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Title:

Northern Hemisphere spring snow cover variability and change over 19222010 including an assessment of uncertainty

Description:

An update is provided of Northern Hemisphere (NH) spring (March, April) snow cover extent (SCE) over the 19222010 period incorporating the new climate data record (CDR) version of the NOAA weekly SCE dataset, with annual 95% confidence intervals estimates from regression analysis and intercomparison of multiple datasets. The uncertainty analysis...

An update is provided of Northern Hemisphere (NH) spring (March, April) snow cover extent (SCE) over the 19222010 period incorporating the new climate data record (CDR) version of the NOAA weekly SCE dataset, with annual 95% confidence intervals estimates from regression analysis and intercomparison of multiple datasets. The uncertainty analysis indicated a 95% confidence interval in NH spring SCE of ±510% over the pre-satellite period and ±35% over the satellite era. The multi-dataset analysis showed there are larger uncertainties monitoring spring SCE over Eurasia (EUR) than North America (NA) due to the more complex regional character of the snow cover variability with the largest dataset uncertainty located over eastern Eurasia in a large region extending from the Tibetan Plateau across northern China. Trend analysis of the updated SCE series provided evidence that NH spring snow cover extent has undergone significant reductions over the past ~90 years and that the rate of decrease has accelerated over the past 40 years. The rate of decrease in March and April NH SCE over the 19702010 period is ~78 million km 2 per 100 years which corresponds to an 811% decrease in NH March and April SCE respectively from pre-1970 values. In March, most of the change is being driven by Eurasia (NA trends are not significant) but both continents exhibit significant SCE reductions in April. The observed trends in SCE are consistent with recent warming trends over northern mid-latitude land areas with NH SCE exhibiting significant negative correlations to air temperature anomalies in March and April. The NH spring SCE-temperature sensitivity has remained relatively stable over the period of record although there is some evidence of contrasting changes in temperature sensitivity over both continents in April. There is evidence that changes in atmospheric circulation around 1980 involving the North Atlantic Oscillation and Scandinavian Pattern have contributed to reductions in March SCE over Eurasia. Minimize

Publisher:

Copernicus Publications

Year of Publication:

2010-11-01T00:00:00Z

Document Type:

article

Language:

English

Subjects:

LCC:Environmental sciences ; LCC:GE1-350 ; LCC:Geography. Anthropology. Recreation ; LCC:G ; DOAJ:Environmental Sciences ; DOAJ:Earth and Environmental Sciences ; LCC:Meteorology. Climatology ; LCC:QC851-999 ; LCC:Physics ; LCC:QC1-999 ; LCC:Science ; LCC:Q ; DOAJ:Meteorology and Climatology ; DOAJ:Earth and Environmental Sciences ; LCC:Environm...

LCC:Environmental sciences ; LCC:GE1-350 ; LCC:Geography. Anthropology. Recreation ; LCC:G ; DOAJ:Environmental Sciences ; DOAJ:Earth and Environmental Sciences ; LCC:Meteorology. Climatology ; LCC:QC851-999 ; LCC:Physics ; LCC:QC1-999 ; LCC:Science ; LCC:Q ; DOAJ:Meteorology and Climatology ; DOAJ:Earth and Environmental Sciences ; LCC:Environmental sciences ; LCC:GE1-350 ; LCC:Geography. Anthropology. Recreation ; LCC:G ; DOAJ:Environmental Sciences ; DOAJ:Earth and Environmental Sciences ; LCC:Meteorology. Climatology ; LCC:QC851-999 ; LCC:Physics ; LCC:QC1-999 ; LCC:Science ; LCC:Q ; DOAJ:Meteorology and Climatology ; DOAJ:Earth and Environmental Sciences ; LCC:Environmental sciences ; LCC:GE1-350 ; LCC:Geography. Anthropology. Recreation ; LCC:G ; LCC:Meteorology. Climatology ; LCC:QC851-999 ; LCC:Physics ; LCC:QC1-999 ; LCC:Science ; LCC:Q ; LCC:Environmental sciences ; LCC:GE1-350 ; LCC:Geography. Anthropology. Recreation ; LCC:G ; LCC:Meteorology. Climatology ; LCC:QC851-999 ; LCC:Physics ; LCC:QC1-999 ; LCC:Science ; LCC:Q Minimize

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333 Economics of land & energy *(computed)*

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http://www.the-cryosphere-discuss.net/4/2483/2010/tcd-4-2483-2010.pdf

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Title:

Northern Hemisphere spring snow cover variability and change over 19222010 including an assessment of uncertainty

Description:

An update is provided of Northern Hemisphere (NH) spring (March, April) snow cover extent (SCE) over the 19222010 period incorporating the new climate data record (CDR) version of the NOAA weekly SCE dataset, with annual 95% confidence intervals estimated from regression analysis and intercomparison of multiple datasets. The uncertainty analysis...

