Profiling the Planetary Boundary Layer from Space: A Review of Capabilities, Limitations, and Future Perspectives

The planetary atmospheric boundary layer (PABL) is the layer of the atmosphere closest to the Earth’s surface, within which most human activities take place. The PABL is directly influenced by the exchange of heat, moisture, and other constituents, with the surface, biosphere and anthropogenic activities. In return, human activities are directly influenced by the PABL in the form of wind, temperature, humidity, fog, clouds, precipitation, and air quality. Atmospheric profiling has the ability to measure atmospheric conditions at various heights and is hence critical for better understanding of key atmospheric processes. The importance of PABL profiling has been recognized for several critical areas of societal needs, such as energy security, public health and safety, transportation, water resources, and food production. Monitoring and forecast of severe weather, renewable energy sources, aviation hazards, and air pollution dispersion are just a few high-impact societal applications that would strongly benefit from accurate PABL profiling. PABL profiling from ground-based remote sensing has increased in the last decade, leading to the establishment of international networks. However, PABL profiling from ground is limited to instrumented sites and lacks global coverage. Instruments capable of PABL profiling from space also exists, with their pros and cons. This paper presents an initial attempt to review the technologies available for PABL profiling from space, introducing advantages and limitations with a hint of current international initiatives and future perspectives.