Meteorology
Meteorology, the study of the atmosphere, is a related field of geology used by forensic investigators, lawyers, and prosecutors to look for specific information to be used in court when climate conditions are of relevance in explaining an event. The term meteorology originates from the Greek, meteoros, for airborne, and logos, for discourse or study.
Meteorologists may be requested by courts or by companies to give information necessary for reconstructing ship or airplane accidents, or on wind chills affecting outdoor workers, or to present a detailed weather reconstruction for a given area on a particular day. Meteorologists are sometimes requested to explain events associated with air pollution and airborne spread of dangerous substances, or to clarify whether a given meteorological event is abnormal or expected in a certain region and period of the year.
Forensic meteorologists may also help in crime investigations. For instance, they can calculate the wind and ocean currents in a particular body of water and thus indicate the most probable area where a disabled boat or even a corpse could be washed onshore.
Mankind has been intrigued since antiquity by meteorological phenomena such as sudden climate changes, the cycle of seasons, and the origins of winds, lightning bolts, storms, and tides. However, meteorology is a relatively young science whose importance and impact on the economic activities and military strategic planning became increasingly evident in the industrial era. Agricultural communities have regulated their activities for thousands of years through the empirical observation of local climatologic cycles. But weather prediction was a very imprecise and challenging task until the end of World War II (1939–1945). The date for the invasion of Normandy by the Allied forces, the famous D day, had to be changed several times because of such limitations. The field was able to remarkably advance after satellites, Doppler radar, and computer technologies allowed the development of more efficient research methods for the understanding and prediction of meteorological phenomena.
Climate variations are determined by the interchange between the atmosphere and terrestrial topography, with noticeable differences in temperature, moisture, and pressure between two localities of a given area due to such features. A large body of water, or the presence or absence of forests and mountains are topographic factors responsible for climate variations, known as local effects. For instance, a mountain chain running parallel to a coastal seashore functions as a dividing barrier, with different local effects on opposite sides of the mountains. Big cities also function as topographic factors, with their industrial and automotive emissions of carbon dioxide increasing the local temperature and changing the patterns of rain and snow precipitation compared with the surrounding countryside. Differences in air temperatures over the sea and coastal lands give rise to breezes and winds that circulate between the two surfaces. Breezes usually start blowing from the sea to the land in the morning, increasing speed until mid afternoon, and then reversing direction in late afternoon and during the night. The main reason for this event is that the air over land heats faster than over the ocean. Water absorbs a great amount of solar radiation and slows down the heating process of the air, whereas land surfaces reflect most of the radiation to the atmosphere. As air temperature rises, atmospheric pressure lowers over the land, allowing the air to move from the sea to land. At night, however, land surfaces loose heat faster than water, causing the wind direction to reverse.
The presence of a maritime current of cold or warm water flowing along a coastline also will interfere with wind patterns as well as the presence of a mountain chain nearby the coastline. Mountains create their own thermal circulations, even when atmospheric pressures are weak, because of the heating variations among different altitude gradients. Air over the valleys heats faster than over the mountain slopes, creating the anabatic air currents that move toward the mountaintop. At evening, the current reverses, and the katabatic winds move down from the mountaintops to the valleys. Anabatic winds are more frequent and stronger in summer and in tropical regions, whereas katabatic winds are more frequent in wintertime and in temperate latitudes. Mountain chains along the coastal line have anabatic, or upwardly moving, winds increased by the breeze blowing from the ocean. They also act as a partial barrier against sea wind propagation toward inland, and promote the formation of cumulus clouds on mountaintops because air is gradually cooled and water vapor condenses as it ascends. Late afternoon or evening precipitation is common in tropical coastlines with these topographic features.
Winds blowing perpendicular to mountain slopes create phenomena known as convergence, by forcing the air around the slopes to move upward, being continuously deflected by the wind as they rise. When the air reaches the top, a strong current is released and sinks on the other side, except when a temperature inversion is present near the mountain summits. Temperature inversion refers to a descending air mass that is warmer than the ascending air. When the ascending air encounters the warmer, less-dense air, it loses pressure and a wavelike turbulence pattern is formed, known as lee waves or orographic waves, which are felt as a "bumpy road" when airplanes fly through them. When a large front of cool high-pressure air descends from higher altitudes and encounters a large warm low-pressure front, complex interactions take place. These may lead to the onset of tropical storms, gusty winds, thunderstorms, or tornadoes, depending on the particular conditions of the resulting super cell.
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