bluuebunny/crossref_metadata_2025 huggingface dataset:
Generative design defended Gender differences discussed
Authors: Shea Kristina
Published: September 2003

Generative design techniques (‘Digital canopy: high-end computation/low-tech
construction’ arq 6/3, pp230–245) tend to intrigue and slightly
scare (arq 6/4, pp293–294 – letter from Sam Price) at the same
time. It is reassuring to know that computers will only be as smart as we can program them.
We can even control if they learn and how they learn. Design capabilities using generative
methods agreeably are a product of both how smart we make the generative algorithms and how
intelligently designers can make use of them. A human designer alone probably would not have
come up with the canopy design built and a computer alone could not have.
Geoffrey Bawa: The Complete Works
Authors: Murphy Richard
Published: September 2003

Geoffrey Bawa died in May, so it is fitting as well as poignant that Thames and Hudson
have published this new and lavish edition on his life's work, written by the
indefatigable David Robson. It will undoubtedly prove to be the definitive publication.
Interest in Bawa's work is clearly very high; the previous monograph by Brian Brace Taylor
published in 1986, was revised and republished in 1995 by the same publisher.
Robson's new work is more comprehensive and includes the very latest projects.
It also sets the scene both in terms of Bawa's unusual career and life story and of the awesome legacy of his home, the fascinating island of Sri Lanka.
Generative design defended Gender differences discussed
Authors: Van Der Heijden Hans
Published: September 2003

In their article, ‘Casbah: a brief history of a design concept’, (arq 6/4, pp. 321–336) Robert Oxman and his co-authors state that the matchbox models are ‘unsigned’, (caption to Figure 3b). They are not. Elsewhere, they are always credited to Herman Hertzberger. for instance in Wim van Heuvel, Structuralism in Dutch Architecture, 010 Publishers, Rotterdam, 1992, p. 13 and also in monographs on Hertzberger.
Surface Architecture
Authors: Sharif Mohamed
Published: September 2003

Notwithstanding contributions such as those articulated in Kenneth Frampton's Studies in Tectonic Culture (MIT Press, 1995), few authors have furthered a clear discourse concerning the relationships between construction techniques and formal ideas in architecture subsequent to the late twentieth-century critiques of Western Modernity. Moreover, such writing as there has been has tended to draw from the supposedly redemptive, recuperative and largely Heideggerian tenor of concerns regarding the relationship of humankind to technology and its desired capacity for architecture to mitigate, if not completely resist, the assumed imminent threat of technology to life itself.
Generative design defended Gender differences discussed
Authors: EDITORS THE
Published: September 2003

Sarah Wigglesworth and Jane Wernick's article, ‘Clear Water Garden; A Study In Design Research and Collaboration’ (arq 6/2, pp214–229) contained (p216) the following passage:

‘There was a very productive equality in our working relationship.
Partly because the power structure between different genders and knowledges
was almost entirely absent.’
Modern Color/Modern Architecture
Authors: Hutton Louisa
Published: September 2003

William Braham writes that this book has been conceived as a genealogy of modern architectural colour, explaining that he uses the term ‘genealogy’ in the (Deleuzean) sense of it automatically bringing one to an understanding of the distance travelled since the particular origins under research. Such an analysis is useful to Braham who wants to bring to the practising architect an informed view of the use of colour in architecture by investigating the discussions that have surrounded it since the 1830s.
Generative design defended Gender differences discussed
Authors: Pride Liz
Published: September 2003

Sarah Wigglesworth and Jane Wernick's article explores how a close collaboration in design can become research when ideas are passed freely between the designers, leading to unexpected and original solutions.
Generative design defended Gender differences discussed
Authors: Saunt Deborah
Published: September 2003

Is the subject of ‘gender difference’ an appropriate subject for a research
journal? Perhaps it is only in the realm if architecture that this question could possibly
arise at all. Elsewhere, in the real world, we know gender difference is accorded the
seriousness and consequent academic research status it deserves as it is understood as
a fundamental component within our culture.
Generative design defended Gender differences discussed
Authors: Long M. J.
Published: September 2003

I don't necessarily think that gender comments are out of place
in a research publication, but it is slightly unsatisfactory to bump into
them in passing.
The gender impact of pension reform
Authors: JAMES ESTELLE , EDWARDS ALEJANDRA COX , WONG REBECA
Published: September 2003

Pension systems may have a different impact on the two genders because women are less likely than men to work in formal labor markets and earn lower wages when they do. Recent multi-pillar pension reforms tighten the link between payroll contributions and benefits, leading critics to argue that they will hurt women. In contrast, supporters of these reforms argue that women will be helped by the removal of distortions pillar and the better targeted redistributions in the new systems. This paper examines the differential impact of the new and old systems in three Latin American countries – Chile, Argentina and Mexico. Based on household survey data, we simulate the wage and employment histories of representative men and women, the pensions that these are likely to generate under the new and old rules, and the relative gains or losses of the two genders due to the reform. We find that women do indeed accumulate private annuities that are only 30–40% those of men in the new systems. However, this effect is mitigated by sharp targeting of the new public pillars toward low earners, many of whom are women, and by restrictions on payouts from the private pillars, particularly joint annuity requirements. As a result, low-earning married women are the biggest gainers from the pension reform.
Solvency requirements for pension annuities
Authors: OLIVIERI ANNAMARIA , PITACCO ERMANNO
Published: September 2003

This paper deals with solvency requirements for life annuities portfolios and funded pension plans. Particular emphasis is devoted to longevity risk, i.e. the risk arising from uncertainty in future mortality trends. This risk must be faced by insurance companies and pension plans that have guaranteed lifelong payoffs.

