hi,all
there is a dataset called "Mean reflectance at
0.47,0.55,0.66,0.87,1.24 ,1.64 and 2.13 Microns " , it represents the
TOA reflectance or the surface reflectance? thank you.

On Mar 26, 1:35 am, highstone wrote:
hi,all
there is a dataset called "Mean reflectance at
0.47,0.55,0.66,0.87,1.24 ,1.64 and 2.13 Microns " , it represents the
TOA reflectance or the surface reflectance? thank you.

Without a link or more information it would be kinder not to guess.
It does sound like parts per million. A little loitering at Google
found me the following:

************************************************** *****************************
*
*
* Readme file for the MODIS_CLAMS_L2_AEROSOL_PRODUCTS Data
Set *
*
*
************************************************** *****************************

1.0 Introduction:

This readme file contains information about the aerosol data
products
provided by the Moderate Resolution Imaging Spectroradiometer
(MODIS)
for the Chesapeake Lighthouse Aircraft Measurements for Satellite
(CLAMS) field campaign. The CLAMS campaign was designed to
validate
and improve EOS Terra satellite data products produced from the
CERES,
MISR, and MODIS sensors onboard Terra. This data set is available
at the
Atmospheric Sciences Data Center as:

MODIS_CLAMS_L2_AEROSOL_PRODUCTS


The MODIS_CLAMS_L2_AEROSOL_PRODUCTS are stored in the Hierarchical
Data
Format (HDF). The Aerosol Product monitors aerosol type, aerosol
optical thickness, particle size distribution, aerosol mass
concentration,
optical properties and radiative forcing. A list of the 53
gridded parameters
is given in section 4.0 below and a detailed description of each
of the
parameters is available at:
http://modis-atmos.gsfc.nasa.gov/MOD04_L2/format.html.


This readme file includes the following sections:

Section 2.0 - Data Set Description
Section 3.0 - Format and Packaging
Section 4.0 - Science Parameters Information
Section 5.0 - Description of Sample Read Software
Section 6.0 - Implementing Sample Read Software
Section 7.0 - Sample Output
Section 8.0 - Additional Data Information

If you have any questions, please contact the Langley Atmospheric
Sciences
Data Center (ASDC) Science, Users and Data Services Office at:

Atmospheric Sciences Data Center
Science, Users and Data Services Office
Mail Stop 157D
2 South Wright Street
NASA Langley Research Center
Hampton, Virginia 23681-2199
U.S.A.

E-mail:
Phone: (757)864-8656
FAX: (757)864-8807
URL: http://eosweb.larc.nasa.gov

2.0 Data Set Description:

The MODIS_CLAMS_L2_AEROSOL_PRODUCTS data set available from the
CLAMS
archive at the Langley ASDC are from the Moderate Resolution
Imaging
Spectroradiometer (MODIS) Aerosol Products. These MODIS aerosol
data
products are for the time period of the CLAMS field campaign, and
give
the ambient aerosol optical thickness over the oceans and over a
portion
of the continents. The aerosol size distribution is derived over
the
oceans, and the aerosol type is derived over the continents. Daily
Level 2
data were produced at the spatial resolution of a 10×10 1-km (at
nadir)-pixel
array. The MODIS_CLAMS_L2_AEROSOL_PRODUCTS cover the time period
from July 10,
2001 (Julian day 191) to August 2, 2001 (Julian day 214) over the
spatial
region nomally from -106 degree longitude to -42 degree longitude
and
from 57 degree N latitude to 18 degree N latitude. A more
detailed
description of the MODIS Aerosol Products is available at
http://modis-atmos.gsfc.nasa.gov/MOD04_L2/index.html,
and of the CLAMS field campaign at
http://www-clams.larc.nasa.gov/clams/.

2.1 Instrumentation Description:

The MODIS instrument provides high radiometric sensitivity (12 bit)
in 36
spectral bands ranging in wavelength from 0.4 µm to 14.4 µm. Two
bands are
imaged at a nominal resolution of 250 m at nadir, with five bands at
500 m
and the remaining 29 bands at 1,000 m. A ±55-degree scanning pattern
at the
EOS orbit of 705 km achieves a 2,330-km swath and provides global
coverage
approcimately every two days.

Additional information on the MODIS instrument is available from:

http://modis.gsfc.nasa.gov/about/index.html


2.2 Data Quality:

There are no known anomalies in these data.

2.3 Science Contact:

Questions pertaining to the data values contained within these
files should
be directed to:

Name: Robert Levy
Address: SSAI/ NASA GSFC Code 913 Greenbelt, MD 20771
Telephone: (301) 614-6123
Fax: (301) 614-6307
Internet Address:

3.0 Format and Packaging:

MOD04_L2 Aerosol Product files are stored in Hierarchical Data
Format
(HDF-Version 4). The MOD04_L2 Aerosol Product files associated
with the
CLAMS field campaign have been bundled in zipped files for each
campaign
day. To read the files, first unzip them with Info-Zip software
or other
appropriate software. Information about downloading and using the
freeware
software, Info-Zip, is available at the following URL:
http://www.cdrom.com/pub/infozip/