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1<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
2<html>
3<head>
4   <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
5   <meta name="Author" content="Alexey Chursin">
6   <meta name="GENERATOR" content="Mozilla/4.72 [en] (Windows NT 5.0; I) [Netscape]">
7   <title>Global Aerosol Data Set (GADS)</title>
8</head>
9<body bgcolor="#999999">
10&nbsp;
11<center><table BORDER=8 COLS=1 WIDTH="80%" BGCOLOR="#FFFF00" >
12<tr>
13<td>
14<center><b><font color="#FF0000">Global Aerosol Data Set (GADS)</font></b></center>
15</td>
16</tr>
17</table></center>
18
19<p><a href="#globdistr">Global distribution of basic aerosol microphysical
20properties and online access to data files</a>
21<br><a href="#hess_art">Integral text of paper by Hess et al., 1998</a>
22<br><a href="#microphys">Computations of aerosol microphysical properties
23in each grid point</a>
24<br><a href="#opt">Computations of aerosol optical properties in each grid
25point</a>
26<br><a href="#opt">Download the complete version of GADS</a>
27<br><a href="#prog_online">GADS programs online</a>
28<br><a href="alexei_aer_ref_gs03.html">References</a>
29<p>&nbsp;&nbsp;&nbsp; Aerosol data globally existing from different measurements
30and extensive models have been compiled by <a href="http://www.lrz-muenchen.de/~uh234an/www/mitarb/mhess.html">Hess</a>
31and Koepke (Meteorolgisches Institut der Universitat Munchen, Germany),
32Schult (Max-Plank-Institut fur Meteorologie, Hamburg, Germany), and Shetle
33(Remote Sensing Division, Naval Research Lab. Washington, USA)&nbsp; into
34<a href="http://www.lrz-muenchen.de/~uh234an/www/radaer/gads.html">Global
35Aerosol Data Set (GADS) </a>(Koepke et al., 1997). The copy of the GADS
36web page is available also <a href="alexei_gads_des_gs03.html">here</a>.
37<br>&nbsp;&nbsp;&nbsp; The GADS is a completely revised version of the
38aerosol climatology by d'Almeida et al., 1991. The data now are consistent
39in number distribution, mass per volume and optical properties. Aerosols
40are modeled as 10 components which are described with size distribution
41and spectral refractive index (on the basis of (WMO, 1983), (d'Almeida
42et al., 1991)). From these data the optical properties are calculated with
43the Mie theory at wavelengths between 0.25 micrometers and 40 micrometers
44and for 8 values of relative humidity, if necessary. The properties of
45the aerosol components themselves are available in the software package
46<a href="alexei_opac_gs03.html">OPAC
47(Optical Properties of Aerosols and Clouds)</a>. In GADS, for the entire
48globe, on a grid of 5 degrees longitude and latitude, with 7 differentiating
49height profiles, and both for summer and winter, the aerosol at the gridpoints
50is composed from the aerosol components.
51<br>&nbsp;&nbsp;&nbsp; This data set consists of aerosol properties averaged
52in space and time and therefore is mainly determined for use in climate
53<br>modelling.
54<center><a NAME="globdistr"></a><b>The following basic averaged aerosol
55microphysical properties at each grid point have been archived in the GADS
56for two seasons of the Northen Hemisphere&nbsp; </b>(into the winter.dat&nbsp;
57and summer.dat files below)<i>:</i></center>
58
59<ul>
60<li>
61Aerosol height profile (7 different profiles are used in GADS. <a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/glodat/profiles.dat">Click
62here to view them</a>.)</li>
63
64<li>
65Total particle number density at surface in particles cm<sup>-3</sup></li>
66
67<li>
68Number and list of aerosol components which compose the aerosol at a given
69grid point (up to 4 aerosol components are used at each grid point). The
70full list of possible aerosol components is given in column 2 of <a href="alexei_gads_comp_gs03.html">Table
711</a>.</li>
72
73<li>
74Mixing ratio of each of these aerosol components</li>
75</ul>
76Click with the mouse left button to view or with the mouse right button
77to download the following files:
78<ul>
79<li>
80<b><a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/glodat/winter.dat">winter.dat</a></b>: valid
81for the period September to February.</li>
82
83<li>
84<b><a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/glodat/summer.dat">summer.dat</a></b>: valid
85for the period March to August.</li>
86</ul>
87&nbsp;The detailed description of the file contents is given in the header
88of each file.
