Operational smoothing of MODIS NDVI time series at BOKU...

Institut für Vermessung, Fernerkundung und Landinformation

Operational smoothing of MODIS NDVI time series at BOKU

for EURODEER

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EURODEER Study Areas & BOKU MODIS Tiles


EURODEER MODIS Tiles – Tile naming I


EURODEER MODIS Tiles – Tile naming II


Principle of Whittaker smoother

Only one smoothing parameter

Interpolates automatically

No boundary effects

Input:

NDVI

composite day of year

data quality

Principle of Whittaker smoother

Offline filtering of entire time series


PNABCD

Processing dayN

2007050

INPUT:window_size = 25 * 7 = 175 days

7-day processing approach for Whittaker filter

For each EURDEER tile is delivered:./REFMIDw/MCD13Q1.A2006324.005.H19V04_h06v01.250m_7_days_NDVI.REFMIDw.tif./Dw/MCD13Q1.A2007022.005.H19V04_h06v01.250m_7_days_NDVI.Dw.tif

REFMID

Approach:• for every week all available MOD13Q1 and MYD13Q1 data

within the defined window of 175 days are used• filtering and interpolation/extrapolation at daily values• output of 7-day values: REFMIDw, Dw, Cw, Bw, Aw, Nw, Pw• Nw represents current Monday = newest product

D2007022

REFMID2007022

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Scaling of NDVI: 8 bit unsigned

𝑽𝑽𝑽𝑽 = 𝑽𝑽𝑽𝑽𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔 � 𝑫𝑫𝑫𝑫 + 𝑽𝑽𝑽𝑽𝒊𝒊𝒊𝒊𝒊𝒊𝒔𝒔𝒊𝒊𝒊𝒊𝒔𝒔𝒔𝒔𝒊𝒊

𝑫𝑫𝑫𝑫 = 𝑽𝑽𝑽𝑽 − 𝑽𝑽𝑽𝑽𝒊𝒊𝒊𝒊𝒊𝒊𝒔𝒔𝒊𝒊𝒊𝒊𝒔𝒔𝒔𝒔𝒊𝒊 / 𝑽𝑽𝑽𝑽𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔

NDVI 8 bit scalingDN flags 251 – ocean

252 – inlandwater255 – missing

DN valid range [0, 250]VIslope 0.0048VIintercept -0.2VI valid range [-0.2, 1.0]Data type uint8

DNdigital numbers [0, 250]

VIvegetation index[-0.2, 1.0]

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Delivery of Data

• delivery once on BOKU ftp:entire archive from 2003 to beginning of 2015172 tiles, products NDVI Dw, NDVI REFMIDw

• folder structure:one older for each tile containing the products Dw & REFMIDw

• weekly update as tar file on BOKU ftp

• see example for latest Monday (23.02.2015): ftp://ivfl-rio.boku.ac.at/EURODEER/update_2015054.tar

• every week tar file of previous week will be deleted

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Operational smoothing of MODIS NDVI time series at BOKU...

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