ATMOS 3110 Introduction to Atmospheric Sciences …pu/5000/study_2011/pu_note_01_2009.pdf ·...

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ATMOS 3110

Prof. Zhaoxia Pu Department of Atmospheric Sciences

University of Utah

Introduction to Atmospheric Sciences

August 24, 2009

ATMOS 3110 Dr. Zhaoxia Pu

Introduction

What is atmospheric sciences?

The science devoted to the description and understanding the phenomena in the atmospheres of the earth and the other planets.

•  Climatology: Long-term statistical properties of the atmosphere that constitute climate. •  Meteorology: Atmospheric phenomena and their time-dependent behavior.

Two major disciplines of atmospheric Sciences:


Introduction (cont.) Three main sub-disciplines of Meteorology:   Physical   Synoptic   Dynamic

Main sub-disciplines of Climatology:   Physical   Applied

Applications of Atmospheric Sciences (P.4):   Forecast   Assessment   Beneficial modification   Provision


 We are always affected by the atmosphere  Many natural disasters are linked with the

atmosphere  There is concern that our climate is changing  …..

Importance of our Atmosphere


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History of Meteorology

  Aristotle around 340 B.C. book on natural philosophy called Meteorologica word ‘meteor’ referred to any particles from sky

  Genuine science with weather instruments 1643 barometer

1700 humidity 1843 telegraph 1869 weather maps 1920 fronts and air masses

1940s daily upper air measurements 1950s computers for calculations 1945 radars used to observe precipitation 1960 first weather satellite

1990s Doppler radars 1990s other sophisticated instruments


Major Developments in Atmospheric Sciences


Progress in Weather Forecast


How acid rain affects stonework


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Objectives of this course

  This course provides an introduction to the field of meteorology for both meteorology majors and other scientists and engineers.

  This course is the first of a series of theoretical and practical courses that you will take to qualify yourself as a meteorologist.


Course Content   1. Introduction   Origin, composition and gas concentrations   Distribution of temperature, wind and precipitation

  2. Atmospheric Thermodynamics   The gas law   The hydrostatic equation   The first law of thermodynamics and adiabatic lapse rate   Water vapor, wet adiabatic laps rate, static stability   Second law of the thermodynamic

  3. Atmospheric Aerosol and Cloud Microphysical Processes   Atmospheric aerosols and cloud nucleation   Microphysical processes   Cloud types & cloud morphology   Thunderstorms, hurricane, & cyclones

  4. Radiative Transfer   Electromagnetic spectrum & blackbody radiation   Absorptivity, emissivety & solar absorption   Infrared radiative transfer & scattering of sunlight   Energy balance in the upper atmosphere & surface   Effects of trace gases, aerosols, & clouds on energy balance

  5. Atmospheric Dynamics   Basic forces   The equation of motion   The thermal wind   The thermodynamic energy equation   The continuity equation


Prerequisite: METEO 1010; MATH 1210 and 1220; PHYSC 2210;

Required Textbook: Wallace, J. M., and P. V. Hobbs, Atmospheric Science: An Introductory Survey, Academic Press, 1977.

Recommended References:

Holton, J. Introduction to Dynamic Meteorology, 4th Edition, Academic Press, 2004

Salby,M.L., Fundamentals of Atmospheric Physics,Academic Press, 1996

Rogers, R. R., and M. K. Yau, A Short Course in Cloud Physics, 3rd Edition, Butterworth-Heinemann, 1989

Petty, G. W., A First Course in Atmospheric Radiation,Sundog Publishing, 2004


Grading policy

Grades will be based upon your performance on the homework exercises, exams, and the class participation. The weighted contribution of each of these items to your final grade is given below: 35% Homework 10% Exam 1: Atmospheric Thermodynamics 10% Exam 2: Cloud Microphysics 10% Exam 3: Radiative Transfer 10% Exam 4: Atmospheric Dynamics 20% Comprehensive Final Exam 5% Class participation (attendance, class discussion,and in-class problem solving) Final grades are based on the following scale: >90 % guarantees an A or A- >80 % guarantees a B+, B, or B- >70 % guarantees a C+, C, or C- >60 % guarantees a D+, D, or D- <60% results in an E


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Homework policy

•  Homework may be assigned after each lecture but will be collected in every week. You are expected to work independently to solve the problems though discussions among classmates are allowed. Plagiarism will not be tolerated. Please hand in your homework at beginning of the class on the due day. Late homework will not be accepted(result a "0" grade).

•  Homework will be rated by professor based on a percentage scale with 100% as excellent completion.

• You are encouraged to correct errors in your homework if the homework was rated below to 90%. As a result, you are able to make up for your lower homework grade to a rate up to 90%.

• Homework achievement will be contributed to your final grade (35% in total).


Instructor

Dr. Zhaoxia Pu

Office: 712 WBB Office Hours: MF 1140-1220

Homework Session: W 1140-1210

It’s important to see me during the office hours. I may or may not be available for you other than the office

hours. However, you can send an email to me [email protected]


Components of the earth system

Atmosphere is one of the components of earth system


Thinness of the atmosphere

Atmosphere is a thin envelope of gases and tiny particles that surround Earth

• 99% of atmosphere's mass is confined to a layer of thickness ¼ % of the earth's diameter; atmosphere around Earth is thus thin, like the peel of an apple

• atmosphere is essential for life: contains oxygen and carbon dioxide for life sustaining processes, supplies water and shields life from harmful ultraviolet radiation from Sun


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Composition of the atmosphere In comparison to the sun, the atmosphere of the earth is remarkably deficient in the noble gases (helium, neon, argon, xenon, and krypton).


Evolution of Atmosphere: Early (Primeval) Phase

  Earth's birth was about 4.6 billion years ago   Lava, ashes, gases from volcanoes ("outgassing")

form Earth's primeval atmosphere, hugging planet due to gravitational field of Earth

  Atmosphere consisted of mostly CO2 (carbon dioxide), N2 (nitrogen) and H2O (water vapor)


Early Phase

  Surface temperature might have been as high as 85 to 110 oC (compared to 15oC today)

  Planet cooled, water vapor condensed to form clouds and rain, hence oceans

  A lot of CO2 in atmosphere dissolved in rainwater   Life formed about 2 billion years ago, and

photosynthesis produced oxygen (O2)   Ozone (O3) shield formed


Evolution of Atmosphere: Modern Phase

  Main atmospheric components are N2 (78.08% by volume) and O2 (20.95%) in layer below 80 km; other constituents are water vapor, trace gases and aerosols  water vapor concentration is highly variable, ranging from

0 to 4%   trace amounts of CO2, O3 and other gases  aerosols in atmosphere are tiny liquid and solid particles

from forest fires, wind erosion of soil, salt from ocean spray, volcanic emission, and meteoric dust


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Recent changes in gas concentrations: Greenhouse gases and global warming

Carbon dioxide in units of part per million.


Water vapor imagery


Zonal-mean mixing ratio of water vapor (contoured) and density of water vapor or absolute humidity (shaded), as functions of latitude and pressure

The shaded levels correspond to 20, 40 and 60% of the maximum value.


Zonal-mean mixing ratio and density of ozone

Ozone filters out incoming solar radiation in the ultraviolet part of the spectrum.


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Aerosol Index


Total fractional cloud cover annual averaged from 1983-1990, compiled using data from the International Satellite Cloud

Climatology Project (ISCCP).


ATMOS 3110 Introduction to Atmospheric Sciences …pu/5000/study_2011/pu_note_01_2009.pdf ·...

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