Hybrid choice model for propensity to travel and tour complexity

During the last years cities around the world have invested important quantities of money in measures for reducing congestion and car-trips. Investments which are nothing but potential solutions for the well-known urban sprawl phenomenon, also called the “development trap” that leads to further congestion and a higher proportion of our time spent in slow moving cars. Over the path of this searching for solutions, the complex relationship between urban environment and travel behaviour has been studied in a number of cases. The main question on discussion is, how to encourage multi-stop tours? Thus, the objective of this paper is to verify whether unobserved factors influence tour complexity. For this purpose, we use a data-base from a survey conducted in 2006-2007 in Madrid, a suitable case study for analyzing urban sprawl due to new urban developments and substantial changes in mobility patterns in the last years. A total of 943 individuals were interviewed from 3 selected neighbourhoods (CBD, urban and suburban). We study the effect of unobserved factors on trip frequency. This paper present the estimation of an hybrid model where the latent variable is called propensity to travel and the discrete choice model is composed by 5 alternatives of tour type. The results show that characteristics of the neighbourhoods in Madrid are important to explain trip frequency. The influence of land use variables on trip generation is clear and in particular the presence of commercial retails. Through estimation of elasticities and forecasting we determine to what extent land-use policy measures modify travel demand. Comparing aggregate elasticities with percentage variations, it can be seen that percentage variations could lead to inconsistent results. The result shows that hybrid models better explain travel behavior than traditional discrete choice models

Influence of ENSO and of the Indian Ocean dipole on the Indian summer monsoon variability

Indian summer monsoon (ISM) variability is forced from external factors (like the El Nino Southern Oscillation, ENSO) but it contains also an internal component that tends to reduce its potential for predictability. Large-scale and local monsoon indices based on precipitation and atmospheric circulation parameters are used as a measure of ISM variability. In a 9-members ensemble of AMIP-type experiments (with same boundary SST forcing and different initial conditions) their potential predictability is comparable using both local and large-scale monsoon indices. In the sample analyzed, about half of more predictable monsoon years coincide with El Nino and/or positive Indian Ocean Dipole (IOD) events. Summer monsoon characteristics during ENSO and IOD years are analyzed through composites computed over a three years period (i.e. one year before and one year after the event peak) to investigate the mutual relationship between the events lagged in time. The connection between ISM and IOD is mostly confined in the summer and autumn, while that with ENSO is stronger and extends more in time. In the coupled model results the IOD influence on the monsoon is large, even because in the model IOD events are intense and easily reproduced due to a strong air-sea feedback in the eastern side of the basin. Monsoon seasons preceding or following an El Nino or a La Nina event are not exactly symmetric, even in terms of their biennial character. In most of the cases, both in reanalysis and model, El Nino and positive IOD events tend to co-occur with larger anomalies either in the Indo-Pacific ocean sector or over India, while La Nina and negative IOD do not. From the observed record, the ENSO-IOD correlation is positive strong and significant since mid-60s and it may correspond with either strong or weak ENSO-monsoon relationship and with strong or weak IOD-monsoon relationship. A main difference between those periods is the relationship between Indian monsoon rainfall and SST in other ocean basins rather than the Indo-Pacific sector alone

Montseciella, a new orbitolinid genus (Foraminiferida) from the Uppermost Hauterivian -Early Barremian of SW Europe

