Variabilidade temporal da evapotranspiração real e da razão entre evapotranspiração real e potencial em Campinas, Estado de São Paulo

Abstract

Temporal variability of the actual evapotranspiration and the ratio between actual and potential evapotranspiration in Campinas, State of São Paulo, Brazil AbstractThe aim of the work was to characterize the temporal variability of ten-day evapotranspiration series, considering the actual evapotranspiration (ETa) and the ratio between actual and potential evapotranspiration (ETa/ETP). Data between 1948 and 2008 were collected with a weather station in Campinas, State of São Paulo, Brazil. Evapotranspiration calculation considered three values of soil water availability (SWA): 50, 100, and 150 mm. Based on autocorrelation function, it was detected a significant level of temporal persistence on ETa and ETa/ETP series. The acf also has indicated that this temporal persistence tends to increase due to high SWA values. The spectral analysis has shown a decreasing power of these series after 1976. The El Niño/southern oscillation influence on ETa and ETa/ETP temporal variability was not conclusive. The Seasonal Mann-Kendall test has shown increasing trends on ETa series in the months of January, May, July, September, November and December. The ETa/ETP series was little affected by the increasing trends detected on ETP series.

Removing the influence of the serial correlation on the Mann-Kendall test

“…Considering only the period between 2002 and 2012, authors such as Yue et al (2002), Elnur, 2002, Adamowski andBougadis (2003), , Yue and Hashino (2003), Burn et al (2004), Yue and Pilon (2004), Sansigolo (2008), Sansigolo and Kayano (2010), Tabari and Talaee (2011), Blain (2011a,b,c), Minuzzi et al (2011), Blain and Pires (2011), Streck et al (2011), Back et al (2012 and Blain (2012a,b) used this test to evaluate signals of climate change in several parts of the Globe. As a consequence of this widespread use, several scientific studies have addressed the strengths and the limitations of this statistical test (Blain, 2013).…”

The modified Mann-Kendall test: on the performance of three variance correction approaches

“…Considering only the years 2010 to 2013, authors such as Back et al (2012); Blain (2010;2011a,b,c;2012a,b;2013); Blain and Pires (2011); Carvalho et al (2013); Minuzzi et al (2011); Sansigolo and Kayano (2010); Streck et al (2011); Tabari and Talaee (2011) and Weng (2010) used this test to evaluate the presence of significant climate trends in distinct parts of the world.…”

“…In this view, the presence of a significant positive serial correlation increases the number of false rejections of the above-mentioned H 0 (Hamed and Rao, 1998;Khaliq et al, 2009;Önöz and Bayazit, 2011;von Storch and Navarra, 1995;Yue et al, 2002;Yue and Wang, 2004). Naturally, this drawback associated with the use of the original MK test is of particular interest for (agro/hydro)meteorological studies given that (agro/hydro) meteorological variables frequently exhibit some form of positive serial correlation (Blain and Pires, 2011;Wilks, 2011, among many others).…”

Validação do zoneamento agrícola de risco climático para soja no município de Regeneração, PI

“…A ETo apresenta variabilidade espacial e temporal menor do que a precipitação pluvial, por ser estimada com base em elementos climáticos de baixa variabilidade tais como a temperatura do ar, umidade relativa do ar e radiação solar global (Oliveira, 2018). Assim, as indicações de datas de semeadura de baixo risco são por causa do efeito da precipitação sobre o balanço de água no solo (Blain & Pires, 2011).…”