Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation:...
-
Upload
truongdung -
Category
Documents
-
view
225 -
download
6
Transcript of Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation:...
![Page 1: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/1.jpg)
Geostatistical Interpolation: Kriging and the Fukushima Data
Erik Hoel Colligium Ramazzini
October 30, 2011
![Page 2: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/2.jpg)
Agenda
• Basics of geostatistical interpolation
• Fukushima radiation – Database – Web site – Geoanalytic application
![Page 3: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/3.jpg)
Geostatistics
• Geostatistics differs from classical statistics as every sample/measurement contains a location – Unless the measurements show spatial correlation,
geostatistics is pointless
• The main objective is to classify spatial systems that are incompletely known; systems that are common in geology – Focused on interpolation
![Page 4: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/4.jpg)
Geostatistical Interpolation
• Predict values at unknown locations using values at measured locations
• Many interpolation methods: Kriging, IDW, etc.
Airborne particulates
![Page 5: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/5.jpg)
Importance of Spatial Proximity
• Spatial interpolation is based on the idea that points which are close together in space tend to have similar attributes
• Spatial autocorrelation – Positive – clustering of similar values – Negative – neighboring values are more dissimilar than by
chance
• Relationship between points and values – Isotropy – distance between points – Anisotropy – distance and direction between points
![Page 6: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/6.jpg)
Uncertainty and Errors in Spatial Data
![Page 7: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/7.jpg)
Uncertainty and Errors in Spatial Data
![Page 8: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/8.jpg)
Semivariogram
![Page 9: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/9.jpg)
What is Spatial Autocorrelation? "Everything is related to everything else, but near things are more related than distant things." - Waldo Tobler’s First Law of Geography (1970)
Waldo
![Page 10: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/10.jpg)
Waldo
What is Spatial Autocorrelation? "Everything is related to everything else, but near things are more related than distant things." - Waldo Tobler’s First Law of Geography (1970)
![Page 11: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/11.jpg)
Optimal Predictions
![Page 12: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/12.jpg)
IDW – Inverse Distance Weighting
• IDW is an exact interpolator – Predicts values identical to measured values at a location – Min and max values occur at measurement points
• IDW is very popular, but lacks most features needed in a predictor – Most significantly, ability to estimate uncertainty of
prediction
• Spatial data analysis should be based upon the analysis of the data and their location, not just the distance between a pair of data observations
![Page 13: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/13.jpg)
Kriging • Developed by D.G. Krige (1951, South Africa), Lev Gandin
(1959, USSR), and Georges Matheron (1962, France)
• Kriging is the optimal geostatistical interpolation method if the data meets certain conditions; e.g., – Normally distributed – Stationary – No clusters – No trends
• How do to check these conditions?
– ESDA
![Page 14: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/14.jpg)
Kriging Output Maps
Prediction Quantile Error of Predictions Probability
![Page 15: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/15.jpg)
Normally Distributed Data
• In order to check, utilize: – Histogram
• Check for bell-shaped distribution • Look for outliers
– Normal Q-Q Plot • Check if data follows 1:1 line
• If the data is not normally distributed – Apply a transformation
• E.g., Log, Box Cox, Arcsin, or Normal Score transformation
![Page 16: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/16.jpg)
Histogram
![Page 17: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/17.jpg)
Normal Q-Q Plot
Logarithmic Transformation
A normal Q-Q plot (quantile-quantile probability plot) graphs the data distribution against the standard normal distribution
![Page 18: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/18.jpg)
Stationarity
• Data stationarity is an assumption that many spatial statistical techniques make:
– Stationarity is present when the spatial relationship between two points depends only on their distance
– Additionally, the variance of the data is constant (after trends have been removed)
• Data variation should be consistent across your study area
• If the data is nonstationary – Transformations can sometimes stabilize variances – Empirical Bayesian Kriging
![Page 19: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/19.jpg)
