| Popis: |
The problem of the present-day methods for determining the sea water absorption coefficient from space is the fact that the valid signal is an order of magnitude lower than the noise. In the present work, the pulse-gating method is considered as a means to increase the ratio of valid to spurious signals. A theoretical model is developed in order to estimate the radiance of the atmosphere–ocean system irradiated by a lidar in the pulse-gating regime in the range of sea-water transmittance (0.400–0.550 μm). The model makes it possible to formulate technical requirements to the lidar (the emergent beam angle, pulse power, etc.), which prove to be quite achievable at the present time. Three typical situations are considered when the method under discussion can be used: 1) at night, with clear skies; 2) daytime, with clear skies; 3) at night, with thin clouds. The estimates are given for each case. The primary emphasis is placed on the expediency of constructing and testing an equipment for measuring optical properties of sea water by the pulse gating method from space. |
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