scholarly journals From zero to infinity: minimum to maximum diversity of the planet by spatio-parametric Rao’s quadratic entropy

2021 ◽  
Author(s):  
Duccio Rocchini ◽  
Matteo Marcantonio ◽  
Daniele Da Re ◽  
Giovanni Bacaro ◽  
Enrico Feoli ◽  
...  
Keyword(s):  
Satellite Image ◽  
Diversity Indices ◽  
Spatial Uncertainty ◽  
Species Determination ◽  
Quadratic Entropy ◽  
In Situ Data ◽  
Rao’S Quadratic Entropy ◽  
Work Done ◽  
First Time

AbstractAimThe majority of work done to gather information on Earth diversity has been carried out by in-situ data, with known issues related to epistemology (e.g., species determination and taxonomy), spatial uncertainty, logistics (time and costs), among others. An alternative way to gather information about spatial ecosystem variability is the use of satellite remote sensing. It works as a powerful tool for attaining rapid and standardized information. Several metrics used to calculate remotely sensed diversity of ecosystems are based on Shannon’s Information Theory, namely on the differences in relative abundance of pixel reflectances in a certain area. Additional metrics like the Rao’s quadratic entropy allow the use of spectral distance beside abundance, but they are point descriptors of diversity, namely they can account only for a part of the whole diversity continuum. The aim of this paper is thus to generalize the Rao’s quadratic entropy by proposing its parameterization for the first time.InnovationThe parametric Rao’s quadratic entropy, coded in R, i) allows to represent the whole continuum of potential diversity indices in one formula, and ii) starting from the Rao’s quadratic entropy, allows to explicitly make use of distances among pixel reflectance values, together with relative abundances.Main conclusionsThe proposed unifying measure is an integration between abundance- and distance-based algorithms to map the continuum of diversity given a satellite image at any spatial scale.

scholarly journals Harmonized in situ JECAM datasets for agricultural land use mapping and monitoring in tropical countries

2021 ◽  
Author(s):  
Audrey Jolivot ◽  
Valentine Lebourgeois ◽  
Mael Ameline ◽  
Valérie Andriamanga ◽  
Beatriz Bellón ◽  
...  
Keyword(s):  
Land Use ◽  
Agricultural Land ◽  
Satellite Image ◽  
Farming Systems ◽  
Agricultural Land Use ◽  
In Situ Data ◽  
Agricultural Census ◽  
Crop Types ◽  
The Tropics

Abstract. The availability of crop type reference datasets for satellite image classification is very limited for complex agricultural systems as observed in developing and emerging countries. Indeed, agricultural land use is very dynamic, agricultural census are often poorly georeferenced, and crop types are difficult to photo-interpret directly from satellite imagery. In this paper, we present nine datasets collected in a standardized manner between 2013 and 2020 in seven tropical and subtropical countries within the framework of the international JECAM (Joint Experiment for Crop Assessment and Monitoring) initiative. These quality-controlled datasets are distinguished by in situ data collected at field scale by local experts, with precise geographic coordinates, and following a common protocol. Altogether, the datasets completed 27 074 polygons (20 257 crop and 6 817 non-crop) documented by detailed keywords. These datasets can be used to produce and validate agricultural land use maps in the tropics, but also, to assess the performances and the robustness of classification methods of cropland and crop types/practices in a large range of tropical farming systems. The dataset is available at https://doi.org/10.18167/DVN1/P7OLAP.

scholarly journals A method for monitoring hydrological conditions beneath herbaceous wetlands using multi-temporal ALOS PALSAR coherence data

2015 ◽  
Vol XL-7/W4 ◽  
pp. 221-226 ◽  
Author(s):  
M. Zhang ◽  
Z. Li ◽  
B. Tian ◽  
J. Zhou ◽  
J. Zeng
Keyword(s):  
Effective Area ◽  
Interferometric Synthetic Aperture Radar ◽  
Alos Palsar ◽  
Hydrological Conditions ◽  
In Situ Data ◽  
Key Indicator ◽  
Multi Temporal ◽  
First Time ◽  
Good Agreement

