weather forecasting - sayson converted

8/6/2019 Weather Forecasting - Sayson Converted

1/51

The History of Weather Forecasting

WEATHER

FORECASTINGPrepared by:

SAYSON, Noah Justine C.


2/51

WHAT

DO WE

MEAN BY

WEATHER?


3/51

What do we mean by weather?

Weather is defined as the hour-by-

hour variations in the atmosphericconditions experienced at a certain

place.


4/51

WHAT

DO WE

MEAN BY

WEATHER

FORECASTING?


5/51

PLAY VIDEO


6/51

PLAY VIDEO


7/51

PLAY VIDEO


8/51

What do we mean by weather

forecasting?

Weather forecasting is the application of

science and technology to predict the state of

the atmosphere for a future time and a given

location.

In meteorology, it is the statement of the

expected weather conditions in a given region

over a period of from one hour into few days inadvance.


9/51

In 650 BC, the Babylonians predicted the weatherfrom cloud patterns as well as astrology.

In about 340 BC, Aristotle described weather

patterns in Meteorologica. Later, Theophrastus compiled a book on weather

forecasting, called the Book of Signs.

Chinese weather prediction lore extends at leastas far back as 300 BC which was also around thesame time ancient Indian astronomers developedweather-prediction methods.

History of Weather Forecasting


10/51

In 904 AD, Ibn Wahshiyya's Nabatean Agriculture

discussed the weather forecasting of atmospheric

changes and signs from the planetary astral

alterations; signs of rain based on observation ofthe lunar phases; and weather forecasts based on

the movement of winds.

Ancient weather forecasting methods usuallyrelied on observed patterns of events, also termed

pattern recognition.



11/51

In 1790, the barometer, thermometer,

anemometer, and hygrometer have been invented.

Extensive observations of the upper atmosphere

were made duringWorld War I with the use of

airplanes, air balloons and radiosonde.

Rockets and artifictial satellites were most helpful

for gathering atmospheric data duringWorld WarII.



12/51

The telegraph (1835)

allowed reports of weather

conditions from a wide areato be received almost

instantaneously by the

late 1840s.

Weather map of Europe, 10 December 1887



13/51

The two men most credited with the birth offorecasting as a science were Francis Beaufort(remembered chiefly for the Beaufort scale) and

his protg Robert Fitzroy (developer of the Fitzroybarometer). Their work formed the basis for all oftoday's weather forecasting knowledge.

A standard vocabulary of describing clouds

necessary to convey information accurately wasachieved by means of a series of classificationsand, in the 1890s, by pictorial cloud atlases.



14/51

Great progress was made in the science ofmeteorology during the 20th century. Thepossibility of numerical weather prediction wasproposed by Lewis Fry Richardson in 1922,thoughcomputers did not exist to complete the vastnumber of calculations required to produce aforecast before the event had occurred.

Practical use of numerical weather prediction

began in 1955,spurred by the development ofprogrammable electronic computers.

In the United States, the first public radio forecastswere made in 1923 by E. B. Rideout, on WEEI in

the Boston area.



15/51

Television forecasts followed with Jimmie Fidler in

Cincinnati in 1940 or 1947 on the DuMont

Television Network.

The Weather Channel is a 24-hour cable network

that began broadcasting in May 1982.



16/51

All About Weather Forecasting

Once an all-human endeavor based mainly uponchanges in barometric pressure, current weatherconditions, and sky condition, forecast models arenow used to determine future conditions.

The chaotic nature of the atmosphere, themassive computational power required to solvethe equations that describe the atmosphere, errorinvolved in measuring the initial conditions, and an

incomplete understanding of atmosphericprocesses mean that forecasts become lessaccurate as the difference in current time and thetime for which the forecast is being made (therange of the forecast) increases.


17/51

Each country has an agency of releasing of theweather forecast. Some are as follows:

Philippine Atmospheric, Geophysical,

Astronomical Services Administration Philippines esp. Weather Bureau

U.K. Meteorological Office United Kingdom

National Aeronautics and Space Administration U.S.A.

At an international level, forecasting iscoordinated by World Meteorological Organization(WMO).

All About Weather Forecasting


18/51

Observation This involve round the clockgathering of meteorological data by land stations,weather ships, radiosondes and satellites.

Analysis This involves the coordinating weatherinformation by the appropriate agencies of eachcountry and plotting them on weather maps; theseare also called synoptic charts. (In this case,

synoptic means displaying conditions of theatmosphere or weather that exist simultaneouslyover a wide area.)

3 main stages involve in Weather Forecasting:


19/51

Forecasting This involves making predictions

of future weather patterns. It may be done by

applying the forecasters experience of the

evolution of past weather patterns to the

current set of data, or it may be on

mathematical computations.

3 main stages involve in Weather Forecasting:


20/51

HOW

MODELS

CREATES

FORECAST?


21/51

Data Collection

- included in the pieces of data being collected

are the surface weather observations of

atmospheric pressure, temperature, wind

speed and direction, humidity and

precipitation level.

How models create forecasts?


22/51

Data Assimilation and Analysis

- information gained from the observations is

used in conjunction with a numerical models

most recent forecast for the time that

observations were made, since this contains

information from previous observations. This

is used to produce a meteorological analysisthat shows the models estimate of the

current state of temperature.



23/51

Numerical Weather Prediction

- takes analysis as the starting point and

evolves the state of the atmosphere forward

in time using physics and fluid dynamics. The

complicated equations which govern how the

state of a fluid changes with time require

supercomputers to solve them.- The output from the model provides the basis

of the weather forecast.



