We have already mentioned that daytime temperatures generally decrease with outdoor altitude. The decrease in temperature and dew point with altitude leads to higher relative humidity at higher altitudes on slopes. However, the scheme is complicated due to the warming of the air next to the slopes, the transport of moisture with slope winds, and the frequent stratification of moisture into layers, so generalizations are difficult. Vegetation attenuates surface temperatures and contributes to moisture through transpiration and evaporation – two factors that affect local relative humidity. A continuous forest roof has the additional effect of decreasing the surface wind speed and the mixing that occurs with the movement of air. The actual amount of moisture in the air varies from air rental to air, and even in an air mass there will be persistent fluctuations in time and space. In calm air during evaporation, water vapor concentrates near the evaporation surface. When this concentration approaches saturation, subsequent evaporation is practically stopped, although the surrounding air is relatively dry. The wind promotes evaporation by carrying away these stagnant layers and replacing them with drier air. Once a surface has dried to the point where open water is no longer exposed to air, the influence of wind on evaporation decreases. In fact, for surfaces such as relatively dry soil or wood, wind can actually help reverse the process by cooling surfaces, thereby lowering the vapour pressure of moisture contained in those surfaces. Winds of this type are also called “snow eaters” because they can quickly melt or sublimate snow and ice.
This is due not only to the heat of the foehn air, but also to its low relative humidity. As a result, foehn winds are known to contribute to the decomposition of ice shelves in the polar regions.  KamikazeLike the Protestant wind, suicide bombers were specific historical winds. Kamikaze, translated as divine winds, were major typhoons that destroyed the invasive Mongolian navy off the coast of Japan in the late 1200s. In the 20th century, kamikaze became the informal name for suicide bombings during World War II. The official name of the Kamikaze strategy is Tokktai. With the disappearance of the LooThere are dozens of names for the winds that blow across certain regions. Some, like the Noreasters, who blow on the east coast from the northeast, are not creatively named. Here are some others:Hairdresser: cold wind laden with moisture that freezes on contact with hair and beard.
Brickfielder: Hot, dry wind that carries huge amounts of red dust from the deserts of South Australia. Cape Doctor: cold and dry wind from the southeast that disinfects the city of Cape Town, South Africa.chinook: warming wind that plunges eastward into the Rocky Mountains of Canada and the United States. Coromuel: strong and warm wind blowing through La Paz, Baja California, Mexico, from the afternoon until the early morning. The wind was named after the British navigator Samuel Cromwell, whose inhabitants could not pronounce the name. Falcon: strong and cool breeze blowing west from Lake Michigan to Chicago.levant: strong winds blowing from the Atlantic Ocean through the narrow Strait of Gibraltar in the western Mediterranean. The Levant, the Middle East region in the eastern Mediterranean, does not know the Levant. Loo: strong and hot summer wind that blows dry deserts to the west over northern India and is stopped only by the arrival of the monsoon. Loo is such a powerful ecological and cultural force that ice cream and sorbets are consumed to combat fatigue caused by Loo. November Witch: Hurricane-force winds that develop when cold Arctic air masses meet warm Gulf air over the Great Lakes.
Pembrokeshire Dangler: Area where prevailing winds converge and swing a line of cold rain and snow in a north-south direction across the Irish Sea. Santa Anas: Hot, dry winds blowing from deserts and mountains from the interior of California to the coast. Santa Anas is often responsible for the spread of destructive wildfires in Southern California, earning them the nickname Murder Winds. Sirocco: Wind that reaches the speed of a hurricane when it crosses the Mediterranean to southern Europe. Siroccos carry tons of dust and sand across North Africa and contribute to wet weather when they reach Europe. Squamish: Cold, fast wind that rushes into the narrow fjords of British Columbia, Canada. There are four known causes of the heating and drying effect of foehn.  These mechanisms often work together, with their contributions varying depending on the size and shape of the mountain barrier and weather conditions such as upstream wind speed, temperature and humidity. The normal pattern of moisture decrease with altitude can sometimes be changed when the horizontal flow brings moist air on medium planes.
Such a river is responsible for much of the summer storm activity over large parts of the west. The extremely low absolute humidity is found in the air that flows at altitude. This dry air comes near the tip of the troposphere and slowly sinks to lower levels. When it reaches the ground or is mixed down, it can lead to extremely low humidity near the surface and an abrupt increase in fire risk. We will take a closer look at the lowering in the next chapter. We have already seen that humidity affects all surface temperatures, including surface fuel temperatures, by controlling radiation in its vapor state and by reflecting and radiating when condensed in clouds. The thermal energy released during condensation provides energy for thunderstorms and associated high winds. Moisture is also necessary for the development of lightning, which is a feared cause of forest fires in many mountain areas. The temperatures of the wet ball and the dry ball are determined using a psychrometer. Dew point, relative humidity and other humidity measurements can be obtained from these measured values. Again, we should be cautious about generalizations. For example, in summer, in the coastal mountains of the Pacific, higher humidity is usually found on the peaks of the ridges during the day than at night.
This anomaly results from slope winds that carry moisture upwards from the humid layer of sea air during the day. Moist air, which is not carried upwards, settles again at night. Foehn winds can raise temperatures up to 25°F (14°C) in just a few hours. Switzerland, southern Germany and Austria have a warmer climate due to the foehn, as wet winds blow from the Mediterranean over the Alps. The vapour pressure depends on the actual water vapour in the air and can vary from near zero in cold, dry air to about 2 inches of mercury column in hot, humid air. High levels can only occur in the warm lower layers of the troposphere. The pressure generated by the steam causes certain water vapor molecules to re-enter the surfaces of the water by condensation. The same amount of thermal energy required for evaporation is released to heat the condensation surface. Relative humidity is more important as a meteorological factor of fire in the ground level layer, where it affects both fuels and fire behavior. Near the ground, humidity, season, time of day, slope, appearance, altitude, clouds and vegetation cause large fluctuations in relative humidity.