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M. Chenoweth, J.M. Vaquero, R. García-Herrera, and D. Wheeler

The first barometers in the Americas were provided by the Royal Society of London in 1677 to correspondents in the Caribbean Island of Barbados. Colonel William Sharpe of Barbados was the first person in the Americas to make daily observations of the weather using a meteorological instrument (other than a wind vane) and made the first known measurements of barometric pressure within the circulation of a hurricane on 12 August 1680. His record provides new insight into the early history of the barometer and early perceptions of tropical weather, vindicates the hypothesis that the barometer would prove useful in detecting hurricanes, and contributes to Edmund Halley's understanding of the empirical distinctions between the Tropics and temperate zones. Sharpe's name and contributions, previously unknown to the meteorological community, can now be properly recognized.

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David Barriopedro, Ricardo García-Herrera, Anthony R. Lupo, and Emiliano Hernández

Abstract

In this paper a 55-yr (1948–2002) Northern Hemisphere blocking climatology is presented. Traditional blocking indices and methodologies are revised and a new blocking detection method is designed. This algorithm detects blocked flows and provides for a better characterization of blocking events with additional information on blocking parameters such as the location of the blocking center, the intensity, and extension. Additionally, a new tracking procedure has been incorporated following simultaneously the individual evolution of blocked flows and identifying coherently persistent blocked patterns.

Using this method, the longest known Northern Hemisphere blocking climatology is obtained and compared with previous studies. A new regional classification into four independent blocking sectors has been obtained based on the seasonally preferred regions of blocking formation: Atlantic (ATL), European (EUR), West Pacific (WPA), and East Pacific (EPA). Global and regional blocking characteristics have been described, examining their variability from the seasonal to interdecadal scales.

The global long-term blocking series in the North Hemisphere showed a significant trend toward weaker and less persistent events, as well as regional increases (decreases) in blocking frequency over the WPA (ATL and EUR) sector. The influence of teleconnection patterns (TCPs) on blocking parameters is also explored, being confined essentially to wintertime, except in the WPA sector. Additionally, regional blocking parameters, especially frequency and duration, are sensitive to regional TCPs, supporting the regional classification obtained in this paper. The ENSO-related blocking variability is evident in blocking intensities and preferred locations but not in frequency. Finally, the dynamical connection between blocking occurrence and regional TCPs is examined through the conceptual model proposed by Charney and DeVore. Observational evidence of a dynamical link between the asymmetrical temperature distributions induced by TCPs and blocking variability is provided with a distinctive contrast “warm ocean/cold land” pattern favoring the blocking occurrence in winter. However, the conceptual model is not coherent in the WPA sector, suggesting different blocking mechanisms operating in this sector.

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R. Garcia-Herrera, D. Barriopedro, E. Hernández, H. F. Diaz, R. R. Garcia, M. R. Prieto, and R. Moyano

Abstract

The authors present a chronology of El Niño (EN) events based on documentary records from northern Peru. The chronology, which covers the period 1550–1900, is constructed mainly from primary sources from the city of Trujillo (Peru), the Archivo General de Indias in Seville (Spain), and the Archivo General de la Nación in Lima (Peru), supplemented by a reassessment of documentary evidence included in previously published literature. The archive in Trujillo has never been systematically evaluated for information related to the occurrence of El Niño–Southern Oscillation (ENSO). Abundant rainfall and river discharge correlate well with EN events in the area around Trujillo, which is very dry during most other years. Thus, rain and flooding descriptors, together with reports of failure of the local fishery, are the main indicators of EN occurrence that the authors have searched for in the documents. A total of 59 EN years are identified in this work. This chronology is compared with the two main previous documentary EN chronologies and with ENSO indicators derived from proxy data other than documentary sources. Overall, the seventeenth century appears to be the least active EN period, while the 1620s, 1720s, 1810s, and 1870s are the most active decades. The results herein reveal long-term fluctuations in warm ENSO activity that compare reasonably well with low-frequency variability deduced from other proxy data.

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Ricardo García Herrera, Rolando R. García, M. Rosario Prieto, Emiliano Hernández, Luis Gimeno, and Henry F. Díaz

Spanish historical archives contain a vast store of information about Spain and its former colonies in America and Asia. Some searches for climate-related information within these archives have been undertaken recently, but they have been by no means exhaustive. This paper discusses the principal archives and shows, by means of several examples, that they exhibit a high potential for inferring past climate over a wide range of timescales and geographical areas. Extraction of such information is often time consuming, and requires a combination of archival, historical, and climatological expertise, and the development of individualized methodologies to fit each situation and type of data. In spite of these difficulties, the archives can be particularly useful in many cases where there are no alternative sources of climate data. Thus, the complexities of the multidisciplinary effort required should not discourage other researchers from undertaking similar studies.

