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This README describes data-set of polluted cloud tracks extracted from MSG SEVIRI CPP product data.
Additional information
Jorma Rahu jorma.rahu@ut.ee
Velle Toll velle.toll@ut.ee

This work is funded by the Estonian Research Council personal research funding grant PSG202.
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DATASET
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The dataset contains SEVIRI filenames and vertice coordinates of pollution tracks.
The locations of polluted cloud tracks in SEVIRI satellite images have been hand-logged
at various heavy industrial locations and metropolitan cities over European part of Russia.

The dataset can be used to study temporal evolution of aerosol impacts on low stratocumulus clouds.

Creators: Jorma Rahu, Velle Toll
Organisation: University of Tartu
Rights-holder: University of Tartu
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TERMS OF USE
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Copyright 2021 University of Tartu. 
This dataset is licensed by the rights-holder under a Creative Commons Attribution 4.0 International Licence: https://creativecommons.org/licenses/by/4.0/.
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CONTENTS
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The file SEVIRI_filenames.txt contains list of SEVIRI filenames in netCDF container
with the timeperiod defined in the filenames.
All the files include data for a whole day with 15-minute time intervals (96 timesteps)
and also include a set of variables within as described on https://msgcpp.knmi.nl/.

The zipped archive named area_vertices contains subfolders for every case included in the study.
In the subfolders there are text files of coordinates (longitude latitude), around polluted cloud tracks. 
The points are hand-logged and can be used to create spatial masks for data selection around the pollution tracks.
The coordinates represent a proportionally (depending on the extent of the pollution track)
wider area around the polluted cloud track to make it possible to compare the polluted pixels
to nearby unpolluted pixels but to exclude nearby clouds with very different macrophysical properties.
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SEVIRI FILENAMES
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SEVIR_OPER_R___MSGCPP__L2__YYYYmmDDT000000_YYYYmmddT000000_0001.nc

YYYY is year.
mm is month as zero padded decimal number.
DD is the beginning day of the dataset as zero padded decimal number.
dd is the end day of the dataset as zero padded decimal number. 
dd=DD+1 because the files include data of single days.
All times are UTC time, not local time.
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COORDINATES OF AREA VERTICES
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The vertice coordinates of each pollution track are defined by a set of WGS84 projection longitude-latitude pairs.
WGS84 longitude is given in the first column and latitude in the second column

File name: area_vertice_yy_MM_DD_?.txt
yy is year without century as a zero padded decimal number.
mm is month as zero padded decimal number.
DD is day as zero padded decimal number.
? is the sampled pollution track number.

Example:
File name: "area_vertice_08_11_06_4.txt" for date 2008-11-06 and fourth sampled track for the dataset.
File content: lon lat
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METHOD and PROCESSING
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The area vertices coordinates of polluted cloud tracks have been hand-logged from SEVIRI satellite images. 
Near-infrared composite images from National Aeronautics and Space Administration (NASA) 
Global Imagery Browse Services are utilized for visually finding the pollution tracks.
Cloud droplet effective radius(R_eff) variable is used to find and study the polluted cloud
properties in SEVIRI data. The pixels are classified as polluted and unpolluted pixels using 
R_eff data and the pixel locations are extended on futher variables available in the CPP dataset
such as Condensed Water Path (CWP) and Cloud Optical Thickness (COT).
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