Search results for "Water content"
showing 10 items of 380 documents
Gaussian processes retrieval of leaf parameters from a multi-species reflectance, absorbance and fluorescence dataset.
2013
Abstract: Biochemical and structural leaf properties such as chlorophyll content (Chl), nitrogen content (N), leaf water content (LWC), and specific leaf area (SLA) have the benefit to be estimated through nondestructive spectral measurements. Current practices, however, mainly focus on a limited amount of wavelength bands while more information could be extracted from other wavelengths in the full range (400-2500 nm) spectrum. In this research, leaf characteristics were estimated from a field-based multi-species dataset, covering a wide range in leaf structures and Chl concentrations. The dataset contains leaves with extremely high Chl concentrations (>100 mu g cm(-2)), which are seldom es…
Application of microwaves dielectric spectroscopy for controlling pork meat (Longissimus dorsi) salting process
2010
Abstract Salting treatment is a common operation in the production of high quality meat products, one of its main problems is the difficulty to control the simultaneous water and salt fluxes into the product and control the protein fibers transformation throughout process. Dielectric properties of salted porcine meat are strongly related to its structure and composition. Thus, dielectric properties measurement appears as a promising method for controlling on-line the salting process in meat industry. Dielectric spectroscopy studies have been performed on raw and salted Longissimus dorsi pork samples. Dielectric spectra were measured in the frequency range from 500 MHz to 20 GHz by an Agilen…
Soil water content monitoring: a verification of thermal inertia approaches on low spatial, high temporal resolutions images
2013
Soil water content is directly connected with soil evaporation and plant transpiration processes; in particular, soil water content within the root zone, is readily available to evapotranspiration. Thus, in agricultural sciences, the assessment of the spatial distribution of soil water content could be of utmost importance in evaluating crop water requirement. In spite of limitations to applicability due to contingent cloud cover, water content of the upper part of the soil can be determined by applying the thermal inertia approach by coupling optical and thermal infrared images. The thermal inertia formulation, rigorously retrieved on bare soil, has been also verified on soils partially co…
Critical analysis of the thermal inertia approach to map soil water content under sparse vegetation and changeable sky conditions
2012
The paper reports a critical analysis of the thermal inertia approach to map surface soil water content on bare and sparsely vegetated soils by means of remotely sensed data. The study area is an experimental area located in Barrax (Spain). Field data were acquired within the Barrax 2011 research project. AHS airborne images including VIS/NIR and TIR bands were acquired both day and night time by the INTA (Instituto Nacional de Tecnica Aeroespacial) between the 11 th and 13 rd of June 2011. Images cover a corn pivot surrounded by bare soil, where a set of in situ data have been collected previously and simultaneously to overpasses. To validate remotely sensed estimations, a preliminary prox…
Influence of heterogeneous freezing on the microphysical and radiative properties of orographic cirrus clouds
2013
The influence of heterogeneous freezing on the microphysical and optical properties of orographic cirrus clouds has been simulated with the large eddy simulation model EULAG. Idealised simulations with different concentrations of ice nuclei (IN) in a dynamically dominated regime with high vertical velocities have been performed. Furthermore the temperature at cloud formation as well as the critical supersaturation for initiation of heterogenous freezing have been varied. The shortwave, longwave and net cloud forcing has been calculated under the assumption that the clouds form between 06:00 and 12:00 local time (LT) or between 12:00 and 18:00 LT. In general it can be seen that the onset of …
A numerical model of the cloud-topped planetary boundary-layer: Impact of aerosol particles on the radiative forcing of stratiform clouds
1997
In a numerical sensitivity study, the microphysical model of stratus MISTRA, is used to investigate the impact of aerosol particles on the evolution of stratiform clouds. Four model runs are presented, each for a different type of background aerosol. Two include aerosol particle size-distributions which are typical of marine and rural continental air masses; a third represents a mixture of marine and rural continental aerosol particles, and the fourth rural continental aerosol particles with a reduced solubility in water. The results show that the microphysical structure of layer clouds was strongly affected by the physico-chemical properties of the aerosol particles from which the cloud dr…
A numerical model of the cloud-topped planetary boundary-layer: radiative forcing of aerosols in stratiform clouds
1998
In a numerical sensitivity study with the microphysical stratus model MISTRA the impact of aerosol particles on the time evolution of stratiform clouds is investigated. Four model runs with different aerosol size distributions are presented. Two size distributions are typical for maritime and continental air masses. The third model run consists of a mixture of maritime and rural aerosol particles, while in the fourth case study rural aerosol particles with a reduced water solubility are utilized. The numerical results show that the microphysical structure of the clouds is strongly affected by the physico-chemical properties of the aerosol particles. In the maritime case, with a relatively l…
Riming of Graupel: Wind Tunnel Investigations of Collection Kernels and Growth Regimes
2009
Abstract Laboratory experiments were carried out in the vertical wind tunnel in Mainz, Germany, to study the collision coalescence growth of single spherical ice particles having initial radii between 290 and 380 μm while they were freely floated in a laminar flow containing a cloud of supercooled droplets with radii between 10 and 20 μm. The experiments were performed in a temperature range between −8 and −12°C, where riming proceeds in the atmosphere, and with cloud liquid water contents lying between 0.9 and 1.6 g m−3 (i.e., values typically found in mixed-phase clouds). The collection kernels were calculated from the mass increase of the rimed ice particles and the average liquid water …
Cloud Particle Interactions
2010
In Chapter 10, we discussed the behavior of isolated cloud particles in sorne detai1. Now we shall consider their hydrodynamic interactions, with a view to providing a quantitative assessment of the processes of particle growth by collision and coalescence, and of collisional breakup. We shall first treat the collision problem for drops of radii less than about 500 μm which, in accordance with our previous description of drop distortion in Section 10.3.2, may be regarded as rigid spheres (at least when falling in isolation). This will be followed by a discussion of the phenomena of drop coalescence and breakup. Finally, we shall consider water drop-ice crystal and ice crystal-ice crystal in…
Growth of Cloud Drops by Collision, Coalescence and Breakup
2010
As we have already learned from our brief historical review in Chapter 1, it has long been established that the presence of ice is not always necessary for precipitation formation in clouds. In more recent times, radar observations have confirmed this early conclusion. In such cases, the flow of water up the spectrum from small droplets to rain must occur by the process of collision and coalescence of drops. This is often referred to as the collection process, and sometimes erroneously as the ‘warm rain’ process. The latter designation is somewhat inappropriate, since collection growth also occurs in clouds colder than 0°C (Braham, 1964).