89<center>
90<p><a NAME="opt"></a><b>The following averaged&nbsp; aerosol optical propertiesat
91each grid point, at wavelengths between 0.25 micrometers and 40 micrometers
92and for 8 values of relative humidity (for some components) can be computed
93using <a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/prog/gads.f">the GADS FORTRAN code</a></b>:</center>
94
95<ul>
96<li>
97Extinction coefficient [km<sup>-1</sup>]</li>
98
99<li>
100Scattering coefficient [km<sup>-1</sup>]</li>
101
102<li>
103Absorption coefficient [km<sup>-1</sup>]</li>
104
105<li>
106Single scattering albedo</li>
107
108<li>
109Asymmetry parameter</li>
110
111<li>
112Optical depth</li>
113
114<li>
115Lidar ratio [sr]</li>
116</ul>
117<a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/example/aererg">Click here</a> to view an example
118of output file with computed aerosol optical properties. File format is
119given in headers of each file.
120<p><a NAME="hess_art"></a>All formulas and definitions are given in the
121basic paper by Hess et al., 1998: Click with the mouse right button and
122select "Save link as" item of the pop-up menu to download :
123<ul>
124<li>
125<a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/doc/hess-etal.pdf">Pdf-version of paper by Hess
126et al., 1998</a></li>
127
128<li>
129<a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/doc/hess-etal.ps">PostScript version of paper
130by Hess et al., 1998</a></li>
131</ul>
132
133<center><a NAME="microphys"></a><b>The following averaged aerosol microphysical
134properties at each grid point can be computed using <a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/prog/gads.f">the
135GADS FORTRAN code</a>:</b></center>
136
137<p><br>
138<br>&nbsp;
139<br>&nbsp;
140<br>&nbsp;
141<center><table BORDER COLS=2 WIDTH="90%" >
142<tr>
143<td>
144<center><b>Aerosol microphysical property</b></center>
145</td>
146
147<td>
148<center><b>Example of an output file of such a type<sup>(*)</sup></b></center>
149</td>
150</tr>
151
152<tr>
153<td>Total number density of aerosol particles in particles cm<sup>-3 </sup>or
154in microgram m<sup>-3</sup>.</td>
155
156<td>
157<center><a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/example/tonde.out">Click here</a></center>
158</td>
159</tr>
160
161<tr>
162<td>Number densities of aerosol components listed in column 2 of <a href="alexei_gads_comp_gs03.html">Table
1631</a>.&nbsp;</td>
164
165<td>
166<center><a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/example/inson.out">Click here</a></center>
167</td>
168</tr>
169
170<tr>
171<td>Aerosol types<sup>(**)</sup>, listed in column 1 of <a href="alexei_opac_gs03.html#TB6">Table
1726</a>, typical for each grid point at sea level</td>
173
174<td>
175<center><a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/example/aetyp.out">Click here</a></center>
176</td>
177</tr>
178
179<tr>
180<td>Aerosol profile types listed in <a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/glodat/profiles.dat">profiles.dat</a>
181file, typical for each grid point.</td>
182
183<td>
184<center><a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/example/prtyp.out">Click here</a></center>
185</td>
186</tr>
187</table></center>
188
189<p><sup>(*)</sup> All output files with microphysical properties have the
190same format: a file header, and rows with 3 values: latitude of a grid
191point (in degree) in column 1, longitude of a grid point (in degree) in
192column 2, a computed parameter (number density in particles cm<sup>-3 </sup>or
193in microgram m<sup>-3</sup>, aerosol type or aerosol profile type for this
194grid point) in column 3.
195<br><sup>(**)</sup> Aerosol types are coded as integers in the GADS output
196files: the fist aerosol listed column 1 of <a href="alexei_opac_gs03.html#TB6">Table
1976</a> (continental clean) is refered as 1, the second one (continental
198average) is refered as 2, etc.
199<center>
200<p><a NAME="avail"></a><b>Availability and use of GADS</b></center>
201
202<p><i>How to get GADS?</i>
203<p>&nbsp;&nbsp;&nbsp; The complete version of the GADS as well as the detailed
204description of its content can be gotten:
205<ol>
206<li>
207directly from the <a href="http://www.lrz-muenchen.de/~uh234an/www/radaer/gads_des.html">GADS
208web site</a></li>
209
210<li>
211from this web site: click <a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/prog/gads22a_tar.gz">here</a>
212with the mouse right button and select the "Save link as" item of the pop-up
213menu. The detailed instructions on installation of the GADS are given <a href="alexei_instgads_gs03.html">here</a>.The
214FORTRAN source of the gads.f program is given <a href="http://ara.lmd.polytechnique.fr/ftpgeisa?geisa/iasi/aerosol/prog/gads.f">here</a>.</li>
215</ol>
216<a NAME="prog_online"></a><i>GADS programs online.</i>
217<p>&nbsp;&nbsp;&nbsp; GADS programs are online accessible from this page:
218<ul>
219<li>
220Global distribution of aerosol microphysical properties => Click
221here <b> (NOT AVAILABLE NOW) </b></li>
222
223<li>
224Global distribution of aerosol optical properties => Click
225here <b>(NOT AVAILABLE NOW)</b></li>
226</ul>
227
228</body>
229</html>
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