Search results for "Computers in Earth Science"

Improvement of the Valencia region ultraviolet index (UVI) forecasting system

2012

The CEAM Foundation (Valencia, Spain) has developed an operational ultraviolet index (UVI) forecasting system based on the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model. The main objective of this system is to provide the general public with a tool to minimize the impact of ultraviolet (UV) radiation, which can cause important human health problems. The system presented in this paper has been developed in collaboration with the Environment Department of the Regional Government of Valencia, and it replaces the one running until 2007. The new system substitutes the previously used Ozone Monitoring Instrument (OMI) observed data with the total ozone column data forecasted …

Correlation of oscillatory behaviour in Matlab using wavelets

2014

Here we present a novel computational signal processing approach for comparing two signals of equal length and sampling rate, suitable for application across widely varying areas within the geosciences. By performing a continuous wavelet transform (CWT) followed by Spearman?s rank correlation coefficient analysis, a graphical depiction of links between periodicities present in the two signals is generated via two or three dimensional images. In comparison with alternate approaches, e.g., wavelet coherence, this technique is simpler to implement and provides far clearer visual identification of the inter-series relationships. In particular, we report on a Matlab? code which executes this tec…

Determination of sea surface temperature at large observation angles using an angular and emissivity-dependent split-window equation

2007

Abstract This paper proposes an angular and emissivity-dependent split-window equation that permits the determination of the sea surface temperature (SST) to a reasonable level of accuracy for any observation angle, including large viewing angles at the image edges of satellite sensors with wide swaths. This is the case of the MODIS radiometer both on EOS Terra/Aqua platforms, with observation angles of up to 65° at the surface, for which the split-window equation has been developed in this study. The algorithm takes into account the angular dependence of both the atmospheric correction (due to the increase of the atmospheric optical path with angle) and the emissivity correction (since sea…

Retrieval of sun-induced fluorescence using advanced spectral fitting methods

2015

Abstract The FLuorescence EXplorer (FLEX) satellite mission, candidate of ESA's 8th Earth Explorer program, is explicitly optimized for detecting the sun-induced fluorescence emitted by plants. It will allow consistent measurements around the O2-B (687 nm) and O2-A (760 nm) bands, related to the red and far-red fluorescence emission peaks respectively, the photochemical reflectance index, and the structural-chemical state variables of the canopy. The sun-induced fluorescence signal, overlapped to the surface reflected radiance, can be accurately retrieved by employing the powerful spectral fitting technique. In this framework, a set of fluorescence retrieval algorithms optimized for FLEX ar…

Calibration of a camera-projector monochromatic system

2015

Camera–projector systems are increasingly being used in many different applications, including object reconstruction. In recent years, a number of approaches have been proposed to calibrate such devices; in this paper a calibration method is presented which can be used with monochromatic systems. The method is based on open-source code, makes use of planar calibration patterns, is fully automatic, easy to use and fast. Additionally, no initial information regarding the camera interior orientation is needed, and both sensors (camera and projector) are fully calibrated during the process. The method is validated by a series of tests, where root mean square errors (RMSEs) in image space are ke…

Multitemporal fusion of Landsat/TM and ENVISAT/MERIS for crop monitoring

2013

Abstract Monitoring Earth dynamics using current and future satellites is one of the most important objectives of the remote sensing community. The exploitation of image time series from sensors with different characteristics provides new opportunities to increase the knowledge about environmental changes and to support many operational applications. This paper presents an image fusion approach based on multiresolution and multisensor regularized spatial unmixing. The approach yields a composite image with the spatial resolution of the high spatial resolution image while retaining the spectral and temporal characteristics of the medium spatial resolution image. The approach is tested using …

Combining hectometric and decametric satellite observations to provide near real time decametric FAPAR product

2017

Abstract A wide range of ecological, agricultural, hydrological and meteorological applications at local to regional scales requires decametric biophysical data. However, before the launch of SENTINEL-2A, only few decametric products are produced and most of them remain limited by the small number of available observations, mostly due to a moderate revisit frequency combined with cloud occurrence. Conversely, kilometric and hectometric biophysical products are now widely available with almost complete and continuous coverage, but the associated spatial resolution limits the application over heterogeneous landscapes. The objective of this study is to combine unfrequent decametric spatial res…

2021

Abstract We propose a signal deconvolution procedure for imaging spectrometer data, where a measured point spread function (PSF) is deconvolved itself before being used for deconvolution of the signal. We evaluate the effectiveness of our procedure for improvement of the spatio-spectral signal, as well as our target application, i.e. estimation of sun-induced fluorescence (SIF). Imaging spectrometers are well established instruments for remote sensing. When used for scientific purposes these instruments are usually calibrated on a regular basis. In our case the point spread function of the optics is measured in an elaborate procedure with a tunable monochromator point light source. PSFs are…

Economic analysis and energy valorisation of by-products of the wine supply chain: the case of the 'Mamertino wine PDO'

2018

The paper reports the analysis of biomass derived from maintenance of a vineyard, to assess its potential as an alternative energy source, instead of the usual disposal of the wine supply chain’s residuals. The site studied is within the province of Messina, Sicily, in the area of Mamertino wine PDO, a wine of superior quality. The analysis suggests that use of this kind of biomass may allow a fossil fuel such as liquefied petroleum gas (LPG) to be replaced by a wine wood chip biomass boiler, thus meeting economic and environmental criteria by reason of recycling for sustainability.

Pollution models and inverse distance weighting: some critical remarks

2013

International audience; When evaluating the impact of pollution, measurements from remote stations are often weighted by the inverse of distance raised to some nonnegative power (IDW). This is derived from Shepard's method of spatial interpolation (1968). The paper discusses the arbitrary character of the exponent of distance and the problem of monitoring stations that are close to the reference point. From elementary laws of physics, it is determined which exponent of distance should be chosen (or its upper bound) depending on the form of pollution encountered, such as radiant pollution (including radioactivity and sound), air pollution (plumes, puffs, and motionless clouds by using the cl…