Montseciella, a new larger foraminiferal orbitolinid genus, is established. It comprises: M. glanensis (Foury, 1968) (uppermost Late Hauterivian to basal Early Barremian) from Serra del Montsec (Lleida Prov., Catalonian Pyrenees, Spain), Basse Provence (France) and the French Subalpine Chains, and its direct phylogenetic descendant M. alguerensis n. sp. (higher Early Barremian) from NW Sardinia (Italy). These two species represent the lower part of a phylogenetic lineage to which also belong 'Dictyoconus' arabicus Henson, 1948 and Rectodictyoconus giganteus Schroeder, 1964, occuring in the Late Barremian and lowermost Early Aptian. Key words: Foraminifers, Orbitolinidae, Catalonian Pyrenees (Spain), Sardinia (Italy), Subalpine Chains (France), Provence (France), Hauterivian, Barremian.Se establece Montseciella, un nuevo género de foraminíferos de gran tamaño, perteneciente a la familia Orbitolinidae. Este nuevo taxón incluye: M. glanensis (Foury, 1968) (Hauteriviense superior terminal - Barremiense inferior basal), encontrandose en la Serra del Montsec (Prov. de Lleida, Pirineo Catalán, España) y en la Baja Provenza y las Cadenas Subalpinas (Francia), y su descendiente directo M. alguerensis n. sp. (Barremiense inferior no basal) de Cerdeña (Italia). Los dos especies representan la parte inferior de una línea filogenética, a la cual pertenecen también 'Dictyoconus' arabicus Henson, 1948 y Rectodictyoconus giganteus Schroeder, 1964, del Barremiense superior y Aptiense inferior basal. Palabras clave: Foraminíferos, Orbitolinidae, Pirineo Catalan (España), Cerdeña (Italia), Cadenas Subalpinas (Francia), Provenza (Francia), Hauteriviense, Barremiens

Impact of extreme CO2 levels on tropical climate: A CGCM study

A coupled general circulation model has been used to perform a set of experiments with high CO2 concentration (2, 4, 16 times the present day mean value). The experiments have been analyzed to study the response of the climate system to strong radiative forcing in terms of the processes involved in the adjustment at the ocean-atmosphere interface. The analysis of the experiments revealed a non-linear response of the mean state of the atmosphere and ocean to the increase in the carbon dioxide concentration. In the 16xCO2 experiment the equilibrium at the ocean-atmosphere interface is characterized by an atmosphere with a shut off of the convective precipitation in the tropical Pacific sector, associated with air warmer than the ocean below. A cloud feedback mechanism is found to be involved in the increased stability of the troposphere. In this more stable condition the mean total precipitation is mainly due to large-scale moisture flux even in the tropics. In the equatorial Pacific Ocean the zonal temperature gradient of both surface and sub-surface waters is significantly smaller in the 16xCO2 experiment than in the control experiment. The thermocline slope and the zonal wind stress decrease as well. When the CO2 concentration increases by about two and four times with respect to the control experiment there is an intensification of El Nino. On the other hand, in the experiment with 16 times the present-day value of CO2, the Tropical Pacific variability weakens, suggesting the possibility of the establishment of permanent warm conditions that look like the peak of El Nino

Workshop Synthesis: Stated Preference Surveys and Experimental Design, an Audit of the Journey so far and Future Research Perspectives

AbstractThis paper is a synthesis of the discussions and ideas that were generated during the workshop on “Stated preference surveys and experimental design” at the 2014 Travel Survey Methods Conference in Leura (Australia). The workshop addressed the challenges related to the design and implementation of stated preference surveys as a way to capture richer behavioural information on the preferences of individuals and groups. The discussion began by reviewing the current state of stated preference surveys and whether and what we have been doing correctly. We then analysed the areas where improvements are still needed, how we can achieve them, and some pros and cons of each improvement

Hallazgo de Paracoskinolina pertenuis Foury (Orbitolinidae) en el Barremiense inferior del Pirineo catalán: reflexiones sobre su posición sistemática y filogenética

A sample of Early Barremian age from the Roca de Narieda (Lleida Prov., Catalonian Pyrenees, Spain) has furnished the orbitolinid Foraminifera Paracoskinolina pertenuis Foury, 1968 and Eopalorbitolina charollaisi Schroeder & Conrad, 1968. P. pertenuis sensu Foury is a mixture of at least three species belonging to different genera. Its holotype has to be assigned to the genus Eopalorbitolina. E. pertenuis is regarded as the direct ancestor of E. charollaisi and the most primitive representative of the phylogenetical lineage Eopalorbitolina - Palorbitolina gr. lenticularis. Key words: Foraminifers, Orbitolinidae, Catalonian Pyrenees (Spain), Alpilles (France), Barremian, Systematics, Phylogeny.En una muestra del Barremiense inferior, proveniente de la Roca de Narieda (Organyà, provincia de Lleida, Pirineo catalán, España), se ha encontrado Paracoskinolina pertenuis Foury, 1968, asociada con Eopalorbitolina charollaisi Schroeder & Conrad, 1968. P. pertenuis sensu Foury es una mezcla de por lo menos tres taxones diferentes. Su holotipo pertenece al género Eopalorbitolina. E. pertenuis está considerada como el antecesor directo de E. charollaisi y el representante más primitivo de la línea filogenética Eopalorbitolina - Palorbitolina gr. lenticularis Palabras clave: Foraminíferos, Orbitolinidae, Pirineo catalán (España), Alpilles (Francia), Barremiense, Sistemática, Filogenia

