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Estimating spatio-temporal air temperature in London (UK) using machine learning and earth observation satellite data / Rochelle Schneider dos Santos in International journal of applied Earth observation and geoinformation, vol 88 (June 2020)
[article]
Titre : Estimating spatio-temporal air temperature in London (UK) using machine learning and earth observation satellite data Type de document : Article/Communication Auteurs : Rochelle Schneider dos Santos, Auteur Année de publication : 2020 Article en page(s) : 10 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] algorithme du gradient
[Termes IGN] apprentissage automatique
[Termes IGN] chaleur
[Termes IGN] classification par forêts d'arbres décisionnels
[Termes IGN] ilot thermique urbain
[Termes IGN] image Aqua-MODIS
[Termes IGN] image Terra-MODIS
[Termes IGN] Londres
[Termes IGN] modèle de régression
[Termes IGN] mortalité
[Termes IGN] Normalized Difference Vegetation Index
[Termes IGN] politique publique
[Termes IGN] Python (langage de programmation)
[Termes IGN] régression linéaire
[Termes IGN] santé
[Termes IGN] station météorologique
[Termes IGN] température au sol
[Termes IGN] température de l'air
[Termes IGN] zone urbaineRésumé : (auteur) Urbanisation generates greater population densities and an increase in anthropogenic heat generation. These factors elevate the urban–rural air temperature (Ta) difference, thus generating the Urban Heat Island (UHI) phenomenon. Ta is used in the fields of public health and epidemiology to quantify deaths attributable to heat in cities around the world: the presence of UHI can exacerbate exposure to high temperatures during summer periods, thereby increasing the risk of heat-related mortality. Measuring and monitoring the spatial patterns of Ta in urban contexts is challenging due to the lack of a good network of weather stations. This study aims to produce a parsimonious model to retrieve maximum Ta (Tmax) at high spatio-temporal resolution using Earth Observation (EO) satellite data. The novelty of this work is twofold: (i) it will produce daily estimations of Tmax for London at 1 km2 during the summertime between 2006 and 2017 using advanced statistical techniques and satellite-derived predictors, and (ii) it will investigate for the first time the predictive power of the gradient boosting algorithm to estimate Tmax for an urban area. In this work, 6 regression models were calibrated with 6 satellite products, 3 geospatial features, and 29 meteorological stations. Stepwise linear regression was applied to create 9 groups of predictors, which were trained and tested on each regression method. This study demonstrates the potential of machine learning algorithms to predict Tmax: the gradient boosting model with a group of five predictors (land surface temperature, Julian day, normalised difference vegetation index, digital elevation model, solar zenith angle) was the regression model with the best performance (R² = 0.68, MAE = 1.60 °C, and RMSE = 2.03 °C). This methodological approach is capable of being replicated in other UK cities, benefiting national heat-related mortality assessments since the data (provided by NASA and the UK Met Office) and programming languages (Python) sources are free and open. This study provides a framework to produce a high spatio-temporal resolution of Tmax, assisting public health researchers to improve the estimation of mortality attributable to high temperatures. In addition, the research contributes to practice and policy-making by enhancing the understanding of the locations where mortality rates may increase due to heat. Therefore, it enables a more informed decision-making process towards the prioritisation of actions to mitigate heat-related mortality amongst the vulnerable population. Numéro de notice : A2020-448 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.jag.2020.102066 Date de publication en ligne : 10/02/2020 En ligne : https://doi.org/10.1016/j.jag.2020.102066 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95524
in International journal of applied Earth observation and geoinformation > vol 88 (June 2020) . - 10 p.[article]Object‐oriented tracking of thematic and spatial behaviors of urban heat islands / Rui Zhu in Transactions in GIS, Vol 24 n° 1 (February 2020)
[article]
Titre : Object‐oriented tracking of thematic and spatial behaviors of urban heat islands Type de document : Article/Communication Auteurs : Rui Zhu, Auteur ; Eric Guilbert, Auteur ; Man Sing Wong, Auteur Année de publication : 2020 Article en page(s) : pp 85 - 103 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] Chine
[Termes IGN] ilot thermique urbain
[Termes IGN] modèle conceptuel de données spatio-temporelles
[Termes IGN] modèle dynamique
[Termes IGN] modélisation spatiale
[Termes IGN] PostgreSQL
[Termes IGN] station météorologique
[Termes IGN] système de gestion de bases de données orientées objet
[Termes IGN] température au sol
