| Autor: |
Higdon NS, Browell EV, Ponsardin P, Grossmann BE, Butler CF, Chyba TH, Mayo MN, Allen RJ, Heuser AW, Grant WB, Ismail S, Mayor SD, Carter AF |
| Jazyk: |
angličtina |
| Zdroj: |
Applied optics [Appl Opt] 1994 Sep 20; Vol. 33 (27), pp. 6422-38. |
| DOI: |
10.1364/AO.33.006422 |
| Abstrakt: |
An airborne differential absorption lidar (DIAL) system has been developed at the NASA Langley Research Center for remote measurements of atmospheric water vapor (H(2)O) and aerosols. A solid-state alexandrite laser with a 1-pm linewidth and > 99.85% spectral purity was used as the on-line transmitter. Solid-state avalanche photodiode detector technology has replaced photomultiplier tubes in the receiver system, providing an average increase by a factor of 1.5-2.5 in the signal-to-noise ratio of the H(2)O measurement. By incorporating advanced diagnostic and data-acquisition instrumentation into other subsystems, we achieved additional improvements in system operational reliability and measurement accuracy. Laboratory spectroscopic measurements of H(2)O absorption-line parameters were perfo med to reduce the uncertainties in our knowledge of the absorption cross sections. Line-center H(2)O absorption cross sections were determined, with errors of 3-6%, for more than 120 lines in the 720-nm region. Flight tests of the system were conducted during 1989-1991 on the NASA Wallops Flight Facility Electra aircraft, and extensive intercomparison measurements were performed with dew-point hygrometers and H(2)O radiosondes. The H(2)O distributions measured with the DIAL system differed by ≤ 10% from the profiles determined with the in situ probes in a variety of atmospheric conditions. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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