7 results on '"Emilio Cuevas"'
Search Results
2. Sharp increase in Saharan dust intrusions over the western Euro-Mediterranean in February–March 2020–2022 and associated atmospheric circulation.
- Author
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Cuevas-Agulló, Emilio, Barriopedro, David, García, Rosa Delia, Alonso-Pérez, Silvia, González-Alemán, Juan Jesús, Werner, Ernest, Suárez, David, Bustos, Juan José, García-Castrillo, Gerardo, García, Omaira, Barreto, África, and Basart, Sara
- Subjects
DUST ,FOOTBALL techniques ,AEROSOLS ,WINTER ,DUST storms - Abstract
During the months of February–March (FM) of the 2020–2022 period, several intense dust intrusions from northern Africa affected Europe. The frequency of dust events was exceptional, considering that wintertime is the season with minimum dust activity in the Mediterranean, and some episodes displayed a duration and/or intensity never recorded before, affecting large areas of the western Euro-Mediterranean (WEM) region. The main objective of this work is to construct a catalogue of FM dust events over the WEM for the 2003–2022 period based on satellite aerosol retrievals and to analyse their atmospheric drivers at the synoptic and large scales, paying special attention to the recent 2020–2022 period of high dust activity. Overall, our results indicate large intraseasonal and interannual variability in the occurrence of wintertime dust events over the WEM. Dust events of FM 2020–2022 were characterized by enhanced dust concentration and high maximum altitudes in comparison with those of previous years (2003–2019). WEM dust events are associated with enhanced activity of high-pressure systems over the Euro-Atlantic sector, which favour the obstruction of the westerlies and the occurrence of cut-off lows at subtropical latitudes. However, these high-pressure systems can exhibit a large variety of configurations, including meridional dipole blocking patterns with poleward shifted jets or Mediterranean subtropical ridges with an intensified mid-latitude jet. The former is the dominant favourable pattern for WEM dust occurrence, but the latter was relatively common during the 2020–2022 period. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. The Langley ratio method, a new approach for transferring photometer calibration from direct sun measurements.
- Author
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Almansa, Antonio Fernando, Barreto, África, Kouremeti, Natalia, González, Ramiro, Masoom, Akriti, Toledano, Carlos, Gröbner, Julian, García, Rosa Delia, González, Yenny, Kazadzis, Stelios, Victori, Stéphane, Álvarez, Óscar, Maupin, Fabrice, Carreño, Virgilio, Cachorro, Victoria Eugenia, and Cuevas, Emilio
- Subjects
PHOTOMETERS ,CALIBRATION ,AIR masses ,RADIOMETERS ,STANDARD deviations ,SUN - Abstract
This article presents a new method for transferring calibration from a reference sun photometer, referred to as the "master", to a secondary sun photometer, referred to as the "field", using a synergetic approach when master and field instruments have different spectral bands. The method was first applied between a precision filter radiometer (denoted PFR) instrument from the World Optical Depth Research and Calibration Center (WORCC), considered the reference by the WMO (World Meteorological Organization), and a CE318-TS photometer (denoted Cimel), the standard photometer used by AERONET (AErosol RObotic NETwork). These two photometers have different optics, sun-tracking systems, and spectral bands. The Langley ratio (LR) method proposed in this study was used to transfer calibration to the closest spectral bands for 1 min synchronous data for air masses between 2 and 5, and it was compared to the state-of-the-art Langley calibration technique. The study was conducted at two different locations, Izaña Observatory (IZO) and Valladolid, where measurements were collected almost simultaneously over a 6-month period under different aerosol regimes. In terms of calibration aspects, our results showed very low relative differences and standard deviations in the calibration constant transferred in IZO from the PFR to the Cimel: up to 0.29 % and 0.46 %, respectively, once external factors such as different fields of view between photometers or the presence of calibration issues were considered. However, these differences were higher in the comparison performed at Valladolid (1.04 %) and in the shorter-wavelength spectral bands (up to 0.78 % in IZO and 1.61 % in Valladolid). Additionally, the LR method was successfully used to transfer calibrations between different versions of the CE318-T photometer, providing an accurate calibration transfer (0.17 % to 0.69 %) in the morning LRs, even when the instruments had differences in their central wavelengths (Δλ up to 91 nm). Overall, our results indicate that the LR method is a useful tool not only for transferring calibrations but also for detecting and correcting possible instrumental issues. This is exemplified by the temperature dependence of the signal on the two Cimel UV spectral bands, which was estimated by means of the LR method, resulting in a signal rate of change of approximately -0.09×10-2 per degree in the case of 380 nm and approximately -0.03×10-2 per degree in the case of 340 nm. This estimation allowed us to implement the first operative temperature correction on ultraviolet (UV) spectral bands. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. New insights from the Jülich Ozone Sonde Intercomparison Experiment: calibration functions traceable to one ozone reference instrument.
- Author
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Smit, Herman G. J., Poyraz, Deniz, Van Malderen, Roeland, Thompson, Anne M., Tarasick, David W., Stauffer, Ryan M., Johnson, Bryan J., and Kollonige, Debra E.
