive to height variations, so we introduce an average-height scaling method to reduce the height effect before leveling in-phase and quadrature components. The method also is effective in recovering some of the attenuated anomalies. After scaling, the differential polynomial fitting method was applied to the data and effectively removed the remaining line-to-line artifacts.

Difference Fourier Analysis of Glucose Embedded and Frozen Hydrated Purple Membrane

1982 ◽  
Vol 40 ◽  
pp. 74-75
Author(s):  
Jules S. Jaffe ◽  
Robert M. Glaeser
Keyword(s):  
Purple Membrane ◽  
Data Set ◽  
High Resolution Data ◽  
X Ray ◽  
X Ray Crystallography ◽  
Fourier Techniques ◽  
Versus Protein ◽  
The Difference ◽  
Difference Fourier ◽  
Ideal Method

Although difference Fourier techniques are standard in X-ray crystallography it has only been very recently that electron crystallographers have been able to take advantage of this method. We have combined a high resolution data set for frozen glucose embedded Purple Membrane (PM) with a data set collected from PM prepared in the frozen hydrated state in order to visualize any differences in structure due to the different methods of preparation. The increased contrast between protein-ice versus protein-glucose may prove to be an advantage of the frozen hydrated technique for visualizing those parts of bacteriorhodopsin that are embedded in glucose. In addition, surface groups of the protein may be disordered in glucose and ordered in the frozen state. The sensitivity of the difference Fourier technique to small changes in structure provides an ideal method for testing this hypothesis.

Short-Term Flood Prediction System

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Konrad Nering
Keyword(s):  
Flash Floods ◽  
Prediction System ◽  
Short Term ◽  
Data Set ◽  
Flood Prediction ◽  
Full Operation

AbstractThis paper describes a fully functional short-term flood prediction system. Its effect has been tested on watershed of Lubieńka river in Małopolska. To use this system it must have a data set also described in this paper. A modification of the system to adopt for predicting flash floods was described. Full operation of the system is shown on example of real flood on Lubieńka river in June 2011.

Measuring Congestion and Reliability Impacts of Safety Projects

2021 ◽  
pp. 036119812110067
Author(s):  
Simona Babiceanu ◽  
Sanhita Lahiri ◽  
Mena Lockwood
Keyword(s):  
Performance Measures ◽  
Positive Impact ◽  
Operating Conditions ◽  
Vehicle Miles Traveled ◽  
Data Set ◽  
Data Points ◽  
Practical Recommendations

This study uses a suite of performance measures that was developed by taking into consideration various aspects of congestion and reliability, to assess impacts of safety projects on congestion. Safety projects are necessary to help move Virginia’s roadways toward safer operation, but can contribute to congestion and unreliability during execution, and can affect operations after execution. However, safety projects are assessed primarily for safety improvements, not for congestion. This study identifies an appropriate suite of measures, and quantifies and compares the congestion and reliability impacts of safety projects on roadways for the periods before, during, and after project execution. The paper presents the performance measures, examines their sensitivity based on operating conditions, defines thresholds for congestion and reliability, and demonstrates the measures using a set of Virginia safety projects. The data set consists of 10 projects totalling 92 mi and more than 1M data points. The study found that, overall, safety projects tended to have a positive impact on congestion and reliability after completion, and the congestion variability measures were sensitive to the threshold of reliability. The study concludes with practical recommendations for primary measures that may be used to measure overall impacts of safety projects: percent vehicle miles traveled (VMT) reliable with a customized threshold for Virginia; percent VMT delayed; and time to travel 10 mi. However, caution should be used when applying the results directly to other situations, because of the limited number of projects used in the study.

scholarly journals THE VALUE OF ROBUST STATISTICAL FORECASTS IN THE COVID-19 PANDEMIC

2021 ◽  
Vol 256 ◽  
pp. 19-43
Author(s):  
Jennifer L. Castle ◽  
Jurgen A. Doornik ◽  
David F. Hendry
Keyword(s):  
Structural Change ◽  
Measurement Errors ◽  
Epidemiological Models ◽  
Short Term ◽  
Data Measurement ◽  
Policy Interventions ◽  
Changing Trends ◽  
Technological Advances ◽  
The Difference ◽  
The Uk

The Covid-19 pandemic has put forecasting under the spotlight, pitting epidemiological models against extrapolative time-series devices. We have been producing real-time short-term forecasts of confirmed cases and deaths using robust statistical models since 20 March 2020. The forecasts are adaptive to abrupt structural change, a major feature of the pandemic data due to data measurement errors, definitional and testing changes, policy interventions, technological advances and rapidly changing trends. The pandemic has also led to abrupt structural change in macroeconomic outcomes. Using the same methods, we forecast aggregate UK unemployment over the pandemic. The forecasts rapidly adapt to the employment policies implemented when the UK entered the first lockdown. The difference between our statistical and theory based forecasts provides a measure of the effect of furlough policies on stabilising unemployment, establishing useful scenarios had furlough policies not been implemented.

Sign in / Sign up

Export Citation Format

Share Document