Adapting to Sea Level Rise: Insights from a New Evaluation Framework of Physical Design Projects

Designers and engineers are developing proposals for physical projects to adapt coastal sites to future sea level rise related threats. This puts pressure on local and regional decision makers to develop strategic frameworks for prioritizing, permitting and funding such projects. However, no systematic evaluation tools exist for the full range of these innovative designs. We build on the literature to develop an evaluation framework that synthesizes two different approaches to categorize these proposals and provide insight for coastal managers and decision makers. We apply this framework to physical projects that address sea level rise in their design around the San Francisco Bay Area, a leading region in sea level rise adaptation. We find that these projects demonstrate a shift toward more habitat-focused strategies, which likely marks the beginning of a larger transformation of the coastal zone. According to our five-part evaluation tool, we also find that the projects’ scores have improved over time, indicating that state agency work may be helping communities implement more flexible adaptation initiatives. Despite these positive signs, we also find that none of the projects achieved high marks in all five of the evaluation criteria. This finding indicates that there is a critical need for improvement in physical planning for adaptation to higher sea levels and associated impacts. Most importantly, we find that an evaluation framework such as the one used here can provide critical insights into the likely risks and benefits of proposed adaptation projects and their long-term implications for coastal zones

Diurnal variation of the potassium layer in the upper atmosphere

Measurements of the diurnal cycle of potassium (K) atoms between 80 and 110km have been made during October (for the years 2004–2011) using a Doppler lidar at Kühlungsborn, Germany (54.1°N,11.7°E). A pronounced diurnal variation is observed in the K number density, which is explored by using a detailed description of the neutral and ionized chemistry of K in a three-dimensional chemistry climate model. The model captures both the amplitude and phase of the diurnal and semidiurnal variability of the layer, although the peak diurnal amplitude around 90 kmis overestimated. Themodel shows that the total potassium density (≈K+K++KHCO3) exhibits little diurnal variation at each altitude, and the diurnal variations are largely driven by photochemical conversion between these reservoir species. In contrast, tidally driven vertical transport has a small effect at this midlatitude location, and diurnal fluctuations in temperature are of little significance because they are small and the chemistry of K is relatively temperature independent

Search for radions at LEP2

No abstract is available for this item

The Endothelium: The Vascular Information Exchange

Maintenance of adequate blood flow to tissues and organs requires that endothelial cells dynamically respond in a stimulus-specific manner to elicit appropriate changes in smooth muscle contractility and thus, arterial diameter. Endothelial cells can be stimulated directly by increases in blood flow and by humoral factors acting on surface receptors, as well as through flux of second messengers from smooth muscle cells activated by release of neurotransmitters from perivascular nerves. The ability of endothelial cells to generate stimulus-specific responses to these diverse inputs is facilitated by organization of ion channels and signaling proteins into microdomains that permit finely-tuned, spatially-restricted Ca2+ events to differentially activate key effectors such as nitric oxide (NO) synthase and Ca2+-activated K+ (KCa) channels. NO is a diffusible mediator which acts locally to cause vasodilation. Opening of KCa channels causes hyperpolarization of the endothelial membrane potential which spreads to surrounding smooth muscle cells to also cause local vasodilation. However, once initiated, hyperpolarization also spreads longitudinally through the endothelium to effect coordinated changes in blood flow within multiple arterial segments. Thus, the signaling pathways activated by a particular stimulus determine whether it’s effects on arterial diameter are localized or can impact blood flow at the level of the vascular bed

First global observations of the mesospheric potassium layer

Metal species, produced by meteoric ablation, act as useful tracers of upper atmosphere dynamics and chemistry. Of these meteoric metals, K is an enigma: at extratropical latitudes, limited available lidar data show that the K layer displays a semiannual seasonal variability, rather than the annual pattern seen in other metals such as Na and Fe. Here we present the first near-global K retrieval, where K atom number density profiles are derived from dayglow measurements made by the Optical Spectrograph and Infrared Imager System spectrometer on board the Odin satellite. This robust retrieval produces density profiles with typical layer peak errors of ±15% and a 2 km vertical grid resolution. We demonstrate that these retrieved profiles compare well with available lidar data and show for the first time that the unusual semiannual behavior is near-global in extent. This new data set has wider applications for improving understanding of the K chemistry and of related upper atmosphere processes

Kinetics of isothermal and non-isothermal precipitation in an Al-6at%Si alloy

A novel theory which describes the progress of a thermally activated reaction under isothermal and linear heating conditions is presented. It incorporates nucleation, growth and impingement and takes account of temperaturedependent solubility. The model generally fits very well to isothermal calorimetry and differential scanning calorimetry data on precipitation in an Al-6 at.% Si alloy. Analysis of the data shows that two processes occur in this precipitation reaction: growth of large Si particles and growth of pre-existing small nuclei. Determination of the sizes of Si precipitates by transmission electron microscopy indicates that interfacial energy contributions are small and have a negligible influence on solubilit

Crushing singularities in spacetimes with spherical, plane and hyperbolic symmetry