Reed marshes, the world’s most widespread type of wetland vegetation, are undergoing major changes as a result of climate changes and human activities. The presence or absence of water in reed marshes has a significant impact on the whole ecosystem and remains a key indicator to identify the effective area of a wetland and help estimate the degree of degeneration. Past studies have demonstrated the use of interferometric synthetic aperture radar (InSAR) to map water-level changes for flooded reeds. However, the identification of the different hydrological states of reed marshes is often poorly understood. The analysis given in this paper shows that L-band interferometric coherence is very sensitive to the water surface conditions beneath reed marshes and so can be used as classifier. A method based on a statistical analysis of the coherence distributions for wet and dry reeds using InSAR pairs was, therefore, investigated in this study. The experimental results were validated by in-situ data and showed very good agreement. This is the first time that information about the water cover under herbaceous wetlands has been derived using interferometric coherence values. This method can also effectively and easily be applied to monitor the hydrological conditions beneath other herbaceous wetlands.

scholarly journals Coronal transients during two solar minima: their source regions and interplanetary counterparts

2011 ◽  
Vol 7 (S286) ◽  
pp. 149-153
Author(s):  
Hebe Cremades ◽  
Cristina H. Mandrini ◽  
Sergio Dasso
Keyword(s):  
Solar Corona ◽  
Coronal Mass Ejections ◽  
Magnetic Clouds ◽  
Time Intervals ◽  
Solar Source ◽  
In Situ Data ◽  
Source Regions ◽  
Multi Wavelength ◽  
First Time

AbstractWe have investigated two full solar rotations belonging to two distinct solar minima, in the frame of two coordinated observational and research campaigns. The nearly uninterrupted gathering of solar coronal data since the beginning of the SOHO era offers the exceptional possibility of comparing two solar minima for the first time, with regard to coronal transients. This study characterizes the variety of outward-travelling transients observed in the solar corona during both time intervals, from very narrow jet-like events to coronal mass ejections (CMEs). Their solar source regions and ensuing interplanetary structures were identified and characterized. Multi-wavelength images from the space missions SOHO, Yohkoh and STEREO, and ground-based observatories were studied for coronal ejecta and their solar sources, while in situ data registered by the ACE spacecraft were inspected for interplanetary CMEs and magnetic clouds. Instrumental aspects such as dissimilar resolution, cadence, and fields of view are considered in order to discern instrumentally-driven disparities from inherent differences between solar minima.

Functional diversity on rocky shores of the SW Atlantic: sewage effluents influence and mask the effects of the latitudinal gradient

2020 ◽  
Vol 648 ◽  
pp. 39-49
Author(s):  
GV Garaffo ◽  
EN Llanos ◽  
MA Saracho Bottero ◽  
E Hines ◽  
R Elías ◽  
...  
Keyword(s):  
Functional Diversity ◽  
Latitudinal Gradient ◽  
Diversity Indices ◽  
Rocky Shores ◽  
Quadratic Entropy ◽  
Sewage Effluents ◽  
Macrobenthic Assemblages ◽  
Sw Atlantic ◽  
Functional Diversity Indices ◽  
Rao’S Quadratic Entropy