Solvency is investigated referring to immediate annuities, and hence the so-called decumulation phase is addressed. To assess solvency, assets are compared with the random present value of liabilities. Several requirements are considered, each leading to a required asset level that must be financed both with premiums (or contributions) and capital allocation.
A life-cycle analysis of defined benefit pension plans
Authors: McCARTHY DAVID
Published: September 2003

This paper employs a lifecycle model from the consumption–savings literature to examine the tradeoffs between defined benefit and defined contribution pension plans. We examine the effects of varying risk aversion, varying initial income and financial wealth, and varying wage processes (that may be correlated with returns on the risky asset).

Results indicate that wage-indexed claims are not an optimal vehicle for retirement policy if the decision to participate is made early in life, because individuals hold most of their wealth in their human capital and would not wish to increase their exposure to income shocks. Later in life, after most of a worker's human capital has been converted to financial assets, defined benefit pension plans help increase diversification by reducing exposure to financial market risk. The access that defined benefit plans provide to annuities markets and possible guaranteed rates of return over the risk-free rate increase the value of defined benefit plans to workers. The model also predicts that wage-indexed claims will be more valuable when equity markets provide low expected returns or are highly variable and when annuity markets are inefficient.

The model illustrates two economic functions performed by defined benefit plans. Firstly, DB plans pool individual wage risks. This allows older workers to buy a wage-linked security that increases their exposure to wage risks. Secondly, they create a group annuities market that reduces the cost of adverse selection.
Overview of the Issue
Authors: BROWN JEFFREY , HABERMAN STEVEN , MILEVSKY MOSHE , ORSZAG MIKE
Published: September 2003

This issue features three original research articles and an issues & policy article. The first article in the issue is by David McCarthy (Oxford University, UK). A Life Cycle Analysis of Defined Benefit Plans examines optimal benefit design within the context of a lifecycle model. The model finds that the structure of defined benefit plans is unlikely to be optimal for younger workers. The intuition is straightforward: defined benefit pensions depend heavily on the evolution of a worker's human capital and young workers are already heavily exposed to human capital risks. Older workers however may find wage indexed claims to be more valuable as most other human capital uncertainty has vanished.
A risk management approach to the pricing of a single equity-linked contract
Authors: JACQUES MICHEL
Published: September 2003

For a single equity-linked contract (hence with no mortality diversification), we examine the implications of using option pricing theory to fix the premium. We consider investment strategies involving the underlying, bonds and European puts and compute different probabilities of real loss at any time during the contract term, a form of VaR calculation. With the objective of chosing a strategy to minimize loss probabilities, we exhibit a variety of situations depending on the guarantee, the volatility and the age of the insured.
Sublinear scaling of fracture aperture versus length: An exception or the rule?
Authors: Olson Jon E.
Published: September 2003

Observations of natural fracture dimensions have sparked a continuing debate as to the nature of the fundamental relationship between fracture aperture (maximum opening) and length. On the basis of theoretical fracture mechanics, some have argued aperture‐to‐length scaling should be linear. This relationship implies that all fractures in a given population have the same driving stress regardless of fracture length, arguably a state that is difficult to reconcile with fracture propagation criteria. Also, some field observations indicate sublinear aperture‐to‐length scaling that is apparently inconsistent with the linear elastic fracture mechanics theory. In this work, a nonlinear aperture‐to‐length relationship is derived, still based on linear elastic fracture mechanics in a homogeneous body, but incorporating subcritical and critical (equilibrium law) fracture propagation criteria. The new hypothesis postulates that fractures of different lengths preserved in a body of rock are all in the same condition with respect to propagation (i.e., they all have the same stress intensity factor). This requires that fractures have driving stresses that vary inversely with the square root of fracture length, producing fracture apertures that scale with length to the 1/2 power. Under these conditions, fracture aspect ratio (aperture/length) decreases with increasing fracture length to the negative 1/2 power. Linear aperture‐to‐length scaling is still considered a possibility but is attributed to a relaxed, postpropagation mechanical state. Deviations in fracture aperture‐to‐length relationships from these idealized models can result from mechanical fracture interaction, fracture segmentation into en echelon arrays, and three dimensional effects in stratabound fractures.
Prediction of surface currents and drifter trajectories on the inner Scotian Shelf
Authors: Thompson Keith R. , Sheng Jinyu , Smith Peter C. , Cong Liangzi
Published: September 2003

