Abstract. In this paper, the quality of a reconstruction of daily snow frequency in the central Andes is evaluated by studying the atmospheric patterns related to anomalies in the reconstructed series. The origin of precipitation anomalies in this part of the world is relatively well known and is has been related to the El Niño/Southern Oscillation cycle through the Pacific South American pattern, which implies changes in the subtropical jet across the Pacific, the blocking activity in the Southeastern Pacific and the ice formation around the Antarctic Peninsula. We found that the reconstructed series of snow frequency reproduces every expected anomaly pattern related to precipitation in the central Andes during the period 1958–1996. The methodology developed can help to validate reconstructed series in absence of instrumental data to perform a direct calibration. In addition, it provides a physical link between the variability of a climate proxy and the underlying atmospheric dynamics.
Abstract.One of the main problems in climate reconstruction from documentary sources is the evaluation of the quality of non instrumental meteorological records in absence of instrumental observations to perform a calibration. In these cases it is mandatory to envision different approaches to assess the climatic signal in a reconstruction. This work is aimed to test the consistency of a snow frequency reconstruction in the central Argentinean Andes by studying the synoptic patterns related to the occurrence of precipitation in this area. While the original reconstruction covers the period between 1885 and 1996, the insufficiency of overlapping instrumental data limited the calibration to a short 15-year interval. In this paper we evaluate the performance of the reconstructed series for the entire 45-year period between 1958 and 1996 by analyzing the displacement in the jet stream and the patterns of geopotential height related to anomalies in the reconstructed snow frequency series. Previous works have linked the precipitation in the central Andes to the ENSO through the Pacific South American mode. We also have found this connection between ENSO and the reconstructed precipitation. Finally, it is shown that the ENSO relationship is the cause of a significant link between the precipitation anomalies in the central Argentinean Andes and the ice extent around the Antarctic Peninsula.
Between 04 to 09 May 2004, part of the state of Rio Grande do Sul (RS), Brazil; have recorded rainfall above 300mm. The east region of this state, mainly on the coast, had the highest rainfall accumulation occurred. A synoptic analysis of this period has shown a persistent trough west of RS in high and middle levels of troposphere, in the first three days of this event. This trough started a cyclonic vortice in the mid-low-tropospheric levels in the following days. The upward movement associated with this trough stayed semi-stationary over the state of RS and acted in almost entire tropospheric layer during great part of this period. In addition, it was observed that this tropospheric layer had high values of relative humidity from surface up to 300 hPa, over the state of RS – greater than 70%. In 09 May 2004, the cyclonic vortice has lost their configuration and has distanced from RS. The state of RS was dominated by an anticyclonic circulation and by a drier tropospheric layer, what disfavors rainfall occurrence in this region. During all analyzed period, it could be observed that the configuration in the middle troposphere has extended up to higher levels, but the same does not occurred to the surface. Also, a cyclonic circulation in 850 hPa was observed over the state of RS, but any cyclogenesis has occurred at surface. A surface cyclogenesis was observed over the coast of the state of Sao Paulo (SP), in 05 May. This cyclone has moved to south, approaching the coast of the states of RS e Santa Catarina (SC), in 08 May. A comparison of the atmospheric behavior with the rainfall recorded in the state of RS between 03 and 09 May suggest that this low-pressure center has no direct influence in the cumulative rainfall observed in this period. In addition, in 08 and 09 May, this low-pressure center weakened and move away from the coast of the states of RS and SC. Therefore, although the weak low-level temperature advection and low-level moisture flux convergence observed over this region, a persistent mid-low-tropospheric trough, what favor persistent upward movement, together with a deep and very humid layer, seems to be the main responsible to the great amounts of rainfall registered in the state of RS.
ResumenEn esta investigación se presenta un caso de estudio de aplicación del procedimiento conocido como Análisis Regional de Frecuencias basado en L-momentos, al estudio de las precipitaciones anuales en la provincia de Camagüey, Cuba. Se ha adoptado la mencionada metodología por ser un procedimiento estadísticamente robusto para compensar la carencia de registros históricos de larga data por su abundancia en el área de estudio. La aplicación de la metodología permitió la estimación de las probabilidades y períodos de retornos de las precipitaciones anuales (cuantil de interés) así como la obtención de mapas de frecuencia. Palabras-clave: análisis regional de frecuencias, l-momentos, Cuba, hidrología probabilística, modelo de frecuencia. Case Study of Regional Frequency Analysis Based in L-Moments to theCase of the Annual Rainfall in the Province of Camagüey, Cuba. AbstractIn this research is presented a case study of application of the procedure known as Regional Frequency Analysis based on L-moments, in the study of the annual rainfall in the province of Camagüey, Cuba. It has adopted the above methodology to be statistically robust procedure to compensate for the lack of long-standing historical records for its abundance in the study area. The application of the methodology allowed the estimation of the probability and returns periods of annual rainfall (quantile of interest) and obtaining frequency maps.
Resumo Nesta segunda parte do estudo sobre eventos persistentes de chuva são avaliadas as condições atmosféricas associadas aos eventos. Compostos de campos diagnósticos são apresentados para os eventos separados em função de sua duração. Eles mostram que sistemas atmosféricos com lento deslocamento propiciam a permanência de áreas de convergência do fluxo de umidade, transporte de calor e movimento vertical ascendente sobre o estado do Rio Grande do Sul por vários dias. A convergência do fluxo de umidade integrada verticalmente mostrou-se como uma boa ferramenta para inferência da importância dos eventos. Os campos diagnósticos apresentados não mostram uma indicação antecipada da duração de um evento de chuva, bem como não demostram com clareza a maior frequência de elevados acumulados de chuva na metade leste do estado do Rio Grande do Sul.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.