Stated preference surveys and experimental design: an audit of the journey so far and future research perspectives

This paper is a synthesis of the discussions and ideas that were generated during the workshop on “Stated preference surveys and experimental design” at the 2014 Travel Survey Methods Conference in Leura (Australia). The workshop addressed the challenges related to the design and implementation of stated preference surveys as a way to capture richer behavioural information on the preferences of individuals and groups. The discussion began by reviewing the current state of stated preference surveys and whether and what we have been doing correctly. We then analysed the areas where improvements are still needed, how we can achieve them, and some pros and cons of each improvement.Australian Research Council Discovery Progra

Effects of increased CO2 levels on monsoons

Increased atmospheric carbon dioxide concentration provided warmer atmospheric temperature and higher atmospheric water vapor content, but not necessarily more precipitation. A set of experiments performed with a state-of-the-art coupled general circulation model forced with increased atmospheric CO2 concentration (2, 4 and 16 times the present-day mean value) were analyzed and compared with a control experiment to evaluate the effect of increased CO2 levels on monsoons. Generally, the monsoon precipitation responses to CO2 forcing are largest if extreme concentrations of carbon dioxide are used, but they are not necessarly proportional to the forcing applied. In fact, despite a common response in terms of an atmospheric water vapor increase to the atmospheric warming, two out of the six monsoons studied simulate less or equal summer mean precipitation in the 16xCO2 experiment compared to the intermediate sensitivity experiments. The precipitation differences between CO2 sensitivity experiments and CTRL have been investigated specifying the contribution of thermodynamic and purely dynamic processes. As a general rule, the differences depending on the atmospheric moisture content changes (thermodynamic component) are large and positive, and they tend to be damped by the dynamic component associated with the changes in the vertical velocity. However, differences are observed among monsoons in terms of the role played by other terms (like moisture advection and evaporation) in shaping the precipitation changes in warmer climates. The precipitation increase, even if weak, occurs despite a weakening of the mean circulation in the monsoon regions(‘‘precipitation-wind paradox’’). In particular, the tropical east-west Walker circulation is reduced, as found from velocity potential analysis. The meridional component of the monsoon circulation is changed as well, with larger (smaller) meridional (vertical) scales

Tropical Pacific-North Pacific teleconnection in a coupled GCM: Remote and local effects

The connection between Tropical Pacific and North Pacific variability is investigated in a state-of-the art coupled ocean-atmosphere model, comparing two 20th century simulations at T30 and T106 atmospheric horizontal resolutions. Despite a better simulation of the frequency and the spatial distribution of the Tropical Pacific anomalies associated with the El Nino Southern Oscillation (ENSO) in the high-resolution experiment, the response in the North Pacific is scarcely different from the low-resolution experiment where the ENSO variability is weaker and at higher than observed frequency. In the North Pacific, the response of surface atmospheric fields to the variability in the Tropical Pacific appears to be affected by local coupling processes significantly different in the two experiments. The coupling between sea level pressure (SLP) and sea surface temperature (SST) in the North Pacific as well as the influence of the Tropical Pacific SST has been measured here by means of the ‘coupled manifold’ technique. In the low-resolution case the SLP variances linked to the fraction of North Pacific SST not influenced by the Tropical Pacific are weak suggesting that the remote influence is strong, consistently with the observations. On the contrary, in the high-resolution experiment the fractions and the patterns of the SLP variances due to the Tropical Pacific SST and those linked to the North Pacific SST are comparable. In the latter case, model systematic errors in the northwestern Pacific influences the local coupling processes thus triggering the remote response. We conclude that an increased atmospheric horizontal resolution does not reduce the coupled model systematic errors in the representation of the teleconnection between the North and the Tropical Pacific and that the validation of coupled models has to consider both remote and local processes