Chapter 7 Environmental geoscience

7.1 Characteristics, status and role of environmental geoscience 7.2 Combined system of human - earth's environment 7.3 Entirety of human - earth's environment as well as influence and response of each circle 7.4 Case study

7.1 Characteristics, status and role of environmental geoscience

Study purpose: master change and development regular of each environmental element and environmental system, implement to predict and management environmental system, and make accord development of human – earth.During environmental science system, environmental geoscience is subject to comprehensively study entirety of combined system of human - earth's environment and correlation between each subsystem.Provide scientific basis and support for other subfield research, and summarize and integrate the results and progress of other subfield research.

7.2 Combined system of human - earth's environment

7.2.1 Combined system of human - earth's environment (1) Weather systemWeather system is a whole system composed with underlayer atmosphere, hydrosphere, cryosphere, biosphere, pedosphere, superior part of lithosphere. They have close and complex interactions between them.(2) Air pollution in atmospheric environment and boundary layerAtmosphere is the most active part with the largest change in earth system, and atmospheric sphere, one of the subsystems in combined system of human - earth's environment, is an important part of the human environment.

Atmospheric environment and air pollution Atmospheric environment, considering atmosphere as the media centre, is physical environment in earth system. Generally, it points ozonosphere and the following parts closely related to human, especially atmospheric condition of boundary layer

Atmospheric pollution generally means substances into the atmosphere induced by human activities and natural processes, showing enough concentration and reaching enough time to harm the human body's comfort, health and welfare or environment.

Anthropogenic emissions is the main reason resulting in air pollution, especially local air pollution

The classification and characteristics of air

pollutants

Diffusion and study methods of pollutant in atmospheric

Generalized atmospheric dispersion means the pollutant entering into air is gradually dispersed and diluted with wind, rapid current, uplift, subsidence, dry and wet deposition, chemical conversion, and other progress.Although it benefits mitigate local air pollution, the influence basin of pollutant will be expanded, and the secondary pollution may be induced or the pollution may be transferred to the soil and water body.The research methods generally are divided into mathematical simulation, physical simulation of indoor fluid (such as wind-tunnel, sink, and convection chamber simulation) as well as field experimentation.

（ 3 ） The value and protection of air resources During animals’ breath, oxygen contained in the fresh air is transferred into each tissue of the body and cells by the blood and participates in every iochemical reactions and metabolic processes. Only in this way, the life can be lasted.Air is the primary producer——essential substances for plant respiration and normal physiological response. Air movement not only promotes exchanges of material, heat and moisture, produces all kinds of atmospheric phenomena, provides clean wind energy for the human, and is the important way to spread seeds.Greenhouse effect of earth's atmosphere greatly inhibits dramatic changes of ground temperature, protects the organism on the earth from the harm of cosmic rays and meteor, and provides rich raw material for industrial and agricultural production.

（ 3 ） The value and protection of air

resources However, as for some area (such as city, valley and basin), air is limited in self-purification and dilution capacity for pollutant discharged by mankind's activity. If the threshold value of atmospheric environmental capacity is exceeded, air quality will significantly get worse. In addition to reinforcement of publicity and education, improvement of environmental consciousness, performance of cleaner production, optimization of the industrial structure and increasing the forest area (figure 7-2), legal measures and economic instruments should be used to protect air resource and improve air quality.

Figure 7-2 1980 ～ 1995 The change of world forest area

（ qouted from World Resources Report UNDP,UNEP,WB,WRI ， 2002 ）

7.2.2 The water environment and the marine environment

（ 1 ） The basic types of water circulation General circulation: occur in water exchange process between global ocean and land. Because it wildly covers the global, it is named as general circulationLesser circulation: occur in water exchange process between ocean and atmosphere, or land and atmosphere. Lesser circulation is also named as internal circulation. The former is also called as marine lesser circulation, and the latter is called as land lesser circulation.

Water balance is quantities of water cycle, i.e. in a certain time-domain space, during the progress of cycle and transform of moisture content, its quantity follows law of conservation of mass, and the difference of water revenue and expand must be equal to variable quantity of water-retention in this area (or water body). Water cycle is the natural phenomenon which objective exist on the earth, water balance is the inherent law of water cycle.