An update is provided of Northern Hemisphere (NH) spring (March, April) snow cover extent (SCE) over the 19222010 period incorporating the new climate data record (CDR) version of the NOAA weekly SCE dataset, with annual 95% confidence intervals estimated from regression analysis and intercomparison of multiple datasets. The uncertainty analysis indicates a 95% confidence interval in NH spring SCE of ±510% over the pre-satellite period and ±35% over the satellite era. The multi-dataset analysis shows larger uncertainties monitoring spring SCE over Eurasia (EUR) than North America (NA) due to the more complex regional character of the snow cover variability and larger between-dataset variability over northern Europe and north-central Russia. Trend analysis of the updated SCE series provides evidence that NH spring snow cover extent has undergone significant reductions over the past ~90 yr and that the rate of decrease has accelerated over the past 40 yr. The rate of decrease in March and April NH SCE over the 19702010 period is ~0.8 million km 2 per decade corresponding to a 7% and 11% decrease in NH March and April SCE respectively from pre-1970 values. In March, most of the change is being driven by Eurasia (NA trends are not significant) but both continents exhibit significant SCE reductions in April. The observed trends in SCE are being mainly driven by warmer air temperatures, with NH mid-latitude air temperatures explaining ~50% of the variance in NH spring snow cover over the 89-yr period analyzed. However, there is also evidence that changes in atmospheric circulation around 1980 involving the North Atlantic Oscillation and Scandinavian pattern have contributed to reductions in March SCE over Eurasia. Minimize

Publisher:

Copernicus GmbH

Year of Publication:

2011-03-01T00:00:00Z

Document Type:

article

Language:

English

Subjects:

LCC:Environmental sciences ; LCC:GE1-350 ; LCC:Geography. Anthropology. Recreation ; LCC:G ; DOAJ:Environmental Sciences ; DOAJ:Earth and Environmental Sciences ; LCC:Meteorology. Climatology ; LCC:QC851-999 ; LCC:Physics ; LCC:QC1-999 ; LCC:Science ; LCC:Q ; DOAJ:Meteorology and Climatology ; DOAJ:Earth and Environmental Sciences ; LCC:Environm...

LCC:Environmental sciences ; LCC:GE1-350 ; LCC:Geography. Anthropology. Recreation ; LCC:G ; DOAJ:Environmental Sciences ; DOAJ:Earth and Environmental Sciences ; LCC:Meteorology. Climatology ; LCC:QC851-999 ; LCC:Physics ; LCC:QC1-999 ; LCC:Science ; LCC:Q ; DOAJ:Meteorology and Climatology ; DOAJ:Earth and Environmental Sciences ; LCC:Environmental sciences ; LCC:GE1-350 ; LCC:Geography. Anthropology. Recreation ; LCC:G ; DOAJ:Environmental Sciences ; DOAJ:Earth and Environmental Sciences ; LCC:Meteorology. Climatology ; LCC:QC851-999 ; LCC:Physics ; LCC:QC1-999 ; LCC:Science ; LCC:Q ; DOAJ:Meteorology and Climatology ; DOAJ:Earth and Environmental Sciences ; LCC:Environmental sciences ; LCC:GE1-350 ; LCC:Geography. Anthropology. Recreation ; LCC:G ; LCC:Meteorology. Climatology ; LCC:QC851-999 ; LCC:Physics ; LCC:QC1-999 ; LCC:Science ; LCC:Q ; LCC:Environmental sciences ; LCC:GE1-350 ; LCC:Geography. Anthropology. Recreation ; LCC:G ; LCC:Meteorology. Climatology ; LCC:QC851-999 ; LCC:Physics ; LCC:QC1-999 ; LCC:Science ; LCC:Q Minimize

DDC:

333 Economics of land & energy *(computed)*

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http://www.the-cryosphere.net/5/219/2011/tc-5-219-2011.pdf

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Title:

Analysis of a Small Loop Antenna with Inductive Coupling to Nearby Loops

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Description:

