Seasonal Winds and Monsoons
The seasonality of weather is also a very important aspect of how weather influences the environment and people. For instance, in India, Society has depended on the timing and degree of monsoon rains that occur when warm, wet air from the Indian Ocean is drawn into the Indian subcontinent and releases rainfall as it rises and cools over the Himalayan mountains. Lack of monsoon rain due to different weather patterns sometimes causes drought, starvation, and death to people living in the region as well as to their animals, crops, and other organisms that depend on seasonal rainfall.
Tornadoes
Unfortunately, pressure differentials can create extremely powerful forces that are destructive in nature. For instance, tornadoes and cyclones are extremely powerful local winds generated by rapid mixing of cold, dry air and warm, wet air. They powerful forces can cause high levels of destruction including loss of life.
“Greenhouse Effect”
Another extremely important aspect of the atmosphere is what is called the 'greenhouse effect". Of the energy that comes from the sun, and impacts on the top of the earth's atmosphere, only about half of the energy reaches the surface of the earth. The energy that is absorbed by the surface of the earth is changed to a lower quality heat energy, and most of that energy is re-emitted as infrared energy. Much of this energy is reflected back to the earth to be absorbed and re-emitted again, particularly when there is high cloud cover. Trapping of the energy with in the earth's atmosphere causes the earth to be warmer than it otherwise would be...like a greenhouse. Notice that the presence of cloud cover greatly changes the reflectivity and absorptivity of the earth, called the albedo. One of the major variables in the greenhouse effect is the presence of cloud cover.
Spectrum of Solar Radiation
Radiation from the sun - source of E. Electromagnetic spectrum that includes light encompasses a wide range of frequencies, and what we can actually see as visible light is a very narrow band within that range. Photosynthesis of plants is driven by the narrow range of visible light, ranging from about 0.4 - 0.7 micrometers.
Other wavelengths can have effects on the environment; for instance, x-rays and gamma rays can be deadly, ultraviolet radiation gives us a sun tan, and also, potentially, skin cancer. Infrared energy heats us, and we use microwaves and radio waves to transmit energy. Microwave E heats lunch.
Climate Change
The Earth's climate changes, often in short or long cycles.
Ice ages, droughts
Orbital shifts, sunspot cycles, ocean currents
Climate does not necessarily change gradually - meteor impacts, methane releases?
Climate = general pattern of weather for a region over time. F i, in Astana in Jan we expect it to be cold and snowy. Weather is the short-time expression of climate which can vary significantly from day-to-day. Throughout the history of the Earth, climate has changed constantly on a long time scale. This is due partially to the movement of crustal plates and the interaction of weather with changing continent structure. Over the last 2 mln yrs, the earth has experienced Ice Ages that occur on a regular basis, along with smaller patterns of change in weather. Evidence of climate change is abundant in the Earth's record. It is thought that climate change normally follows long term cycles caused by shifts in the orbit of the earth, sunspot cycles, and possibly changes and ocean currents due to the movement of the continents. Certain catastrophic events such as a large asteroid or comet slamming into the earth could cause major climate change in a relatively short period of time. The possibility that a major impact such as this did in the dinosaurs about 65 mln yrs ago is highly likely.
F.I, these figures show the variation in temp-re during 400,000 years. Note that there were relatively large fluctuations in the average T-re of the earth including warmer periods and cooler periods than the present that lasted thousands of years. Note that large decreases and increases in temperatures are part of the climate record.