Search Results

You are looking at 1 - 7 of 7 items for

  • Author or Editor: Manuel Castro x
  • Refine by Access: All Content x
Clear All Modify Search
Miguel A. Gaertner
and
Manuel Castro

Abstract

A new method for vertical interpolation of the mass field, starting from data on standard p levels, has been devised. The method extracts information about vertical temperature profiles from geopotential values on these levels, thus recovering part of the relevant details about atmospheric thermal stratification that get lost in this widely used type of representation. Through the proposed procedure, a vertical temperature profile with a piece-wise linear dependence on height is obtained. It conserves original geopotential thicknesses while maintaining the initial temperature values on standards p levels. By statistically comparing the method with usual interpolations of T and ϕ, it is shown that the proposed method provides a clearly better reproduction of internal and potential energy of atmospheric columns. This feature may be important, for example, in the assignment of initial and boundary values for numerical simulations, where a correct model reproduction of thermal stratification is essential.

Full access
Klaus P. Hoinka
and
Manuel de Castro

In the Renaissance, impressive weather features inspired considerable interest among artists. The depiction of a tornado and other weather features are discussed that appear on a sixteenth-century series of 12 huge tapestries (“Conquest of Tunis”) woven by the carpet manufacturer Willem de Pannemaker in Brussels, Belgium, between 1549 and 1551. The outstanding depiction of the tornado is presumably the earliest pictorial presentation of a tornado, at least in the Latin west.

During the Renaissance, tapestries were an obligatory fixture of a European court and were used as an instrument for political propaganda and dynastic demonstration. The “Conquest of Tunis” tapestries are important pieces of European art commissioned by the Habsburgian emperor Charles V (1500–58), one of the most important ruling personalities in European history. In 1535, he undertook a crusade to Tunis, Tunisia, in order to diminish the Ottoman emperor's power in the western Mediterranean region. Charles V wanted to ensure that the expedition would not be forgotten. In order to guarantee this, the emperor took along the Flemish painter Jan Cornelisz Vermeyen who painted sketches that were used as prototypes for the “Conquest of Tunis” tapestries. These present a highly detailed narrative of the expedition to Tunis.

The depiction of a tornado, along with heavy rain and a sandstorm, raises the question of why these meteorological features are included in the scene. To the authors' knowledge, no mention is made of them in the art literature (except for the sandstorm, which actually occurred). This is particularly surprising because the tornado, at least, appears so prominently in one of the tapestries. Therefore, the weather features are discussed in terms of their meteorological, decorative, and symbolic importance. The tornado and the heavy rain seem to have been rendered in order to emphasize symbolically the beginning and ending of the military campaign. Although these weather elements are depicted naturalistically, they are portrayed not for their own sake, but to support the related historical event in an emblematic manner.

Full access
Miguel A. Gaertner
,
Casimiro Fernández
, and
Manuel Castro

Abstract

The forcing mechanisms of the diurnal thermal depression formed over the Iberian Peninsula in the summer and the typical air circulation induced over the Northern Plateau are analyzed by a two-dimensional hydrostatic, high-resolution, primitive equation model applied in a vertical plane perpendicular to the coastline of the Bay of Biscay. Such circulation is characterized by a low-level flow of relatively cold air that progresses inward over the elevated central plateau throughout the afternoon and evening, reaching inland distances up to 150 km at dawn, which tends to fill up the already formed thermal depression. Despite the simplicity of the model, the results obtained show a satisfactory agreement with observations. Finally, a comparison is made between results obtained from a set of simulations with different combinations of land-use types, topographic profiles, thermal stability, and synoptic wind, keeping the other conditions fixed, in order to analyze the individual effects of different terrain and atmospheric-related forcings.

