Download LIVAS user manual

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LIVAS
Lidar Climatology of Vertical Aerosol Structure for
Space-Based Lidar Simulation Studies
ESTEC Contract No. 4000104106/11/NL/FF/fk
User’s Manual
Date of Issue: 30 June 2013
Institute for Space Applications and Remote Sensing, National Observatory of Athens
Vas. Pavlou & I. Metaxa • 152 36 Penteli, Greece• Tel: +30-2108109116 • Fax:+30-2106138343• http://www.space.noa.gr
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THIS PAGE IS INTENTIONALLY LEFT BLANK
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Table of Contents
Introduction ............................................................................................................... 4
1
LIVAS Home page ................................................................................................. 5
2
LIVAS regional climatology GUI ............................................................................ 7
2.1 The dynamic World Map ................................................................................................. 8
2.1.1
Product OD .............................................................................................................. 8
2.1.2
Number of overpasses............................................................................................. 9
2.1.3
Number of profiles .................................................................................................. 9
2.2 The dynamic product selector ....................................................................................... 10
2.3 The chart panel .............................................................................................................. 11
2.4 The Statistics panel ........................................................................................................ 12
3
LIVAS Selected Scenes GUI ................................................................................. 13
3.1
3.2
3.3
4
The scene selector ......................................................................................................... 13
The description panel .................................................................................................... 14
The chart panel .............................................................................................................. 15
Portal content, available file downloads and respective formats ........................ 17
4.1 LIVAS global climatology................................................................................................ 18
4.1.1
ASCII format description........................................................................................ 18
4.1.2
NetCDF format description.................................................................................... 24
4.1.3
FTP site for climatological NetCDF files ................................................................. 39
4.2 LIVAS selected scenes .................................................................................................... 39
4.2.1
NetCDF format description.................................................................................... 39
5
Summary and Conclusions ................................................................................. 45
List of Figures............................................................................................................ 46
List of Tables............................................................................................................. 47
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Introduction
In the framework of the LIVAS ESA Study, a number of actions were taken in order to develop an
integrated online system which shall store and expose the LIVAS Lidar Climatology and Selected
Scenes datasets. The LIVAS Web Portal has been developed and is available online via the
following url:
http://lidar.space.noa.gr:8080/livas
The portal is freely available to the public since the completion of the study (autumn 2013).
Here, a user-oriented description of the online system and related GUIs is given, focusing on the
usage of the portal and its content.
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1 LIVAS Home page
The LIVAS home page (Figure 1-1) is designed to act as an information gateway to the portal.
The two (2) fundamental LIVAS Web Graphical User Interfaces (GUIs) are introduced on the
header area under the menus “Climatology” or “Selected Scenes”. The descriptive text of the
home page briefly describes the project objectives and methodological approaches followed.
Then, the final products are listed, segregated in two categories following the “Climatology” and
“Selected Scenes” definitions.
Specifically, the home page provides brief information on:
-
The project objectives and methodological approaches
The LIVAS products under each category (Climatology or selected scenes) as well as their
spatial and temporal resolution
The portal content and architecture in general containing information on the available
content and respective file downloads, formats and tools for access/quick-viewing
Instructions on portal’s usage
The links to full documentation
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Figure 1-1: LIVAS web portal homepage
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2 LIVAS regional climatology GUI
The “Climatology” page of the portal contains the LIVAS GUI for the global climatology,
consisting of the following four major components:




The dynamic World map (spatial grid selector)
The dynamic Product Selector
The Chart panel
The Statistics panel
The components are integrated under the “Climatology” page of LIVAS portal, which is
presented in Figure 2-1.
Figure 2-1: The Climatology page of LIVAS portal
In this chapter, the description of the GUI components is given along with examples that
demonstrate the usage of the climatology page.
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2.1 The dynamic World Map
LIVAS dynamic Global Map displays a world map with a Google Earth background and the World
grid of 1x1 degree spatial resolution as an overlay layer. The user selects on this map the cell of
his/her interest for which the climatological products shall be displayed/provided. Additional
map rendering controls are included in order to enrich user interaction.
Figure 2-2: The grid selector of LIVAS
Moreover, the user can utilize three buttons which are located in the lower-right part of the
map in order to project overlay layers that may facilitate his/her selection. These options are
described in the following paragraphs.
2.1.1 Product OD
The selection of the “Product OD” button causes the projection of an overlay contour layer that
represents the 4-year averaged value of aerosol or cloud optical depth. Aerosol or cloud optical
depths are projected respectively for aerosol or cloud selections from the product selector. An
example is given in the following figure for aerosol optical depth at 532 nm.
Figure 2-3: Aerosol optical depth layer
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2.1.2 Number of overpasses
The “Number of overpasses” button provides the possibility to project an overlay map layer
representing the approximate number of CALIPSO overpasses on each 1x1 degree spatial
resolution for the four years of data used for LIVAS. This number is indicative of the availability
of CALIPSO data for each cell. An example is given in the following figure.
Figure 2-4: Number of CALIPSO overpasses
2.1.3 Number of profiles
The “number of profiles” button provides the possibility to project an overlay map layer
representing the CALIPSO profiles used by the LIVAS averaging procedure for the four years of
data used. This number is indicative of the statistical representativeness of the final averaged
product. An example is given in the following figure.
Figure 2-5: 4-year number of CALIPSO profiles used for the averaging procedure
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2.2 The dynamic product selector
In order to provide to the final user a selection menu customized to the needs of LIVAS study,
having functionality and following a minimalistic approach, the dynamic LIVAS Product Selector
component was designed and created (Figure 2-6).
A
B
C
D
E
Figure 2-6: The dynamic LIVAS Product Selector
Product selector contains LIVAS products structure. When a user hovers the menu from left to
right, at each level, allowable selections are greyed lighter (A, B). When a user clicks on the
desired product, this product is considered the user selection (C, D). In Figure 2-6 it is shown
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that when a specific level does not have children sub-products, then the user is not allowed to
make a respective selection. In order to select a different product, the user should first release
(by left clicking) the previous level selected (already plotted on LIVAS chart area).
2.3 The chart panel
When the user selects a product from the dynamic LIVAS Product Selector, the JavaScript library
is triggered in order to create and display user requested charts for the cell selected on the
global map. An example is given in Figure 2-7.
Figure 2-7: The data plotting module
The left panel shows the user-requested parameter as this has been defined in product selector
(for the example of Figure 2-7, the Aerosol Extinction at 532 nm). The mean value of the
parameter is plotted in grey colour, while the mean profiles per aerosol type contributing to the
total mean value are represented by six colours, described correspondingly in the embedded
label. The right panel shows the number of total aerosol samples used by the averaging
procedure, as well as the number of samples used per aerosol type.
LIVAS chart offers to the user several functionalities. The user has the possibility to zoom each
plot according to his/her preferences. The numerical values for the x and y axis are displayed by
hovering the mouse over the plot line. Moreover, the user can select from the upper-left corner
of the plot two predefined zoom projections, one for “fixed x-axis range” and one for
“automatic x-axis range”. If for example the user wants to project different cells simultaneously
in order to compare, then the predefined “fixed x-axis range” choice would be more
appropriate. If however the user wants to focus on a selected cell of interest, the automatic
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selection would be more appropriate in order to fit the scale on the maximum parameter value,
achieving the optimum zooming option. Furthermore, the user has the possibility to select
specific profiles for projection, by using left mouse clicks over the six labels of different aerosol
types. Finally, an exporting module is available which allows users to download images in raster
or vector format (e.g. PDF). A direct printing capability is also provided.