The predictive skill of a simple model of surface flow on the Scotian Shelf is assessed using oceanographic data collected in February 1996. The model is forced by wind stress, water density, and sea level along the open boundaries of the model domain. The skill of the model with respect to subtidal variations of alongshore current and bottom pressure is quantified by the ratio γ2 = Var(O − P)/Var(O), where Var(O − P) and Var(O) are the variance of the prediction errors and observations, respectively. Skill is highest for bottom pressure (γ2 = 0.2) followed, in order, by cross‐shelf gradients in bottom pressure (γ2 = 0.5), horizontally averaged currents (0.4 < γ2 < 0.7), and currents at individual current meters (0.6 < γ2 < 1.4). The skill of the model with respect to drifter position is quantified by the search radius, centered on the predicted drifter position, that ensures a 50% chance of locating the drifter. Skill varies significantly with time but is generally highest when the drifter motion is strongest. We conclude with a comparison of the performance of the model against predictions based on the release point of the drifters and the operational scheme presently used to guide marine search and rescue in this region.
Biological signature of Scotian Shelf Water crossovers on Georges Bank during spring 1997
Authors: Wishner Karen F. , Gifford Dian J. , Sullivan Barbara K. , Bisagni James J. , Outram Dawn M. , Van Keuren Donna E.
Published: September 2003

Episodic crossovers of cold low salinity Scotian Shelf Water (SSW) onto the Northeast Peak of Georges Bank are a potentially important mechanism transporting plankton species, including the copepod Calanus finmarchicus and its prey and predators, onto the Bank each spring. We provide the first detailed investigation of horizontal and vertical zooplankton distributions in SSW crossovers compared to other onbank locations from three GLOBEC cruises during spring 1997. SSW crossovers are physically and biologically distinct from other Bank locations. In late spring, chlorophyll concentrations and in vivo fluorescence are elevated and light transmission is reduced in SSW, while during early spring, these parameters are more variable. SSW communities do not contain a unique zooplankton assemblage or indicator species but instead show differences in abundance and life history parameters for various taxa compared to other Bank locations. SSW has high abundances of young C. finmarchicus life history stages, almost no diel vertical migration of zooplankton, low abundances of invertebrate predators, and low fish egg abundance. Population development of C. finmarchicus in SSW lags that in adjacent water. The potential biological impact of SSW crossovers on Georges Bank varies seasonally. In April, density inversions and interleaving of SSW and non‐SSW suggest active mixing, resulting in similar community composition of SSW and adjacent non‐SSW. SSW crossovers are probably an important source to Georges Bank of young stages of C. finmarchicus in early spring. In May, after stratification strengthens, the greater differentiation between SSW plankton and elsewhere indicates that mixing between communities is more limited.
ULF wave identification in the magnetosheath: The k‐filtering technique applied to Cluster II data
Authors: Sahraoui F. , Pinçon J. L. , Belmont G. , Rezeau L. , Cornilleau‐Wehrlin N. , Robert P. , Mellul L. , Bosqued J. M. , Balogh A. , Canu P. , Chanteur G.
Published: September 2003

The magnetic fluctuations in the magnetosheath are studied, thanks to Cluster II data. The k‐filtering technique is applied to explore ULF magnetic fluctuations using STAFF (Spatio‐Temporal Analysis of a Field Fluctuations) data. Based on multipoint measurements, the k‐filtering technique allows, for the first time, to estimate the Magnetic Field Energy Distribution (MFED) in both the angular frequency and wave vector space. We show how the localisation of the magnetic energy in the (ω, k) domain can be used to identify the linear modes that can propagate in the magnetosheath. A comparison between k‐filtering results and prediction of the linear theory is performed. For the frequencies examined the magnetic energy seems to be distributed over the low frequency modes: mirror, Alfvén, and slow modes. Estimation of Doppler shift shows that each frequency observed is the superposition of different frequencies in the plasma frame. This “mixture of modes” at a given observed frequency explains why the fluctuations are generally not observed to be polarized, as shown in previous studies. Some other implications on a weak turbulence approach of the magnetic fluctuations in the magnetosheath are discussed.
Formation of thin current sheets in the magnetotail: Effects of propagating boundary deformations
Authors: Birn Joachim , Schindler Karl , Hesse Michael
Published: September 2003

Observations and simulations have demonstrated the important role of thin current sheet formation in the course of substorms. Previously, using two‐dimensional magnetohydrostatic equilibrium theory together with magnetic flux, entropy, and topology conservation, we demonstrated that a finite boundary deformation of magnetotail equilibria can lead to a loss of equilibrium; that is, equilibrium configurations that satisfy the constraints cease to exist when the boundary deformation exceeds a critical value. When the critical threshold is approached, locally the current density becomes infinite; that is, a thin current sheet is formed. Using time‐dependent MHD simulations, we confirm the basic theoretical results. We further extend this work to study the effects of tailward propagating boundary perturbations, corresponding to the rise and subsequent reduction of a duskward electric field (rise and subsequent northward turning of southward IMF Bz). We demonstrate that these boundary conditions again can lead to thin current sheet formation and the possible loss of equilibrium (catastrophe) or onset of instability. Finite perturbations of magnitudes consistent with those observed can produce a strong local increase of the current density and a local reduction of the magnetic field component Bz in the center of the plasma sheet, so that kinetic instabilities and a dynamic evolution may be triggered. The current sheet formation is influenced not only by the magnitude and the duration of the applied electric field but also by the temporal profile: A sudden decrease of the driving electric field following a more gradual increase is more effective than a gradual decrease following a sudden increase. This may provide a clue for the apparent substorm triggering by sudden northward turning of the IMF.
Using radio‐induced aurora to measure the horizontal structure of ion layers in the lower thermosphere
Authors: Bernhardt P. A. , Gondarenko N. A. , Guzdar P. N. , Djuth F. T. , Tepley C. A. , Sulzer M. P. , Ossakow S. L. , Newman D. L.
Published: September 2003

