4,033 research outputs found
High-resolution methods for fluorescence retrieval from space
The retrieval from space of a very weak fluorescence signal was studied in the O2A and O2B oxygen atmospheric absorption bands. The accuracy of the method was tested for the retrieval of the chlorophyll fluorescence and reflectance terms contributing to the sensor signal. The radiance at the top of the atmosphere was simulated by means of a commercial radiative-transfer program at a high resolution (0.1 cm-1). A test data set was generated in order to simulate sun-induced chlorophyll fluorescence at the top of the canopy. Reflectance terms were spectrally modeled using cubic splines and fluorescence by means of the sum of two Voigt functions. Sensor radiance residual minimization was performed in the presence of a multiplicative noise, thus ensuring that the sensor simulations were realistic. The study, which focused on the possibility of retrieving fluorescence with an accuracy better than 10%, was performed for instrument resolutions ranging from about 0.4 cm-1 to 2 cm-1 in order to test the algorithm for the characteristics of existing and planned hyper-spectral sensors. The algorithm was also used to retrieve fluorescence in the single O2A band at the OCO and TANSO-FTS instrument spectral resolution
Increasing insightful thinking in analytic geometry
Elsewhere in this issue Ferdinand Verhulst described the discussion of the interaction of anal-
ysis and geometry in the 19th century. In modern times such discussions come up again and again. As of 2014, synthetic geometry will not be part of the Dutch `vwo ¿ mathematics B¿
programme anymore. Instead, the focus will be more on analytic geometry. Mark Timmer and Nellie Verhoef explored possibilities to connect the two disciplines in order to have students look at analytical exercises from a more synthetic point of vie
Technique for validating remote sensing products of water quality
Remote sensing of water quality is initiated as an additional part of the on going activities of the EAGLE2006 project.
Within this context intensive in-situ and airborne measurements campaigns were carried out over the Wolderwijd and
Veluwemeer natural waters. However, in-situ measurements and image acquisitions were not simultaneous. This poses
some constraints on validating air/space-borne remote sensing products of water quality. Nevertheless, the detailed insitu
measurements and hydro-optical model simulations provide a bench mark for validating remote sensing products.
That is realized through developing a stochastic technique to quantify the uncertainties on the retrieved aquatic inherent
optical properties (IOP).
The output of the proposed technique is applied to validate remote sensing products of water quality. In this processing
phase, simulations of the radiative transfer in the coupled atmosphere-water system are performed to generate spectra
at-sensor-level. The upper and the lower boundaries of perturbations, around each recorded spectrum, are then modelled
as function of residuals between simulated and measured spectra. The perturbations are parameterized as a function of
model approximations/inversion, sensor-noise and atmospheric residual signal. All error sources are treated as being of
stochastic nature. Three scenarios are considered: spectrally correlated (i.e. wavelength dependent) perturbations,
spectrally uncorrelated perturbations and a mixed scenario of the previous two with equal probability of occurrence.
Uncertainties on the retrieved IOP are quantified with the relative contribution of each perturbation component to the
total error budget of the IOP.
This technique can be used to validate earth observation products of water quality in remote areas where few or no in–
situ measurements are available
P05.60. Dragon boat racing: an evaluation of its influence on the health-related quality of life of breast cancer survivors
Scale, Scope and Cognition: Context Analysis of Multiple Stated Choice Experiments on the Values of Life and Limb
Composite Valuation of Immaterial Damage in Flooding: Value of Statistical Life, Value of Statistical Evacuation and Value of Statistical Injury
The battle of the brands : the formulation and explorative empirical testing of a typology of strategic reactions of leading national brands against private labels
Decision-making about complementary and alternative medicine by cancer patients: integrative literature review
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