- Subjects
OZONE ,OZONESONDES ,CALIBRATION ,STANDARD operating procedure ,ELECTRIC batteries - Abstract
Although in principle ECC (electrochemical concentration cell) ozonesondes are absolute measuring devices, in practice they have several "artefacts" which change over the course of a flight. Most of the artefacts have been corrected in the recommendations of the Assessment of Standard Operating Procedures for Ozone Sondes (ASOPOS) report (Smit et al., 2021), giving an overall uncertainty of 5 %–10 % throughout the profile. However, the conversion of the measured cell current into the sampled ozone concentration still needs to be quantified better, using time-varying background current and more appropriate pump efficiencies. We describe an updated methodology for ECC sonde data processing that is based on the Jülich Ozone Sonde Intercomparison Experiment (JOSIE) 2009/2010 and JOSIE Southern Hemisphere Additional Ozonesondes (JOSIE-SHADOZ) 2017 test chamber data. The methodology resolves the slow and fast time responses of the ECC ozonesonde and in addition applies calibration functions to make the sonde data traceable to the JOSIE ozone reference UV photometer (OPM). The stoichiometry (O3/I2) factors and their uncertainties along with fast and slow reaction pathways for the different sensing solution types used in the global ozonesonde network are determined. Experimental evidence is given for treating the background current of the ECC sensor as the superposition of a constant ozone-independent component (IB0 , measured before ozone exposure in the sonde preparation protocol) and a slow time-variant ozone-dependent current determined from the initial measured ozone current using a first-order numerical convolution. The fast sensor current is refined using the time response determined in sonde preparation with a first-order deconvolution scheme. Practical procedures for initializing the numerical deconvolution and convolution schemes to determine the slow and fast ECC currents are given. Calibration functions for specific ozonesondes and sensing solution type combinations were determined by comparing JOSIE 2009/2010 and JOSIE-SHADOZ 2017 profiles with the JOSIE OPM. With fast and slow currents resolved and the new calibration functions, a full uncertainty budget is obtained. The time response correction methodology makes every ozonesonde record traceable to one standard, i.e. the OPM of JOSIE, enabling the goal of a 5 % relative uncertainty to be met throughout the global ozone network. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Evaluation and improvement of parameterization methods for estimating cloudy-sky downwelling surface longwave radiation from geostationary satellite data.
- Author
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Yun Jiang and Bo-Hui Tang
- Abstract
Estimating downwelling surface longwave radiation (DSLR) under cloudy-sky conditions presents a significant challenge, the parameterization methods used to estimate cloudy-sky DSLR may yield disparate results for the same scenario. Hence, it is imperative to undertake a comparative and validation study of these methods to comprehend their applicability. This study compares and validates five parameterized schemes for estimating cloudy-sky DSLR using data from the Fengyun-4A (FY-4A) and Himawari-8 geostationary satellites. Additionally, an improved algorithm for cloudysky DSLR estimation is proposed, integrating the radiation effect of the entire cloud layer and a nonlinear parameterization algorithm. The verification results demonstrate that the nonlinear parameterization algorithm exhibits higher accuracy compared to those reliant on cloudbase temperature. Among these, the improved algorithm has high accuracy similar to the nonlinear algorithms in BSRN (Baseline Surface Radiation Network) and TPDC (National Tibetan Plateau Data Center) sites, its RMSE are 29.62 and 30.09 W/m², respectively. Sensitivity analysis reveals that cloud type and cloud-base temperature exert a pronounced influence on DSLR estimation, particularly within parameterization algorithms based on cloud-base temperature, warranting thorough consideration. Furthermore, the influence of land cover type and surface elevation, especially in high-altitude regions with bare surfaces, should not be disregarded in DSLR estimation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. A Historical Geography of Christopher Columbus’s First Voyage and His Interactions with Indigenous Peoples of the Caribbean
- Author
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Al M. Rocca and Al M. Rocca
- Subjects
- Indians of the West Indies--History--15th century
- Abstract
This book offers a unique account of Christopher Columbus's first voyage, the most consequential voyage in world history. It provides a detailed day-by-day account of the explorer's travels and activities, richly illustrated with thematic maps.This work expands our understanding of Columbus's first voyage by mapping his sea and land experiences, offering both a historical and geographical exploration of his first voyage. Traveling chronologically through events, the reader builds a spatial insight into Columbus's perspectives that confused and confirmed his pre-existing notions of Asia and the Indies, driving him onward in search of new geographic evidence. Drawing from a diverse range of primary and secondary historical resources, this book is beautifully adorned with illustrations that facilitate an in-depth exploration of the connections between the places Columbus encountered and his subsequent social interactions with Indigenous people. This methodology allows the reader to better understand Columbus's actions as he analyzes new geographic realities with pre-existing notions of the “Indies.” Attention is given to Columbian primary sources which analyze how those materials have been used to create a narrative by historians. Readers will learn about the social and political structures of the Lucayan, Taíno, and Carib peoples, achieving a deeper understanding of those pre-Columbian cultures at the time of contact.The book will appeal to students and researchers in the disciplines of history, geography, and anthropology, and the general reader interested in Colombus.
- Published
- 2024
7. Las sociedades agrícolas en los valles de la Sierra Gorda
- Author
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Jorge Quiroz, Alma Rosa Espinosa Ruiz, Jerónimo Hernández Mejía, Sara Carolina Corona Lozada, Lliria Benítez Galván, Andrea Pérez Martínez, Erika Olivares Flores, Pablo I López Hernández, Jorge Quiroz, Alma Rosa Espinosa Ruiz, Jerónimo Hernández Mejía, Sara Carolina Corona Lozada, Lliria Benítez Galván, Andrea Pérez Martínez, Erika Olivares Flores, and Pablo I López Hernández
- Abstract
Este libro es el resultado de varias exploraciones que comienzan al norte, en el Valle de Arroyo Seco y continúa hasta el Valle de Tilaco. Aquí se presenta la metodología que se siguió tanto para la recuperación de los datos como en el análisis de estos, el estudio del patrón de asentamiento y una propuesta sobre el funcionamiento de los conjuntos arquitectónicos al interior los valles recorridos. En el presente volumen, se expondrán los avances del Proyecto Arqueológico Valles de la Sierra Gorda.
- Published
- 2024
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