Two‐dimensional images of sporadic E layers have been produced using a technique called radio‐induced aurora. This technique makes the ion layer regions glow when being stimulated by high‐power radio waves. Normally, the neutral regions near the ion layers do not radiate visible emissions. Experiments in January 1998 at Arecibo Observatory in Puerto Rico have shown that the ion layer regions at 120 km altitude can be made to glow at 557.7 nm and other wavelengths by illuminating them with radio waves at 3.175 MHz with effective radiated powers of 80 MW. The regions of the sporadic E layers that have electron densities greater than the critical density for reflection of the radio waves emit energetic electrons that collide with and excite atmospheric atomic oxygen and molecular nitrogen. Because the electron collisions increase at lower altitudes where the neutral densities are higher, major differences in excitation can occur between layers at 120 km altitude and at 100 km altitude. A charge‐coupled device imager located on the ground is used to capture images of the glowing E region structures. The camera exposure times were in the range of 15–45 s. The images obtained using this technique show a wide variety of structures in the sporadic E layers. Some layers cover the 15 × 30 km region illuminated by the radio wave beam. Other layers show strong modulation of the E region by instabilities driven by a shear in the neutral wind. Two‐dimensional computer simulations of the coupling between neutral wind turbulence and the ion layers replicate the structure shown in the images. The optical emissions are explained using one‐ and two‐dimensional simulations of radio propagation to produce localized regions of large electric fields. Electrons are accelerated out of these regions yielding the artificial aurora.
Negative ionospheric storms seen by the IMAGE FUV instrument
Authors: Zhang Y. , Paxton L. J. , Kil H. , Meng C.‐I. , Mende S. B. , Frey H. U. , Immel T. J.
Published: September 2003

Data from the IMAGE SI‐13 instrument are used to study depletions in the OI 135.6 nm dayglow intensity due to two magnetic storms observed on 8 June and 15 July 2000. Results show that the SI‐13 instrument is sensitive to changes in the 135.6 nm dayglow caused by depletion of the O/N2 column density ratio. It is found that depletion levels in the SI‐13 images are weaker than those in the true O/N2 values or electron density parameters, such as NmF2 (peak F2 electron density) due to the N2 LBH contribution in the SI‐13 intensities. A depletion of −20% (8 June 2000) and −50% (15 July 2000) in the SI‐13 intensities corresponds to −50% and −90% reductions in NmF2, respectively. AURIC simulations indicate that −67% is the maximum depletion level that can be seen in the SI‐13 intensities. The Millstone radar, digisonde and DMSP observations reveal that the electron density depletion extended from the low F‐layer altitudes up to 840 km. Owing to the prevailing thermospheric circulation pattern, the depletions cover a wide area (at least 1/8 Earth surface) over the Northern Hemisphere for both of the cases. A deep depletion was always seen first in the morning side and then at later local times. The atmosphere took about 12 hours (8 June case) and more than 24 hours (15 July case) to recover. The results from the SI‐13 images are in a good agreement with digisonde, radar, and DMSP observations. The depletion in the SI‐13 intensity can be explained by the Joule and particle heating in the high‐latitude regions. The heating has two effects: (1) The heated air is nitrogen‐rich/oxygen‐depleted and (2) a wind surge created by the heating in the night side moves the oxygen‐deplete air upward and transports it to lower latitudes together with the neutral wind. Corotation with the Earth brings the oxygen‐depleted air to the dayside.
Magmatic history of the northeastern Tibetan Plateau
Authors: Gehrels George E. , Yin An , Wang Xiao‐Feng
Published: September 2003

The northeastern margin of the Tibetan Plateau is underlain by the Qaidam and Qilian terranes, which consist primarily of mid‐Proterozoic through lower Paleozoic oceanic and arc‐type assemblages that have been accreted to the southern margin of the Tarim/Sino‐Korean craton. Most previous models suggest that these assemblages formed along a northeast dipping subduction system constructed along the margin of the Tarim/Sino‐Korean craton during early Paleozoic time. The main components are interpreted to have formed either as an archipelago of volcanic arcs and back arc basins, or as a broad expanse of accretionary complexes. Our geochronologic data support a model, suggested by Sobel and Arnaud [1999], in which the Qaidam and Qilian terranes are separated from the Tarim/Sino‐Korean craton by a mid‐Paleozoic suture that closed along a southwest dipping subduction zone. The basement to these terranes consists of oceanic assemblages that were amalgamated into a coherent crustal fragment prior to emplacement of ∼920–930 Ma granitoids. Early Paleozoic arc‐type magmatism occurred between ∼480 and ∼425 Ma, apparently sweeping southwestward across much of the Qilian and Qaidam terranes. Accretion‐related magmatism along the inboard margin of the Qilian terrane occurred between ∼423 Ma and ∼406 Ma. Following Silurian‐Devonian accretion, the region has experienced late Paleozoic and Mesozoic uplift and erosion and has been severely overprinted by Tertiary thrusting, uplift, and strike‐slip motion along the Altyn Tagh fault. Correlation of geologic features and magmatic histories between the Altun Shan and the Nan Shan suggests that the eastern Altyn Tagh fault has a total left‐lateral offset of ∼375 km.
In situ mineralogy and permeability logs from downhole measurements: Application to a case study in chlorite‐coated sandstones
Authors: Rabaute A. , Revil A. , Brosse E.
Published: September 2003

