Shipping forecast is partly cloudy

Full Optical Simulation of Partly Cloudy Scenes

This paper discusses recent advances in the full spectral simulation of scenes with partial cloud cover. We examine the effect of broken cloud fields on the solar illumination reaching the ground. Application of aerosol retrieval techniques in the vicinity of broken clouds leads to significant over-prediction of aerosol optical depth because of the enhancement of visible illumination due to sca...

HIA forecast: cloudy with sunny spells later?

Cloudy forecast for weather satellite data.

IN THE NEWS FOCUS STORY “WEATHER forecasts slowly clearing up” (9 November, p. 734), R. Kerr nicely summarizes how the growing improvement in prediction is coming from a focus on “more computer power, the assimilation of radar observations, and more physically realistic models.” He emphasizes that better assimilation of satellite data is a key element of improved forecasting. Unfortunately, the...

Digital all-sky polarization imaging of partly cloudy skies.

Clouds reduce the degree of linear polarization (DOLP) of skylight relative to that of a clear sky. Even thin subvisual clouds in the "twilight zone" between clouds and aerosols produce a drop in skylight DOLP long before clouds become visible in the sky. In contrast, the angle of polarization (AOP) of light scattered by a cloud in a partly cloudy sky remains the same as in the clear sky for mo...

Aerosol optical depth increase in partly cloudy conditions

[1] Remote sensing observations of aerosol from surface and satellite instruments are extensively used for atmospheric and climate research. From passive sensors, the apparent cloud-free atmosphere in the vicinity of clouds often appears to be brighter than further away from the clouds, leading to an increase in the retrieved aerosol optical depth (t). Mechanisms contributing to this enhancemen...