365
Airborne Water Vapor Differential Absorption Lidar
selection of the H 2 O absorption line is accomplished by a precise current pulse to the
diode that has been characterized.
14.4 CONCLUSIONS
Airborne H 2 O DIAL has been proven to be the most suitable tool for two-dimensional
water vapor measurements along extended cross sections, with high accuracy and
spatial resolution. Its measurement range covers the ground to the lower strato. Its measurement range covers the ground to the lower stratothe lower stratolower
stratosphere. The water vapor profiles produced by airborne H 2 O DIAL improved our
understanding of water vapor trends and of radiative forcing by water vapor in the
upper troposphere and lower stratosphere. Moreover, these high-resolution data can
improve the weather forecast accuracy (such as tropic storm/hurricane).
Any lidar technique is dependent on the availability of suitable lasers, but for
DIAL, the requirements are especially inflexible, because the required laser characteristics are determined by the spectra of the molecules to be measured. The biggest
problem has historically been to develop reliable lasers with outputs at appropriate
wavelengths. Fortunately, steady progress is being made with tunable laser sources,
an injection seeding technique, and an active feedback control loop. Tunable lasers
enable researchers to optimize the wavelength choices. In addition, OPOs and
LD-pumped solid-state lasers hold the promise of compact, all-solid-state systems.
Continued progress can be expected in the area of multiwavelength DIAL; this
area of research has already produced larger humidity dynamic range, higher spatial
resolution, and DIAL accuracy. Ultimately, one might expect that instruments and
algorithms will be developed to obtain range profiles of multiple gasses simultaneously, along with aerosol characteristics. Airborne H 2 O DIAL systems will, no
doubt, continue to gain acceptance as costs become lower, reliability gets better, and
algorithms to provide reduced data in real time are implemented in software.
REFERENCES
Barnes, J. C., Barnes, N. P., Wang, L. G., and Edwards, W. C. (1993a). Injection Seeding II:
Ti:Al 2 O 3 experiments. IEEE Journal of Quantum Electronics, 29, 2683–2692.
Barnes, J. C., Edwards, W. C., Petway, L. B., and Wang, L. G. (1993b). NASA Lidar
Atmospheric Sensing Experiment’s titanium-doped sapphire tunable laser system.
Optical Remote Sensing of the Atmosphere, Sixth Topical Meeting.
Barnes, N. P. and Barnes, J. C. (1993). Injection seeding I: Theory. IEEE Journal of Quantum
Electronics, 29, 2670–2683.
Bougeault, P., Binder, P., Buzzi, A., Dirks, R., Houze, R., Kuettner, J., Smith. R., Steinacker,
R., and Volkert, H. (2001). The MAP special observing period. Bulletin of the American
Meteorology Society, 82, 433–462.
Browell, E. V., Ismail, S., Hall, W. M., Moore, A. S., Kooi, S. A., Brackett, V. G., Clayton,
M. B., Barrick, J. D. W., Schmidlin, F. J., Higdon, N. S., Melfi, S. H., and Whiteman,
D. N. (1997). LASE validation experiment, in Advances in Atmospheric Remote Sensing
with Lidar, A. Ansmann, R. Neuber, P. Rairoux, and U. Wandinger, eds., SpringerVerlag, Berlin, 289–295.
Bruneau, D., Quaglia, P., Flamant, C., Meissonnier, M., and Pelon, J. (2001a). Airborne
lidar LEANDRE II for water-vapor profiling in the troposphere. I. System description.
Applied Optics, 40, 3450–3461.
Airborne Water Vapor Differential Absorption Lidar
selection of the H 2 O absorption line is accomplished by a precise current pulse to the
diode that has been characterized.
14.4 CONCLUSIONS
Airborne H 2 O DIAL has been proven to be the most suitable tool for two-dimensional
water vapor measurements along extended cross sections, with high accuracy and
spatial resolution. Its measurement range covers the ground to the lower strato. Its measurement range covers the ground to the lower stratothe lower stratolower
stratosphere. The water vapor profiles produced by airborne H 2 O DIAL improved our
understanding of water vapor trends and of radiative forcing by water vapor in the
upper troposphere and lower stratosphere. Moreover, these high-resolution data can
improve the weather forecast accuracy (such as tropic storm/hurricane).
Any lidar technique is dependent on the availability of suitable lasers, but for
DIAL, the requirements are especially inflexible, because the required laser characteristics are determined by the spectra of the molecules to be measured. The biggest
problem has historically been to develop reliable lasers with outputs at appropriate
wavelengths. Fortunately, steady progress is being made with tunable laser sources,
an injection seeding technique, and an active feedback control loop. Tunable lasers
enable researchers to optimize the wavelength choices. In addition, OPOs and
LD-pumped solid-state lasers hold the promise of compact, all-solid-state systems.
Continued progress can be expected in the area of multiwavelength DIAL; this
area of research has already produced larger humidity dynamic range, higher spatial
resolution, and DIAL accuracy. Ultimately, one might expect that instruments and
algorithms will be developed to obtain range profiles of multiple gasses simultaneously, along with aerosol characteristics. Airborne H 2 O DIAL systems will, no
doubt, continue to gain acceptance as costs become lower, reliability gets better, and
algorithms to provide reduced data in real time are implemented in software.
REFERENCES
Barnes, J. C., Barnes, N. P., Wang, L. G., and Edwards, W. C. (1993a). Injection Seeding II:
Ti:Al 2 O 3 experiments. IEEE Journal of Quantum Electronics, 29, 2683–2692.
Barnes, J. C., Edwards, W. C., Petway, L. B., and Wang, L. G. (1993b). NASA Lidar
Atmospheric Sensing Experiment’s titanium-doped sapphire tunable laser system.
Optical Remote Sensing of the Atmosphere, Sixth Topical Meeting.
Barnes, N. P. and Barnes, J. C. (1993). Injection seeding I: Theory. IEEE Journal of Quantum
Electronics, 29, 2670–2683.
Bougeault, P., Binder, P., Buzzi, A., Dirks, R., Houze, R., Kuettner, J., Smith. R., Steinacker,
R., and Volkert, H. (2001). The MAP special observing period. Bulletin of the American
Meteorology Society, 82, 433–462.
Browell, E. V., Ismail, S., Hall, W. M., Moore, A. S., Kooi, S. A., Brackett, V. G., Clayton,
M. B., Barrick, J. D. W., Schmidlin, F. J., Higdon, N. S., Melfi, S. H., and Whiteman,
D. N. (1997). LASE validation experiment, in Advances in Atmospheric Remote Sensing
with Lidar, A. Ansmann, R. Neuber, P. Rairoux, and U. Wandinger, eds., SpringerVerlag, Berlin, 289–295.
Bruneau, D., Quaglia, P., Flamant, C., Meissonnier, M., and Pelon, J. (2001a). Airborne
lidar LEANDRE II for water-vapor profiling in the troposphere. I. System description.
Applied Optics, 40, 3450–3461.