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D. Barriopedro, P. M. Sousa, R. M. Trigo, R. García-Herrera, and A. M. Ramos
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D. Wheeler, R. Garcia-Herrera, J. M. Vaquero, M. Chenoweth, and C. J. Mock

This paper draws on a range of contemporary documentary evidence from the New and Old Worlds as well as from the oceanic regions to reconstruct the trajectory and intensity of an Atlantic hurricane from August 1680. In doing so, it offers the example of one of the earliest and most comprehensive hurricane reconstructions thus far attempted. The source material includes evidence from land-based observers and some of the earliest examples of instrumental barometric data from the Caribbean and from Europe; importantly, it also calls on the written accounts offered in ships' logbooks from various parts of the Atlantic. The latter provide the opportunity of tracking the system across the otherwise data-deficient areas of the North Atlantic as it recurved toward Europe. The findings are of intrinsic interest in documenting a notable historical event. They also offer a methodological model of how such a variety of documentary sources can be drawn together and used to identify, track, and reconstruct such events from the distant past and thereby improve the chronology of hurricanes and make more reliable our interpretation of their changing frequencies.

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J. M. Vaquero, R. García-Herrera, D. Wheeler, M. Chenoweth, and C. J. Mock

This paper documents a rare spell of severe weather in Spain that took place during the mid-nineteenth century when a tropical storm struck the southwest of the country on 29 October 1842. The use of a variety of independent documentary sources has provided unprecedented scope for the analysis of this event, allowing it to be set within its wider context, and for a judgement to be made on its tropical origin. The evidence suggests that this was similar, though stronger, to the more recent Hurricane Vince, which made landfall in Spain on 10 October 2005. This case study not only places Hurricane Vince, suggested at the time to have been unique, in its more proper long-term context, but it also demonstrates how documentary sources can improve our wider understanding of climate dynamics during historical times in the Atlantic basin.

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Natalia Calvo Fernández, Ricardo GarcÍa Herrera, David Gallego Puyol, Emiliano Hernández MartÍn, Rolando R. GarcÍa, Luis Gimeno Presa, and Pedro Ribera RodrÍguez

Abstract

The El Niño–Southern Oscillation (ENSO) signal in the troposphere and lower stratosphere was investigated using Microwave Sounding Unit (MSU) data for the period 1979–2000. Empirical orthogonal functions (EOFs) were computed separately for zonal-mean and eddy temperatures in the Tropics and shown to provide a compact, physically intuitive description of ENSO that captures many of the details of its inception and evolution. Regressions of the MSU data on the principal components (PCs) of the tropical EOFs were then used to estimate the global signal of ENSO. The results show that ENSO accounts for over two-thirds of the temperature variability in the tropical troposphere, where its signature is composed of distinct zonal-mean and eddy patterns whose evolution is not simultaneous. In the tropical stratosphere, and outside the Tropics, ENSO explains a much smaller fraction of the variance (∼10%), and manifests itself purely in the form of eddy anomaly patterns. The PCs of the eddy EOFs of the tropical stratosphere are almost perfectly correlated with those of the troposphere, suggesting that together the EOFs describe the vertical structure of equatorial waves. Volcanic eruptions and the quasi-biennial oscillation (QBO) are responsible for most of the variability (∼87%) of the tropical lower stratosphere, and this variability is uncorrelated with ENSO; in the tropical troposphere, the effect of volcanic eruptions is detectable but small, accounting for about 3% of the variance.

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Rolando R. Garcia, Henry F. Díaz, Ricardo García Herrera, Jon Eischeid, María del Rosario Prieto, Emiliano Hernández, Luis Gimeno, Francisco Rubio Durán, and Ana María Bascary

Historical accounts of the voyages of the Manila galleons derived from the Archivo General de Indias (General Archive of the Indies, Seville, Spain) are used to infer past changes in the atmospheric circulation of the tropical Pacific Ocean. It is shown that the length of the voyage between Acapulco, Mexico, and the Philippine Islands during the period 1590–1750 exhibits large secular trends, such that voyages in the middle of the seventeenth century are some 40% longer than those at the beginning or at the end of the century, and that these trends are unlikely to have been caused by societal or technological factors. Analysis of a series of “virtual voyages,” constructed from modern wind data, indicates that sailing time to the Philippines depended critically on the strength of the trade winds and the position of the western Pacific monsoon trough. These results suggest that the atmospheric circulation of the western Pacific underwent large, multidecadal fluctuations during the seventeenth century.

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F. Domínguez-Castro, M. C. Gallego, J. M. Vaquero, R. García Herrera, M. Peña-Gallardo, A. El Kenawy, and S. M. Vicente-Serrano

Abstract

The weather diary of Felipe de Zúñiga y Ontiveros was recorded in Mexico City from 1775 to 1786. It is the earliest meteorological observational record of Mexico. The diary provides daily meteorological information for rain frequency, temperature, frost, hail, thunderstorms, and wind, with higher resolution than any other contemporary documentation or natural proxy from this region. The seasonal distributions of rainy days, temperature, hail, and thunderstorms correspond well with those from the Tacubaya Observatory in Mexico City (1886–2016). Two drought periods (1780/81 and 1785/86) and one wet period (1782/83) were identified. The drought spanning from 1785 to 1786 is known in the literature as “the hunger year” because it represented the most severe famine during the colonial period (1521–1821). This paper analyzes—for the first time—this event at a daily scale. Similar to the reported droughts of 1909/10 and 2010/11, 1785/86 was a very dry period. But the dry conditions of 1785 were followed by intense frosts that started in late August and continued through September and October. This combination led to the destruction of crops and subsequent famine. The duration of the frost does not have analogs during the instrumental period, probably because of the intense warming and land changes registered over the last years in the region.

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