Well‐logging techniques provide continuous profiles of various in situ physical properties like the bulk density, the photoelectric effect, and the natural gamma radioactivity of geological formations. Our purpose is to use this information to determine a continuous profile of the mineralogy with depth. The well‐log derived mineralogy is then combined with a petrophysical model to infer continuous permeability and saturation profiles in chlorite‐bearing sandstone formations. Our mineralogical inversion algorithm combines a cluster analysis of the raw data and their inversion using the generalized nonlinear inverse method developed by Tarantola and Valette [1982]. A field case is treated concerning a borehole intersecting an alternation of sandstones and shales. The mineralogical logs we obtained are in very good agreement with the mineral proportions measured independently on core samples. Mineralogical profiles are combined with a specific textural model to derive a continuous profile of permeability. We found a very good agreement between this computed permeability log and independent core permeability measurements over 3 orders of magnitude.
Time‐dependent land uplift and subsidence in the Santa Clara valley, California, from a large interferometric synthetic aperture radar data set
Authors: Schmidt David A. , Bürgmann Roland
Published: September 2003

We invert 115 differential interferograms derived from 47 synthetic aperture radar (SAR) scenes for a time‐dependent deformation signal in the Santa Clara valley, California. The time‐dependent deformation is calculated by performing a linear inversion that solves for the incremental range change between SAR scene acquisitions. A nonlinear range change signal is extracted from the ERS InSAR data without imposing a model of the expected deformation. In the Santa Clara valley, cumulative land uplift is observed during the period from 1992 to 2000 with a maximum uplift of 41 ± 18 mm centered north of Sunnyvale. Uplift is also observed east of San Jose. Seasonal uplift and subsidence dominate west of the Silver Creek fault near San Jose with a maximum peak‐to‐trough amplitude of ∼35 mm. The pattern of seasonal versus long‐term uplift provides constraints on the spatial and temporal characteristics of water‐bearing units within the aquifer. The Silver Creek fault partitions the uplift behavior of the basin, suggesting that it acts as a hydrologic barrier to groundwater flow. While no tectonic creep is observed along the fault, the development of a low‐permeability barrier that bisects the alluvium suggests that the fault has been active since the deposition of Quaternary units.
Numerical modeling of infragravity wave response during DELILAH
Authors: Van Dongeren Ap , Reniers Ad , Battjes Jurjen , Svendsen Ib
Published: September 2003

The nearshore circulation model SHORECIRC is applied to simulate the infragravity wave conditions at two intervals during the 1990 DELILAH campaign at Duck, N. C. The model has been extended to solve the energy equation for random short waves (on the timescale of the wave groups) which acts as a wave driver for the long‐wave model. To simulate the wave conditions an algorithm has been derived which synthesizes a directional offshore wavefield from measured data including the bound, directional low‐frequency components. The model‐data comparison shows that the mean short wave transformation and mean longshore current are predicted well. The structure of the infragravity spectrum as measured in the nearshore array is correctly represented, albeit that the energy levels are underpredicted in most locations. The 2‐D frequency longshore‐wavenumber spectra show that the infragravity wave energy consists mostly of edge waves, and that the computations qualitatively resemble the measurements. It is shown that for 1 day, bar‐trapped edge waves are present. The model is also used to show that the influence of the longshore variability is small for this particular beach and that the directional spreading in the offshore wave field is critical in predicting the nearshore infragravity wave conditions correctly. Edge waves which propagate against the current are generated by the directionally broad short‐wave forcing and to a lesser extent by back‐scattering. The nonlinear terms are relatively unimportant for the prediction of the infragravity wave climate. The cross‐shore gradient of the onshore‐directed radiation stress is the most important of the forcing terms.
Validation of ground‐based observations of stratomesospheric ozone
Authors: Schneider N. , Lezeaux O. , de La Noë J. , Urban J. , Ricaud P.
Published: September 2003

Since January 1995, an ozone line at 110 GHz is observed with a ground‐based microwave radiometer at the Bordeaux Observatory, France (45°N), belonging to the Network for the Detection of Stratospheric Change (NDSC). Ozone profiles from 25 to 75 km are retrieved from the microwave emission spectra using the Optimal Estimation Method. Improvements on the data acquisition process and calibration procedure are presented. A comprehensive comparison with satellite (Halogen Occultation Experiment (HALOE), Microwave Limb Sounder (MLS), and Stratospheric Aerosol and Gas Experiment II (SAGE II)) and ground‐based instrument data (microwave radiometer in Bern, Switzerland, lidar at the Observatoire de Haute‐Provence, France) is given. The average profiles, using the statistically most significant data sets, deviate not more than 15% in the stratosphere and 30% in the mesosphere. We can thus assert that the Bordeaux radiometer is a well‐validated instrument providing consistent and high‐quality data.
Optical properties of aerosols during APEX and ACE‐Asia experiments
Authors: Sano Itaru , Mukai Sonoyo , Okada Yasuhiko , Holben Brent N. , Ohta Sachio , Takamura Tamio
Published: September 2003

