Information Regarding PEM-Tropics Images

PEM-Tropics Field Experiment Description

Major PEM-Tropics Campaign References

INFORMATION REGARDING PEM-Tropic 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 color scales. The vertical scale is consistent between images, but the horizontal scale may change from one image to the next without any specific notation. The spacing of time ticks should be sufficient to indicate when this has occurred. The aerosol scattering images are generally from the visible channel, except when it was unavailable. In these cases, the infrared channel was used. Aerosol data are reported as Atmospheric Scattering Ratios. Ozone data are reported as mixing ratios (ppbv).

Resolution of the data are:



      VERTICAL RESOLUTION:



Vertical averaging interval
        Aerosol    30 meters
Ozone      300 meters (nadir)
300 meters (zenith)

Vertical display interval for averaged data
        Aerosol    30 meters
Ozone      30 meters




       HORIZONTAL RESOLUTION:



Horizontal averaging interval
        Aerosol    2.00 seconds, or approximately 470 meters
Ozone      300 seconds, or approximately 70 kilometers

Horizontal display interval for averaged data
        Aerosol    either 2, 4, or 6 seconds, or
approximately 470, 930, or 1400 meters respectively
Ozone      either 2, 4, or 6 seconds, or
approximately 470, 930, or 1400 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 Images are not to be published without permission from NASA.




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