High-pressure area radiation and temperatures rise. At night, the absence of clouds means that outgoing longwave radiation (i.e. heat energy from the surface) is not absorbed, giving cooler diurnal low temperatures in all seasons. When surface winds become light, the subsidence produced directly under a high-pressure system can lead to a buildup of particulates in urban areas under the ridge, leading to widespread haze. If the low level relative humidity rises towards 100 percent overnight, fog can form. Strong, vertically shallow high-pressure systems moving from higher latitudes to lower latitudes in the northern hemisphere are associated with continental arctic air masses. Once
Low pressure receptors Low pressure receptors Low pressure receptors are baroreceptors located in large systemic veins, in the pulmonary arteries, in the walls of the atria, and ventricles of the heart.[2] They are also called volume receptors. These receptors respond to changes in the wall tension, which is proportional to the filling state of the low pressure side of circulation (below 60mmHg). Thus, low pressure baroreceptors are involved with the regulation of blood volume. The blood volume determines the mean pressure throughout the system, in particular in the venous side where most of the blood is held. Increasing stretch of the receptors stimulates