24/51

Model Output Post Processing

- The raw output is often modified before being

presented as the forecast.

- This can be in the form of statistical

techniques to remove known biases in the

model, or of adjustment to take into

account consensus among othernumerical weather forecasts.



25/51

TECHNIQUES

USED IN

WEATHER

FORECASTING


26/51

Persistence

- This is the simplest method of forecastingthe weather relies upon todays conditions to

forecast the conditions tomorrow. Use of a Barometer

- The barometric pressure tendency (thechange of temperature over time) has beenused in forecasting the weather since the late19th century.

What techniques are used in

Forecasting?


27/51

- The larger the change in pressure, esp. if

more the 3.5 hPa, the larger the change in

weater can be expected.

- If the pressure drop is rapid, a low pressure

system is approaching, and there is a greater

chance of rain. Rapid pressure rises are

associated with improving weather conditions,such as clearing skies.


Forecasting?


28/51

Looking at the sky

- Along with pressure tendency, use of the sky

condition is one of the most important weather

parameters that can be used to forecast

weather in mountainous areas.

Nowcasting

- Forecasting of the weather within the next sixhours.


Forecasting?


29/51

Mares tail shows moisture at high altitude, signalingthe later arrival of wet weather.


Forecasting?


30/51

Use of forecast models

- Using a consensus of forecast models, as wellas ensemble members of the various models,

can help reduce forecast error. Analog technique

- a complex way of making a forecast, requiringthe forecaster to remember a previousweather event which is expected to bemimicked by an upcoming event


Forecasting?


31/51

An example of 500 mbar geopotential height

prediction from a numerical weather prediction model.


Forecasting?


32/51

FORECASTING EXPERIENCE

(SAMPLE)

Observation Forecast Reason

NightCooler

than day

Ground Cools

(Outgoing Longwave Radiation> Incoming Shortwave

Radiation +Incoming Longwave Radiation)

Clear SkyCool

Evening

The atmosphere is mostly transparent to the outgoing

longwave radiation.

Calm Winds

Cool

Evening

Little mixing of air from aloft keeps the air close to the

ground cooler.

Low

Humidity

Cool

Evening

The lack of moisture will mean less heat will be reradiated

back to earth.


33/51

ELEMENTS

OF

WEATHER

AND

CLIMATE


34/51

Temperature - hotness or coldness of a body or

environment

Pressure amount of force acting per unit area

Wind speed

Wind direction

Humidity amount of water vapor in the air

Clouds

Elements of Weather and Climate


35/51

Precipitation

Visibility greatest distance under given weather

conditions which it is possible to see without

instrumental assisstance

Elements of Weather and Climate


36/51

DIFFERENT

MODEL

FORECAST


37/51

Analog model

Analytical model

Conceptual model

Continuous model

Deterministic model

Empirical model

Explicit model

Implicit model

Mass balance model

Numerical model

One-dimensional model

Pseudo-deterministic

model

Stochastic

mathematical model

Two-dimensional model

What forecast models are used in Forecasting?


38/51

VARIOUS WEATHER MAPS AND MODELS


39/51

WHY IS

WEATHER

FORECASTING

IMPORTANT?


40/51

WHY STUDY WEATHER?(ANDREA DISCOVERS PETES MOTIVATION)

Foxtrot Comic Strip


41/51

Public uses. Most end users of forecasts are

members of the general public.

Severe weather alerts and advisories. A major part

of modern weather forecasting is the severe

weather alerts and advisories which the national

weather services issue in the case that severe or

hazardous weather is expected. This is done toprotect life and property.

Why is weather forecasting important?


42/51

PLAY VIDEO


43/51

Modern weather

predictions aid in

timely evacuationsand potentially save

lives and property

damage.



44/51

Public uses. Most end users of forecasts aremembers of the general public.

Severe weather alerts and advisories. A major partof modern weather forecasting is the severeweather alerts and advisories which the nationalweather services issue in the case that severe orhazardous weather is expected. This is done toprotect life and property.

Air traffic. Because the aviation industry isespecially sensitive to the weather, accurateweather forecasting is essential.



45/51

Ash cloud from the

2008 eruption of

Chaitn volcanostretching across

Patagonia from the

Pacific to theAtlantic Ocean.



46/51

Marine. Commercial and recreational use of

waterways can be limited significantly by wind

direction and speed, wave periodicity and heights,

tides, and precipitation. Agriculture. Farmers rely on weather forecasts to

decide what work to do on any particular day.

Forestry.Weather forecasting of wind, precipitations

and humidity is essential for preventing and

controlling wildfires. Conditions for the development

of harmful insects can be predicted by forecasting

the evolution of weather, too.



47/51

Utility companies. Electricity and gas companies

rely on weather forecasts to anticipate demand

which can be strongly affected by the weather.



48/51

An air handling unit

is used for the

heating andcooling

of air in a central

location.



49/51

Utility companies. Electricity and gas companiesrely on weather forecasts to anticipate demandwhich can be strongly affected by the weather.

Private sector. Increasingly, private companies payfor weather forecasts tailored to their needs sothat they can increase their profits or avoid largelosses.

Military applications. Similarly to the private sector,military weather forecasters present weatherconditions to the war fighter community.



50/51

PLAY VIDEO


51/51

THANK

YOUFOR

LISTENING!!!

weather forecasting - sayson converted

Documents