（ 2 ） Water balance

Figure 7-3 world hydrological cycle process

(according to Moore, repaint in 1996)

（ 3 ） Water pollution or water auto-purification When pollutant into rivers, lakes, oceans or groundwater, and other water body, its content is exceeds self-cleaning ability of the water body, which makes physical, chemical nature or biological components of water quality and bottom material of the water body change, and then reduces useful value and use function of the water body. Therefore, it is called water pollution.After pollutant enters into the water body, with the complex physical, chemical and biological actions, the concentration of pollutant is reduced. After a period, the water body will be recovered to the situation before pollution. This phenomenon is called as automatic depuration of water body.

Automatic depuration of water body can be divided into three kinds of depuration models according to its mechanism: Physical depuration: the progress of the concentration of pollutant reduced with mixing, dilution, diffusion, evaporation, precipitation of pollutant in the water body.Chemical depuration: pollutant migrate in water body with simple or complex ions or molecules state, and the changes of chemical property, morphology, or valence happen, which makes water quality produce changes of chemical property, while not participates in biological actionBiological depuration: during the progress of biology metabolism, the concentration of environmental pollutant and toxicity are reduced, even disappear with biologic absorption and degradation.

Ocean environment Continuous water areas wildly exist on the earth is generally called ocean, and its area occupies 70.8% of the total area of earth's surface. The formation of seawater has a relationship with overall evolution of the material on the earth. Generally speaking, seawater is the production under the venting action of internal material on the earth, i.e. water vapor and other gas are discharged continuously from the internal earth with lava activity and volcanism.

（ 4 ） Ocean environment and ocean—interaction of air, ocean, and land

a. Quantity of heat exchange. The ocean transport energy to air with convection, conduction (sensible heat), evaporation (latent heat), heat radiation, and other forms, this is a progress of discharge entropy. Its result is to make movement of the atmosphere over the ocean constantly changing and form a variety of weather phenomena.b. Quantity of motion exchange. On the surface of ocean-gas, quantity of motion exchange mainly shows provide momentum by wind stress, and then waves and ocean currents are formed, leading to large-scale energy and mass transferc. Material exchange. Moisture exchange implemented by evaporation and atmospheric water is the main process of material exchange on the surface of ocean-gas.

Interaction of ocean and gas

a. Material exchange. Stream flow into the ocean will carry sediment from the land into the sea. Meanwhile, nutrients and pollutants in the land such as N2, P, and other compounds will be discharged into the ocean.b. Momentum exchange. In the littoral zone alternating of ocean and land, marine abrasion exists by wave impact makes rock collapse.c. Sea-level change. Because global climate is warming, seawater expanding, field ice in polar region and glacier thawing in continent results in sea level rising

Ocean-land interaction

Ice and snow covering has a significant impact on global climate and environment. Because ice and snow have high surface reflectivity, the absorption of solar radiation on underlying surface is greatly reduced. Ice and snow has lower thermoconductivity, which can weaken vertical conduction of heat quantity in the medium under ice and snow. Glacier is the product of climate and topography. However, it has a strong impact on climate and topography. Amount of precipitation in glacierized mountain area is often higher than that of unglacierized mountain area.

（ 5 ） Effect of ice and snow underlying surface on climatic change

7.2.3 Status and role of other layers

（ 1 ） Relation between lithosphere and mankind survival and development

Lithosphere is the outermost layer of the earth composed by all kinds of rocks, and its vertical structure contains olivinite on the top of petrosphere and upper earth's mantle. It is the source of a large number of mineral resources and a variety of fuels, which are essential for the soil and life, and has a close relationship with survival and development of the human. For quite a long time, 80% of the raw materials and 90% of the energy required for human society are from the lithosphere

（ 2 ） Environmental effect of changes of soil environment and land cover

Soil means loosened surface layer, located in land surface of the earth with certain fertility and the ability of growing plants, and is the product by combined effects of rocks, topography, climate, biology, time and human activities, and other soil-forming factors. Soil fertility is the ability of soil supplying and coordinating of nutrition factor and environmental condition for plant growing. Soil environment is located in transition zone among atmosphere, hydrosphere, lithosphere and biosphere in the environment system of earth surface, and it is a tie connecting inorganic and organic environment.

