In the present paper, the climatic variability over several time scales, from the year up to millennia is discussed. After reviewing some modelling efforts of the latter, it will be shown evidence that periods ranging from the year up to the century contain a great deal of variability that differs from that produced by a red noise process. The analysis is based on 50 years of precipitation data derived from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis. After transforming the data into a Gaussian index, known as the standardized precipitation index (SPI), the time evolution of this index has been studied, first over the globe and then zooming over Europe. It has been found that significative trends can be detected in the data. The technique here employed is a standard principal component analysis (PCA), which, for the case of the Gaussian field under study, exhausts the knowledge of the multivariate probability density function field. On these grounds some speculations on the interaction between drought occurrence and the North Atlantic Ocean circulation will be offered. (C) 2003 Elsevier B.V. All rights reserved.
Drought variability and its climatic implications / Bordi, Isabella; Sutera, Alfonso. - In: GLOBAL AND PLANETARY CHANGE. - ISSN 0921-8181. - 40:1-2(2004), pp. 115-127. (Intervento presentato al convegno International Conference on Global Climate Changes During the Late Quarternary tenutosi a ROME, ITALY nel MAY 03-04, 2001) [10.1016/s0921-8181(03)00102-4].
Drought variability and its climatic implications
BORDI, Isabella;SUTERA, Alfonso
2004
Abstract
In the present paper, the climatic variability over several time scales, from the year up to millennia is discussed. After reviewing some modelling efforts of the latter, it will be shown evidence that periods ranging from the year up to the century contain a great deal of variability that differs from that produced by a red noise process. The analysis is based on 50 years of precipitation data derived from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis. After transforming the data into a Gaussian index, known as the standardized precipitation index (SPI), the time evolution of this index has been studied, first over the globe and then zooming over Europe. It has been found that significative trends can be detected in the data. The technique here employed is a standard principal component analysis (PCA), which, for the case of the Gaussian field under study, exhausts the knowledge of the multivariate probability density function field. On these grounds some speculations on the interaction between drought occurrence and the North Atlantic Ocean circulation will be offered. (C) 2003 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
