第一章、地球大氣的垂直結構
• 地球大氣的垂直結構
• 地球大氣的質量分布
• 地球大氣的組合成份
• http://www.ucar.edu/
• http://www.ametsoc.org/AMS/
• http://www.wmo.ch/
由太空中觀看地球大氣。相對地球而言，地球大氣相當的薄。
圖中遠處淡藍色所顯示即為地球大氣之影像。
外氣層
大氣壓力隨高度迅速減少，在5.5km高度，氣壓為500mb，約
有一半的大氣分子集中在此高度以下。
均勻層 異質層
近地表大氣之組合成份
地球大氣
的源起
Volcano: H2O,
CO2, SOx
地球大氣的氧和臭氧
地球大氣中的氧氣是如何產生的?
• 2H2O + hν 2H2 + O2 水分子的光化分解
(dissociation of water by ultraviolet radiation)
• H2O + CO2  {CH2O} + O2 可見光催化的光合作用
(photosynthesis reaction via visible radiation, closely
linked with biological processes)
臭氧層的形成Chapman reaction
• O2 + hν  O1D + O3P
• O + O2 + M  O3 + M
• O3 + hν → O2 + O
• O + O3 → 2 O 2
Hydrological cycle/water cycle
•
•
The water cycle, also known as the hydrological cycle or H2O cycle, describes the
continuous movement of water on, above and below the surface of the Earth. Although
the balance of water on Earth remains fairly constant over time, individual water
molecules can come and go, in and out of the atmosphere. The water moves from one
reservoir to another, such as from river to ocean, or from the ocean to the atmosphere,
by the physical processes of evaporation, condensation, precipitation, infiltration,
runoff, and subsurface flow. In so doing, the water goes through different phases: liquid,
solid (ice), and gas (vapor).
The water cycle involves the exchange of heat, which leads to temperature changes. For
instance, when water evaporates, it takes up energy from its surroundings and cools the
environment. When it condenses, it releases energy and warms the environment. These
heat exchanges influence climate. By transferring water from one reservoir to another,
the water cycle purifies water, replenishes the land with freshwater, and transports
minerals to different parts of the globe. It is also involved in reshaping the geological
features of the Earth, through such processes as erosion and sedimentation. Finally, the
water cycle figures significantly in the maintenance of life and ecosystems on Earth.
水循環系統
Average reservoir residence times[8]
Reservoir
Average residence time
Antarctica
20,000 years
Oceans
Glaciers
3,200 years
20 to 100 years
Seasonal snow cover
2 to 6 months
Soil moisture
1 to 2 months
Groundwater: shallow
Groundwater: deep
Lakes (see lake retention time)
Rivers
100 to 200 years
10,000 years
50 to 100 years
2 to 6 months
地球水循環收支
地球的碳循環
Carbon cycle
• The carbon cycle is the biogeochemical cycle by which carbon is
exchanged among the biosphere, pedosphere, geosphere, hydrosphere,
and atmosphere of the Earth. Along with the nitrogen cycle and the
water cycle, the carbon cycle comprises a sequence of events that are
key to making the Earth capable of sustaining life; it describes the
movement of carbon as it is recycled and reused throughout the
biosphere.
• The global carbon budget is the balance of the exchanges (incomes
and losses) of carbon between the carbon reservoirs or between one
specific loop (e.g., atmosphere ↔ biosphere) of the carbon cycle. An
examination of the carbon budget of a pool or reservoir can provide
information about whether the pool or reservoir is functioning as a
source or sink for carbon dioxide. The carbon cycle was initially
discovered by Joseph Priestley and Antoine Lavoisier, and popularized
by Humphry Davy.[1]
碳循環是一生態系統的物質循環，指碳元素在地球上的生物圈、地圈、水圈及
大氣中交換。碳的主要來源有四個，分別是大氣、陸上的生物圈（包括淡水系
統及無生命的有機化合物）、海洋及沉積物。
Carbon cycle (bn of tons/year)
Nitrogen cycle
• The nitrogen cycle is the process by which nitrogen is converted
between its various chemical forms. This transformation can be carried
out to both biological and physical processes. Important processes in the
nitrogen cycle include fixation, mineralization, nitrification, and
denitrification. The majority of Earth's atmosphere (approximately 78%)
is nitrogen,[1] making it the largest pool of nitrogen. However,
atmospheric nitrogen has limited availability for biological use, leading to
a scarcity of usable nitrogen in many types of ecosystems. The nitrogen
cycle is of particular interest to ecologists because nitrogen availability
can affect the rate of key ecosystem processes, including primary
production and decomposition. Human activities such as fossil fuel
combustion, use of artificial nitrogen fertilizers, and release of nitrogen in
wastewater have dramatically altered the global nitrogen cycle.
• A 2011 study found that nitrogen from rocks may also be a significant
source of nitrogen, that had not previously been included.[2][3][4]
氮循環 (earth-atmosphere)
nitrogen fixation
conversion of nitrogen
assimilation
ammonification
(mineralization)
nitrification
denitrification
anaerobic ammonium oxidation