[Termes IGN] zone urbaineRésumé : (auteur) Modeling thematic and spatial dynamic behaviors of urban heat islands (UHIs) over time is important for understanding the evolution of this phenomenon to mitigate the warming effect in urban areas. Although previous studies conceptualized that a UHI only has a single life cycle with spatial behaviors, a UHI can be detected to appear and disappear several times periodically in terms of thematic and spatial integrated behaviors. Such multiple behaviors have not yet been illustrated with proof or evidence. This study conceptualizes a UHI as an object which has thematic and spatial behaviors simultaneously and proposes several graphs to depict periodic life‐cycle transitions triggered by behaviors. The conceptualized behaviors have been modeled and implemented in an object‐relational database management system and temperature readings collected from numerous weather stations were interpolated as temperature images per hour. The results of this study indicate that the model could track the spatial and thematic evolution of UHIs continuously and reveal their periodical patterns and abnormal cases. Numéro de notice : A2020-102 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12586 Date de publication en ligne : 22/10/2019 En ligne : https://doi.org/10.1111/tgis.12586 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94693
in Transactions in GIS > Vol 24 n° 1 (February 2020) . - pp 85 - 103[article]Temporal and spatial high-resolution climate data from 1961 to 2100 for the German National Forest Inventory (NFI) / Helge Dietrich in Annals of Forest Science, vol 76 n° 1 (March 2019)
[article]
Titre : Temporal and spatial high-resolution climate data from 1961 to 2100 for the German National Forest Inventory (NFI) Type de document : Article/Communication Auteurs : Helge Dietrich, Auteur ; Thilo Wolf, Auteur ; Tobias Kawohl, Auteur ; Jan Wehberg, Auteur ; Gerald Kändler, Auteur ; Tobias Mette, Auteur ; Arno Röder, Auteur ; ürgen Böhner, Auteur Année de publication : 2019 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Allemagne
[Termes IGN] changement climatique
[Termes IGN] données environnementales
[Termes IGN] données météorologiques
[Termes IGN] historique des données
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] largeur de bande
[Termes IGN] modèle numérique de surface
[Termes IGN] productivité
[Termes IGN] rayonnement solaire
[Termes IGN] régression géographiquement pondérée
[Termes IGN] série temporelle
[Termes IGN] station météorologique
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) The “NFI 2012 environmental data base climate” is part of the environmental database of the German National Forest Inventory. It contains climate information for 26,450 inventory points generated from gridded daily climate data for 1961–2100 at a spatial resolution of 250 m. Grids are based on DWD-Observations and REMO EURO-CORDEX climate projections. Access to the databases is provided via the URL: https://doi.org/10.3220/DATA/20180823-102429. Associated metadata are available at https://agroenvgeo.data.inra.fr/geonetwork/srv/fre/catalog.search#/metadata/d0789030-c94e-4883-8d38-2a7332c98673. Numéro de notice : A2019-043 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-018-0788-5 Date de publication en ligne : 23/01/2019 En ligne : https://doi.org/10.1007/s13595-018-0788-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92049
in Annals of Forest Science > vol 76 n° 1 (March 2019)[article]
Titre : GNSS meteorology in spatially dense networks Type de document : Thèse/HDR Auteurs : Fabian Peter Hurter, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2014 Collection : Astronomisch-Geodätische Arbeiten in der Schweiz, ISSN 0025-6676 num. 91 Importance : 185 Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-37-6 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Bernese
[Termes IGN] données GNSS
[Termes IGN] météorologie
[Termes IGN] propagation du signal
[Termes IGN] retard troposphérique zénithal
[Termes IGN] signal GNSS
[Termes IGN] station GNSS
[Termes IGN] station météorologique
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] traitement du signalIndex. décimale : 30.84 Applications de géodésie spatiale à l'atmosphère Résumé : (auteur) Two basic products from GNSS meteorology have been investigated in detail: (a) the Zenith Total Delay (ZTD) and, (b) wet refractivity fields reconstructed from Zenith Wet Delays (ZWD).The thesis aims at quantifying the accuracies of GNSS-derived ZTDs and refractivities and at characterizing their temporal and spatial resolution. In a first study using operational radiosondes and Global Navigation Satellite System (GNSS) data from the Swiss meteorological station in Payerne, the following uncertainty figures are obtained: With respect to the radiosonde, the GNSS-derived ZTD has a 1–3mm dry bias. Annual systematic variations of the comparison are found to have an amplitude of 1–2 mm . Removal of most systematic effects from the GNSS minus radiosonde ZTD time series plus a thorough budget of the radiosonde uncertainties allows the derivation of the random GNSS uncertainties. In the winter half-year, the standard deviation is shown to be 2.5–3.5 mm , during the summer half-year we obtain 3.5–5.0 mm.