2.4 The Statistics panel
The portal provides statistical parameters for each grid cell for the corresponding product
selected by the product selector. These are displayed on a table located at the upper-right panel
of the home page. The statistics presented are related to certain cell properties as the surface
elevation, the number of CALIPSO overpasses and the number of profiles examined over the
selected cell. Aerosol or cloud statistics are then presented in terms of samples averaged,
averaged columnar optical depth (along with median and standard deviation of the averaging),
as well as subtype occurrence. An example of statistics for the example of Aerosol Extinction
selection at 532 nm is given in Figure 2-8.
Figure 2-8: Statistics panel
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3 LIVAS Selected Scenes GUI
The LIVAS Web Graphical User Interface (GUI) for the selected scenes is displayed by the
selection of the “Selected Scenes” menu provided on the header of the portal. The selected
scenes GUI includes the following three major components:



The Scene Selector
The description panel
The Chart panel
Figure 3-1: The selected scenes GUI of LIVAS portal
In this chapter, the description of the components is given along with examples that
demonstrate the usage of the selected scenes GUI.
3.1 The scene selector
The scene selector is a tree structure that provides to the user the possibility to select the scene
of his/her interest from the case studies analysed in LIVAS. The LIVAS selected scenes refer
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mainly to extreme atmospheric episodes (e.g. dust outbreaks, volcanic eruption, polar
stratospheric clouds). The first layer in the scene selector categorizes the scenes in aerosol,
cloud or stratospheric related cases. After the user selects the category, then the type of each
case is projected. When the user selects the final scene of his/her interest, a list containing the
available multi-wavelength products is displayed. The example presented in Figure 3-2 shows
the selection of an aerosol scene related to a dust episode. When the scene is selected, the
available optical parameters are listed.
Figure 3-2: The scene selector
3.2 The description panel
When a scene is selected, a short description of the case analysed is provided in the lower-right
panel of the page. For the dust example selected in Figure 3-2, the descriptive information is
shown in Figure 3-3. A short description is first given, in which the available ground-based data
are referenced as well. The CALIPSO collocated ground data are used for the spectral
conversions. Moreover, the date and location of the scene analysed as well as the CALIPSO files
used and the literature which is related to the ground-data used for the spectral conversions is
given.
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Figure 3-3: The description panel
3.3 The chart panel
The chart panel projects the time-height plot of the optical parameter selected by the user for
the specific selected scene. In our dust example of Figure 3-2, the aerosol extinction at 355 nm
has been retrieved from CALIPSO aerosol extinction at 532 nm using the backscatter and
extinction-related conversion factors provided by the collocated ground-based lidar
measurements that we found in the literature (mentioned in the description panel). The aerosol
extinction at 355 nm is plotted in the chart panel of LIVAS selected scenes page, as this is
presented in Figure 3-4.
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Figure 3-4: Time-height plot of the aerosol extinction at 355 nm
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4 Portal content, available file
downloads and respective formats
LIVAS global climatology and selected scenes are provided in ASCII and NetCDF-4 format (which
is compatible to HDF-5 format). The users can select the file format of their preference for each
selection in the climatology or selected scenes GUI. Moreover, an option for downloading the
complete global climatological record in NetCDF-4 format is provided via an FTP site embedded
in LIVAS portal. Software tools to read NetCDF files are provided through appropriate links to
corresponding developer’s page. In this chapter, the file formats and nomenclatures are
described along with the download procedures.
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4.1 LIVAS global climatology
For each selected cell of LIVAS climatology, the user has the possibility to download ASCII or
NetCDF files containing the full multi-wavelength dataset provided. The ASCII or NetCDF option
is selected by respective buttons which are located at the bottom of the product selector panel,
as shown in Figure 4-1.
Figure 4-1: ASCII and NetCDF buttons
The “Save to ASCII” button will trigger a procedure to export ASCII datasets for the selected cell
and deliver them in zip file format. In the exported zip file, the full dataset describing a 10X10
spatial resolution cell is archived. NetCDF data have been also produced for LIVAS and have
been embedded into LIVAS database in binary datatype and are available for download through
LIVAS Web GUI through the “Save to NetCDF” button. A description of the formats and
nomenclature of ASCII and NetCDF exported files is given in the following paragraphs.
4.1.1 ASCII format description
ASCII exported datasets are delivered in zip file format. The generic nomenclature for the zip file
is:
LIVAS_lon_XX.X_lat_YY.Y_ascii_data.zip
where XX.X is the cell centroid longitude and YY.Y the cell centroid longitude in degrees.
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In the exported zip file, the full dataset describing a 10X10 spatial resolution cell is archived. A
group of 14 ASCII files composes the full dataset describing a 10X10 spatial resolution cell. Each
filename is indicative of the products delivered. 13 files are provided for the LIVAS products and
one file is provided for the statistics. The generic nomenclature for the 13 filenames containing
the products is:
LIVAS_OX_Product_Subproduct.txt
The keys in bold are variable and are given in Table 4-1
Table 4-1: Description of ASCII filename nomenclature keys
key
OX
values
description
O1
all data per spectral range
O2
data per feature sub-type products
O3
seasonal data products
Aerosol
Product
Cloud
Type
Stratospheric
Backscatter
Subproduct
Depolarization
Optical property
Extinction
The nomenclature for the columnar statistics filename and the contents of this file are selfexplained and constant:
LIVAS_Statistics.txt
The datasets included in the files consist of tab delimited text encoded in ASCII file format. The
first line of each file contains the header where each attribute’s name is encoded. Below header,
the actual values are encoded in a column wise manner. In the first column the actual height of
each observation is encoded, while “no data” values are encoded as “NULL”.
