A Sea-Breeze is a thermally driven circulation on the coastlines of sea and large lake areas. It is commonly observed during the spring and summer, when the temperature difference between sea and adjacent land areas is large.

• In satellite images a Sea-Breeze is characterized by a cloud-free area along coastal land areas which protrudes inland. Further inland, away from the influence of Sea-Breeze, cumuliform clouds are often present.
• The detection of this boundary separating the cloud-free and cumuliform clouds is possible using either VIS (cumuliform clouds are seen as white pixel values) or IR (white to grey pixel values) channels.
• Water vapour imagery doesn't generally allow the detection of a Sea-Breeze, but in cases where there is deeper convection within the boundary (e.g. Sea-Breeze front), a line of convective cells can be seen.
• A Sea-Breeze front (the narrow zone separating the air over the land from the air streaming from the sea) may appear as an intensifying line of Cu or Cbs at the leading edge of the Sea-Breeze.

The example below shows a Sea-Breeze over Scandinavian coasts. IR and VIS images show a Sea-Breeze front with associated line cloudiness on western parts of Finland, while in Central and Southern Sweden and in the Baltic States the cumulus cloudiness further away from the Sea-Breeze is more homogeneous. The cloud-free areas along the coasts are clearly seen. In the VIS image loop below, the development of the Sea-Breeze can be seen as rather rapid growth and spreading of cumulus cloudiness around local noon. During the afternoon the Sea-Breeze develops and a cloud-free area on the west coast of Finland and E. Sweden moves slowly inland. Another example of Sea-Breeze cloudiness on the Black Sea coast is shown below. Convective clouds can be seen surrounding the Black Sea more or less continuously. The clouds north of the Black Sea have already grown into Cb, while a less prominent line of cumulus can be seen on western side of the Black Sea.

Appearance in AVHRR images

AVHRR images help to locate the location of the Sea-Breeze more accurately over land because of the better spacial resolution. Even quite small cumulus clouds can be seen.
The diurnal variation of Sea-Breeze cloudiness and the movement of Sea-Breeze front can be seen using consecutive AVHRR images.

The Sea-Breeze on the Scandinavian coasts can be seen as cloud-free areas more or less following the shape of coastline. Cumuliform cloudiness marking the Sea-Breeze boundary can be seen as lumps of white - bluish clouds over land. In western Finland the Sea-Breeze front clouds is more line-like and clearly shows the extension of the Sea-Breeze inland, even though the air further inland is too dry to support any cumulus development.