In a further study in the western part of Switzerland, wet refractivities have been derived on the basis of interpolated ZWDs from the Automatic GNSS Network for Switzerland (AGNES). The employed interpolation algorithm is termed least-squares collocation. It makes use of a deterministic function to describe the general parametric field and a correlation function describing the spatial and temporal correlations between the zenith wet delays. Corresponding wet refractivities show accuracies superior to results from tomographic reconstructions of a similar data set. Further inclusion of ground meteorological measurements of temperature and water vapour pressure im- prove the derived refractivities in the lowest 2 km of the troposphere. Radio occultations are added to the reconstruction. The data combination enables the extension of the radio occultation profiles down to the ground. It is also shown that the GNSS data largely contributes to the profile quality above the atmospheric boundary layer. Transformation of the wet refractivities to humidity values with temperature profiles from a radiometer in Payerne show accuracies of a similar order of mag nitude to those from numerical weather prediction analysis. Hence, application of the algorithm in nowcasting of rain or investigating boundary layer processes are envisaged.
The third part of the thesis investigates the results from a campaign network of 34 geodetic- grade receivers. They were deployed close to and around Zermatt (Switzerland) for one month in summer 2010. The stations were spaced at distances of a few kilometers from each other and at heights between 1600–3500 m above mean sea level. The mountainous region provides an excellent natural laboratory to investigate the influences affecting the accuracy of the ZTD. Additionally, the Alpine region is prone to small-scale fluctuations in the troposphere. Thus, the spatial and temporal variability of the ZTD has been investigated. The influences of satellite obstructions, antenna and receiver types and a number of processing strategies on the estimated ZTD are analysed and validated with measurements from radiosondes launched during the campaign. The analysis suggests that 1 hour temporal resolution should not be undercut for estimated ZTDs. A temporal resolution of 30 minutes introduces more noise without better following the tropospheric fluctuation. The horizontal variability observed in ZTDs indicates correlation scale lengths of a few kilometers. From comparison with radiosondes, the ZTD uncertainty is shown to have 4–6 mm standard deviation. Some stations show signs of systematic effects caused by multipath and low- quality antenna patterns. Through the GNSS-inherent negative correlation of height with zenith delay, both parameters are similarly affected by these systematic influences. The performance of the numerical weather prediction model COSMO-2 is characterized in terms of integrated atmospheric state. The analysis yields preliminary recommendations on the assimilation of zenith total path delays into weather models in regions of highly complex topography such as the Swiss Alps.Note de contenu : 1 Introduction
1.1 Review of GNSS meteorology
1.2 Potential synergies with other water vapour measurements . 1.3 Challenges in GNSS meteorology
1.4 Objectives and structure of the thesis
2 Theory
2.1 Refractivity and path delay in the atmosphere
2.2 Collocation with the software COMEDIE
2.3 Water vapour tomography software AWATOS2
3 Comparison of zenith path delays from GNSS and radiosonde measurements
3.1 Data description
3.2 Formal uncertainties of ZTD estimates from GNSS
3.3 Comparison of ZTDs
3.4 Influence of processing strategy on GNSS ZTDs
3.5 2nd and 3rd order ionospheric effects .
3.6 Comparison of ZWDs
3.7 Formal uncertainty of radiosonde-derived ZTDs
3.8 Derivation of random GNSS ZTD uncertainty
3.9 Correlation between GNSS heights and ZTDs
3.10 Discussion .
3.11 Conclusion .
4 Payerne profile study
4.1 Abstract
4.2 Introduction
4.3 Description of data sets
4.4 Processing
4.5 Results .
4.6 Discussion
4.7 Conclusions
5 Geodetic water vapor campaign in Zermatt
5.1 Data description and processing
5.2 Troposphere results
5.3 Conclusions
6 ConclusionsNuméro de notice : 12952 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère En ligne : http://www.sgc.ethz.ch/sgc-volumes/sgk-91.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76823 Réservation
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