Rocky shores are a transitional ecosystem between land and marine environments, and, together with other benthic coastal habitats, have a diverse macrobenthic community. Although there is enough information about the taxonomic diversity of Argentinean rocky shores, studies with a functional approach are scarce. We applied biological traits analysis and functional diversity indices to evaluate the geographic variation of the functional diversity of macrobenthic assemblages on rocky shores along a latitudinal gradient in the SW Atlantic (from 37° to 50°S). A total of 11 beaches with rocky hard substrate belonging to 2 biogeographical provinces (Magellanic and Argentinean) were studied during April 2016. The trait composition of macrobenthic assemblages and functional diversity indices (Rao’s quadratic entropy) varied significantly along the Argentinean coast, suggesting that the latitudinal gradient influences the distribution of species with respect to combinations of trait modalities. Rao’s quadratic entropy, species richness, evenness, and Shannon-Wiener diversity showed a pattern with higher values in the sites located in high latitudes. The functional diversity patterns found coincide with the biogeographical provinces. The presence of intertidal sewage effluents considerably influence functional diversity and mask the effects of the latitudinal gradient on the macrobenthic communities on rocky shores.

scholarly journals Detiding Measurement on Transport of the Changjiang-Derived Buoyant Coastal Current

2013 ◽  
Vol 43 (11) ◽  
pp. 2388-2399 ◽  
Author(s):  
Hui Wu ◽  
Bing Deng ◽  
Rui Yuan ◽  
Jun Hu ◽  
Jinghua Gu ◽  
...  
Keyword(s):  
Large River ◽  
Volume Transport ◽  
Surface Velocity ◽  
Coastal Current ◽  
In Situ Data ◽  
Freshwater Transport ◽  
Chinese Coast ◽  
First Time ◽  
O 10

Abstract Measuring the transport of the Changjiang (also known as the Yangtze) River–derived buoyant coastal current, that is, the Min–Zhe Coastal Current, is of great importance for understanding the fate of terrestrial materials from this large river into the open ocean, but it is usually difficult to achieve because of the energetic tidal currents along the Chinese coast. In February 2012, a detiding cruise survey was carried out using the phase-averaging method. For the first time, this coastal current has been quantified with in situ data and has been shown to have a volume transport of 0.215 Sv (1 Sv ≡ 106 m3 s−1) and a maximum surface velocity of ~50 cm s−1. The ratio between the volume transport of the buoyant coastal current and that of the Changjiang is O(10). Freshwater transport by the buoyant coastal current accounts for over 90% of the Changjiang River's discharge. Buoyancy and winds are both important in driving this current.

scholarly journals Harmonized in situ datasets for agricultural land use mapping and monitoring in tropical countries

2021 ◽  
Vol 13 (12) ◽  
pp. 5951-5967
Author(s):  
Audrey Jolivot ◽  
Valentine Lebourgeois ◽  
Louise Leroux ◽  
Mael Ameline ◽  
Valérie Andriamanga ◽  
...  
Keyword(s):  
Land Use ◽  
Agricultural Land ◽  
Satellite Image ◽  
Farming Systems ◽  
Agricultural Land Use ◽  
In Situ Data ◽  
Assessment And Monitoring ◽  
Crop Types ◽  
The Tropics

Abstract. The availability of crop type reference datasets for satellite image classification is very limited for complex agricultural systems as observed in developing and emerging countries. Indeed, agricultural land use is very dynamic, agricultural censuses are often poorly georeferenced and crop types are difficult to interpret directly from satellite imagery. In this paper, we present a database made of 24 datasets collected in a standardized manner over nine sites within the framework of the international JECAM (Joint Experiment for Crop Assessment and Monitoring) initiative; the sites were spread over seven countries of the tropical belt, and the number of data collection years depended on the site (from 1 to 7 years between 2013 and 2020). These quality-controlled datasets are distinguished by in situ data collected at the field scale by local experts, with precise geographic coordinates, and following a common protocol. Altogether, the datasets completed 27 074 polygons (20 257 crops and 6817 noncrops, ranging from 748 plots in 2013 (one site visited) to 5515 in 2015 (six sites visited)) documented by detailed keywords. These datasets can be used to produce and validate agricultural land use maps in the tropics. They can also be used to assess the performances and robustness of classification methods of cropland and crop types/practices in a large range of tropical farming systems. The dataset is available at https://doi.org/10.18167/DVN1/P7OLAP (Jolivot et al., 2021).