Header attribute names are encoded in an abbreviated form as presented in Table 4-2 and in
association with LIVAS Categorization Definition Entities: l1.l2.l3.[l4 or l5].data_attribute
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Table 4-2: Exported ASCII header attribute nomenclature keys
l1
l2
id
abbr
full_name
description
id
abbr
1
a
aerosol
Aerosol Products
2
c
Clouds
Cloud Products
3
s
1
2
3
e
b
d
stratospheric Stratospheric Products
full_name
description
extinction
Extinction Subproducts
backscatter
Backscatter Subproducts
depolarization Depolarization Subproducts
l3
l5
id
1
2
3
abbr
355
532
1064
full_name
wavelength 355nm
wavelength 532nm
wavelength 1064nm
description
Wavelength 355nm
Wavelength 532nm
Wavelength 1064nm
2
spr
Spring
Spring
4
1570
wavelength 1570nm
Wavelength 1570nm
3
sum
Summer
Summer
5
2050
wavelength 2050nm
Wavelength 2050nm
4
aut
Autumn
Autumn
Id
abbr
full_name
description
1
win
Winter
Winter
l4
id
fk_l1id abbr
Data attribute
full_name
description
1
2
3
1
1
1
t1
t2
t3
clean marine
dust
polluted continental
clean marine
dust
polluted continental
4
5
1
1
t4
t5
clean continental
polluted dust
clean continental
polluted dust
6
1
t6
smoke
smoke
7
1
t7
other
other
2
t0
low overcast
(transparent)
low overcast (transparent)
8
9
t1
10
11
2
t2
stratocumulus
transition stratocumulus
2
t3
low (broken cumulus)
low (broken cumulus)
2
t4
altocumulus
(transparent)
altocumulus (transparent)
2
2
t5
t6
altostratus (opaque)
cirrus (transparent)
altostratus (opaque)
cirrus (transparent)
15
16
17
18
deep convective
2
3
3
3
t7
t0
t1
t2
19
20
21
low overcast (opaque)
transition
12
13
14
(opaque)
(opaque)
deep convective (opaque)
not determined
not determined
non-depolarizing PSC
non-depolarizing PSC
depolarizing PSC
depolarizing PSC
non-depolarizing
3
3
3
t3
t4
t7
aerosol
depolarizing aerosol
other
dval
uval
stdv
med
season_nobs
low overcast
2
Abbr
non-depolarizing aerosol
depolarizing aerosol
other
sep_nobs
full_name
Mean (total) product value for a
specific grid and height
Uncertainty value
standard deviation of the data
sample that contributed to the
calculation of mean product value
median value of the data sample
that contributed to the
calculation of total product value
number of observations that
contributed to the calculation of
partial products (per-type &
seasonal)
perc
Percentage of the number of
samples that contribute to the
calculation of partial products in
relation to the total data sample
for a specific grid and height
nobs
number of observations that
contributed to the calculation of
mean (total) product value for a
specific grid and height
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The vertical distributions that are finally provided in the columns of each ASCII file are:
O1 Aerosol Extinction
LIVAS_O1_Aerosol_Extinction.txt
Column Names
height
a.e.532.dval
a.e.532.uval
a.e.532.stdv
a.e.532.med
a.e.1064.dval
a.e.1064.uval
a.e.1064.stdv
a.e.1064.med
a.e.355.dval
a.e.355.uval
a.e.355.stdv
a.e.355.med
a.e.1570.dval
a.e.1570.uval
a.e.1570.stdv
a.e.1570.med
a.e.2050.dval
a.e.2050.uval
a.e.2050.stdv
a.e.2050.med
nobs
O1 Aerosol Backscatter
LIVAS_O1_Aerosol_Backscatter.txt
Column Names
height
a.b.532.dval
a.b.532.uval
a.b.532.stdv
a.b.532.med
a.b.1064.dval
a.b.1064.uval
a.b.1064.stdv
a.b.1064.med
a.b.355.dval
a.b.355.uval
a.b.355.stdv
a.b.355.med
a.b.1570.dval
a.b.1570.uval
a.b.1570.stdv
a.b.1570.med
a.b.2050.dval
a.b.2050.uval
a.b.2050.stdv
a.b.2050.med
nobs
O1 Aerosol Depolarization
LIVAS_O1_Aerosol_Depolarization.txt
Column Names
height
nobs
a.d.532.dval
a.d.532.uval
a.d.532.stdv
a.d.532.med
a.d.355.dval
a.d.355.uval
a.d.355.stdv
a.d.355.med
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O1 Cloud Extinction
LIVAS_O1_Cloud_Extinction.txt
Column Names
height
c.e.532.dval
c.e.532.uval
c.e.532.stdv
c.e.532.med
c.b.532.stdv
c.b.532.med
nobs
O1 Cloud Backscatter
LIVAS_O1_Cloud_Backscatter.txt
Column Names
height
c.b.532.dval
c.b.532.uval
nobs
O1 Cloud Depolarization
LIVAS_O1_Cloud_Depolarization.txt
Column Names
height
c.d.532.dval
c.d.532.uval
c.d.532.stdv
c.d.532.med
nobs
O2 Aerosol Extinction
LIVAS_O2_Aerosol_Extinction.txt
Column Names
height
nobs
a.e.532.t1.dval
a.e.532.t1.stdv
a.e.532.t1.sep_nobs
a.e.532.t1.perc
a.e.532.t2.dval
a.e.532.t2.stdv
a.e.532.t2.sep_nobs
a.e.532.t2.perc
a.e.532.t3.dval
a.e.532.t3.stdv
a.e.532.t3.sep_nobs
a.e.532.t3.perc
a.e.532.t4.dval
a.e.532.t4.stdv
a.e.532.t4.sep_nobs
a.e.532.t4.perc
a.e.532.t5.dval
a.e.532.t5.stdv
a.e.532.t5.sep_nobs
a.e.532.t5.perc
a.e.532.t6.dval
a.e.532.t6.stdv
a.e.532.t6.sep_nobs
a.e.532.t6.perc
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O2 Cloud Extinction
LIVAS_O2_Cloud_Extinction.txt
Column Names
height
c.e.532.t1.dval
c.e.532.t1.stdv
c.e.532.t1.sep_nobs
c.e.532.t1.perc
c.e.532.t2.dval
c.e.532.t2.stdv
c.e.532.t2.sep_nobs
c.e.532.t2.perc
c.e.532.t3.dval
c.e.532.t3.stdv
c.e.532.t3.sep_nobs
c.e.532.t3.perc
c.e.532.t4.dval
c.e.532.t4.stdv
c.e.532.t4.sep_nobs
c.e.532.t4.perc
c.e.532.t5.dval
c.e.532.t5.stdv
c.e.532.t5.sep_nobs
c.e.532.t5.perc
c.e.532.t6.dval
c.e.532.t6.stdv
c.e.532.t6.sep_nobs
c.e.532.t6.perc
nobs
O3 Aerosol Extinction
LIVAS_O3_Aerosol_Extinction.txt
Column Names
height
a.e.532.win.dval
a.e.532.win.uval
a.e.532.win.stdv
a.e.532.win.season_nobs
a.e.532.spr.dval
a.e.532.spr.uval
a.e.532.spr.stdv
a.e.532.spr.season_nobs
a.e.532.sum.dval
a.e.532.sum.uval
a.e.532.sum.stdv
a.e.532.sum.season_nobs
a.e.532.aut.dval
a.e.532.aut.uval
a.e.532.aut.stdv
a.e.532.aut.season_nobs
nobs
O3 Cloud Extinction
LIVAS_O3_Cloud_Extinction.txt
Column Names
height
c.e.532.win.dval
c.e.532.win.uval
c.e.532.win.stdv
c.e.532.win.season_nobs
c.e.532.spr.dval
c.e.532.spr.uval
c.e.532.spr.stdv
c.e.532.spr.season_nobs
c.e.532.sum.dval
c.e.532.sum.uval
c.e.532.sum.stdv
c.e.532.sum.season_nobs
c.e.532.aut.dval
c.e.532.aut.uval
c.e.532.aut.stdv
c.e.532.aut.season_nobs
nobs
O1 Stratospheric Extinction
LIVAS_O1_Stratospheric_Extinction.txt
Column Names
height
nobs
a.e.532.dval
a.e.532.uval
a.e.532.stdv
a.e.532.med
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O1 Stratospheric Backscatter
LIVAS_O1_Stratospheric_Backscatter.txt
Column Names
height
a.b.532.dval
a.b.532.uval
a.b.532.stdv
a.b.532.med
nobs
O1 Stratospheric Depolarization
LIVAS_O1_Stratospheric_Depolarization.txt
Column Names
height
s.d.532.dval
s.d.532.uval
s.d.532.stdv
s.d.532.med
nobs
4.1.2 NetCDF format description
LIVAS climatological product is provided in NetCDF4 format for each cell of 1x1 degree. The
filename format is:

NetCDF filename: LIVAS_lon_XX.X_lat_YY.Y_vV.V.nc
Where XX.X is the longitude of the cell midpoint, YY.Y is the latitude of the cell midpoint and
V.V is the version of LIVAS product.
The parameters included in LIVAS NetCDF files are organized into two major categories, i.e.
“STATISTICAL PARAMETERS” and “VERTICAL DISTRIBUTIONS”, which are described in detail
herein.
A. STATISTICAL PARAMETERS
For each cell, the statistical averages and corresponding deviations are given for the number of
the optical properties used. These parameters are given as attributes in the NetCDF files and
refer to the following thematic categories:
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1.