Sun/sky photometry and polarimetry of atmospheric light have been undertaken by multispectral photometers (CE‐318‐1 and ‐2, Cimel Electronique, France) and a polarimeter (PSR‐1000, Opto Research, Japan) over Amami, Noto, and Shirahama, Japan, during APEX‐E1, ‐E2, and ACE‐Asia field campaigns. Radiometers provide us with the optical thickness of aerosols and Ångström exponent. Other aerosol characteristics, e.g., size distribution, refractive index, etc., are retrieved based on each inversion method corresponding each equipment. The former takes a standard AERONET processing, and the latter is according to our own procedure to analyze the polarimetry with PSR‐1000. After several aerosol parameters are derived, the HYSPLIT4 backward trajectory analysis is adopted to search the origin of aerosols. It is shown from these ground measurements that aerosol optical thickness, Ångström exponent, and refractive index are classified into two typical categories as a background type detected in winter, and a soil dust type appeared in Asian dust events in spring. Further, it is found that the obtained size distribution of Asian dust indicates the dominance of large particles.
Climate dynamics along the arid northern coast of Chile: The 1997–1998 Dinámica del Clima de la Región de Antofagasta (DICLIMA) experiment
Authors: Rutllant José A. , Fuenzalida Humberto , Aceituno Patricio
Published: September 2003

The DICLIMA field experiment was designed to test and quantify the hypothesis of an afternoon enhancement of the coastal subsidence in the extremely arid northern Chile because of solar heating over the west slope of the Andes. Ten‐day campaigns near Antofagasta (23°S) were carried out in January 1997, July 1997, and January 1998. Significant diurnal cycles in temperature, mixing ratio, and wind from about 1000 to 4000 m above sea level were observed. This layer was decoupled from the marine boundary layer circulation below by the subsidence inversion when its base was under the average height of the coastal mountain range. The solar heating cycle over the Andes and associated circulation resulted in a mean afternoon zonal divergence above the subsidence inversion base of about 30 × 10−6 s−1, exceeding by a factor of 5 typical subtropical west coast divergences. The corresponding early morning convergence was particularly intense during the austral winter experiment. In spite of the very strong El Niño conditions that prevailed during the July 1997 and January 1998 experiments, the overwhelming control that radiation exerts on the daily cycles of the atmospheric circulation over the west slope of the Andes seems to guarantee the general validity of the results.
Measurements of the Doppler and multipath spread of HF signals received over a path oriented along the midlatitude trough
Authors: Warrington E. M. , Stocker A. J.
Published: September 2003

The presence of the midlatitude trough can severely impact on HF radio systems since the electron density depletion within the trough reduces the maximum frequency which can be reflected by the ionosphere along the great circle path. Furthermore, the associated horizontal gradients in the electron density distribution frequently result in propagation well displaced from the great circle path. The signal characteristics associated with this type of propagation have been investigated for a 1400 km link oriented along the midlatitude trough between Sweden and the UK. As anticipated, the observed delay and Doppler spread characteristics are strongly dependent upon time of day and season since the trough is a nighttime feature which occurs predominantly during the winter. In particular, the Doppler spread is often large when great circle propagation has been suppressed and reflections are from the north of the great circle path (i.e., from the poleward wall of the trough or from gradients and/or irregularities associated with the auroral zone).
A study of cleaning procedures used for foraminiferal Mg/Ca paleothermometry
Authors: Barker S. , Greaves M. , Elderfield H.
Published: September 2003

The various cleaning steps required for preparation of foraminiferal samples for Mg/Ca (and Sr/Ca) analysis are evaluated for their relative importance and effects on measured elemental ratios. It is shown that the removal of silicate contamination is the most important step for the measurement of Mg/Ca ratios. In an example, bulk sample Mg/Ca decreases from 10.5 to 2.5 mmol mol−1 during clay removal. Oxidation of organic material causes a lowering of sample Mg/Ca in the order of 10% or approximately 1°C when converted to temperature. Use of dilute acid leaching to remove adsorbed contaminants causes partial dissolution of the sample carbonate and a corresponding decrease in Mg/Ca. Reductive treatment also causes dissolution of the sample and a decrease in the Mg/Ca ratio of up to 10–15%. Sample preparation for Sr/Ca analysis does not require the same degree of rigor as is necessary for Mg/Ca work. The “within‐run” reproducibility of the method described here for G. ruber in a core‐top sample from the Arabian Sea was ±1.8% (mean sample ratio was 4.72 mmol mol−1). When converted to temperature, this becomes 28 ± 0.2°C. The equivalent result for Sr/Ca was ±0.5% (mean ratio = 1.44 mmol mol−1).
Seasonal and interannual variability of North American isoprene emissions as determined by formaldehyde column measurements from space
Authors: Abbot Dorian S. , Palmer Paul I. , Martin Randall V. , Chance Kelly V. , Jacob Daniel J. , Guenther Alex
Published: September 2003