Full access
Francisco J. Tapiador
,
Miguel A. Gaertner
,
Raquel Romera
, and
Manuel Castro
Full access
Carlos Manuel Minjarez-Sosa
,
Christopher L. Castro
,
Kenneth L. Cummins
,
Julio Waissmann
, and
David K. Adams

Abstract

A lightning–precipitation relationship (LPR) is studied at high temporal and spatial resolution (5 min and 5 km). As a proof of concept of these methods, precipitation data are retrieved from the National Severe Storms Laboratory (NSSL) NMQ product for southern Arizona and western Texas while lightning data are provided by the National Lightning Detection Network (NLDN). A spatial- and time-invariant (STI) linear model that considers spatial neighbors and time lags is proposed. A data denial analysis is performed over Midland, Texas (a region with good sensor coverage), with this STI model. The LPR is unchanged and essentially equal, regardless of the domain (denial or complete) used to obtain the STI model coefficients. It is argued that precipitation can be estimated over regions with poor sensor coverage (i.e., southern Arizona) by calibrating the LPR over well-covered domains that are experiencing similar storm conditions. To obtain a lightning-estimated precipitation that dynamically updates the model coefficients in time, a Kalman filter is applied to the STI model. The correlation between the observed and estimated precipitation is statistically significant for both models, but the Kalman filter provides a better precipitation estimation. The best demonstration of this application is a heavy-precipitation, high-frequency lightning event in southern Arizona over a region with poor radar and rain gauge coverage. By calibrating the Kalman filter over a data-covered domain, the lightning-estimated precipitation is considerably greater than that estimated by radar alone. Therefore, for regions where both rain gauge and radar data are compromised, lightning provides a viable alternative for improving QPE.

Full access
Carlos Manuel Minjarez-Sosa
,
Christopher L. Castro
,
Kenneth L. Cummins
,
E. Philip Krider
, and
Julio Waissmann

Abstract

The relationship between convective precipitation and cloud-to-ground (CG) lightning is examined over a study area in southwest Arizona and northwest Mexico. Using seasonal-to-daily and hourly time resolution, the National Climatic Data Center (NCDC) stage IV precipitation product and the U.S. National Lightning Detection Network lightning data have been analyzed with the aim of developing an improved understanding of the relationship between these variables. A Gaussian method of spatially smoothing discrete lightning counts is used to estimate convective rainfall and improve the quality and spatial coverage of radar-derived precipitation in areas of complex terrain. For testing the dependence of the relationship between CG lightning and precipitation, a precipitation “sensor coverage” analysis has been performed. If locations that have poor sensor coverage are excluded, R 2 between lightning and precipitation improves by up to 15%. A complementary way to estimate convective precipitation is proposed based on 1-h lightning occurrence intervals, which is the maximum time resolution in this study. We find that ~67% of the seasonal 2005 precipitation over the analysis domain is associated with CG lightning. Daily precipitation estimates are improved by specifying a “diurnal day” based on the diurnal maxima and minima in precipitation and CG lightning within the domain. Our method for improving quantitative precipitation estimation (QPE) using lightning is able to track and estimate convective precipitation over regions that have poor sensor coverage, particularly in both air mass storms and large multicellular events, with R 2 up to 70%.

Full access
Daniel Argüeso
,
José Manuel Hidalgo-Muñoz
,
Sonia Raquel Gámiz-Fortis
,
María Jesús Esteban-Parra
, and
Yolanda Castro-Díez

Abstract

The ability of the Weather Research and Forecasting model (WRF) to simulate precipitation over Spain is evaluated from a climatological point of view. The complex topography and the large rainfall variability make the Iberian Peninsula a particularly interesting region and permit assessment of model performance under very demanding conditions.

Three high-resolution (10 km) simulations over the Iberian Peninsula have been completed spanning a 30-yr period (1970–99) and driven by different datasets: the 40-yr European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-40) as “perfect boundary conditions” and two general circulation models (GCMs), the Max Planck Institute ECHAM5 model (ECHAM5/MPI) and the NCAR Community Climate System Model, version 3 (CCSM3). The daily precipitation observational grid Spain02 is employed to evaluate the model at varying time scales. Not only are the long-term means (annual, seasonal, and monthly) examined but also the high-order statistics (extreme events).

The WRF provides valuable information on precipitation at high resolution and enhances local spatial distribution due to orographic features. Although substantial errors are still observed in terms of monthly precipitation, especially during the spring, the model is largely able to capture the various precipitation regimes. The major benefits of using WRF are related to the spatial distribution of rainfall and the simulation of extreme events, two facets of climate that can be barely explored with GCMs.

This study shows that WRF can be a useful tool for generating high-resolution climate information for Spanish precipitation at spatial and temporal scales that are crucial for both the environment and human life.

Full access