Revealing Relationships among Relevant Climate Variables with Information Theory

A primary objective of the NASA Earth-Sun Exploration Technology Office is to understand the observed Earth climate variability, thus enabling the determination and prediction of the climate's response to both natural and human-induced forcing. We are currently developing a suite of computational tools that will allow researchers to calculate, from data, a variety of information-theoretic quantities such as mutual information, which can be used to identify relationships among climate variables, and transfer entropy, which indicates the possibility of causal interactions. Our tools estimate these quantities along with their associated error bars, the latter of which is critical for describing the degree of uncertainty in the estimates. This work is based upon optimal binning techniques that we have developed for piecewise-constant, histogram-style models of the underlying density functions. Two useful side benefits have already been discovered. The first allows a researcher to determine whether there exist sufficient data to estimate the underlying probability density. The second permits one to determine an acceptable degree of round-off when compressing data for efficient transfer and storage. We also demonstrate how mutual information and transfer entropy can be applied so as to allow researchers not only to identify relations among climate variables, but also to characterize and quantify their possible causal interactions.Comment: 14 pages, 5 figures, Proceedings of the Earth-Sun System Technology Conference (ESTC 2005), Adelphi, M

Oleander is more than a flower twenty-five years of oceanography aboard a merchant vessel

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Rossby, T., Flagg, C. N., Donohue, K., Fontana, S., Curry, R., Andres, M., & Forsyth, J. Oleander is more than a flower twenty-five years of oceanography aboard a merchant vessel. Oceanography, 32(3), (2019): 126-137, doi:10.5670/oceanog.2019.319.Since late fall 1992, CMV Oleander III has been measuring upper ocean currents during its weekly trips between Bermuda and Port Elizabeth, New Jersey, by means of an acoustic Doppler current profiler installed in its hull. The overarching objective of this effort has been to monitor transport in the Gulf Stream and surrounding waters. With 25 years of observation in hand, we note that the Gulf Stream exhibits significant year-to-year variations but no evident long-term trend in transport. We show how these data have enabled studies of oceanic variability over a very wide range of scales, from a few kilometers to the full 1,000 km length of its route. We report that the large interannual variations in temperature on the continental shelf are negatively correlated with flow from the Labrador Sea, but that variability in the strength of this flow cannot account for a longer-term warming trend observed on the shelf. Acoustic backscatter data offer a rich trove of information on biomass activities over a wide range of spatial and temporal scales. A peek at the future illustrates how the new and newly equipped Oleander will be able to profile currents to greater depths and thereby contribute to monitoring the strength of the meridional overturning circulation.First and foremost we extend our heartfelt thanks to the Bermuda Container Line/Neptune Group Management Ltd for permission to operate an acoustic Doppler current profiler on board CMV Oleander III, a 150 kHz ADCP between 1992 and 2004, and a 75 kHz ADCP between 2005 and 2018. Their interest and support is gratefully acknowledged. Cor Teeuwen, our initial contact in Holland while the ship was still under construction, played an important role in facilitating the original ADCP installation. His evident interest to make this concept work has stimulated similar activities on other commercial vessels. The interest and willingness of the shipping industry to be supportive of science has been a very positive experience for all of us who have ventured in this direction. Initial funding came from NOAA and the Office of Naval Research. Since 1999, the National Science Foundation has supported the project through funding to the University of Rhode Island and Stony Brook University, and now also to the Bermuda Institute of Ocean Sciences (BIOS), which will be taking over the Oleander operation. NSF is also funding the current transition to the new CMV Oleander. In the early years, G. Schwartze and E. Gottlieb were very helpful with technical support for the project. This included frequent visits to the ship before we had the capability to transfer the data through the Ethernet. We thank Jules Hummon and Eric Firing for adapting the UNOLS-wide UHDAS ADCP operating system to the merchant marine environment. We thank E. Williams and P. Ortner at the Rosenstiel School of Marine and Atmospheric Science, University of Miami, for making the 38 kHz ADCP data from Explorer of the Seas available to us. We also want to thank the NOAA Ship Of Opportunity Program for continued interest in and support of XBT operations along the Oleander section. That support started over 40 years ago and is now stronger than ever. All ADCP data from 1992 through 2018 have been archived at the Joint Archive for Shipboard ADCP (JASADCP), established at the University of Hawaii by NOAA’s National Centers for Environmental Information (NCEI). Averaged yearly data sets can be downloaded in ASCII text or NetCDF formats (http://ilikai.soest.hawaii.edu/​sadcp/main_inv.html). We thank Patrick Caldwell, JASADCP’s manager, for his assistance. All ADCP and XBT data can be obtained at the Stony Brook website: http://po.msrc.sunysb.edu/Oleander/. The URL to the project website is http://oleander.bios.edu—an updated data portal and products will soon be accessible here. An ERDDAP server for Oleander data (in the process of being configured) is at this address: http://erddap.​oleander.​bios.edu:​8080/​erddap/. The following link to BIOS lists over 40 publications that have used the ADCP data one way or another: http://oleander.bios.edu/publications/. We thank the two reviewers for their many interesting and helpful comments and suggestions

