Information Regarding PEM-West A Images
PEM-West A Field Experiment
Description
Major PEM-West A Campaign
References
INFORMATION REGARDING PEM-West A IMAGES
In an attempt to make the airborne DIAL ozone and aerosol scattering images
included in this WWW document easy to use, the images were generated using a
limited number of ozone and aerosol color scales. The vertical scale is consistent
between images, but the horizontal scale may change by a factor of two from one
image to the next. The spacing of time ticks should be sufficient to indicate
when this has occurred. The majority of the aerosol scattering images are from the
infrared channel (1064 nm), and they are reported as relative scattering values.
Due to lack of infrared data, or when the visible channel (offline 598.4 nm, online
576.4 nm) showed an aerosol feature more clearly, visible relative scattering images
were used. Ozone nadir and zenith profiles were combined. The ozone is interpolated
from DIAL nadir/zenith to in-situ. "Modeled" data is only used to extrapolate the
DIAL profiles to the ground. Archival data has flag values to allow identification
of interpolated and extrapolated values.
Resolution of the data are:
VERTICAL RESOLUTION:
Vertical averaging interval
Aerosol 30 meters
Ozone 300 meters (nadir)
600 meters (zenith)
Vertical display interval for averaged data
Aerosol 30 meters
Ozone 30 meters
HORIZONTAL RESOLUTION:
Horizontal averaging interval (All flight except 16, 17, and 20 past 17:32 UT.)
Aerosol 1.75 seconds, or approximately 408 meters
Ozone 180 seconds, or approximately 42 kilometers
Horizontal averaging interval (Flights 16 and 17.)
Aerosol 1.5 seconds, or approximately 350 meters
Ozone 154.5 seconds, or approximately 36 kilometers
Horizontal averaging interval (Flight 20 past 17:32 UT.)
Aerosol 2.33 seconds, or approximately 543 meters
Ozone 240 seconds, or approximately 56 kilometers
Horizontal display interval for averaged data (All Flights except 16, 17, and 20 past 17:32 UT.)
Aerosol either 3.5 or 7 seconds, or
approximately 817 or 1634 meters respectively.
Ozone either 3.5 or 7 seconds, or
approximately 817 or 1634 meters respectively.
Horizontal display interval for averaged data (Flights 16 and 17.)
Aerosol either 3 or 6 seconds, or
approximately 700 or 1400 meters respectively.
Ozone either 3 or 6 seconds, or
approximately 700 or 1400 meters respectively.
Horizontal display interval for averaged data (Flight 20 past 17:32 UT.)
Aerosol either 2.33 or 4.66 seconds, or
approximately 543 or 1086 meters respectively.
Ozone either 2.33 or 4.66 seconds, or
approximately 543 or 1086 meters respectively.
Times on the images are Universal Time (UT).
The GIF areosol and ozone image dimensions are 1050 X 850 pixels in order to retain resolution. Your WWW browser/GIF viewer may handle the image in various ways. On displays of less than 1050 X 850 pixels the image may have to be scrolled or the image may get resized, losing some clarity of the fonts.
The airborne DIAL data images are to be used as a reference to the digital data located in the
Langley Distributed Active Archive Center (DAAC). The images (both aerosol and ozone) viewed on this WWW page are from a full resolution data set, whereas, the digital data archived at the DAAC are a sub-sampled data set (1 profile/minute). If full resolution digital data are required, please contact the Lidar Applications Group. Images are not to be published without permission from NASA.
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Last Updated: by Vince Brackett, curator v.g.brackett@larc.nasa.gov
Responsible NASA organization/official:Dr. Edward Browell,Head of Lidar Applications Group e.v.browell@larc.nasa.gov