chapter 1 physical meteorology. introduction we all have some skills when it comes to the weather...

Chapter 1

Physical Meteorology

Introduction

We all have some skills when it comes to the weather

What will be lacking is both scope and depth

This chapter looks at what you probably know about the weather

Class Exercise 1.1

Conduct a class discussion about the sources of weather information and the types of information that we receive

Complete the important terms list found on Page 12 of these notes

Meteorology vs Climatology

What is meteorology?

Meteorology is the study of the weather

What is climatology?

Climatology is the study of weather averages

The concept of scales

There are three common scales used in meteorology;

Global (macro)

Synoptic (meso)

Local (micro)

There are many more scales used in meteorology

The scales of the weather

Meteorology & Society

The history First written discussion by Greeks Bloomed during Industrial Revolution Great advances were made during the wars of the 20th

Century due to wars After WW2, computers changed the volume of data

processed This led to the Numerical Weather Prediction methods

used today

Meteorology in the news

We have all watched TV and seen the following;

Storms and hail damage

Flood

Cyclones, tornadoes and hurricanes

Drought

Snow and blizzards

Class Exercise 1.2

Weather phenomena Country/Landmass or Region

Monsoon

Doldrums

Roaring forties

Southerly buster

Cyclones

Tornadoes

Trade winds

Typhoons

Hurricanes

East asia/Asutralasia

30° Latitude

North Eastern Pacific

Southern USA, Mexico area

South Eastern Australia

South Western Australia

Equatorial regions

Mainly Northern USA

Northern Australia

The social importance of weather

It really isn’t difficult to see why meteorology is socially important.

If you are a surfer for example, then you will know what weather brings good surf, and bad.

The same applies if you are a farmer, or even an office worker, but for different reasons.

Government based meteorological, hydrological and related information and services make important contributions for achieving an increased social awareness of the importance of meteorology


Weather and climate information and forecasts contribute to the development of well managed and less vulnerable agriculture, combating droughts (and subsequent drought proofing), desertification, better air quality, reduced health problems and better quality of everyday life,


Exercise 1.3

Occupation Reason for observation

Farmer

Surfer

Salesperson

Sewer worker

Environmental technician

Meteorologist

Politician

Pilot

Ecologist

Why do you need to know about meteorology?

This is the age of environmental legislation and regulation (i.e. laws).

To monitor air pollution properly,

we need to now about where that pollution came from,

and where that pollution is going (amongst many other things),

RESULT? We need to know about meteorology!

Meteorology and Climatology in Australia

So who runs meteorology and climatology in Australia?

The Bureau of Meteorology (BoM, or ‘the Bureau’).

Although legislated in 1906, the Bureau started operation in 1908, and has grown in conjunction with other national meteorological institutions overseas into a world leader in meteorological services.

The BoM is a member of the World Meteorological Organisation (WMO).

The WMO started operations in 1950, with the BoM being a foundation member.

The WMO has allowed for otherwise impossible work to be done.

The WMO cornerstone is the Global Weather Experiment in 1979, which is the largest single scientific experiment ever undertaken.


The BoM, and the WMO are only two of a plethora of international organisations that work with weather and weather related information (such as geographers and oceanographers) to provide the world with meteorological information and data.


The Australian Climate

It is impossible to ‘average’ Australia’s climate

There are many different climate ‘zones’, and each has its own average climate.

Over the years there have been numerous attempts to define different climate zones, globally, and in Australia.

The BoM currently (2005) use the Koppen (Koeppen) system of classification, of which there are six climate zones;

Equatorial

Tropical

Subtropical

Desert

Grassland

Temperate


The north of Australia lies close to the equator,

It also lies in the equatorial monsoonal region (monsoon is rain that accompanies biannual wind changes in the South-East Asia region)

So this area exhibits hot dry winters with hot wet summers.


Australia's southern coastline is what makes the southern Australian climate.

The other southern hemisphere continents do not have long coastlines parallel to Antarctica.

The southern African coastline is more rounded, and is further north.

While the tip of South America comes to within 1000km of the Palmer Peninsula on Antarctica, the long spine of the Andes means that there is no contrasting hot interior.


To the south of the Australian coast, the Southern Ocean extends 3000km to the Antarctic continent.

From there, outbreaks of very cold polar air move northwards, warming somewhat as they pass over the ocean which results in the ‘cold fronts’ you see on the TV weather segments.


Inland from the southern coast, a large proportion of the country is arid or semi-arid, with low rainfall and very hot summers.

This is due to a process called mid latitude desertification, and air that travels from the hot interior to the coast meets the cold air from Antarctica, giving southern Australia highly variable weather.