Protecting the UK Infrastructure: A System to Detect GNSS Jamming and Interference

Abstract The vulnerability of space based position navigation and timing (PNT) systems to RF interference sources is becoming well known outside of the traditional PNT sector for example, into the critical infrastructure operations area. Risk managers of organisations in this area are becoming aware of the vulnerabilities and dependencies in using space based PNT systems. This paper presents work performed and work on-going in the UK, to develop capabilities that provide detection and early warning for operators of critical infrastructure and law enforcement agencies (LEA), to the presence of RF interference in the bands associated with space based PNT. These capabilities can detect and will be able to locate source(s) of RF interference which allows infrastructure operators and LEA to take advantage of quality of service and trust concepts when applied to these space based PNT systems. This paper also presents a case study of the detection of an intentional RF interference device, which impacted upon one organisation's critical infrastructure

The Structure and Evolution of Magnetized Cloud Cores in a Zero--Density Background

Molecular-line observations of star-forming cloud cores indicate that they are not the flattened structures traditionally considered by theory. Rather, they are elongated, perhaps in the direction of their internal magnetic field. We are thus motivated to consider the structure and evolution of axisymmetric, magnetized clouds that start from a variety of initial states, both flattened (oblate) and elongated (prolate). We devise a new technique, dubbed the $q$-method, that allows us to construct magnetostatic equilibria of any specified shape. We find, in agreement with previous authors, that the field lines in oblate clouds bend inward. However, those in prolate clouds bow outward, confining the structures through magnetic tension. We next follow the quasi-static evolution of these clouds via ambipolar diffusion, under the assumption of constant core mass. An oblate cloud either relaxes to a magnetically force-free sphere or, if sufficiently massive, flattens along its polar axis as its central density runs away. A prolate cloud always relaxes to a sphere of modest central density. We finally consider the evolution of an initially spherical cloud subject to the tidal gravity of neighboring bodies. Although the structure constricts equatorially, it also shortens along the pole, so that it ultimately flattens on the way to collapse. In summary, none of our initial states can evolve to the point of collapse while maintaining an elongated shape. We speculate that this situation will change once we allow the cloud to gain mass from its environment.Comment: 19 pages, plus 20 postscript figures. Accepted by Ap

Measurement of the quasi-elastic axial vector mass in neutrino-oxygen interactions

The weak nucleon axial-vector form factor for quasi-elastic interactions is determined using neutrino interaction data from the K2K Scintillating Fiber detector in the neutrino beam at KEK. More than 12,000 events are analyzed, of which half are charged-current quasi-elastic interactions nu-mu n to mu- p occurring primarily in oxygen nuclei. We use a relativistic Fermi gas model for oxygen and assume the form factor is approximately a dipole with one parameter, the axial vector mass M_A, and fit to the shape of the distribution of the square of the momentum transfer from the nucleon to the nucleus. Our best fit result for M_A = 1.20 \pm 0.12 GeV. Furthermore, this analysis includes updated vector form factors from recent electron scattering experiments and a discussion of the effects of the nucleon momentum on the shape of the fitted distributions.Comment: 14 pages, 10 figures, 6 table