2.
3.
4.
5.
6.
7.
8.
General Statistics
Surface Elevation and Overflight Parameters
Aerosol Statistics
Cloud Statistics
Stratospheric Statistics
Subtype percentages in the aerosol total observations
Subtype percentages in the cloud total observations
Subtype percentages in the stratospheric total observations
The statistical parameters for each thematic category along with their description are given
here:
1. General Statistics:
Averaging_Time_Start
Averaging_Time_End
The UTC start and end time of the CALIPSO record used for the production of LIVAS climatology
data. For LIVAS version 1.0 product, these values are:
Averaging_Time_Start : 01-01-2008 and Averaging_Time_End : 31-12-2011.
Fill_Values
The fill value is reported as -999.0.
Longitude_Midpoint
Latitude_Midpoint
Longitude and Latitude, in degrees, at the grid cell midpoint. These values are provided in the
filename as well.
2. Surface Elevation and Overflight Parameters:
Surface_Elevation_maximum
Surface_Elevation_mean
Surface_Elevation_median
Surface_Elevation_minimum
Surface elevation statistics in kilometers above local mean sea level, as obtained from the
GTOPO30 digital elevation map (DEM) for all columns reported in the latitude/longitude grid
cell.
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Number_CALIPSO_overpasses
The number of CALIPSO overpasses used for the derivation of the climatological profiles.
Number_CALIPSO_profiles
The number of CALIPSO profiles used for the derivation of the climatological profiles.
3. Aerosol Statistics:
Samples_Aerosol_Averaged
The number of aerosol samples contributing to the mean, median and standard deviation of
aerosol and total extinction coefficients in each latitude/longitude grid cell. Only the samples
with aerosol extinction coefficients passing all quality assurance filtering criteria are included.
The numbers are reported based on a 5 km horizontal x 60 meter vertical resolution grid,
matching the resolution of CALIPSO level 2 aerosol and cloud profile product. The number is the
same for aerosol backscatter and depolarization profiles of the grid cell.
Samples_Aerosol_plus_ClearAir_Averaged
The number of samples contributing to the mean, median and standard deviation of aerosol
extinction coefficients in each latitude/longitude grid cell. This number includes both the aerosol
extinction coefficient passing all quality assurance filtering criteria, as well as the number of
"clear air" extinction values of the grid cell. In computing the statistics, regions identified as
"clear air" are assumed to have an aerosol extinction coefficient of 0.0 km-1. The sample
numbers are reported based on a 5 km horizontal x 60 meter vertical resolution grid, matching
the resolution of CALIPSO level 2 aerosol and cloud profile products.
532_AOD_Mean
532_AOD_Median
532_AOD_Standard_Deviation
355_AOD_Mean
355_AOD_Median
355_AOD_Standard_Deviation
Mean, median and standard deviation of aerosol optical depth (AOD) at 532 & 355 nm
respectively, of cloud-free columns or the height range above clouds in the latitude/longitude
grid cell. AOD is calculated as the vertical integral of LIVAS’s aerosol extinction profiles at 532 or
355 nm and is a dimensionless quantity.
27
4. Cloud Statistics:
Samples_Cloud_Averaged
The number of cloud samples contributing to the mean and standard deviation of cloud and
total extinction coefficient for each latitude/longitude grid cell. This number includes only the
cloud extinction coefficient values passing all quality assurance filtering criteria. They are
reported based on a 5 km horizontal x 60 meter vertical resolution grid, matching the resolution
of CALIPSO level 2 aerosol and cloud profile product. The number is the same for cloud
backscatter and depolarization profiles of the grid cell.
Samples_Cloud_plus_ClearAir_Averaged
The number of samples contributing to the mean and standard deviation of cloud extinction
coefficient for each latitude/longitude grid cell. The samples include both the cloud extinction
coefficient values passing all quality assurance filtering criteria and the "clear air" extinction
values in the grid cell. In computing the statistics, regions identified as "clear air" are assumed to
have a cloud extinction coefficient of 0.0 km-1. The sample numbers are reported based on a 5
km horizontal x 60 meter vertical resolution grid, matching the resolution of CALIPSO level 2
aerosol and cloud product.
532_COD_Mean
532_COD_Median
532_COD_Standard_Deviation
Mean, median and standard deviation of cloud optical depth (COD) at 532 nm, for the
latitude/longitude grid cell. COD is calculated as the vertical integral of LIVAS’s cloud extinction
profiles at 532 nm and is a dimensionless quantity.
5. Stratospheric Statistics:
Samples_Stratospheric_Averaged
The number of stratospheric samples contributing to the mean and standard deviation of
stratospheric and total extinction coefficient for each latitude/longitude grid cell. This number
includes only the stratospheric extinction coefficient values passing all quality assurance filtering
criteria. They are reported based on a 5 km horizontal x 60 meter vertical resolution grid,
matching the resolution of CALIPSO level 2 aerosol and cloud profile product. The number is the
same for stratospheric backscatter and depolarization profiles of the grid cell.
Samples_Stratospheric_plus_ClearAir_Averaged
The number of samples contributing to the mean and standard deviation of stratospheric
extinction coefficient in each latitude/longitude grid cell. The samples include both the
stratospheric extinction coefficient values passing all quality assurance filtering criteria and the
"clear air" extinction values in the grid cell. In computing the statistics, regions identified as
28
"clear air" are assumed to have a stratospheric extinction coefficient of 0.0 km-1. The sample
numbers are reported based on a 5 km horizontal x 60 meter vertical resolution grid, matching
the resolution of CALIPSO level 2 aerosol and cloud profile product.
532_SOD_Mean
532_SOD_Median
532_SOD_Standard_Deviation
355_SOD_Mean
355_SOD_Median
355_SOD_Standard_Deviation
Mean, median and standard deviation of stratospheric optical depth (SOD) at 532 & 355 nm
respectively, for the latitude/longitude grid cell. SOD is calculated as the vertical integral of
LIVAS’s stratospheric extinction profiles at 532 or 355 nm and is a dimensionless quantity.
6. Subtype percentages in the aerosol total observations:
Aerosol_Subtypes
A string denoting the full names of CALIPSO aerosol subtypes as given in CALIPSO Level 2 aerosol
product, i.e.: “/ Clean_Marine / Dust / Polluted_Continental / Clean_Continental /
Polluted_Dust / Smoke /”.
Clean_Continental_Percentage_Occurence_in_Aerosols
Clean_Marine_Percentage_Occurence_in_Aerosols
Dust_Percentage_Occurence_in_Aerosols
Polluted_Dust_Percentage_Occurence_in_Aerosols
Polluted_Continental_Percentage_Occurence_in_Aerosols
Smoke_Percentage_Occurence_in_Aerosols
The columnar percentage of each aerosol type contributing to the total AOD for each
latitude/longitude grid cell.
7. Subtype percentages in the cloud total observations:
Cloud_Subtypes
A string denoting the full names of CALIPSO cloud subtypes as given in CALIPSO Level 2 cloud
product: “/ Low_overcast, transparent /Low_overcast, opaque/ Transition_stratocumulus / Low,
broken_cumulus / Altocumulus (transparent) / Altostratus (opaque) / Cirrus (transparent) /
Deep_convective (opaque) /”.
