Kriging and other estimators of spatial field characteristics (with special reference to environmental studies)

Федоров, В. В.

doi:10.1016/0004-6981(89)90110-8

Cited by 40 publications

(13 citation statements)

References 9 publications

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“…However, the assumption of stationarity (i.e. that the same pattern of variation can be observed at all locations on the surface) is rarely met in reality (Fedorov 1989). To test this assumption, the mean and variance of the residuals in blocks of approximately 600 km (roughly equivalent to the range of the variogram plots) were considered.…”

Section: Model Limitations and Future Researchmentioning

confidence: 99%

GIS-based construction of baseline climatologies for the Mediterranean using terrain variables

Agnew¹,

Palutikof²

2000

Clim. Res.

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A GIS-based method for constructing high-resolution (in space) maps of mean seasonal temperature and precipitation is developed for the Mediterranean Basin. Terrain variables and geographical location are used as predictors of the climate variables at all points on a grid with a 1 km resolution, using a regression-based approach. Variables used for model development include: longitude, latitude, elevation, distance from the nearest coast, direction to the nearest coast, slope, aspect, and the ratio of land to sea within given radii. Seasonal mean temperature and precipitation data, for the observation period 1952 to 1989, were assembled from 248 temperature sites and 285 precipitation sites in order to initialise the regression model. Temperature data from 36 stations and precipitation data from 35 stations were retained for model validation. Climate surfaces were constructed using the regression equations, and refined by kriging the residuals from the regression model and subtracting the result from the predicted 'observation' surface. Latitude, elevation and distance from the sea are found to be the most effective predictors of local seasonal climate. Validation determined that regression plus kriging predicts mean seasonal temperatures with a coefficient of determination (R 2 ), between the expected and observed values, of 0.87 (summer) and 0.97 (winter), and mean seasonal precipitation with an R 2 of 0.46 (autumn) and 0.94 (summer). A simple regression model without kriging yields less accurate results in all seasons except for the temperature data in spring.

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Section: Model Limitations and Future Researchmentioning

confidence: 99%

GIS-based construction of baseline climatologies for the Mediterranean using terrain variables

Agnew¹,

Palutikof²

2000

Clim. Res.

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“…In view of the variety of information sources as given by observations, with all their heterogeneity in terms of accuracy, spatial representativeness, spatial observation density and temporal frequency, and various retrieval techniques on the one hand, and model results on the other hand, advanced data assimilation and inverse modelling techniques provide the appropriate data fusion and analysis technique. Early attempts to analyse tracer fields were based on monovariate kriging techniques in the troposphere (e.g., Fedorov, 1998), and other purely spatial methods in the stratosphere (e.g., Stajner et al, 2001;Struthers et al, 2002). These methods produce chemical state estimates, frequently referred to as analyses, after assimilation of observations in model simulated fields as background.…”

Section: Introductionmentioning

confidence: 99%

Emission rate and chemical state estimation by 4-dimensional variational inversion

et al. 2007

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Abstract. This study aims to assess the potential and limits of an advanced inversion method to estimate pollutant precursor sources mainly from observations. Ozone, sulphur dioxide, and partly nitrogen oxides observations are taken to infer source strength estimates. As methodology, the fourdimensional variational data assimilation technique has been generalised and employed to include emission rate optimisation, in addition to chemical state estimates as usual objective of data assimilation. To this end, the optimisation space of the variational assimilation system has been complemented by emission rate correction factors of 19 emitted species at each emitting grid point, involving the University of Cologne mesoscale EURAD model. For validation, predictive skills were assessed for an August 1997 ozone episode, comparing forecast performances of pure initial value optimisation, pure emission rate optimisation, and joint emission rate/initial value optimisation.Validation procedures rest on both measurements withheld from data assimilation and prediction skill evaluation of forecasts after the inversion procedures. Results show that excellent improvements can be claimed for sulphur dioxide forecasts, after emission rate optimisation. Significant improvements can be claimed for ozone forecasts after initial value and joint emission rate/initial value optimisation of precursor constituents. The additional benefits applying joint emission rate/initial value optimisation are moderate, and very useful in typical cases, where upwind emission rate optimisation is essential. In consequence of the coarse horizontal model grid resolution of 54 km, applied in this study, comparisons indicate that the inversion improvements can rest on assimilating ozone observations only, as the inclusion of NO x observations does not provide additional forecast skill. Emission estimates were found to be largely independent from initial Correspondence to: H. Elbern (he@eurad.uni-koeln.de) guesses from emission inventories, demonstrating the potential of the 4D-var method to infer emission rate improvements. The study also points to the need for improved horizontal model resolution to more efficient use of NO x observations.

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“…At a smaller scale, along each profile, it is not possible either to highlight a clear pattern within the dataset. To avoid such erroneous data description (e.g., Fedorov, 1989) it is preferred to attempt another approach. Both CO 2 and 222 Rn data are taken separately and automatically ranged under 10 different concentration classes.…”

Section: Discussionmentioning

confidence: 99%

Radon, helium and CO2 measurements in soils overlying a former exploited oilfield, Pechelbronn district, Bas-Rhin, France

Pierrès

Gal

Brach

et al. 2010

Journal of Environmental Radioactivity

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Kriging and other estimators of spatial field characteristics (with special reference to environmental studies)

Cited by 40 publications

References 9 publications

GIS-based construction of baseline climatologies for the Mediterranean using terrain variables

GIS-based construction of baseline climatologies for the Mediterranean using terrain variables

Emission rate and chemical state estimation by 4-dimensional variational inversion

Radon, helium and CO2 measurements in soils overlying a former exploited oilfield, Pechelbronn district, Bas-Rhin, France

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