The quest for the solar g modes

Solar gravity modes (or g modes) -- oscillations of the solar interior for which buoyancy acts as the restoring force -- have the potential to provide unprecedented inference on the structure and dynamics of the solar core, inference that is not possible with the well observed acoustic modes (or p modes). The high amplitude of the g-mode eigenfunctions in the core and the evanesence of the modes in the convection zone make the modes particularly sensitive to the physical and dynamical conditions in the core. Owing to the existence of the convection zone, the g modes have very low amplitudes at photospheric levels, which makes the modes extremely hard to detect. In this paper, we review the current state of play regarding attempts to detect g modes. We review the theory of g modes, including theoretical estimation of the g-mode frequencies, amplitudes and damping rates. Then we go on to discuss the techniques that have been used to try to detect g modes. We review results in the literature, and finish by looking to the future, and the potential advances that can be made -- from both data and data-analysis perspectives -- to give unambiguous detections of individual g modes. The review ends by concluding that, at the time of writing, there is indeed a consensus amongst the authors that there is currently no undisputed detection of solar g modes.Comment: 71 pages, 18 figures, accepted by Astronomy and Astrophysics Revie

Determinação da equação intensidade-duração-frequência para três estações meteorológicas do Estado de Mato Grosso Determination of the intensity-duration-frequency equation for three meteorological stations in Mato Grosso State

Objetivou-se, com este trabalho, determinar a equação intensidade-duração-frequência para três estações meteorológicas pertencentes à rede hidrometeorológica do Instituto Nacional de Meteorologia (INMET), no Estado de Mato Grosso (Cáceres, Cuiabá e Rondonópolis) utilizando-se as metodologias de análise de pluviogramas, desagregação de chuvas de 24 h e de Bell e comparar as estimativas da intensidade de precipitação aplicando-se as equações obtidas através dessas metodologias. Dados pluviográficos e pluviométricos foram utilizados para obtenção da equação de chuvas intensas. As séries históricas de intensidades máximas médias de precipitação, correspondentes às diversas durações, foram submetidas à análise estatística a fim de identificar o modelo probabilístico que apresentasse melhor ajuste aos dados, sendo esta identificação realizada utilizando-se o teste de aderência de Kolmogorov-Smirnov a nível de significância de 5%. O método da Desagregação não só apresentou melhor desempenho global (ERM = 27%) em comparação ao de Bell (ERM = 31%), como possui melhor desempenho em estações com séries mais longas mostrando-se, assim, mais sensível ao tamanho da série em relação ao método de Bell.<br>The main objective of this study was to determine the intensity-duration-frequency equation for three meteorological stations (Cáceres, Cuiabá and Rondonópolis) belonging to the hydrometeorological network of the National Institute of Meteorology (INMET) in Mato Grosso using the methodologies of pluviograms analysis, daily rain disaggregation and Bell, as well as comparing the estimates of intensity of precipitation by applying the equations obtained through these methodologies. Pluviometric and pluviographic data were used to obtain intense precipitation equation. The historical series of average maximum intensity of precipitation, corresponding to the different durations were submitted to statistical analysis to identify the probabilistic model that presented best fit for the data, this identification being performed using the adherence test of Kolmogorov-Smirnov at 5% level of significance. The methodology of the Disaggregation not only presented better overall performance (ERM = 27%) in comparison to the one of Bell (ERM = 31%), as it has better performance in stations with longer series, revealing, thus, more sensitive to the size of the series in relation to the Bell's method