Inicio  /  Water  /  Núm: Vol. 11 Par: PP (PP)  /  Artículo
ARTÍCULO
TITULO

A 60-Year Time Series Analyses of the Upwelling along the Portuguese Coast

Francisco Leitão    
Vânia Baptista    
Vasco Vieira    
Patrícia Laginha Silva    
Paulo Relvas and Maria Alexandra Teodósio    

Resumen

Coastal upwelling has a significant local impact on marine coastal environment and on marine biology, namely fisheries. This study aims to evaluate climate and environmental changes in upwelling trends between 1950 and 2010. Annual, seasonal and monthly upwelling trends were studied in three different oceanographic areas of the Portuguese coast (northwestern?NW, southwestern?SW, and south?S). Two sea surface temperature datasets, remote sensing (RS: 1985?2009) and International Comprehensive Ocean?Atmosphere Data Set (ICOADS: 1950?2010), were used to estimate an upwelling index (UPWI) based on the difference between offshore and coastal sea surface temperature. Time series analyses reveal similar yearly and monthly trends between datasets A decrease of the UPWI was observed, extending longer than 20 years in the NW (1956?1979) and SW (1956?1994), and 30 years in the S (1956?1994). Analyses of sudden shifts reveal long term weakening and intensification periods of up to 30 years. This means that in the past 60 years a normal climate UPWI occurred along the Portuguese coast. An intensification of UPWI was recorded in recent decades regardless of the areas (RS: 1985?2009). Such an intensification rate (linear increase in UPWI) is only significant in S in recent decades (increase rate: ICOADS = 0.02 °C decade-1; RS = 0.11 °C decade-1) while in NW and SW the increase rate is meaningless. In NW more stable UPWI conditions were recorded, however average UPWI values increased in autumn and winter in NW in recently decades (RS: 1985?2009). An intensification rate of UPWI was recorded during summer (July, August and September) in SW and S in latter decades (RS: 1985?2009). The average UPWI values increased in recent decades in autumn in S. Marked phenological changes were observed in S in summer (before downwelling conditions prevail whilst recently when UPWI regimes prevail) with UPWI seasonal regime in S in recent decades becoming similar to those found in SW and NW. Results of this work can contribute to a better understanding of how upwelling dynamics affect/are correlated with biological data.

 Artículos similares

       
 
Jianzhao Liu, Liping Gao, Fenghui Yuan, Yuedong Guo and Xiaofeng Xu    
Soil water shortage is a critical issue for the Southwest US (SWUS), the typical arid region that has experienced severe droughts over the past decades, primarily caused by climate change. However, it is still not quantitatively understood how soil water... ver más
Revista: Water

 
Angel E. Muñoz-Zavala, Jorge E. Macías-Díaz, Daniel Alba-Cuéllar and José A. Guerrero-Díaz-de-León    
This paper reviews the application of artificial neural network (ANN) models to time series prediction tasks. We begin by briefly introducing some basic concepts and terms related to time series analysis, and by outlining some of the most popular ANN arc... ver más
Revista: Algorithms

 
Daniel Einarson, Fredrik Frisk, Kamilla Klonowska and Charlotte Sennersten    
Machine learning (ML) is increasingly used in diverse fields, including animal behavior research. However, its application to ambiguous data requires careful consideration to avoid uncritical interpretations. This paper extends prior research on ringed m... ver más
Revista: Applied Sciences

 
Xiongchuan Chen, Shuangcheng Zhang, Bin Wang, Guangwei Jiang, Chuanlu Cheng, Xin Zhou, Zhijie Feng and Jingtao Li    
The motion of a continuously operating reference station is usually dominated by the long-term crustal motions of the tectonic block on which the station is located. Monitoring changes in the coordinates of reference stations located at tectonic plate bo... ver más
Revista: Applied Sciences

 
Nicholas V. Sarlis, Efthimios S. Skordas, Stavros-Richard G. Christopoulos and Panayiotis K. Varotsos    
Here, we employ natural time analysis of seismicity together with non-extensive statistical mechanics aiming at shortening the occurrence time window of the Kahramanmaras-Gazientep M7.8 earthquake. The results obtained are in the positive direction point... ver más
Revista: Applied Sciences