Abstract not provided

Abstract not provided Minimize

Year of Publication:

2014-02-10

Subjects:

71 CLASSICAL AND QUANTUMM MECHANICS ; GENERAL PHYSICS; 42 ENGINEERING; 47 OTHER INSTRUMENTATION

71 CLASSICAL AND QUANTUMM MECHANICS ; GENERAL PHYSICS; 42 ENGINEERING; 47 OTHER INSTRUMENTATION Minimize

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Title:

Summary Statistics for Fun Dough Data Acquired at LLNL

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Using x-ray computerized tomography (CT), we have characterized the x-ray linear attenuation coefficients (LAC) of a Play Dough{trademark}-like product, Fun Dough{trademark}, designated as PD. Table 1 gives the first-order statistics for each of four CT measurements, estimated with a Gaussian kernel density estimator (KDE) analysis. The mean val...

Using x-ray computerized tomography (CT), we have characterized the x-ray linear attenuation coefficients (LAC) of a Play Dough{trademark}-like product, Fun Dough{trademark}, designated as PD. Table 1 gives the first-order statistics for each of four CT measurements, estimated with a Gaussian kernel density estimator (KDE) analysis. The mean values of the LAC range from a high of about 2100 LMHU{sub D} at 100kVp to a low of about 1100 LMHU{sub D} at 300kVp. The standard deviation of each measurement is around 1% of the mean. The entropy covers the range from 3.9 to 4.6. Ordinarily, we would model the LAC of the material and compare the modeled values to the measured values. In this case, however, we did not have the composition of the material and therefore did not model the LAC. Using a method recently proposed by Lawrence Livermore National Laboratory (LLNL), we estimate the value of the effective atomic number, Z{sub eff}, to be near 8.5. LLNL prepared about 50mL of the Fun Dough{trademark} in a polypropylene vial and firmly compressed it immediately prior to the x-ray measurements. Still, layers can plainly be seen in the reconstructed images, indicating that the bulk density of the material in the container is affected by voids and bubbles. We used the computer program IMGREC to reconstruct the CT images. The values of the key parameters used in the data capture and image reconstruction are given in this report. Additional details may be found in the experimental SOP and a separate document. To characterize the statistical distribution of LAC values in each CT image, we first isolated an 80% central-core segment of volume elements ('voxels') lying completely within the specimen, away from the walls of the polypropylene vial. All of the voxels within this central core, including those comprised of voids and inclusions, are included in the statistics. We then calculated the mean value, standard deviation and entropy for (a) the four image segments and for (b) their digital gradient images. (A digital gradient image of a given image was obtained by taking the absolute value of the difference between the initial image and that same image offset by one voxel horizontally, parallel to the rows of the x-ray detector array.) The statistics of the initial image of LAC values are called 'first order statistics;' those of the gradient image, 'second order statistics.' Minimize

Year of Publication:

2010-04-29

Subjects:

99 GENERAL AND MISCELLANEOUS; ATOMIC NUMBER; ATTENUATION; BUBBLES; BULK DENSITY; COMPUTER CODES; COMPUTERIZED TOMOGRAPHY; CONTAINERS; DATA; DISTRIBUTION; ENTROPY; KERNELS; LAWRENCE LIVERMORE NATIONAL LABORATORY; POLYPROPYLENE; STATISTICS

99 GENERAL AND MISCELLANEOUS; ATOMIC NUMBER; ATTENUATION; BUBBLES; BULK DENSITY; COMPUTER CODES; COMPUTERIZED TOMOGRAPHY; CONTAINERS; DATA; DISTRIBUTION; ENTROPY; KERNELS; LAWRENCE LIVERMORE NATIONAL LABORATORY; POLYPROPYLENE; STATISTICS Minimize

DDC:

500 Natural sciences & mathematics *(computed)*

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Title:

Lectures on sieves

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These are notes of a series of lectures on sieves, presented during the Special Activity in Analytic Number Theory, at the Max-Planck Institute for Mathematics in Bonn, during the period January--June 2002. ; Comment: 50 pages

These are notes of a series of lectures on sieves, presented during the Special Activity in Analytic Number Theory, at the Max-Planck Institute for Mathematics in Bonn, during the period January--June 2002. ; Comment: 50 pages Minimize

Year of Publication:

2002-09-25

Document Type:

text

Subjects:

Mathematics - Number Theory

Mathematics - Number Theory Minimize

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Title:

Zeros of p-adic forms

Description:

A variant of Brauer's induction method is developed. It is shown that quartic p-adic forms with at least 9127 variables have non-trivial zeros, for every p. For odd p considerably fewer variables are needed. There are also subsidiary new results concerning quintic forms, and systems of forms. ; Comment: Misprints and other errors corrected, lead...

