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Presented by: VIVIEN S. ESQUIVEL CADS / Climatology and Agrometeorology Division PAGASA - DOST


CONCEPT OF WEATHER AND CLIMATE Weather • specific condition of the atmosphere at a particular place and time • measured in terms of wind, temperature, humidity, atmospheric pressure, cloudiness and precipitation • in most places, weather can change from hour-to-hour and season-to-season


CONCEPT OF WEATHER AND CLIMATE Climate •

is the “average weather” and its long term variability over a particular period (over a month, season, year, or several years)

Climate variability •

refers to the fluctuations / variations of climate observed since the instrumental period (1860 to present). These fluctuations are due to natural causes and to human activities


CLIMATE SYSTEM Five components: • • • •

Atmosphere Ocean Land Surface Ice and snow surface • Biosphere


– interactive system consisting of 5 major components, forced or influenced by various external forcing (i.e. sun and human activity)


Philippine geography & topography BAGUIO CITY

MANILA PAGSANJAN FALLS

MAYON VOLCANO

BORACAY ISLAND

AKLAN Ati-atihan ROXAS SEAFOOD CAPITAL .

PALAWAN

MT. APO


Climate of the Philippines has been described in terms of rainfall distribution received in a locality. With the use of the average monthly distribution of rainfall at the different stations, four types of rainfall distributions in the Philippines are defined, two of which altogether are opposite types.


The Philippine Climate

‌Characterized by humid equatorial or tropical maritime

Type 1 Climate: Type 3 Climate: dryrain from December NoTwo verypronounced pronouncedseasons: maximum period, with to May, wet lasting from June November. a short dryand season onlytofrom one to three Type 4 Climate: Maximum rain is from June to September. months. typeperiod is intermediate between the TypeThis 2 Climate: Rainfall more or less evenly distributed Areas characterized by this climate type are preceding although it resembles the first type No two, dry season with a very pronounced throughout the year. This resembles second generally toit the monsoon and more closelyexposed because has aDecember short drythe season. maximum rain period insouthwest and January, type more closely since it has no dry season. get aoffair share of is the rainfall brought aboutfrom by Areas this climate type partly although there not aare single dryshielded month. Areas the tropical cyclones, especially during the northeast monsoon but are exposed the characterized by thisoccurring climate type aretogenerally the maximum These generally are the southwest monsoon and also benefited by the along or veryrain nearperiod. theare eastern coasts, thus are areas alongtothe portion of the country. rainfall caused by tropical cyclones. exposed thewestern northeast monsoon. Monthl y

Ra infa l l of Ta gbila ra n City, Bohol (Type IV)

200 180

Rainfall (mm)

160

Mean Annual RR: 1519.4 mm.

140 120

M onthly Rainfall of Le gaspi City (Type

100

Monthly Rainfall of Port Area, Manila (T ype

80

Monthly Rainfall of Tugue garao, Cag.

II)

I)

(Type

III)

600

500

300 60 Rainfall (mm)

Rainfall (mm)

Rainfall (mm)

450 40

500

250 400 20

350

0 200 300

400 JA N

FEB

MA R

200

150

Infanta =3967.3 Hinatuan =4168.3

Dipolog

JUN

JUL

A UG

SEP

OCT

NOV

DEC

200

Climate Type IV

100

50

100

50

0

0

Gen San

MA Y

Month

100

Mean annual rr=2379.3

A PR

300

150 250

0

JAN

JAN

FEB

JA N

FEB

FEB

MAR

MAR MA R

APR

APR A PR

MAY

MAY

MA Y

JUN

JUN

JUN

JUL

JUL

A UG

Month

Climate ClimateType TypeIIIII

AUG

AUG

Month

JUL Month

Climate Type I

SEP

SEP

SEP

OCT

OCT

OCT

NOV

NOV

NOV DEC

DEC

DEC


Seasonal Rainfall Distribution in the Philippines First Second semester semester AVERAGE RAINFALL APRIL-SEPTEMBER (1951-2000)

AVERAGE RAINFALL OCTOBER-MARCH (1951-2000)


El Ni単o Southern Oscillation (ENSO)

a large-scale natural fluctuation of the global climate system resulting from the interactions between the ocean and atmosphere in the central and eastern equatorial Pacific (CEEP).


H

L

Australia

L

H

Australia

< -8

EL NIÑO CONDITION

>+8

LA NIÑA CONDITION


EL ELNIÑO NIÑO

LA LANIÑA NIÑA


TWO PHASES OF ENSO El Nino •

• •

Excessive warming of the surface ocean in the central and eastern Pacific; Associated with westerly anomaly; and High negative values of Southern Oscillation Index (SOI)


TWO PHASES OF ENSO La Nina • Excessive cooling of the surface ocean in the central and eastern Pacific; • Associated with enhanced easterly; and • High positive values of Southern Oscillation Index (SOI)


CONDITIONS IN THE TROPICAL PACIFIC OCEAN

NORMAL • Walker circulation over western tropical Pacific • Strong trade winds • Convective precipitation and cumulus clouds in western tropical Pacific


CONDITIONS IN THE TROPICAL PACIFIC OCEAN

EL NIテ前 窶「 Walker circulation is displaced 窶「 Trade winds weaken 窶「 Convective precipitation and cumulus clouds move to Central Pacific Ocean


CONDITIONS IN THE TROPICAL PACIFIC OCEAN

LA NIÑA • Walker circulation intensifies • Trade winds enhanced • Convective precipitation and cumulus clouds intensify in western Pacific Ocean


EXTREME CLIMATIC CONDITIONS - EL NIテ前


EXTREME CLIMATIC CONDITIONS - LA NIÑA


Tropical Cyclones During August 2004 El Ni単o

Did not bring much rainfall in the eastern portions, not rain-effective


ANGAT DAM

• AGRICULTURE • WATER RESOURCES SECTOR


Floods in Calapan, Isabela, Camarines Sur, Iloilo, Quezon and Palawan Damage to Agriculture – P 508M No. of families affected – 300,000


BASICS OF ENSO_bong_FINAL  
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