João Filipe Santos

TL;DR: In this article, an analysis of droughts in mainland Portugal based on monthly precipitation data, from September 1910 to October 2004, in 144 rain gages distributed uniformly over the country is presented.

TL;DR: In this article, the frequency of droughts for the period September 1910 to October 2004 in mainland Portugal, based on monthly precipitation data from 144 rain gauges distributed across the country, were characterized using the standardized precipitation index (SPI) applied to time scales of 1, 3, 6 and 12 consecutive months.

TL;DR: In this paper, the authors test the ability of neural network approaches to hindcast the spring standardized precipitation index on a 6-month time scale (SPI6) in Portugal, based on winter large-scale climatic indices.

TL;DR: In this article, regional drought modes in Portugal are identified applying the Principal Component Analysis (PCA) and Varimax rotation to the Standardized Precipitation Index (SPI) computed on various time scales using the three precipitation datasets covering the period 1950-2003: (i) the observation dataset composed of 193 rain-gauges distributed almost uniformly over the country, (ii) the PT02 high-resolution gridded dataset provided by the Portuguese Meteorological Institute, and (iii) the GPCC dataset with 0.5° spatial resolution.

TL;DR: In this paper, a region comprising Paraguay, southern Brazil and northeastern Argentina was analyzed using principal component analysis (PCA) and a new approach, the Kernel occurrence rate estimation method coupled with bootstrap confidence band was used to quantify yearly drought occurrence rates.