Impacts of Fire Emissions and Transport Pathways on the Interannual Variation of CO In the Tropical Upper Troposphere

This study investigates the impacts of fire emission, convection, various climate conditions and transport pathways on the interannual variation of carbon monoxide (CO) in the tropical upper troposphere (UT), by evaluating the field correlation between these fields using multi-satellite observations and principle component analysis, and the transport pathway auto-identification method developed in our previous study. The rotated empirical orthogonal function (REOF) and singular value decomposition (SVD) methods are used to identify the dominant modes of CO interannual variation in the tropical UT and to study the coupled relationship between UT CO and its governing factors. Both REOF and SVD results confirm that Indonesia is the most significant land region that affects the interannual variation of CO in the tropical UT, and El Nino-Southern Oscillation (ENSO) is the dominant climate condition that affects the relationships between surface CO emission, convection and UT CO. In addition, our results also show that the impact of El Nino on the anomalous CO pattern in the tropical UT varies strongly, primarily due to different anomalous emission and convection patterns associated with different El Nino events. In contrast, the anomalous CO pattern in the tropical UT during La Nina period appears to be less variable among different events. Transport pathway analysis suggests that the average CO transported by the "local convection" pathway (Delta COlocal) accounts for the differences of UT CO between different ENSO phases over the tropical continents during biomass burning season. Delta COlocal is generally higher over Indonesia-Australia and lower over South America during El Nino years than during La Nina years. The other pathway ("advection within the lower troposphere followed by convective vertical transport") occurs more frequently over the west-central Pacific during El Nino years than during La Nina years, which may account for the UT CO differences over this region between different ENSO phases.NASA Aura Science Team (AST) program NNX09AD85GJackson School of Geosciences at the University of Texas at AustinJet Propulsion Laboratory, California Institute of Technology, under NASAGeological Science

Subtropical middle atmosphere dynamics observed by the Chung Li radar

The Chung Li Radar (24.91 N; 121.24 E) has been operating since 1986. A five beam observational configuration was used on a regular basis to study the various dynamics processes in the atmosphere-lower stratosphere height region. Due to its geographical location, the annual Typhoon and Mei-Yu seasons provide good opportunities to study the various interesting dynamic processes such as instabilities, generation of gravity waves, wave mean field interaction, etc. Three dimensional air motions due to these fronts are presented. Special cases of gravity wave generation, propagation and their effects on the turbulent layers are discussed

Potential distribution surrounding a photo- emitting plate in a dilute plasma

Potential distribution in photo-emitting plate in dilute plasma

Beyond relativistic mean-field studies of low-lying states in neutron-deficient krypton isotopes

Neutron-deficient krypton isotopes are of particular interest due to the coexistence of oblate and prolate shapes in low-lying states and the transition of ground-state from one dominate shape to another as a function of neutron number. A detailed interpretation of these phenomena in neutron-deficient Kr isotopes requires the use of a method going beyond a mean-field approach that permits to determine spectra and transition probabilities. The aim of this work is to provide a systematic calculation of low-lying state in the even-even 68-86Kr isotopes and to understand the shape coexistence phenomenon and the onset of large collectivity around N=40 from beyond relativistic mean-field studies. The starting point of our method is a set of relativistic mean-field+BCS wave functions generated with a constraint on triaxial deformations (beta, gamma). The excitation energies and electric multipole transition strengths of low-lying states are calculated by solving a five-dimensional collective Hamiltonian (5DCH) with parameters determined by the mean-field wave functions. To examine the role of triaxiality, a configuration mixing of both particle number (PN) and angular momentum (AM) projected axially deformed states is also carried out within the exact generator coordinate method (GCM) based on the same energy density functional. The energy surfaces, the excitation energies of 0^+_2, 2^+_1, 2^+_2 states, as well as the E0 and E2 transition strengths are compared with the results of similar 5DCH calculations but with parameters determined by the non-relativistic mean-field wave functions, as well as with the available data...Comment: 23 pages, 10 figure

Resolving Land Disputes in East Asia: Exploring the Limits of Law

Land disputes are increasing in East Asia as economic and demographic growth intensifies the demand for farmland and urban spaces. Nowhere is this more evident than in China and Vietnam. Reforms that brought Socialist Asia into the globalized economy and returned private property have also sparked intense competition between farmers and residents with outsiders, such as private developers and government agencies. From a legal perspective, the proliferation of land disputes is puzzling, because it is occurring at the same time as governments in China and Vietnam are clarifying property rights and improving formal dispute resolution institutions, such as the courts. Rather than promoting uniformity, order, and predictability, this paper shows that law reforms have produced mixed results. Land claims and property rights often conflict, producing unpredictable and multi-layered dispute resolution processes. Highly ambiguous and contested patterns of land access persist in these countries. Consequently, courts and administrative agencies such as grand mediation struggle to use property rights to find lasting solutions to land disputes. This paper draws on a body of empirical studies to explore why state laws and institutions struggle to gain the upper hand in many land cases.preprin

