17.  Conclusion

In situ measurement technologies are evolving slowly, as the applicable physical principles have been identified for decades. The decreasing cost of electronics and processing power may make certain principles more economical, such as ultrasound for anemometers and GNSS (Global Navigation Satellite System) signals for radiosonde positioning.

Camera image analysis has been explored for years to detect the presence of precipitation and its type, or to estimate visibility or cloud cover. However, automatic analysis has not yet achieved operational results.

The remote sensing techniques discussed in this article are the ones most likely to evolve, with a decrease in costs. However, these remote sensing techniques remain linked to the physical principles used.