Formaldehyde (HCHO) columns measured from space by solar UV backscatter allow mapping of reactive hydrocarbon emissions. The principal contributor to these emissions during the growing season is the biogenic hydrocarbon isoprene, which is of great importance for driving regional and global tropospheric chemistry. We present seven years (1995–2001) of HCHO column data for North America from the Global Ozone Monitoring Experiment (GOME), and show that the general seasonal and interannual variability of these data is consistent with knowledge of isoprene emission. There are some significant regional discrepancies with the seasonal patterns predicted from current isoprene emission models, and we suggest that these may reflect flaws in the models. The interannual variability of HCHO columns observed by GOME appears to follow the interannual variability of surface temperature, as expected from current isoprene emission models.
Eyewall Contraction, Breakdown and Reformation in a Landfalling Typhoon
Authors: Wu Chun‐Chieh , Chou Kun‐Hsuan , Cheng Hsiu‐Ju , Wang Yuqing
Published: September 2003

The interesting eyewall evolution of Typhoon Zeb before, during, and after its landfall at Luzon was documented from both the satellite observation and numerical simulation. It is proposed that the terrain plays a critical role in leading to such evolution: first the eyewall contraction just before landfall, a following breakdown, and then the eyewall reformation after the storm returned to the ocean. Further studies of the physical mechanisms responsible for such eyewall evolution shall improve both our understanding of and the skill in predicting the structure and intensity changes of tropical cyclones in general and landfalling ones in particular.
Lateral mixing in the equatorial Pacific: The importance of inertial instability
Authors: Richards K. J. , Edwards N. R.
Published: September 2003

Mixing in the ocean plays a key role in the ocean's dynamics and thermodynamics and how the ocean interacts with the atmosphere. Here we focus on lateral mixing in the equatorial ocean, and in particular the part played by inertial instability. We demonstrate the effectiveness of the instability in promoting mixing in the equatorial thermocline, that is sufficient to affect the large scale structure of the equatorial ocean, and which rectifies problems in existing ocean models. The spatial and temporal variability of the process is likely to impinge on interannual variations of the ocean and El Niño.
Estimates of M2 internal tide energy fluxes along the margin of Northwestern Pacific using TOPEX/POSEIDON altimeter data
Authors: Tian Jiwei , Zhou Lei , Zhang Xiaoqian , Liang Xinfeng , Zheng Quanan , Zhao Wei
Published: September 2003

TOPEX/POSEIDON altimeter data from October 1992 to June 2002 are used to calculate the energy flux of M2 internal tides along the margin of Northwestern Pacific. This arc borderline of the Pacific Basin is characterized by sharp changes in bottom topography, which constitute good boundary conditions for internal tidal energy concentration. We extract baroclinic tides, that yield energy transmission, from temporarily coherent internal tide signals in the altimeter data. We use the field measurements of current velocities in the South China Sea (SCS) to test the method. The results show that satellite‐derived M2 tide components agree with the field data very well. Computation results indicate that the maximum energy flux of M2 internal tides, 3 kW m−1, appears in the Ryukyu Trench. The total energy flux of M2 internal tides along the margin of Northwestern Pacific is about 15GW.
Penetration of interstellar dust grains into the heliosphere
Authors: Czechowski A. , Mann I.
Published: September 2003

We study penetration of small (less than ∼0.2 micron) charged dust grains of interstellar origin from the vicinity of the heliopause into the inner solar system including the effects of the heliospheric current sheet (downstream and upstream from the termination shock) and the solar cycle variation of the magnetic field. The method consists of integrating the equations of motion of charged dust grains in the model of the heliosphere and the heliospheric magnetic field based on that of Nerney et al. [1991, 1993, 1995] for sample sets of dust grains. The solar cycle variation of the tilt of the heliospheric current sheet and the magnetic field reversals with the time period of 11 years are taken into account. We find that the wavy current sheet can facilitate the entry of charged dust grains into the inner solar system. The unipolar field regions approaching the ecliptic act as an obstacle, but their effect is reduced if the minimum tilt of the current sheet is not taken equal to zero. Our results suggest that beyond a minimum distance of about 40 AU from the Sun, there should exist a stream of small interstellar dust grains entering the inner heliosphere close to the ecliptic plane.
Slope failure and volcanic spreading along the submarine south flank of Kilauea volcano, Hawaii
Authors: Morgan Julia K. , Moore Gregory F. , Clague David A.
Published: September 2003

