Search results for "Oscillation"

Effects of dead time losses on terrestrial gamma ray flash measurements with the Burst and Transient Source Experiment

2010

[1] Measurements from the Burst and Transient Source Experiment (BATSE) instrument on the Compton Gamma Ray Observatory (CGRO) are the only ones where characteristics of single terrestrial gamma ray flashes (TGFs) have been obtained thus far. However, it has been reported that the measurements suffer from significant dead time losses which complicates the analysis and raises question about earlier BATSE studies. These losses are due to the high-intensity flux combined with limitations of the time resolution of the instrument. Since these losses will affect both the spectrum and the temporal distribution of the individual TGFs, results based on BATSE data need to be revisited, including our …

Influence of climate change on phenological phases in Latvia and Lithuania

2009

To investigate the impact of recent climatic changes on plant development, this study used phenological data of the volunteer networks in Latvia and Lithuania from the 1971-2000 period. The phenological calendar method was applied. Phenological seasons were described using data on 6 phenological phases at 10 stations. The growing season was described using birch Betula pendula as an example. Correlation analysis, linear regression and non-parametric Mann-Kendall trend tests were applied to establish the relationship between phenological phases and meteorological factors (temperature, precipitation) and the North Atlantic Oscillation (NAO). The results indicate a statisti- cally significant …

20th century droughts in southern Africa: spatial and temporal variability, teleconnections with oceanic and atmospheric conditions

2001

Southern African rainfall does not show any trend to desiccation during the 20th century. However, the subcontinent experienced particularly severe droughts in the 1980s and at the beginning of the 1990s and the magnitude of the interannual summer rainfall variability shows significant changes. Modifications of the intensity and spatial extension of droughts is associated with changes in ocean–atmosphere teleconnection patterns. This paper focuses mostly on the well-documented 1950–1988 period and on late summer season (January–March). A principal component analysis on southern African rainfall highlights modifications of the rainfall variability magnitude. The 1970–1988 period had more var…

Seasonality and atmospheric dynamics of the teleconnection between African rainfall and tropical sea-surface temperature: Atlantic vs. ENSO

2001

A 47-year record (1951-1997) of gridded data covering Africa south of the Sahara was used to document the spatial and seasonal patterns of the correlation between precipitation and sea-surface temperatures (SST) in key tropical areas, as depicted by the NIN O3, South Atlantic and North Atlantic indices. El Nino -Southern Oscillation (ENSO) is confirmed as playing a dominant part in northeastern, eastern and southern Africa. However, its impact is also found over the Sahel during the northern summer, and other parts of the Gulf of Guinea region outside this season, a hitherto poorly documented feature. Over these two areas, ENSO and Atlantic SST (predominantly South Atlantic) contribute to d…

Trends of mean temperatures and warm extremes in northern tropical Africa (1961-2014) from observed and PPCA-reconstructed time series

2016

Trends in daily maximum (TX) and minimum (TN) temperatures and indices of warm extremes are studied in tropical North Africa, west of the eastern African highlands, from 1961 to 2014. The analysis is based on the concatenation and cross-checking of two observed databases. Due to the large number of missing entries (~25%), a statistical infilling using probabilistic principal component analysis was applied. Averaged over 90 stations, the linear trends of annual mean TX and TN equal respectively +0.021 °C/yr and +0.028 °C/yr. The frequency of very hot days (TX > 35°C) and tropical nights (TN > 20°C), as well as the frequency of daily TX and TN above the 90th percentile (p90) (“warm days” and …

Predicting dengue fever outbreaks in French Guiana using climate indicators

2016

Background Dengue fever epidemic dynamics are driven by complex interactions between hosts, vectors and viruses. Associations between climate and dengue have been studied around the world, but the results have shown that the impact of the climate can vary widely from one study site to another. In French Guiana, climate-based models are not available to assist in developing an early warning system. This study aims to evaluate the potential of using oceanic and atmospheric conditions to help predict dengue fever outbreaks in French Guiana. Methodology/Principal Findings Lagged correlations and composite analyses were performed to identify the climatic conditions that characterized a typical e…

Enhanced Tropospheric Wave Forcing of Two Anticyclones in the Prephase of the January 2009 Major Stratospheric Sudden Warming Event

2017

Monthly Weather Review, 145 (5)

Late Holocene precipitation and temperature changes in Northern Europe linked with North Atlantic forcing

2015

POLY 496-Behavior of the Belousov-Zhabotinsky oscillator in the presence of carboxymethyl-cellulose

2008

Numerical and experimental validation of a LiFePO<inf>4</inf> battery model at steady state and transient operations

2013

In the paper some of the battery models proposed in literature are analysed in order to predict the battery performance and, then, make sure that the Battery Management System (BMS) that is a key component to check and control the status of the batteries within their specified safe operating conditions, works in best conditions. In fact to reach an extended battery lifetime and increase the reliability of the system, is necessary to guarantee an accurate evaluation of the state of the whole stack of batteries to track their operations. Therefore, an accurate battery model that captures the dynamics of the battery is required. Lithium batteries are in particular considered because of their h…