Francisco Valero

Characterization of the Martian Convective Boundary Layer

The authors have carried out an extensive characterization of the Martian mixed layer formed under convective conditions. The values of the mixed layer height, convective velocity scale, convective temperature scale, mean temperature standard deviation, mean horizontal and vertical velocity standard deviations, and mean turbulent viscous dissipation rate have been obtained during the strongest convective hours for the mixed layer. In addition, the existing database of the surface layer has been improved by recalculating some parameters (e.g., Monin–Obukhov length, friction velocity, or scale temperature) that had already been obtained in previous papers by other means and also by calculating new ones, such as the standard deviation of the vertical wind speed velocity, the turbulent viscous dissipation rate, and eddy transfer coefficients for momentum and heat. The Earth counterparts of all these magnitudes are also shown. In this paper, a comprehensive database concerning the whole convective planetary boundary layer on Mars is displayed, and a detailed terrestrial comparison is established. nThe inputs of this work are hourly in situ temperature, hourly in situ horizontal wind speed, and hourly simulated ground temperature for specific selected Sols of the Viking and Pathfinder landers. These data correspond to typical low and midlatitude northern summertime conditions, with weak prevailing winds. To handle this set of data, surface layer and mixed layer similarity theory have been used at the strongest convective hours. In addition, the inclusion of a parameterization of a molecular sublayer and prescribed values of the surface roughness has been considered.

Characterization of the Martian Surface Layer

Abstract The authors have estimated the diurnal evolution of Monin–Obukhov length, friction velocity, temperature scale, surface heat flux, eddy-transfer coefficients for momentum and heat, and turbulent viscous dissipation rate on the Martian surface layer for a complete sol belonging to the Pathfinder mission. All these magnitudes have been derived from in situ wind and temperature measurements at around 1.3-m height and simulated ground temperature (from 0600 sol 25 to 0600 sol 26). Previously, neither values of turbulent viscous dissipation rate and eddy-transfer coefficients from in situ measurements for the Martian surface layer nor diurnal evolutions of all the previously mentioned turbulent parameters for the Pathfinder had been obtained. Monin–Obukhov similarity theory for stratified surface layers has been applied to obtain the results. The values assigned to the surface roughness and the applied parameterization of the interfacial sublayer will be discussed in detail with respect to the results...

Tropospheric ozone concentrations related to atmospheric conditions at Izaña BAPMoN weather station, Canary Islands

SummaryThe 24h average concentrations of tropospheric ozone were measured in the BAPMoN (Background Atmospheric Pollution Monitoring Network) baseline station of Izaña (Canary Islands, Spain). Concentrations were studied through a methologody based on nonparametric statistics. Three sectors of wind direction were selected and the air mass properties from these were characterized. The ozone concentration data were related to air masses in terms of aerometric elements. Highest values of ozone concentrations were found when the wind direction was from Sector I or Atlantic Sector because fair-weather conditions are associated with air flows from this sector and with long-range transport possibly from North Atlantic and Europe. Furthermore, the dependence of daily ozone concentration on some cloud types was investigated. Higher ozone concentrations were associated with high clouds having a lesser rate of depletion for solar radiation than middle and low clouds.

Sensitivity Analysis of the WRF Model: Wind-Resource Assessment for Complex Terrain

AbstractWind energy requires accurate forecasts for adequate integration into the electric grid system. In addition, global atmospheric models are not able to simulate local winds in complex terrain, where wind farms are sometimes placed. For this reason, the use of mesoscale models is vital for estimating wind speed at wind turbine hub height. In this regard, the Weather Research and Forecasting (WRF) Model allows a user to apply different initial and boundary conditions as well as physical parameterizations. In this research, a sensitivity analysis of several physical schemes and initial and boundary conditions was performed for the Alaiz mountain range in the northern Iberian Peninsula, where several wind farms are located. Model performance was evaluated under various atmospheric stabilities and wind speeds. For validation purposes, a mast with anemometers installed at 40, 78, 90, and 118 m above ground level was used. The results indicate that performance of the Global Forecast System analysis and Eu...

A METHOD FOR THE RECONSTRUCTION AND TEMPORAL EXTENSION OF CLIMATOLOGICAL TIME SERIES

A method for the reconstruction and temporal extension of climatological time series is provided. This method was focused on a combination of methods, including harmonic analysis, seasonal weights, and the Durbin–Watson (DW) regression method. The DW method has been modified in this paper and is described in detail because it represents a novel use of the original DW method. n n n nThe method is applied to monthly means of daily wind-run data sets recorded in two historical observatories (M series and A series) within the Parque del Retiro in Madrid (Spain) and covering different time periods with an overlapping period (1901–1919). The aim of the present study is to fill up to and to construct a historical time series ranging from 1867 to 1992. The proposed model is developed for the 1906–1919 calibration period and validated over the 1901–1905 verification period, which includes the hypothesis of constant ratio of variances. The verification results are almost as good as those for the calibration period. Hence, the M series was extended back to 1867, which results in the longest climatological wind-run data-set in Spain. Also, the reconstruction is shown to be reliable.

The Martian Planetary Boundary Layer: Turbulent kinetic energy and fundamental similarity scales

We review selected in situ measurements and models aimed at the study of the Martian Planetary Boundary Layer (PBL). We also discuss critically the advantages and limitations of applying similarity theories to the Martian PBL and calculate the fundamental scales predicted by these theories. Finally, we obtain values of the turbulent kinetic energy (TKE) and address its budget by weighting the significance of the different terms involved in it. In situ measurements taken by the Viking and Pathfinder missions along with similarity theories conveniently adapted to Mars are used to obtain the fundamental scales, the TKE and its budget.

A short-range ensemble precipitation prediction system over the Iberian Peninsula and Balearics

A short-range ensemble precipitation forecast system has been constructed over the Iberian Peninsula and Balearics by means of the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Model (MM5). The ensemble system consists of ten members, each run with a different combination of two different initial conditions from global models, IFS-ECMWF and GFS-NCEP, and five different subgrid-scale physics configurations for one month period, October 2006. The mesoscale verification is made by using observational precipitation data of the Spanish Climatic Network. The created short-range ensemble shows high spread-skill correlation values for daily precipitation. However, the asymmetric shape of the rank histogram indicates some underdispersion, suggesting a biased behaviour. The Talagrand shows as well the underdispersive effect because of its asymmetric distribution. The Relative Operating Characteristic curve shows a very outstanding area indicating the good discrimination capacity. The reliability diagrams are also indicative of the good reliability of the forecasting system, depicting in general good agreement between forecast probability and the mean observed frequency. Because of that, the verification proves the usefulness of the forecasting system over the study area.

Stochastic approach to study the atmospheric pollutants in the urban area of Rome

Abstract The aim of this article is to present some results obtained by adapting ‘structural” and ‘temporal series’ models to data on atmospheric chemical contaminants detected by stations for continuous monitoring of the Istituto Superiore di Sanita (ISS), located in an urban area of Rome. The reported results allow us to quantify the interrelation among contaminants, periodicity, persistence, behavioral trend over 24 h with particular reference to carbon monoxide (CO) and its correlations with benzene. The results are in agreement with the information available on the traffic flow in this area. The present work, which constitutes part of methodological research on the treatment of data supplied by monitoring stations points out that by using mathematical models it is possible to produce consistent and reliable information, reproducible in space and time, on the basis of actual data on contaminants. The results obtained point towards the advantage of using the predictive model for CO.