29
Altocumulus_Percentage_Occurence_in_Clouds
Altostratus_Percentage_Occurence_in_Clouds
Cirrus_Percentage_Occurence_in_Clouds
Deep_Convective_Percentage_Occurence_in_Clouds
Low_Broken_Cumulus_Percentage_Occurence_in_Clouds
Low_Overcast_Opaque_Percentage_Occurence_in_Clouds
Low_Overcast_Transparent_Percentage_Occurence_in_Clouds
Transition_Stratocumulus_Percentage_Occurence_in_Clouds
The columnar percentage of each cloud type contributing to the total COD for each
latitude/longitude grid cell.
8. Subtype percentages in the stratospheric total observations
Aerosol_Percentage_in_Stratospheric
PSC_Percentage_in_Stratospheric
The columnar percentage of stratospheric Aerosol or PSC contributing to the total SOD for each
latitude/longitude grid cell.
B. VERTICAL DISTRIBUTIONS
Vertical distributions are given as array variables in the NetCDF files and are grouped per
wavelength and per optical parameter. The wavelength groups are 0355_nm, 0532_nm,
1064_nm, 1570_nm and 2050_nm. The optical parameter groups are Backscatter,
Depolarization and Extinction for the corresponding wavelengths. An extra group
(Samples_Used) reports the frequency distribution of aerosol, cloud and stratospheric features
observed as well as the samples used for the production of the optical parameter profiles. The
parameters reported along with their description are given here:
Altitudes
Altitude array in kilometers above mean sea level. This array is the same with the altitude array
of CALIPSO Level 2 aerosol profile product.
30

Mean, median and standard deviation of extinction and backscatter aerosol profiles at 355,
532, 1064, 1570 and 2050 nm:
Backscatter
Extinction
355_Aerosol_Backscatter_Mean
355_Aerosol_Extinction_Mean
355_Aerosol_Backscatter_Median
355_Aerosol_Extinction_Median
355_Aerosol_Backscatter_Standard_Deviation
355_Aerosol_Extinction_Standard_Deviation
532_Aerosol_Backscatter_Mean
532_Aerosol_Extinction_Mean
532_Aerosol_Backscatter_Median
532_Aerosol_Extinction_Median
532_Aerosol_Backscatter_Standard_Deviation
532_Aerosol_Extinction_Standard_Deviation
1064_Aerosol_Backscatter_Mean
1064_Aerosol_Extinction_Mean
1064_Aerosol_Backscatter_Median
1064_Aerosol_Extinction_Median
1064_Aerosol_Backscatter_Standard_Deviation 1064_Aerosol_Extinction_Standard_Deviation
1570_Aerosol_Backscatter_Mean
1570_Aerosol_Extinction_Mean
1570_Aerosol_Backscatter_Median
1570_Aerosol_Extinction_Median
1570_Aerosol_Backscatter_Standard_Deviation 1570_Aerosol_Extinction_Standard_Deviation
2050_Aerosol_Backscatter_Mean
2050_Aerosol_Extinction_Mean
2050_Aerosol_Backscatter_Median
2050_Aerosol_Extinction_Median
2050_Aerosol_Backscatter_Standard_Deviation 2050_Aerosol_Extinction_Standard_Deviation
Vertical profiles of mean, median and standard deviation of aerosol extinction and backscatter
coefficient in units of km-1 and km-1sr-1, respectively, for each latitude/longitude/altitude grid
cell. The profiles are derived with the use of all quality screened CALIPSO lidar level 2 aerosol
extinction/backscatter product and the application of LIVAS spectral conversion factors. All
aerosol types are included in the statistics. In computing these statistics, regions identified as
"clear air" by the feature finder are assumed to have an aerosol extinction/backscatter
coefficient of 0.0 km-1 (this is consistent with CALIPSO L3 aerosol extinction products). Aerosol
extinction/backscatter coefficient within 180 meters of the surface elevation maximum are most
probably untrustworthy and should be ignored.

Mean and standard deviation of extinction and backscatter cloud profiles at 532 nm:
532_Cloud_Backscatter_Mean
31
532_Cloud_Backscatter_Standard_Deviation
532_Cloud_Extinction_Mean
532_Cloud_Extinction_Standard_Deviation
Vertical profiles of mean and standard deviation of cloud extinction and backscatter coefficients
in units of km-1 and km-1sr-1, respectively, for each latitude/longitude/altitude grid cell. These
profiles are derived with the use of all quality screened CALIPSO lidar level 2 cloud
extinction/backscatter coefficient profiles. All cloud types are included in the statistics. In
computing these statistics, regions identified as "clear air" by the feature finder are assumed to
have a cloud extinction/backscatter coefficient of 0.0 km-1 (this is consistent with CALIPSO L3
aerosol extinction products).

Mean and standard deviation of extinction and backscatter stratospheric profiles at 355,
532, 1064, 1570 and 2050 nm:
Backscatter
Extinction
355_Stratospheric_Backscatter_Mean
355_Stratospheric_Extinction_Mean
355_Stratospheric_Backscatter_Standard_Deviation
355_Stratospheric_Extinction_Standard_Deviation
532_Stratospheric_Backscatter_Mean
532_Stratospheric_Extinction_Mean
532_Stratospheric_Backscatter_Standard_Deviation
532_Stratospheric_Extinction_Standard_Deviation
1064_Stratospheric_Backscatter_Mean
1064_Stratospheric_Extinction_Mean
1064_Stratospheric_Backscatter_Standard_Deviation
1064_Stratospheric_Extinction_Standard_Deviation
1570_Stratospheric_Backscatter_Mean
1570_Stratospheric_Extinction_Mean
1570_Stratospheric_Backscatter_Standard_Deviation
1570_Stratospheric_Extinction_Standard_Deviation
2050_Stratospheric_Backscatter_Mean
2050_Stratospheric_Extinction_Mean
2050_Stratospheric_Backscatter_Standard_Deviation
2050_Stratospheric_Extinction_Standard_Deviation
Vertical profiles of mean and standard deviation of stratospheric extinction and backscatter
coefficients in units of km-1 and km-1sr-1, respectively, for the latitude/longitude/altitude grid
cell. These profiles are derived with the use of all quality screened CALIPSO level 2 aerosol
extinction/backscatter coefficient profiles, categorized from CALIPSO’s feature classification
scheme as stratospheric features, and the application of LIVAS conversion factors. In computing
these statistics, regions identified as "clear air" by the feature finder are assumed to have a
stratospheric extinction/backscatter coefficient of 0.0 km-1 (this is consistent with CALIPSO L3
aerosol extinction products).
32

Mean and standard deviation of extinction and backscatter total profiles at 355, 532, 1064,
1570 and 2050 nm:
Backscatter
Extinction
355_Total_Backscatter_Mean
355_Total_Extinction_Mean
355_Total_Backscatter_Standard_Deviation
355_Total_Extinction_Standard_Deviation
532_Total_Backscatter_Mean
532_Total_Extinction_Mean
532_Total_Backscatter_Standard_Deviation
532_Total_Extinction_Standard_Deviation
1064_Total_Backscatter_Mean
1064_Total_Extinction_Mean
1064_Total_Backscatter_Standard_Deviation
1064_Total_Extinction_Standard_Deviation
1570_Total_Backscatter_Mean
1570_Total_Extinction_Mean
1570_Total_Backscatter_Standard_Deviation
1570_Total_Extinction_Standard_Deviation
2050_Total_Backscatter_Mean
2050_Total_Extinction_Mean
2050_Total_Backscatter_Standard_Deviation
2050_Total_Extinction_Standard_Deviation
Vertical profiles of mean and standard deviation of total extinction and backscatter coefficients
in units of km-1 and km-1sr-1, respectively, for each latitude/longitude/altitude grid cell. These
profiles are derived with the use of all quality screened CALIPSO lidar level 2 aerosol & cloud
extinction/backscatter coefficient profiles, and the application of LIVAS spectral conversion
factors (the stratospheric features are included as well). In computing these statistics, regions
identified as "clear air" by the feature finder are assumed to have an aerosol
extinction/backscatter coefficient of 0.0 km-1 (this is consistent with CALIPSO L3 aerosol
extinction product). Aerosol extinction/backscatter coefficients within 180 meters of the surface
elevation maximum are most probably untrustworthy and should be ignored.