scholarly journals Validation of a method for determining the depth of glacial melt ponds using satellite imagery

2011 ◽  
Vol 52 (59) ◽  
pp. 15-22 ◽  
Author(s):  
William A. Sneed ◽  
Gordon S. Hamilton
Keyword(s):  
Satellite Imagery ◽  
Satellite Image ◽  
Minor Effect ◽  
Melt Pond ◽  
In Situ Data ◽  
Melt Ponds ◽  
Simplifying Assumptions ◽  
A Minor ◽  
Water Depths

AbstractIn situ measurements of water depth and optical properties of a melt pond in East Greenland were collected to verify a previously developed algorithm for determining supraglacial water depths using satellite imagery. That algorithm made five simplifying assumptions which we have tested using the in situ data and laboratory analysis of water samples. We conclude that three assumptions were justified, one was not and the remaining one (substrate homogeneity) requires further study, but probably has a minor effect on the retrieved water depths and volumes. Measured water depths of 0.2–3.0m agree well with those derived from a satellite image using the algorithm. Numerically modeled depths also agree well with those from the satellite image. This new analysis demonstrates the validity of our algorithm as a means for determining meltwater volumes in supraglacial ponds and lakes.

Thysanoptera diversity associated with Mexican lemon (Citrus aurantifolia Christm.)

2020 ◽  
Vol 13 (9) ◽  
Author(s):  
Francisco Javier Avendaño-Gutiérrez ◽  
Salvador Aguirre Paleo ◽  
Alejandro Morales Hernández ◽  
Venecia Quesadas-Béjar
Keyword(s):  
Biosphere Reserve ◽  
Simple Random Sampling ◽  
Diversity Indices ◽  
Diaphorina Citri ◽  
Program Calculation ◽  
Homogeneous Relation ◽  
Candidatus Liberibacter ◽  
Scirtothrips Citri ◽  
Species Richness And Abundance ◽  
First Time

Objective: To calculate the monthly relative abundance of Thysanoptera species, according to the Margalef, Simpson and Shannon-Wiener diversity indices. Design / Methodology / Approach: The work was carried out in three geographic units with conventional management, during January-December, 2019 in the Reserva de la Biosfera Zicuirán-Infiernillo (Biosphere Reserve), Michoacán, Mexico. In each unit, 10 trees were selected through simple random sampling. Thrips counts were performed on ten shoots per tree every 15 d, for a total of 7200 shoots in the three geographic units. Thysanoptera individuals were placed in entomological jars. The variables were: number of thrips collected per shoot in sampled tree and geographic unit (orchard). To estimate the specific richness and structure of species, the program "calculation of diversity indices DIVERS" was used. Results: In the three geographical units studied, the recorded presence of Thysanoptera accounted for 12 to 17 species. For Nueva Italia 12 recorded species, two were permanent (16.66%), five abundant (41.66%), one scarce (8.3%) and four rare (33.33%). In Zicuirán, three species were permanent (17.64%), six abundant (35.29%), two scarce (11.76%) and six rare (35.29%). In Los Hoyos, four species were permanent (26.66%), four abundant (26.66%) and seven rare (46.66%). The abundance of species was represented by the genus Frankliniella and the species Scolothrips sexmaculatus and Scirtothrips citri. The highest species richness and abundance was found from January to May. In October and November, the value of the calculated indices was zero, which shows less richness and abundance of individuals. The best species uniformity was recorded during January and December, which meant a more stable and homogeneous relation. Study limitations/Implications. Pest resurgence, presence of Candidatus Liberibacter spp. and its vector Diaphorina citri. Findings / Conclusions: in Nueva Italia, 12 species were taxonomically determined; in Los Hoyos 15, and in Zicuirán 17 species, which are reported for the first time in the state of Michoacán, Mexico. At the geographic unit "Los Hoyos" diversity was higher, uniform and stable.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

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