Exercise 1.4

Go to http://www.bom.gov.au/climate/environ/other/kpn_group.shtml

and print the map. On the map, indicate the reasons why you think the climate zones exist where they do.


Physically, we feel the weather.

We use all of our senses to gauge what the day will bring, and what we should do about it.

Our senses are (and were) the first meteorological instruments that we had, as we could see and hear a storm coming, and we could taste and smell the rain or dust, and we could feel wet or dry, or simply uncomfortable.

Emotionally the weather makes us happy or sad, anything else is up to you

Of all the senses, it is sight that has given us the science.

We have found ways of taking visual information and using that information to provide us with clues as to what the weather will be like tomorrow, i.e. the weather forecast – the holy grail of meteorology!

And the information we collect, we put onto a visual device called a weather map.

If we look at maps over time, we start to see trends in the weather, which gives us confidence to say what definitely will, and definitely will not happen tomorrow


The Weather Map

The weather map would probably be the most looked upon, and the most misunderstood map in the world. A weather map has a enormous amount of information on it, with most of this information being symbolic in nature, which of course, needs to be explained (in full, later in these notes).

Class Exercise 1.5

Look at the weather map below, and hold a class discussion describing as many of the features on the map as possible.

This is designed to test what you already know - you are yet to be taught how to read a weather map properly.

Class Exercise 1.5

Exercise 1.5

You may have been able to describe the following;

Isobars

Pressure values

High (H) and low (L) pressure systems

Wind direction and speed

Rainfall

At least that the country is Australia!

The Weather Map

Hopefully, by the end of this course, you will have the skills to not only read a weather map, but you will be able to predict from the information on the map what is going to happen over the next few days.

Physical components of the atmosphere

Dusts, particulates and pollution

Is dust a nuisance or essential to weather?

Without solid material, (termed particulate), precipitation would not form as the water (or ice) needs something to ‘stick’ onto (termed a nucleus).

Dust can be natural or pollution from human activites

Two very important terms arise from a discussion of dusts and the like

Aerosol refers only to those liquid and solid particles that are suspended in the air such as acid, dust, and smoke particles

Pollutant refers to any substance (solid, liquid, or gas) that contaminates the atmosphere and can potentially cause adverse effects to our health and environment


Clouds

Clouds are classified according to their height in the sky

low (from the earth's surface to 2.5 km)

middle (2.5 to 6 km)

high (above 6 km), and

According to their shape, colour and the weather they bring.


In Australia (and generally worldwide), there are ten major cloud types Cirrus Cirrocumulus Cirrostratus Altocumulus Altostratus Nimbostratus Stratocumulus Stratus Cumulus Cumulonimbus


Go to http://www.bom.gov.au/info/clouds

For each of the clouds mentioned above, state whether they are low medium or high

Provide a description of the weather they bring (if any)

Exercise 1.6

Fog What exactly is fog?

Simply put, fog is a special type of stratus cloud, of which there are two main types;

Radiation fog

Advection fog

Other types of fog include; Steam fog

Maritime fog

Hill fog


Radiation fog – occurs when moist air above the ground cools faster than air higher above

Steam fog – occurs when cold air moves over warm water

Maritime fog – is special as it can occur when air moisture is very low due to slat particles in the air

Advection fog – occurs when warm humid air travels over a colder land

Hill fog – occurs is actually a low lying cloud on a hill


Haze

Remember the concept of aerosols we mentioned earlier?

Well some aerosols, such as salt and certain dust particles, have an attraction to water (termed hydrophilic).

For this reason, the relative humidity does not have to reach 100% before water vapour condenses onto them.

At a relative humidity of about 70%, these aerosols start to attract water vapour and dissolve, forming a tiny solution droplet much smaller than a cloud droplet.


High concentrations of these solution particles in the air form what we call haze.

Haze does not qualify as either a cloud or fog, but greatly reduces visibility in the air both near the ground and aloft.

Decreasing visual air quality as a result of haze is an indicator of the increasing concentrations of pollutants in our air


Precipitation

Rather than insult you, we shall just remind you that the term precipitation covers rain, hail, snow, and sleet

Lastly, it is this (and temperature and wind) that we look out for most in the weather segment on the news.


Wind

Wind is mentioned here due to its obvious importance and effects.

Firstly, it is one mechanism by which all of the other physical components of the atmosphere are transported (such as clouds, fog and dusts),

To plant the seed for you that wind measurements are crucial for environmental technicians due to its direct influence on noise and air pollution analysis


chapter 1 physical meteorology. introduction we all have some skills when it comes to the weather...

Documents

physical meteorology

importance of meteorology

meteorology society

meteorology vs climatology

bureau of meteorology

sources of weather information

study of weather averages

class exercise