Centro de Previsão de Tempo e Estudos Climáticos, Instituto Nacional de Pesquisas Espaciais, Cachoeira Paulista, Postal Code: 12630-000, Brazil
Eniuce Menezes de Souza
Departamento de Estatística - Universidade Estadual de Maringá, Maringá, Postal Code: 87020-900, Brazil
Thamiris B. Campos
Programa de Pós Graduação em Meteorologia, Instituto Nacional de Pesquisas Espaciais, São José dos Campos Postal Code: 12227-010, Brazil
Abstract. A rapid increase in atmospheric water vapor is a fundamental ingredient for many intense rainfall events. High-frequency precipitable water vapor (PWV) estimates from a Global Positioning System meteorological site (GPS) are evaluated here for intense rainfall events during the CHUVA Vale field campaign in Brazil (November–December 2011), in which precipitation events of differing intensities and spatial dimensions, as observed by an X-band radar, have been explored. A wavelet cross-correlation analysis shows that there are important spikes in the PWV that precede the more intense rainfall events on a timescale from 30 to 60 minutes. The correlation and lags between the GPS-PWV and rainfall events are evaluated, and a sharp increase in the GPS-PWV prior to the more intense events has been found and termed GPS-PWV "jumps". These jumps are associated with water vapor convergence and the continued formation of cloud condensate and precipitation particles. The GPS-PWV time-derivative histogram for the period of 60 minutes before the rainfall event reveals different distributions for higher intensity events. This feature could indicate the occurrence of severe precipitation and consequently has the potential for application in nowcasting activities.
How to cite. Sapucci, L. F., Machado, L. A. T., Menezes de Souza, E., and Campos, T. B.: GPS-PWV jumps before intense rain events, Atmos. Meas. Tech. Discuss. [preprint], https://doi.org/10.5194/amt-2016-378, 2016.
Received: 16 Nov 2016 – Discussion started: 28 Nov 2016
This study employs precipitable water vapor from a Global Positioning System (GPS-PWV) signal, in high time resolution, to be used as precursor information of intense rainfall events. A typical jump in the GPS-PWV values before the occurrence of more intense rainfalls has been found, it is probably related to humid convergence occurring before intense rainfall events. The results from this manuscript create the physical basis for further development of a nowcasting tool in future studies.
This study employs precipitable water vapor from a Global Positioning System (GPS-PWV) signal,...