Persistent Skyrmion Lattice of Noninteracting Electrons with Spin-Orbit Coupling

A persistent spin helix (PSH) is a robust helical spin-density pattern arising in disordered 2D electron gases with Rashba $\alpha$ and Dresselhaus $\beta$ spin-orbit (SO) tuned couplings, i.e., $\alpha=\pm\beta$. Here we investigate the emergence of a Persistent Skyrmion Lattice (PSL) resulting from the coherent superposition of PSHs along orthogonal directions -- crossed PSHs -- in wells with two occupied subbands $\nu=1,2$. For realistic GaAs wells we show that the Rashba $\alpha_\nu$ and Dresselhaus $\beta_\nu$ couplings can be simultaneously tuned to equal strengths but opposite signs, e.g., $\alpha_1= \beta_1$ and $\alpha_2=-\beta_2$. In this regime and away from band anticrossings, our {\it non-interacting} electron gas sustains a topologically non-trivial skyrmion-lattice spin-density excitation, which inherits the robustness against spin-independent disorder and interactions from its underlying crossed PSHs. We find that the spin relaxation rate due to the interband SO coupling is comparable to that of the cubic Dresselhaus term as a mechanism of the PSL decay. Near anticrossings, the interband-induced spin mixing leads to unusual spin textures along the energy contours beyond those of the Rahsba-Dresselhaus bands. Our PSL opens up the unique possibility of observing topological phenomena, e.g., topological and skyrmion Hall effects, in ordinary GaAs wells with non-interacting electrons.Comment: 5 pages, 2 figures; changed the presentation and added supplemental material (17 pages, 1 figure

The first operation and results of the Chung-Li VHF radar

The Chung-Li Very High Frequency (VHF) radar is used in the dual-mode operations, applying Doppler beam-swinging as well as the spaced-antenna-drift method. The design of the VHF radar is examined. Results of performance tests are discussed

Global modeling of secondary organic aerosol formation from aromatic hydrocarbons: high- vs low-yield pathways

Formation of SOA from the aromatic species toluene, xylene, and, for the first time, benzene, is added to a global chemical transport model. A simple mechanism is presented that accounts for competition between low and high-yield pathways of SOA formation, wherein secondary gas-phase products react further with either nitrogen oxide (NO) or hydroperoxy radical (HO2) to yield semi- or non-volatile products, respectively. Aromatic species yield more SOA when they react with OH in regions where the [NO]/[HO2] ratios are lower. The SOA yield thus depends upon the distribution of aromatic emissions, with biomass burning emissions being in areas with lower [NO]/[HO2] ratios, and the reactivity of the aromatic with respect to OH, as a lower initial reactivity allows transport away from industrial source regions, where [NO]/[HO2] ratios are higher, to more remote regions, where this ratio is lower and, hence, the ultimate yield of SOA is higher. As a result, benzene is estimated to be the most important aromatic species with regards to formation of SOA, with a total production nearly equal that of toluene and xylene combined. In total, while only 39% percent of the aromatic species react via the low-NOx pathway, 72% of the aromatic SOA is formed via this mechanism. Predicted SOA concentrations from aromatics in the Eastern United States and Eastern Europe are actually largest during the summer, when the [NO]/[HO2] ratio is lower. Global production of SOA from aromatic sources is estimated at 3.5 Tg/yr, resulting in a global burden of 0.08 Tg, twice as large as previous estimates. The contribution of these largely anthropogenic sources to global SOA is still small relative to biogenic sources, which are estimated to comprise 90% of the global SOA burden, about half of which comes from isoprene. Compared to recent observations, it would appear there are additional pathways beyond those accounted for here for production of anthropogenic SOA. However, owing to differences in spatial distributions of sources and seasons of peak production, there are still regions in which aromatic SOA produced via the mechanisms identified here are predicted to contribute substantially to, and even dominate, the local SOA concentrations, such as outflow regions from North America and South East Asia during the wintertime, though total SOA concentrations there are small (~0.1 μg/m^³)

Evidence from the Very Long Baseline Array that J1502SE/SW are Double Hotspots, not a Supermassive Binary Black Hole

SDSS J150243.09+111557.3 is a merging system at z = 0.39 that hosts two confirmed AGN, one unobscured and one dust-obscured, offset by several kiloparsecs. Deane et al. recently reported evidence from the European VLBI Network (EVN) that the dust-obscured AGN exhibits two flat-spectrum radio sources, J1502SE/SW, offset by 26 mas (140 pc), with each source being energized by its own supermassive black hole (BH). This intriguing interpretation of a close binary BH was reached after ruling out a double-hotspot scenario, wherein both hotspots are energized by a single, central BH, a configuration occuring in the well-studied Compact Symmetric Objects. When observed with sufficient sensitivity and resolution, an object with double hotspots should have an edge-brightened structure. We report evidence from the Very Long Baseline Array (VLBA) for just such a structure in an image of the obscured AGN with higher sensitivity and resolution than the EVN images. We thus conclude that a double-hotspot scenario should be reconsidered as a viable interpretation for J1502SE/SW, and suggest further VLBA tests of that scenario. A double-hotspot scenario could have broad implications for feedback in obscured AGNs. We also report a VLBA detection of high-brightness-temperature emssion from the unobscured AGN that is offset several kiloparsecs from J1502SE/SW.Comment: 12 pages, 1 figure, accepted by ApJL on 2014 July 2