Lidar Measurements: Atmospheric Constituents ...
TRANSMITTER TELESCOPE
GRATING
POL YCHROMATOR
RECEIVER TELESCOPE
DISCRIMINATOR
XeCI EXCIMER
LASER
FILTER
POLYCHROMATOR
Figure 10.12: Schematic diagram of the combined Raman lidar.
235
Figure 10.13: Filter polychromator (left) and grating polychromator (right), schematic. L
lenses, EA and H entrance aperture, DB dictroic beam splitter, SP uncoated fused silica plate, F
interference filters, M mirrors, Gl echelle grating, G2 holographic grating, PMT photomultiplier
tubes.
systematic deviations occurred that could not be explained from this difference. In Fig. 10.14
the maximum values of these radiosoundings are plotted vs temperature. It later turned out
that the process used for the measurement of moisture with the radiosondes is not suited in
temperatures below -40°C, and routine users of radiosonde data had to take this shortcoming
into account for their practical applications.
Measurements of cirrus is another example in which the combined Raman lidar can provide
valuable results. The separate measurement of the height profiles of particle backscatter and
extinction coefficients, (3 and n, not only allows a direct assessment of geometric and radiative
TRANSMITTER TELESCOPE
GRATING
POL YCHROMATOR
RECEIVER TELESCOPE
DISCRIMINATOR
XeCI EXCIMER
LASER
FILTER
POLYCHROMATOR
Figure 10.12: Schematic diagram of the combined Raman lidar.
235
Figure 10.13: Filter polychromator (left) and grating polychromator (right), schematic. L
lenses, EA and H entrance aperture, DB dictroic beam splitter, SP uncoated fused silica plate, F
interference filters, M mirrors, Gl echelle grating, G2 holographic grating, PMT photomultiplier
tubes.
systematic deviations occurred that could not be explained from this difference. In Fig. 10.14
the maximum values of these radiosoundings are plotted vs temperature. It later turned out
that the process used for the measurement of moisture with the radiosondes is not suited in
temperatures below -40°C, and routine users of radiosonde data had to take this shortcoming
into account for their practical applications.
Measurements of cirrus is another example in which the combined Raman lidar can provide
valuable results. The separate measurement of the height profiles of particle backscatter and
extinction coefficients, (3 and n, not only allows a direct assessment of geometric and radiative