New multichannel reflection data and high‐resolution bathymetry over the submarine slopes of Kilauea volcano provide evidence for current and prior landsliding, suggesting a dynamic interplay among slope failure, regrowth, and volcanic spreading. Disrupted strata along the upper reaches of Kilauea's flank denote a coherent slump, correlated with the active Hilina slump. The slump comprises mostly slope sediments, underlain by a detachment 3–5 km deep. Extension and subsidence along the upper flank is compensated by uplift and folding of the slump toe, which surfaces about midway down the submarine flank. Uplift of strata forming Papa`u seamount and offset of surface features along the western boundary of Kilauea indicate that the slump has been displaced ∼3 km in a south‐southeast direction. This trajectory matches coseismic and continuous ground displacements for the Hilina slump block on land, and contrasts with the southeast vergence of the rest of the creeping south flank. To the northeast, slope sediments are thinned and disrupted within a recessed region of the central flank, demonstrating catastrophic slope failure in the recent past. Debris from the collapsed flank was shed into the moat in front of Kilauea, building an extensive apron. Seaward sliding of Kilauea's flank offscraped these deposits to build an extensive frontal bench. A broad basin formed behind the bench and above the embayed flank. Uplift and back tilting of young basin fill indicate recent, and possibly ongoing, bench growth. The Hilina slump now impinges upon the frontal bench; this buttress may tend to reduce the likelihood of future catastrophic detachment.
Applicability of the steady state approximation to the interpretation of atmospheric observations of NO3 and N2O5
Authors: Brown Steven S. , Stark Harald , Ravishankara A. R.
Published: September 2003

This paper examines the conditions under which a steady state analysis is valid for modeling NO3 and N2O5 chemistry in the atmosphere. The conclusions come from a simple box model analysis that considers a limited number of reactions between NO2, O3, NO3, N2O5 and the presumed sinks for the latter two. The applicability of the steady state depends on the strength of the sinks for NO3 and N2O5, the concentration of NO2, and the ambient temperature. Under clean conditions, weak sinks for NO3 prevent the system from passing through the induction period during the time between sunset and sunrise, thus keeping the system out of steady state. Under polluted (i.e., large NO2 concentrations) or cold conditions, the presence of an equilibrium between NO3 and N2O5 markedly slows the approach to steady state even though the two species are close to equilibrium. The time required to approach equilibrium between NO2, NO3, and N2O5 is not a good measure of the time required to achieve a steady state among these compounds. The paper considers the conditions for which steady state may be valid and outlines a method for identification of individual sinks for NO3 and N2O5 from observed concentration measurements for the steady state case.
Global inventory of nitrogen oxide emissions constrained by space‐based observations of NO2 columns
Authors: Martin Randall V. , Jacob Daniel J. , Chance Kelly , Kurosu Thomas P. , Palmer Paul I. , Evans Mathew J.
Published: September 2003

We use tropospheric NO2 columns from the Global Ozone Monitoring Experiment (GOME) satellite instrument to derive top‐down constraints on emissions of nitrogen oxides (NOx ≡ NO + NO2), and combine these with a priori information from a bottom‐up emission inventory (with error weighting) to achieve an optimized a posteriori estimate of the global distribution of surface NOx emissions. Our GOME NO2 retrieval improves on previous work by accounting for scattering and absorption of radiation by aerosols; the effect on the air mass factor (AMF) ranges from +10 to −40% depending on the region. Our AMF also includes local information on relative vertical profiles (shape factors) of NO2 from a global 3‐D chemical transport model (GEOS‐CHEM); assumption of a globally uniform shape factor, as in most previous retrievals, would introduce regional biases of up to 40% over industrial regions and a factor of 2 over remote regions. We derive a top‐down NOx emission inventory from the GOME data by using the local GEOS‐CHEM relationship between NO2 columns and NOx emissions. The resulting NOx emissions for industrial regions are aseasonal, despite large seasonal variation in NO2 columns, providing confidence in the method. Top‐down errors in monthly NOx emissions are comparable with bottom‐up errors over source regions. Annual global a posteriori errors are half of a priori errors. Our global a posteriori estimate for annual land surface NOx emissions (37.7 Tg N yr−1) agrees closely with the GEIA‐based a priori (36.4) and with the EDGAR 3.0 bottom‐up inventory (36.6), but there are significant regional differences. A posteriori NOx emissions are higher by 50–100% in the Po Valley, Tehran, and Riyadh urban areas, and by 25–35% in Japan and South Africa. Biomass burning emissions from India, central Africa, and Brazil are lower by up to 50%; soil NOx emissions are appreciably higher in the western United States, the Sahel, and southern Europe.
A stochastic sediment delivery model for a steep Mediterranean landscape
Authors: Gabet Emmanuel J. , Dunne Thomas
Published: September 2003

It is a truism in geomorphology that climatic events operate on a landscape to drive sediment transport processes, yet few investigations have formally linked climate and terrain characteristics with geomorphological processes. In this study, we incorporate sediment transport equations derived from fieldwork into a computer model that predicts the delivery of sediment from hillslopes in a steep Mediterranean landscape near Santa Barbara, California. The sediment transport equations are driven by rainstorms and fires that are stochastically generated from probability distributions. The model is used to compare the rates and processes of sediment delivery under two vegetation types: coastal sage scrub and grasslands. Conversion of vegetation from sage to exotic grasses is a common land management strategy in the region and may also be engendered by regional climate change due to global warming. Results from the model suggest that (1) approximately 40% more sediment is delivered from grasslands (98 t km−2 yr−1) than the sage scrub (71 t km−2 yr−1) and (2) chronic soil creep processes dominate under grasslands whereas catastrophic processes dominate under coastal sage scrub. Results from the model also suggest that changes in the spatial distribution of vegetation arising from climate change will have a greater effect on sediment delivery than changes in the magnitude and frequency of meteorological events.