Mean, median and standard deviation of depolarization aerosol profiles at 532 nm.
532_Aerosol_Depolarization_Mean
532_Aerosol_Depolarization_Median
532_Aerosol_Depolarization_Standard_Deviation
Vertical profiles of mean, median and standard deviation of aerosol depolarization for the
latitude/longitude/altitude grid cell. These profiles are derived with the use of all quality
screened CALIPSO lidar level 2 aerosol depolarization profiles. In computing these statistics,
regions identified as "clear air" by the feature finder are assumed to have aerosol depolarization
of 0.0.
33

Mean and standard deviation of depolarization cloud, stratospheric and total profiles at 532
nm.
532_Cloud_Depolarization_Mean
532_Cloud_Depolarization_Standard_Deviation
532_Stratospheric_Depolarization_Mean
532_Stratospheric_Depolarization_Standard_Deviation
532_Total_Depolarization_Mean
532_Total_Depolarization_Standard_Deviation
Vertical profiles of mean and standard deviation of cloud, stratospheric and total depolarization
for the latitude/longitude/altitude grid cell. In computing these statistics, regions identified as
"clear air" by the feature finder are assumed to have depolarization of 0.0.

Seasonal variability of aerosols and clouds at 532 nm (mean, median and standard
deviation).
Aerosol
Cloud
532_Aerosol_Extinction_Mean_Autumn
532_Cloud_Extinction_Mean_Autumn
532_Aerosol_Extinction_Mean_Spring
532_Cloud_Extinction_Mean_Spring
532_Aerosol_Extinction_Mean_Summer
532_Cloud_Extinction_Mean_Summer
532_Aerosol_Extinction_Mean_Winter
532_Cloud_Extinction_Mean_Winter
532_Aerosol_Extinction_Median_Autumn
532_Cloud_Extinction_Standard_Deviation_Autumn
532_Aerosol_Extinction_Median_Spring
532_Cloud_Extinction_Standard_Deviation_Spring
532_Aerosol_Extinction_Median_Summer
532_Cloud_Extinction_Standard_Deviation_Summer
532_Aerosol_Extinction_Median_Winter
532_Cloud_Extinction_Standard_Deviation_Winter
532_Aerosol_Extinction_Standard_Deviation_Autumn
532_Aerosol_Extinction_Standard_Deviation_Spring
532_Aerosol_Extinction_Standard_Deviation_Summer
532_Aerosol_Extinction_Standard_Deviation_Winter
Seasonal vertical profiles of mean, standard deviation (and median for the aerosol subtypes
only) of aerosol/cloud extinction coefficients in units of km-1, for the latitude/longitude/altitude
grid cell. These profiles are derived with the use of all quality screened lidar level 2
34
aerosol/cloud extinction coefficient profiles. In computing extinction statistics, regions identified
as "clear air" by the feature finder are assumed to have an extinction coefficient of 0.0 km-1.
Extinction coefficients within 180 meters of the surface elevation maximum are most probably
untrustworthy and should be ignored.

Per feature type climatology of aerosols and clouds at 532 nm (mean, median and standard
deviation).
Aerosol
532_Aerosol_Extinction_Mean_Clean_Continental
532_Aerosol_Extinction_Mean_Clean_Marine
532_Aerosol_Extinction_Mean_Dust
532_Aerosol_Extinction_Mean_Polluted_Continental
532_Aerosol_Extinction_Mean_Polluted_Dust
532_Aerosol_Extinction_Mean_Smoke
532_Aerosol_Extinction_Median_Clean_Continental
532_Aerosol_Extinction_Median_Clean_Marine
532_Aerosol_Extinction_Median_Dust
532_Aerosol_Extinction_Median_Polluted_Continental
532_Aerosol_Extinction_Median_Polluted_Dust
532_Aerosol_Extinction_Median_Smoke
532_Aerosol_Extinction_Standard_Deviation_Clean_Continental
532_Aerosol_Extinction_Standard_Deviation_Clean_Marine
532_Aerosol_Extinction_Standard_Deviation_Dust
532_Aerosol_Extinction_Standard_Deviation_Polluted_Continental
532_Aerosol_Extinction_Standard_Deviation_Polluted_Dust
532_Aerosol_Extinction_Standard_Deviation_Smoke
35
Cloud
532_Cloud_Extinction_Mean_Altocumulus
532_Cloud_Extinction_Mean_Altostratus
532_Cloud_Extinction_Mean_Cirrus
532_Cloud_Extinction_Mean_Deep_convective
532_Cloud_Extinction_Mean_Low_broken_cumulus
532_Cloud_Extinction_Mean_Low_overcast_opaque
532_Cloud_Extinction_Mean_Low_overcast_transparent
532_Cloud_Extinction_Mean_Transition_stratocumulus
532_Cloud_Extinction_Standard_Deviation_Altocumulus
532_Cloud_Extinction_Standard_Deviation_Altostratus
532_Cloud_Extinction_Standard_Deviation_Cirrus
532_Cloud_Extinction_Standard_Deviation_Deep_convective
532_Cloud_Extinction_Standard_Deviation_Low_broken_cumulus
532_Cloud_Extinction_Standard_Deviation_Low_overcast_opaque
532_Cloud_Extinction_Standard_Deviation_Low_overcast_transparent
532_Cloud_Extinction_Standard_Deviation_Transition_stratocumulus
Vertical profiles of mean, standard deviation per aerosol/cloud type (plus median for the aerosol
subtypes only) of aerosol/cloud extinction coefficients in units of km-1, for the
latitude/longitude/altitude grid cell. These profiles are derived with the use of all quality
screened CALIPSO level 2 aerosol/cloud extinction coefficient profiles. In this “per feature type”
LIVAS product, only layers classified as the specific type are used to compute the profile
climatological statistics. Regions identified as "clear air" by the feature finder are assumed to
have an extinction coefficient of 0.0 km-1 (this is compatible with CALIPSO L3 aerosol extinction
product). Also, where other aerosol / cloud types exist, the region is identified as "clear air by
the specific feature” and the aerosol extinction coefficient is assumed to be equal to 0.0 km-1.
Extinction coefficients within 180 meters of the surface elevation maximum are most probably
untrustworthy and should be ignored.
36

Mean and standard deviation of extinction stratospheric profiles at 532 nm, separated for
Aerosol and PSC types.
532_Stratospheric_Extinction_Mean_Aerosols
532_Stratospheric_Extinction_Mean_PSCs
532_Stratospheric_Extinction_Standard_Deviation_Aerosols
532_Stratospheric_Extinction_Standard_Deviation_PSCs
Vertical profiles of mean and standard deviation per stratospheric Aerosol or PSC categorization
of stratospheric extinction coefficient in units of km-1, for the latitude/longitude/altitude grid
cell. These profiles are derived with the use of all quality screened CALIPSO level 2 stratospheric
extinction coefficient profiles and the application of LIVAS PSC categorization. In this “per
feature type” LIVAS product, only stratospheric layers classified as the specific type are used to
compute the profile climatological statistics. Regions identified as "clear air" by the feature
finder are assumed to have an aerosol extinction/backscatter coefficient of 0.0 km -1 (this is
compatible with CALIPSO L3 aerosol extinction product). Also, where other stratospheric types
exist, the region is identified as "clear air by the specific feature” and the extinction coefficient is
assumed to be equal to 0.0 km-1. Extinction coefficients within 180 meters of the surface
elevation maximum are most probably untrustworthy and should be ignored.