Checking for Stationary
• Voronoi map symbolized by entropy or standard deviation – Look for randomness in the
classified Thiessen Polygons
![Page 20: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/20.jpg)
Checking for Stationary
• Voronoi map symbolized by entropy or standard deviation – Look for randomness in the
classified Thiessen Polygons
![Page 21: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/21.jpg)
Data Clusters
• Clusters of data points will give too much emphasis to points within clusters if a transformation is used
• Solution: cell declustering – Points are averaged within
each cell – Weights are assigned to
cells by number of points in the cell
![Page 22: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/22.jpg)
Data Trends
• Trends are systematic changes in the mean of the data values across the area of interest – Trend analysis ESDA tools
• If the data has trends – Use trend removal capabilities of
the Kriging model
• Potential problems – Trends are often
indistinguishable from autocorrelation and anisotropy
![Page 23: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/23.jpg)
Selecting the Best Model
• Predictions should be unbiased – Mean prediction error should be near zero (depends on
the scale of the data) so, – Standardized mean nearest to 0
• Predictions should be close to known values – Small root mean prediction errors
• Correctly assessing the variability: – Average standard-error nearest the RMS prediction error – Standardised RMS prediction error nearest to 1
![Page 24: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/24.jpg)
Types of Kriging
• Ordinary Kriging – Assumes the constant mean is unknown and the data have
no trend
• Simple Kriging – Assumes a constant but known mean value - more
powerful than ordinary kriging
• Universal Kriging – Assumes that there is an overriding trend in the data
• Indicator Kriging – Uses thresholds to create binary data and then uses
ordinary kriging for this indicator data
![Page 25: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/25.jpg)
Common Problems with Interpolation
• Input data uncertainty – Too few data points – Limited or clustered spatial coverage – Data not normally distributed – Uncertainty about location and/or value
• Edge effects – Need data points outside study area
![Page 26: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/26.jpg)
Data Outliers
• Outliers statistically affect your data • They may be real and important or may be errors
(such as input errors) – Voronoi maps: clear class breaks in the data
![Page 27: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/27.jpg)
Semivariogram Cloud
• Shows the relationship between points – Points close together have high differences in their values
may be outliers
Semivariogram Cloud Semivariogram Surface
![Page 28: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/28.jpg)
Histogram and Q-Q Plot
– Histogram: values in far removed bars to the left or right may indicate outliers
– Q-Q Plot: values at tails of a normal can be outliers
![Page 29: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/29.jpg)
Geostatistical Software
ESDA
Vario
grap
hy
Det
rend
ing
Cokr
igin
g In
dica
tor K
rigin
g
Dis
junc
tive
Krig
ing
Gau
ssia
n Kr
igin
g
Bino
mia
l Krig
ing
Pois
son
Krig
ing
Baye
sian
Krig
ing
Esri
GeoR
Geostokos
GS+
GSLIB
Gstat
MGstat
SADA
SAS
![Page 30: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/30.jpg)
Summary: Geostatistical Interpolation
• Create surfaces using the relationships between data locations and their values
• These methods assume: – Data is normally distributed – Data exhibits stationarity (no local variation)
• Empirical Bayesian Kriging can address
– Data has spatial autocorrelation – Data is not clustered
• Simple Kriging has declustering options
– Data has no local trends • Local trends can be removed during interpolation (and these
trends are accounted for in the prediction calculations)
![Page 31: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/31.jpg)
RADIATION DATABASE
![Page 32: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/32.jpg)
Radiation Database
• MEXT, Fukushima Prefecture, and other Japanese government and scientific organizations have been publishing radiation data – Commonly in PDF format – Recently in HTML
• Majority of data is airborne ionizing radiation sampled at 0.5 or 1m heights – Some soil, water, and food data:
131I, 134Cs, 137Cs, 129Te, 132Te, 136Cs, 140La, 89Sr, 90Sr, 110Ag, 95Nb, and 140Ba
![Page 33: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/33.jpg)
Radiation Database
• MEXT, Fukushima Prefecture, and other Japanese government and scientific organizations have been publishing radiation data – Commonly in PDF format – Recently in HTML
• Majority of data is airborne ionizing radiation sampled at 0.5 or 1m heights – Some soil, water, and food data:
131I, 134Cs, 137Cs, 129Te, 132Te, 136Cs, 140La, 89Sr, 90Sr, 110Ag, 95Nb, and 140Ba
Location?
