Search results for "Transpiration"

Photosynthesis and Transpiration in Damaged and Undamaged Spruce Trees

1996

Abstract The investigations presented here focus on the CO2/H2O gas exchange in damaged and undamaged spruce trees while using open-air measurements as well as measurements under defined conditions in the laboratory. The studies were performed at two different sites in the Hunsrück and the Westerwald mountains. In the laboratory the CO2/H2O gas exchange was measured on detached branches under controlled conditions in the course of two years. CO2 saturation curves were also generated. In addition CO2 compensation points were deter­ mined employing a closed system. In the natural habitat diurnal course measurements of photosynthesis and transpiration as well as light-saturation curves for pho…

Measurement of Photosynthesis and Transpiration in Spruce Trees with Various Degrees of Damage

1987

Summary In the context of a project on physiological and biochemical characterization of spruce with different degrees of damage, the C02 and H2O gas exchange of 22-year-old spruce from a location in the Hunsru.ck (West Germany) were measured in summer 1985. The measurements were carried out on shoots from 1984 and were set up as a pair comparison, i.e. the measurement data of a tree with symptoms of damage were always compared with a tree in the immediate vicinity which phenotypically showed less damage. Diurnal course measurements in the open air revealed a marked reduction of photosynthesis depending on the degree of damage of the trees. If one plots photosynthetic rate against light int…

Partitioning ET measurements for sparse vegetation: application to an olive orchard.

2011

Mapping daily evapotranspiration at field to global scales using geostationary and polar orbiting satellite imagery

2010

Abstract. Thermal infrared (TIR) remote sensing of land-surface temperature (LST) provides valuable information about the sub-surface moisture status required for estimating evapotranspiration (ET) and detecting the onset and severity of drought. While empirical indices measuring anomalies in LST and vegetation amount (e.g., as quantified by the Normalized Difference Vegetation Index; NDVI) have demonstrated utility in monitoring ET and drought conditions over large areas, they may provide ambiguous results when other factors (soil moisture, advection, air temperature) are affecting plant stress. A more physically based interpretation of LST and NDVI and their relationship to sub-surface mo…

Monitoring Water and Energy Cycles at Climate Scale in the Third Pole Environment (CLIMATE-TPE)

2021

A better understanding of the water and energy cycles at climate scale in the Third Pole Environment is essential for assessing and understanding the causes of changes in the cryosphere and hydrosphere in relation to changes of plateau atmosphere in the Asian monsoon system and for predicting the possible changes in water resources in South and East Asia. This paper reports the following results: (1) A platform of in situ observation stations is briefly described for quantifying the interactions in hydrosphere-pedosphere-atmosphere-cryosphere-biosphere over the Tibetan Plateau. (2) A multiyear in situ L-Band microwave radiometry of land surface processes is used to develop a new microwave r…

The use of shallow dripwater as an isotopic marker of seepage in karst areas: A comparison between Western Sicily (Italy) and the Harz Mountains (Ger…

2013

Abstract The isotopic signature of slow-flowing dripwater collected in caves located in Western Sicily (Italy) was determined for evaluating its possible use as an isotopic tracer of the local groundwater recharge. These spot measures were compared with a longer series of local rain and spring compositions and with other samples taken, under different hydrogeological conditions, in caves of the Harz Mountains (Northern Germany). The slow flowing dripwater from Sicily showed δ 18 O/δD ratios similar to those of local rain and groundwater, demonstrating that these three are all parent waters. A parallel similarity was found in the vertical isotopic gradient (Δδ 18 O) of the three groups of wa…

Application of energy balance models for actual evapotranspiration assessment by means of airborne and satellite remote sensing data

2008

Effects of morphology on watershed actual evapotranspiration estimation by means of SEBAL model

2008

Comparative analysis of surface energy balance models for actual evapotranspiration estimation through remotely sensed images

2012

Pampa Biome Environmental Particularities Regarding to Energy Balance

2020

Ecosystem evapotranspiration (ET) has been quantified around the world by different methodologies to understand the energy balance, especially to control the evolution of climate change. It is known that the vegetation of the pampa biome is natural grasslands, it has a large variety of species (flora and fauna), however is it different in the environmental aspects related to the energy balance when compared to the grassland cultivated? In this study the objective was to analyze the environmental differences of the Pampa Biome related to the energy balance in comparison with the pastures cultivated in Barrax, Spain. In the first one the minimum daily ET is 0.99 mm/day, while in the second is…