A variant of Brauer's induction method is developed. It is shown that quartic p-adic forms with at least 9127 variables have non-trivial zeros, for every p. For odd p considerably fewer variables are needed. There are also subsidiary new results concerning quintic forms, and systems of forms. ; Comment: Misprints and other errors corrected, leading to a small improvement Minimize

Year of Publication:

2008-05-05

Document Type:

text

Subjects:

Mathematics - Number Theory ; 11D88 ; 11D72

Mathematics - Number Theory ; 11D88 ; 11D72 Minimize

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Title:

The density of rational points on Cayley's cubic surface

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The Cayley cubic surface is given by the equation sum_{i=1}^4 X_i^{-1}=0. We show that the number of non-trivial primitive integer points of size at most B is of exact order B(log B)^6, as predicted by Manin's conjecture. ; Comment: 29 pages

The Cayley cubic surface is given by the equation sum_{i=1}^4 X_i^{-1}=0. We show that the number of non-trivial primitive integer points of size at most B is of exact order B(log B)^6, as predicted by Manin's conjecture. ; Comment: 29 pages Minimize

Year of Publication:

2002-10-21

Document Type:

text

Subjects:

Mathematics - Number Theory

Mathematics - Number Theory Minimize

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Title:

Sums and Differences of Three k-th Powers

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Let k>2 be a fixed integer exponent and let \theta > 9/10. We show that a positive integer N can be represented as a non-trivial sum or difference of 3 k-th powers, using integers of size at most B, in O(B^{\theta}N^{1/10}) ways, providing that N << B^{3/13}. The significance of this is that we may take \theta strictly less than 1. We also prove...

Let k>2 be a fixed integer exponent and let \theta > 9/10. We show that a positive integer N can be represented as a non-trivial sum or difference of 3 k-th powers, using integers of size at most B, in O(B^{\theta}N^{1/10}) ways, providing that N << B^{3/13}. The significance of this is that we may take \theta strictly less than 1. We also prove the estimate O(B^{10/k}), (subject to N << B) which is better for large k. The results extend to representations by an arbitrary fixed nonsingular ternary from. However ``non-trivial'' must then be suitably defined. Consideration of the singular form x^{k-1}y-z^k allows us to establish an asymptotic formula for (k-1)-free values of p^k+c, when p runs over primes, answering a problem raised by Hooley. Minimize

Year of Publication:

2008-06-26

Document Type:

text

Subjects:

Mathematics - Number Theory ; Mathematics - Algebraic Geometry ; 11D45

Mathematics - Number Theory ; Mathematics - Algebraic Geometry ; 11D45 Minimize

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Title:

Small Solutions of Quadratic Congruences, and Character Sums with Binary Quadratic Forms

Description:

Let $Q(x,y,z)$ be an integral quadratic form with determinant coprime to some modulus $q$. We show that $q\mid Q$ for some non-zero integer vector $(x,y,z)$ of length $O(q^{5/8+\varepsilon})$, for any fixed $\varepsilon>0$. Without the coprimality condition on the determinant one could not achieve an exponent below $2/3$. The proof uses a bound ...

Let $Q(x,y,z)$ be an integral quadratic form with determinant coprime to some modulus $q$. We show that $q\mid Q$ for some non-zero integer vector $(x,y,z)$ of length $O(q^{5/8+\varepsilon})$, for any fixed $\varepsilon>0$. Without the coprimality condition on the determinant one could not achieve an exponent below $2/3$. The proof uses a bound for short character sums involving binary quadratic forms, which extends a result of Chang. Minimize

Year of Publication:

2014-11-18

Document Type:

text

Subjects:

Mathematics - Number Theory

Mathematics - Number Theory Minimize

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Title:

$p$-adic Zeros of Systems of Quadratic Forms

Description:

This survey describes work on the number of variables required to ensure that a system of r quadratic forms over the p-adics has a non-trivial common zero.

This survey describes work on the number of variables required to ensure that a system of r quadratic forms over the p-adics has a non-trivial common zero. Minimize

Year of Publication:

2012-01-04

Document Type:

text

Subjects:

Mathematics - Number Theory

Mathematics - Number Theory Minimize

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