![Page 34: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/34.jpg)
Radiation Database
• Esri built a database to store this information • Authoritative data sources:
– MEXT, MHLW, MAFF – JAEA, SPEEDI, NAIST, NIMS – Fukushima, Gunma, Miyagi, Niigata, Tochigi, and Yamagata
Prefectures – Fukushima, Nihon, and Tokyo Universities – TEPCO
• Authoritative data sources are growing with time – Additional prefectures, cities, and others
![Page 35: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/35.jpg)
Radiation Database
• The database has been populated by transcribing the information contained in the PDFs provided by various authoritative sources
– Expensive and time consuming manual process (even if
utilizing PDF to Excel data harvesting frameworks)
– Approximately 100,000 sample measurements in database • This is continually growing in size
![Page 36: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/36.jpg)
Radiation Website
• Public website constructed and managed by Esri and Keio University – Japanese and English versions – Intended for laymen as well as scientists
• Supports visualization by day (March – October) of:
– Geostatistical estimation of ionizing radiation – Standard error of geostatistical estimation – Probability maps (including radioisotopes in soil and food) – Time series view of estimations at user selected locations
![Page 37: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/37.jpg)
![Page 38: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/38.jpg)
![Page 39: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/39.jpg)
![Page 40: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/40.jpg)
![Page 41: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/41.jpg)
![Page 42: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/42.jpg)
![Page 43: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/43.jpg)
![Page 44: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/44.jpg)
PROBABILITY MAPS
![Page 45: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/45.jpg)
Predictions and Standard Error
• Difficult to visualize in tandem
• More effective visualization and decision making technique is to use probability maps
Prediction Standard Error
< 0.08 0.08 – 0.19 0.19 – 2.36 2.36 – 5.0 5.0 – 28.74 > 28.74
< 0.25 0.25 – 1 1 – 2 2 – 5 5 – 10 > 10
![Page 46: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/46.jpg)
Probability Surfaces
outdoors indoors
![Page 47: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/47.jpg)
May 1 – 0.114µSv/h Probability <5% 5% - 25% 25% - 75% 75% - 90% 90% - 95% 95% - 99% >99%
![Page 48: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/48.jpg)
May 1 – 2.283µSv/h Probability <5% 5% - 25% 25% - 75% 75% - 90% 90% - 95% 95% - 99% >99%
![Page 49: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/49.jpg)
May 1 – 3.8µSv/h Probability <5% 5% - 25% 25% - 75% 75% - 90% 90% - 95% 95% - 99% >99%
![Page 50: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/50.jpg)
137Cs – 1.0 Ci/Km2 Probability
<5% 5% - 25% 25% - 75% 75% - 90% 90% - 95% 95% - 99% >99%
![Page 51: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/51.jpg)
137Cs – 5.0 Ci/Km2 Probability
<5% 5% - 25% 25% - 75% 75% - 90% 90% - 95% 95% - 99% >99%
![Page 52: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/52.jpg)
137Cs – 15.0 Ci/Km2 Probability
<5% 5% - 25% 25% - 75% 75% - 90% 90% - 95% 95% - 99% >99%
![Page 53: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/53.jpg)
129mTe – 1.0 Ci/Km2 Probability
<5% 5% - 25% 25% - 75% 75% - 90% 90% - 95% 95% - 99% >99%
![Page 54: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/54.jpg)
90St – 0.005 Ci/Km2 Probability
<5% 5% - 25% 25% - 75% 75% - 90% 90% - 95% 95% - 99% >99%
![Page 55: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/55.jpg)
Summary
• Geostatistical interpolation
– Ability to quantitatively estimate the uncertainty of prediction is critical to understanding and decision making
• Fukushima radiation
– Database – Web site – Geoanalytic application
![Page 56: Geostatistical Interpolation: Kriging and the Fukushima … · Geostatistical Interpolation: Kriging and the Fukushima Data Erik Hoel Colligium Ramazzini . October 30, 2011](https://reader031.fdocuments.in/reader031/viewer/2022022513/5aecdb067f8b9a66258f203c/html5/thumbnails/56.jpg)
Future Work
• Database – Continue to incorporate additional authoritative data
sources and measurements – Obtaining digital source data directly from authoritative
sources, rather than PDFs or HTML, will be critical – The more samples, the better the quality of the estimates
• Website – Expose food-based radioisotope data – Provide download capability of raw data in a database – Provide integrated radiation estimates
• E.g., at a given location, how much radiation exposure has there been since the earthquake