ABSTRACT

We may ask: why should remote sensing be welcome in support, or even in place, of conventional weather observation techniques? For these are particularly well-developed and long established activities in many areas of the world. This question is important, for the costs of remote sensing systems can seem high in comparison with in situ sensor systems. Of course, the advantages of remote sensing systems for weather studies are many. They include the following, although of course not all may necessarily apply to a particular investigation.

The remote sensor does not need to be carried into the (perhaps hostile), medium that is to be measured.

This measurement system, unlike many in situ sensor systems, does not modify any parameter being measured, since it is, by definition, remote from it.

A high level of automation can be achieved easily in the data-gathering process.

It is possible to scan the atmosphere more or less continuously by remote sensing in one, two or even three dimensions. This is better than the single point and/or line measurement capabilities to which most in situ sensors are restricted.

Integration of given parameters along lines, over areas, or through volumes, is often obtained readily in the outputs of remote sensing systems.

Relatively sophisticated and elusive parameters, such as the spectrum of atmospheric turbulence, and momentum flux, may be available as direct outputs from remote sensing systems.

Single instrument packages may be able to provide data for the whole globe, whereas each in situ sensor package is limited to very local use, and big differences and/or variations are commonplace amongst in situ sensor networks.