Radiosounding-derived convective parameters for the Alcântara Launch Center

Abstract

Climatological features of convective parameters (K index, IK; 950 hPa K index, IK950; Showalter index, IS; lifted index, ILEV; total totals index, ITT; and convective available potential energy, CAPE) derived from 12 UTC radiosounding data collected at the Alcântara Launch Center (CLA; 2°18'S, 44º22'W) from 1989 to 2008 were computed. The parameters IK, IK950, IS and ITT (ILEV and CAPE) showed a seasonal variation coherent (not coherent) to the annual cycle of precipitation. Interdaily variability was high all year round and was comparable to the monthly average seasonal variation. For IK and IK950, the monthly fraction of days with favorable conditions for precipitation occurrence (FRAC) showed good agreement with the monthly fraction of days with precipitation greater than 0.1 mm (PRP). For ITT and IS, the seasonal variation of FRAC was lower than the seasonal variation of PRP; for ILEV and CAPE, there were marked differences between FRAC and PRP. IK seasonal variation was primarily due to the presence of a deeper (shallower) low-level moist layer in the wet (dry) season. Among the studied convective parameters, the use of IK or IK950 for assessing precipitation occurrence was recommended.

Concurrent climate impacts of tropical South America land‐cover change

“…Therefore, for humid regions (AMZ) and/or periods (rainy season of NEB), when moisture supply from large‐scale systems is active, the moisture mechanism may be neglected and the linear assumption would hold. During humid periods, this could be explained by the weakening of the vertical moisture gradient due to moistening of mid atmospheric levels (Oliveira and Oyama, 2009), which limits the anomalies of vertical moisture advection and, therefore, the action of the moisture mechanism.…”

A Fuzzy Logic Method for Lightning Prediction Using Thermodynamic and Kinematic Parameters from Radio Sounding Observations in South Korea

“…They determined that these environmental parameters are storm dependent rather than location or season dependent. For tropical humid regions, Oliveira and Oyama (2009) investigated climatological features for some widely used convective parameters calculated from radio sounding observations at the Alcantara Launch Center, located along the northern coast of northeastern Brazil.…”

Avaliação dos Índices Termodinâmicos na Previsibilidade de Chuvas em Belém-PA: o Uso Alternativo de Sondagens Atmosféricas por Satélite

“…Portanto, estes índices indicam as condições da estrutura termodinâmica vertical da atmosfera, permitindo uma análise ampla da formação da convecção úmida e consequente precipitação. Neste contexto, estudos têm sido feitos para avaliar o desempenho dos índices de instabilidade na previsibilidade de chuvas, principalmente de eventos extremos, na região tropical utilizando os dados de radiossondagens convencionais (Gille & Mota 2014;Oliveira & Oyama 2009;Tavares & Mota 2012). Como exemplo, se tem o trabalho de Santos, Mota & Rocha (2014), os quais utilizaram uma climatologia da Energia Potencial Disponível para a Convecção (CAPE), para verificar a possibilidade da ocorrência de convecção e associando esse índice a eventos extremos de precipitação em Belém-PA. Os resultados mostraram, que a CAPE não é condição suficiente para a formação de nuvens e, consequentemente, de precipitação, pois há outras forçantes de meso e grande escala que contribuem decisivamente para a modulação do clima da cidade.…”