It is shown that the initial singularities in spatially compact spacetimes with spherical, plane or hyperbolic symmetry admitting a compact constant mean curvature hypersurface are crushing singularities when the matter content of spacetime is described by the Vlasov equation (collisionless matter) or the wave equation (massless scalar field). In the spherically symmetric case it is further shown that if the spacetime admits a maximal slice then there are crushing singularities both in the past and in the future. The essential properties of the matter models chosen are that their energy-momentum tensors satisfy certain inequalities and that they do not develop singularities in a given regular background spacetime.Comment: 19 page

Low temperature studies of the removal reactions of¹CH<inf>2</inf>with particular relevance to the atmosphere of Titan

Methylene, CH 2 , is one of the major photolysis products of methane by Lyman-α radiation and is involved in the photochemistry of the atmospheres of Titan and the giant planets. The kinetics of the reactions of the first excited state of methylene, 1 CH 2 , with He, N 2 , O 2 , H 2 and CH 4 have been measured over the temperature range 43–160 K by pulsed laser photolysis, monitoring 1 CH 2 removal by laser induced fluorescence. Low temperatures were obtained with either a pulsed Laval expansion (43–134 K) or a, slow flow reaction cell (160 K). The rate coefficients for the reactions with N 2 , O 2 , H 2 and CH 4 all showed a strong negative temperature dependence. In combination with other literature data, the rate coefficients can be parameterised as: k He (43 < T/K < 800) = (1.90 ± 0.23) × 10 −12 × (T/298) 1.74±0.16 × exp ((88±23)/ T ) k N 2 (43 < T/K < 800) = (2.29 ± 1.12) × 10 −12 × (T/298) −2.15±1.38 × exp ((-74±96)/ T ) + (3.91 ± 0.78) × 10 −11 × exp ((-469±114)/ T ) k O 2 (43 < T/K < 300) = (6.16 ± 1.09) × 10 −11 × (T/298) −0.65±0.14 k H 2 (43 < T/K < 800) = (1.10 ± 0.04) × 10 −10 × (T/298) −0.40±0.06 × exp ((11.1±6.9)/ T ) k CH 4 (43 < T/K < 475) = (8.20 ± 0.46) × 10 −11 × (T/298) −0.93±0.10 × exp ((-20.5±12.8)/ T ) For the reactions of 1 CH 2 with H 2 and CH 4 , the branching ratio for quenching to ground state, 3 CH 2 , vs chemical reaction was also determined at 160 and 73 K. The values measured (H 2 : 0.39 ± 0.10 at 160 K, 0.78 ± 0.15 at 73 K; CH 4 : 0.49 ± 0.09 at 160 K, 0.64 ± 0.19 at 73 K) confirm trends of an increased proportion of reactive loss with increasing temperature determined at higher temperatures. The impacts of the new measurements for Titan's atmosphere have been ascertained using a 1D chemistry and transport model. A significant decrease (∼40%) in the mixing ratio of ethane between 800 and 1550 km is calculated due to the decrease contribution of methyl production from the reaction of 1 CH 2 with CH 4 , with smaller increases in the concentrations of ethene and acetylene. Ethene production is enhanced by more methylene being converted to methylidene, CH, and the subsequent reaction of CH with CH 4 to generate ethene. Photolysis of ethene is the major route to acetylene formation

The intensification of metallic layered phenomena above thunderstorms through the modulation of atmospheric tides

We present a multi-instrument experiment to study the effects of tropospheric thunderstorms on the mesopause region and the lower ionosphere. Sodium (Na) lidar and ionospheric observations by two digital ionospheric sounders are used to study the variation in the neutral metal atoms and metallic ions above thunderstorms. An enhanced ionospheric sporadic E layer with a downward tidal phase is observed followed by a subsequent intensification of neutral Na number density with an increase of 600 cm−3 in the mesosphere. In addition, the Na neutral chemistry and ion-molecule chemistry are considered in a Na chemistry model to simulate the dynamical and chemical coupling processes in the mesosphere and ionosphere above thunderstorms. The enhanced Na layer in the simulation obtained by using the ionospheric observation as input is in agreement with the Na lidar observation. We find that the intensification of metallic layered phenomena above thunderstorms is associated with the atmospheric tides, as a result of the troposphere-mesosphere-ionosphere coupling

Estimating the climate significance of halogen-driven ozone loss in the tropical marine troposphere

We have integrated observations of tropospheric ozone, very short-lived (VSL) halocarbons and reactive iodine and bromine species from a wide variety of tropical data sources with the global CAM-Chem chemistry-climate model and offline radiative transfer calculations to compute the contribution of halogen chemistry to ozone loss and associated radiative impact in the tropical marine troposphere. The inclusion of tropospheric halogen chemistry in CAM-Chem leads to an annually averaged depletion of around 10% (~2.5 Dobson units) of the tropical tropospheric ozone column, with largest effects in the middle to upper troposphere. This depletion contributes approximately −0.10 W m&lt;sup&gt;−2&lt;/sup&gt; to the radiative flux at the tropical tropopause. This negative flux is of similar magnitude to the ~0.33 W m&lt;sup&gt;−2&lt;/sup&gt; contribution of tropospheric ozone to present-day radiative balance as recently estimated from satellite observations. We find that the implementation of oceanic halogen sources and chemistry in climate models is an important component of the natural background ozone budget and we suggest that it needs to be considered when estimating both preindustrial ozone baseline levels and long term changes in tropospheric ozone