Land cover means generic name of vegetation cover and artificial cover on earth surface. Land utilization is the external driving force of land cover changing, while land cover also can affect land use with feedback.The characteristics of land cover have important effects on climate, geochemical cycle of global biodiversity, as well as abundance and composition of terrestrial species.Land use and land cover change affect regional climate with changes in surface reflectivity, and content of greenhouse gases and trace gases.At the same time, it affects energy exchange, water exchange, erosion and deposition, biological cycle and crop production, and other main ecological processes of soil.

Interplay and interaction of biosphere and other layers of compound system of human-earth environment is an important part to prompting unceasing evolution and development of the whole composite system. Biosphere constitutes a human ecological environment together with soil, water and air and other circles. With the flows and exchange of energy and matter within and between layers, balance and stability of earth system can be maintained.

（ 3 ） Relation between biosphere and compound system of

human-earth environment

The main body of wisdom circle is human, while principal character expressed by the total of a variety of human processes and human phenomena is sociality. Activities of human society are associated with each other and combined into a society as a whole. In fact, the formation and development history of wisdom circle results from unceasing effect and action of human social, economic, political, cultural and technological development on natural environmental systems, and gradually evolves into the history of human-earth relation.

（ 4 ） Relation between wisdom circle and human-earth

7.3 Entirety of compound system of human-earth

environment and influence and response between each layer.

7.3.1 Entirety of compound system of human-earth environment

Entirety of compound system of human-earth environment involves in interaction of each layer. Physical, chemical and biological processes interwork with human process, showing entirety characteristics of organic unity of combined system, which makes joint connection of the whole world and region, macroeconomics and microeconomics, as well as earth's environment and life processes.

7.3.2 Interaction within and between each layer

The important of interaction within each layer is ocean-gas interaction, land-gas interaction, and land-ocean interaction.（ figure 7-3）

Figure 7-3 Important process in marine - atmosphere - land system

（ according to IGBP -all, repaint in 2001Ⅱ ）

The characteristic of current human activities on surface systems reflects two aspects: ①Creativity of human science and technology is increasing.

②The scale of destruction of ecological environment is more and more with the regional and global characteristics.

The condition of underlaying surface decides the distribution of solar radiation on the earth's surface, and affects weather system. Wetlands, forests, urban, and other surface changes are important source of greenhouse gases of CO2, CH4 and N2O. Vegetative cover can increase solar radiation absorbed on the earth's surface, reduce thermal flux from the earth surface downward, and decrease effective radiation on the earth.

Once land cover is changed, it can affect migration of moisture interaction, erosion and deposition, biological cycle, producing crops, and other main ecological processes of soil, leading to a series of ecological environment. Therefore, the proportion of urban built-up area is large, and it will inevitably lead to local environmental quality decreased.

7.3.3 Intervention of human progress

Figure 7-4 The built-up area of some European cities in 1995

（ quoted from World Resources Report ， UNDP,UNEP,WB,WRI ， 2002 ）

Case study - energy cycle Energy cycle in compound system of human-earth is the basic power to drive all progress. In order to keep thermodynamic equilibrium, earth-gas system must send radiation equivalent with solar incoming radiation. However, as for some local area, radiation revenue and expenditure is not balance. With the increase of latitude, the balance of radiation becomes form positive value to negative value. Therefore, trans-regional energy transmission should be finished by atmospheric circulation and ocean circulation. During this progress, a series of energy exchange process also exists in the interface of atmosphere, oceans, land and ice.Besides, triphase change progress of volcanic eruption and water is accompanied with absorption, release and re-distribution of energy. Energy cycle during biogeochemical processes shows conversion of chemical energy. Solar energy absorbed for use of terrestrial and marine plants can maintain synthesis, decomposition and distribution of the product, and enter into biogeochemical cycles with various elements.（ figure 7-5 ）

Figure 7-5 Energy cycle of human-land compound system

（ quoted from Zhucheng, etc. Introduction to global change ， 2003 ）

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