Frequency distribution of aerosol, cloud and stratospheric features observed and the
samples used for the production of the optical parameters profiles.
Samples Averaged
Samples_Aerosol_plus_ClearAir
Samples_All_Features_plus_ClearAir
Samples_Cloud_plus_ClearAir
Samples_Stratospheric_plus_ClearAir
Samples_Aerosol_plus_ClearAir_Clean_Continental
Samples_Aerosol_plus_ClearAir_Clean_Marine
Samples_Aerosol_plus_ClearAir_Dust
Samples_Aerosol_plus_ClearAir_Polluted_Continental
Samples_Aerosol_plus_ClearAir_Polluted_Dust
Samples_Aerosol_plus_ClearAir_Smoke
Samples_Cloud_plus_ClearAir_Altostratus
Samples_Cloud_plus_ClearAir_Cirrus
37
Samples_Cloud_plus_ClearAir_Clean_Altocumulus
Samples_Cloud_plus_ClearAir_Deep_convective
Samples_Cloud_plus_ClearAir_Low_broken_cumulus
Samples_Cloud_plus_ClearAir_Low_overcast_opaque
Samples_Cloud_plus_ClearAir_Low_overcast_transparent
Samples_Cloud_plus_ClearAir_Transition_stratocumulus
Samples_Stratospheric_plus_ClearAir_Aerosols
Samples_Stratospheric_plus_ClearAir_PSCs
Samples_Aerosol_plus_ClearAir_Autumn
Samples_Aerosol_plus_ClearAir_Spring
Samples_Aerosol_plus_ClearAir_Summer
Samples_Aerosol_plus_ClearAir_Winter
Samples_Cloud_plus_ClearAir_Autumn
Samples_Cloud_plus_ClearAir_Spring
Samples_Cloud_plus_ClearAir_Summer
Samples_Cloud_plus_ClearAir_Winter
Samples Detected Accepted
Samples_Aerosol
Samples_All_Features
Samples_Cloud
Samples_Stratospheric
Samples_Aerosol_Clean_Continental
Samples_Aerosol_Clean_Marine
Samples_Aerosol_Dust
Samples_Aerosol_Polluted_Continental
Samples_Aerosol_Polluted_Dust
Samples_Aerosol_Smoke
Samples_Cloud_Altostratus
38
Samples_Cloud_Cirrus
Samples_Cloud_Clean_Altocumulus
Samples_Cloud_Deep_convective
Samples_Cloud_Low_broken_cumulus
Samples_Cloud_Low_overcast_opaque
Samples_Cloud_Low_overcast_transparent
Samples_Cloud_Transition_stratocumulus
Samples_Aerosol_Autumn
Samples_Aerosol_Spring
Samples_Aerosol_Summer
Samples_Aerosol_Winter
Samples_Cloud_Autumn
Samples_Cloud_Spring
Samples_Cloud_Summer
Samples_Cloud_Winter
Samples_Stratospheric_Aerosols
Samples_Stratospheric_PSCs
The Samples Averaged group, reports the number of samples contributing to the mean, median
and standard deviation of the relevant optical parameter profiles in each
latitude/longitude/altitude grid cell. In computing these statistics, regions identified as "clear
air" are assumed to have an extinction coefficient of 0.0 km-1. Therefore, the number of
samples averaged includes both the features passing all quality assurance filtering criteria and
the number of "clear air" extinction values in the grid cell. The numbers are reported based on a
5 km horizontal x 60 meter vertical resolution grid, matching the resolution of CALIPSO level 2
aerosol and cloud profile product.
The Samples Detected Accepted group, reports the number of the relevant feature samples
that were detected and passed all quality assurance filtering criteria for the production of the
optical parameter profiles in each latitude/longitude/altitude grid cell. However, this is not the
number of samples that contributes to the mean, median and standard deviation of the relevant
optical parameter profiles because clear air samples are included in the calculations. The
numbers are reported based on a 5 km horizontal x 60 meter vertical resolution grid, matching
the resolution of CALIPSO level 2 aerosol and cloud profile product.
39
4.1.3 FTP site for climatological NetCDF files
The user can download the complete LIVAS climatology for the globe in NetCDF format via an
FTP server that operates under LIVAS portal. The ftp address is:
ftp://lidar.space.noa.gr
The user can contact Vassilis Amiridis ([email protected]) in order to receive login credentials.
4.2 LIVAS selected scenes
For each LIVAS selected scene, the user has the possibility to download a NetCDF file containing
the full multi-wavelength dataset provided. The download procedure is triggered by double
clicking the selected scene. In the example given in the following figure, the dust scene is
selected and the download window is projected.
Figure 4-2: NetCDF download option for selected scenes
4.2.1 NetCDF format description
LIVAS selected Scenes product is provided in NetCDF format for each selected scene. The
filename format is:
 NetCDF files: LIVAS_Selected_Scene_ScenesName_Date_version.nc
 Example: LIVAS_Selected_Scene_Dust_and_Smoke_2008-02-06_v0.1.nc
The parameters included in LIVAS NetCDF files are organized into two major categories, i.e.
“SCENE INFO” and “VERTICAL DISTRIBUTIONS”, which are described in detail herein.
40
A. SCENE INFO
Scene info are divided in 2 groups, the one given as attributes and the ones given as profiles in
the NetCDF files.
Attributes info:
Selected_Scene
The name of the selected scene.
Date_Time_Start
Date_Time_End
The UTC date and time of the first and last profile of the scene are given in these two strings.
Their format is: YYYY/MM/DD HH:MM:SS.
Fill_Values
The fill value in the profiles, defined as -999.0.
Latitude_Range
Longitude_Range
Longitude and Latitude range of the scene are given in two strings. One example: for the cirrus
clouds selected scene at 2006/08/11 the scene start at 33.06 degrees and ends at 38.90 degrees
latitude so the latitude range is “33.06..38.90”.
Profiles info:
Altitudes
Altitude array in kilometers above mean sea level. This array is the same with the altitude array
of CALIPSO Level 2 aerosol profile product.
Longitude
Latitude
Geodetic longitude and latitude, in degrees, of the laser footprint. The values reported
correspond to the footprint longitude and latitude at the temporal midpoint of the 5 km
CALIPSO track.
Profile_UTC_Time
Time expressed in Coordinated Universal Time (UTC), and formatted as 'yymmdd.ffffffff', where
'yy' represents the last two digits of year, 'mm' and 'dd' represent month and day, respectively,
and 'ffffffff' is the fractional part of the day.
Surface_Elevation_Maximum
41
Surface_Elevation_Minimum
Surface_Elevation_Mean
Surface_Elevation_Standard_Deviation
Maximum, minimum, mean, and standard deviation of the surface elevation in kilometers above
sea level, obtained from the GTOPO30 digital elevation map (DEM) for the horizontal distance
spanned by the averaged profile.
CALIPSO_Feature_Type
CALIPSO_Feature_Sub_type
The provided CALIPSO feature Types and Feature Subtypes as derived from CALIPSO Level 2
aerosol profile product AVD (Atmospheric Volume Description) arrays. These data are stored as
3-D arrays of the size [#profiles, # altitude bins, 2]. The first dimension, [ : , : , 1], corresponds to
the standard altitude array of the Profile Product. Thus, below 8.3 km, the first dimension
contains the descriptive flags of the higher of the two full resolution (30 m) bins that comprise
the single 60 m bin reported in the Profile Products. Meanwhile, below 8.3 km, the second
dimension [: , : , 2] contains the descriptive flags for the lower of the two 30 m range bins.