Search for the W-exchange decays B0 --> Ds(*)- Ds(*)+

We report a search for the decays $B^{0} \to D_{s}^{-} D_{s}^{+}$, $B^{0} \to D_{s}^{*-} D_{s}^{+}$, $B^{0} \to D_{s}^{*-} D_{s}^{*+}$ in a sample of 232 million $\Upsilon(4S)$ decays to \BBb ~pairs collected with the \babar detector at the PEP-II asymmetric-energy $e^+ e^-$ storage ring. We find no significant signal and set upper bounds for the branching fractions: ${\cal B}(B^{0} \to D_{s}^{-} D_{s}^{+}) < 1.0 \times 10^{-4}, {\cal B}(B^{0} \to D_{s}^{*-} D_{s}^{+}) < 1.3 \times 10^{-4}$ and ${\cal B}(B^{0} \to D_{s}^{*-} D_{s}^{*+}) < 2.4 \times 10^{-4}$ at 90% confidence level.Comment: 8 pages, 2 figures, submitted to PRD-R

Evidence for the η_b(1S) Meson in Radiative Υ(2S) Decay

We have performed a search for the η_b(1S) meson in the radiative decay of the Υ(2S) resonance using a sample of 91.6 × 10^6 Υ(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at E_γ = 609.3^(+4.6)_(-4.5)(stat)±1.9(syst) MeV, corresponding to an η_b(1S) mass of 9394.2^(+4.8)_(-4.9)(stat) ± 2.0(syst) MeV/c^2. The branching fraction for the decay Υ(2S) → γη_b(1S) is determined to be [3.9 ± 1.1(stat)^(+1.1)_(-0.9)(syst)] × 10^(-4). We find the ratio of branching fractions B[Υ(2S) → γη_b(1S)]/B[Υ(3S) → γη_b(1S)]= 0.82 ± 0.24(stat)^(+0.20)_(-0.19)(syst)

Search for rare quark-annihilation decays, B --> Ds(*) Phi

We report on searches for B- --> Ds- Phi and B- --> Ds*- Phi. In the context of the Standard Model, these decays are expected to be highly suppressed since they proceed through annihilation of the b and u-bar quarks in the B- meson. Our results are based on 234 million Upsilon(4S) --> B Bbar decays collected with the BABAR detector at SLAC. We find no evidence for these decays, and we set Bayesian 90% confidence level upper limits on the branching fractions BF(B- --> Ds- Phi) Ds*- Phi)<1.2x10^(-5). These results are consistent with Standard Model expectations.Comment: 8 pages, 3 postscript figues, submitted to Phys. Rev. D (Rapid Communications

Middle-late Pleistocene deep water circulation in the southwest subtropical Pacific

International audienceThe modern δ13CDIC distribution in southwest subtropical Pacific deep waters is consistent with a regional mixing regime between water masses of open Pacific Ocean and Tasman Sea origin. This mixing regime is reconstructed across the middle-late Pleistocene using a record of benthic foraminiferal δ13C in a sediment core from the New Caledonia Trough. The relative influence on the mixing regime from open Pacific Ocean deep waters is seen to be significantly reduced during glacial in comparison to interglacial stages over the past 1.1 Ma. The spatial δ13C gradient in the Southern Ocean between deep waters entering the Tasman Sea and the open Pacific Ocean is shown to be consequently greater during glacial than interglacial stages but was generally reduced across the period of the Middle Pleistocene Transition. The existence of strong spatial chemical gradients in the glacial Southern Ocean limits its capacity to act as an enhanced sink for atmospheric carbon

Mice Deficient in GEM GTPase Show Abnormal Glucose Homeostasis Due to Defects in Beta-Cell Calcium Handling

Glucose-stimulated insulin secretion from beta-cells is a tightly regulated process that requires calcium flux to trigger exocytosis of insulin-containing vesicles. Regulation of calcium handling in beta-cells remains incompletely understood. Gem, a member of the RGK (Rad/Gem/Kir) family regulates calcium channel handling in other cell types, and Gem over-expression inhibits insulin release in insulin-secreting Min6 cells. The aim of this study was to explore the role of Gem in insulin secretion. We hypothesised that Gem may regulate insulin secretion and thus affect glucose tolerance in vivo