Bower ratio-energy balance associated errors in vineyards under dripping irrigation

Abstract

This study was conducted at the Bebedouro Experimental Station in Petrolina-PE, Brazil, to evaluate the errors associated to the application of the Bowen ratio-energy balance in a 3-years old vineyard (Vitis vinifera, L), grown in a trellis system, irrigated by dripping. The fi eld measurements were taken during fruiting cycle (July to November, 2001), which was divided into eigth phenological stages. A micrometeorological tower was mounted in a grape-plants row in which sensors of net radiation, global solar radiation and wind speed were installed at about 1.0 m above the canopy. Also in the tower, two psicometers were installed at two levels (0.5 and 1.8 m) above the vineyard canopy. Two soil heat fl ux plates were buried at 0.02 m beneath the soil surface. All these sensors were connected to a Data logger 21 X of Campbell Scientifi c Inc., programmed for collecting data once every 5 seconds and storage averages for every 15 minutes. A comparative analysis were made among four Bowen ratio accepting/rejecting rules, according to the methodology proposed by Spano et al. (2000): βr1 -values of β calculated by Bowen (1926) equation; βr2 -values of β as proposed by Verma et al. (1978) equation; βr3 -exclusion of the β values obtained as recommended by Unland et al. (1996) and βr4 -exclusion of the β values calculated as proposed by Bowen (1926), out of the interval (-0.7 < β < 0.7). Constacted that the Unland et al. (1996) and Soares (2003) accepting/rejection rules were better than that of Verma et al. (1978) for attenuating the advective effects on the calculations of the Bowen ratio. The comparison of βr1 with βr2 rules showed that the statistical errors reaching maximum values of 0.015. When comparing βr1 with βr3 e βr4, the β errors reaching maximum values of 5.80 and 3.15, respectively. Keywords: latent and sensible heat fl uxes, evapotranspiration, semi-arid region. RESUMO: ERROS ASSOCIADOS PELA RAZÃO DE BOWEN AO BALANÇO DE ENERGIA EM PARREIRAIS SOB IRRIGAÇÃO POR GOTEJAMENTO.Este estudo foi conduzido na Estação Experimental de Bebedouro, Petrolina-PE, Brasil, para avaliar os erros associados com a aplicação do balanço de energia com base na razão de Bowen em um parreiral (Vitis vinifera, L) com três anos de idade, conduzido em latada, sob irrigação por gotejamento. As medições foram feitas durante o ciclo produtivo de julho a novembro de 2001, que foi dividido em oito estádios fenológicos. Numa torre micrometeorológica localizada no centro do parreiral, foram instalados a 1,00 m acima do dossel da videira, os seguintes instrumentos: saldo radiômetro, radiômetro global e anemômetro; a 0,5 e 1,80 m acima do dossel dois psicrômetros e a 0,02m de profundidade dois fl uxímetros. Todos esses sensores foram conectados a um datalogger CR 21X programado para coletar dados a cada 5s e armazenar média a cada 15 minutos, durante 24h00 por dia. Foi feita análise comparativa entre quatro metodologias ou regras de aceitação/rejeição da razão de Bowen, utilizando a metodologia proposta por Spano et al. (2000), co...

Diurnal Energy Balance in a Mango Orchard in the Northeast of Pará, Brazil

“…The type of instruments used by the other authors also contributed to the differences obtained. The Bowen ratio method is based on vertical profiles of air temperature and water vapor pressure, with several measuring instruments such as automatic systems based on a single cooled dew point hygrometer and thermocouple profiles (Silva, et al, 2005;Savage et al, 2009), through integrated sensors of temperature (resistors) and relative humidity (capacitors) (Todd et al, 2000, Savage et al, 2010, or even by simple equipments based on dry and wet bulb thermocouple profiles (Soares et al, 2007).…”

“…However, the accuracy and precision of the method in estimating the energy balance depend not only on atmospheric conditions (Teixeira and Bastiaanseen, 2012), or on data quality control method (Soares et al, 2007), but mainly on quality of the data and of the error inherent in the type of sensor used (Savage et al, 2010).…”

Bitki Yüzeyinin Enerji Dengesi Bileşenlerinin Belirli Fenolojik Aşamalarda Analizi

“…Çalışmada kararsız atmosfer koşulları ile Bowen Oranı'nın minimum değerleri arasındaki ilişki ortaya konmuştur [7]. Brezilya'da üzüm bağlarında yürütülen bir araştırma çalışmasında, BREB Yöntemi'nin damla sulama uygulaması altında geçerliliği dört farklı yaklaşımla test edilmiştir [8]. Mısır bitkisinin transpirasyonundan kaynaklanan buharlaşma gizli ısı akısının, yüzeyin toplam evapotranspirasyonunun gizli ısı akı miktarı ile ilişkisinin incelenmesine yönelik Japonya'da yürütülen bir araştırmada BREB ve ağırlıklı lizimetre ölçüm sonuçları karşılaştırmalı olarak ortaya konmuş ve sonuçta BREB yaklaşımının özellikle bitkinin su kullanım etkinliğinin arttırılması araştırmalarında tercih edilebilir olduğu saptanmıştır [9] [15].…”