Above 8.3 km, where the range resolution of the Level 1 data is 60 m or greater, the descriptive
flags for each single 60 m (or 180 m) range bin are replicated in both array elements.
Feature Type and Subtype Definition
Field Description
Interpretation
Feature Type
0 = invalid (bad or missing data)
1 = "clear air"
2 = cloud
3 = aerosol
4 = stratospheric feature
5 = surface
6 = subsurface
7 = no signal (totally attenuated)
Feature Sub-type
If feature type = aerosol
0 = not determined
1 = clean marine
2 = dust
3 = polluted continental
4 = clean continental
5 = polluted dust
6 = smoke
42
7 = other
If feature type = cloud
0 = low overcast, transparent
1 = low overcast, opaque
2 = transition stratocumulus
3 = low, broken cumulus
4 = altocumulus (transparent)
5 = altostratus (opaque)
6 = cirrus (transparent)
7 = deep convective (opaque)
If feature type = Polar Stratospheric Cloud
0 = not determined
B. VERTICAL DISTRIBUTIONS
Vertical distributions are given as array variables in the NetCDF files and are grouped per
wavelength and per optical parameter. The wavelength groups are 0355_nm, 0532_nm,
1064_nm, 1570_nm and 2050_nm. The optical parameter groups are Backscatter,
Depolarization and Extinction for the corresponding wavelengths.
355_Backscatter_Aerosol
532_Backscatter_Aerosol
1064_Backscatter_Aerosol
1570_Backscatter_Aerosol
2050_Backscatter_Aerosol
532_Backscatter_Cloud
355_Backscatter_Total
532_Backscatter_Total
1064_Backscatter_Total
1570_Backscatter_Total
2050_Backscatter_Total
Particulate total backscatter coefficients reported for each profile range bin in which the
appropriate particulates (i.e., clouds or aerosols or all) were detected. The range bins in which
neither clear air nor the specific particulates were detected contain fill values (-999). Units are
43
km-1sr-1. The profiles are derived with the use of CALIPSO level 2 aerosol & cloud backscatter
coefficient profiles and the application of LIVAS spectral conversion factors.
355_Extinction_Aerosol
532_Extinction_Aerosol
1064_Extinction_Aerosol
1570_Extinction_Aerosol
2050_Extinction_Aerosol
532_Extinction_Cloud
355_Extinction_Total
532_Extinction_Total
1064_Extinction_Total
1570_Extinction_Total
2050_Extinction_Total
Particulate extinction coefficients reported for each profile range bin in which the appropriate
particulates (i.e., clouds or aerosols or all) were detected. Those range bins in which neither
clear air nor the specific particulates were detected contain fill values (-999). Units are km-1.
These profiles are derived with the use of CALIPSO level 2 aerosol & cloud extinction coefficient
profiles and the application of LIVAS spectral conversion factors.
532_Depolarization_Aerosol
532_Depolarization_Cloud
532_Depolarization_Total
Particulate depolarization ratio reported for each profile range bin in which the appropriate
particulates (i.e., clouds or aerosols or all) were detected. Those range bins in which neither
clear air nor the specific particulates were detected contain fill values (-999). These profiles are
derived with the use of CALIPSO level 2 aerosol & cloud particulate depolarization ratio profiles.
355_Backscatter_Aerosol_Uncertainty
532_Backscatter_Aerosol_Uncertainty
1064_Backscatter_Aerosol_Uncertainty
1570_Backscatter_Aerosol_Uncertainty
2050_Backscatter_Aerosol_Uncertainty
532_Backscatter_Cloud_Uncertainty
355_Backscatter_Total_Uncertainty
44
532_Backscatter_Total_Uncertainty
1064_Backscatter_Total_Uncertainty
1570_Backscatter_Total_Uncertainty
2050_Backscatter_Total_Uncertainty
Uncertainty in the backscatter coefficients reported for each profile range bin in which the
appropriate particulates were detected. These are absolute uncertainties, not relative, thus the
units are identical to the units of the backscatter coefficients (km-1sr-1). The range bins in which
no particulates were detected contain fill values (-999). These profiles are computed with the
use of CALIPSO level 2 aerosol & cloud backscatter uncertainties profiles and the application of
LIVAS conversion factors.
.355_Extinction_Aerosol_Uncertainty
532_Extinction_Aerosol_Uncertainty
1064_Extinction_Aerosol_Uncertainty
1570_Extinction_Aerosol_Uncertainty
2050_Extinction_Aerosol_Uncertainty
532_Extinction_Cloud_Uncertainty
355_Extinction_Total_Uncertainty
532_Extinction_Total_Uncertainty
1064_Extinction_Total_Uncertainty
1570_Extinction_Total_Uncertainty
2050_Extinction_Total_Uncertainty
Uncertainty in the particulate extinction coefficients reported for each profile range bin in which
the appropriate particulates were detected. These are absolute uncertainties, not relative, thus
the units are identical to the units of extinction coefficients (km-1). The range bins in which no
particulates were detected contain fill values (-999). The profiles are computed with the use of
CALIPSO level 2 aerosol & cloud extinction uncertainties profiles and the application of LIVAS
conversion factors.
532_Depolarization_Aerosol_Uncertainty
532_Depolarization_Cloud_Uncertainty
532_Depolarization_Total_Uncertainty
The uncertainties reported for the particulate depolarization ratios provide an estimate for
random error in the particulate depolarization ratio for each range bin.
45
5 Summary and Conclusions
LIVAS products are available through the project’s web portal, which is capable of providing the
output formats required, i.e.:
-
Real-time visualization tools with graph parameterizing options and downloading
capability of images in raster and vector format
Quick-views
Downloading of products in ASCII and NetCDF-4 format
The aforementioned capabilities are provided for LIVAS climatology (grid point data) and for the
selected scenes separately, under different GUIs.
Livas Web Portal is available online under the following url: http://lidar.space.noa.gr:8080/livas
46
List of Figures
Figure 1-1: LIVAS web portal homepage ........................................................................................................ 6
Figure 2-1: The Climatology page of LIVAS portal .......................................................................................... 7
Figure 2-2: The grid selector of LIVAS ............................................................................................................. 8
Figure 2-3: Aerosol optical depth layer ........................................................................................................... 8
Figure 2-4: Number of CALIPSO overpasses.................................................................................................... 9
Figure 2-5: 4-year number of CALIPSO profiles used for the averaging procedure ........................................ 9
Figure 2-6: The dynamic LIVAS Product Selector .......................................................................................... 10
Figure 2-7: The data plotting module ........................................................................................................... 11
Figure 2-8: Statistics panel ........................................................................................................................... 12
Figure 3-1: The selected scenes GUI of LIVAS portal ..................................................................................... 13
Figure 3-2: The scene selector ...................................................................................................................... 14
Figure 3-3: The description panel ................................................................................................................. 15
Figure 3-4: Time-height plot of the aerosol extinction at 355 nm ................................................................ 16
Figure 4-1: ASCII and NetCDF buttons .......................................................................................................... 18
Figure 4-2: NetCDF download option for selected scenes ............................................................................ 39
47
List of Tables
Table 3-1: Description of ASCII filename nomenclature keys ....................................................................... 19
Table 3-2: Exported ASCII header attribute nomenclature keys ................................................................... 20