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Every time the atmosphere interacts with a body of water(often ocean) nabubuo yung
Hydrometeorological Hazards
Hydrometeorological Hazards
• Hydro – water
• Meteorological – atmosphere
• Natural processesatmospheric hydrological or oceanographic nature that may cause loss
of life, injuries or oth
• Processes or phenomena of er health impacts, property damages, loss of livelihoods and
services, social and economic disruptions and even environmental damages.
• Tropical cyclones, thunder storms, hail storms, tornadoes, storm surges, water
avalanches, blizzards, heavy snowfall, flash floods, drought, heatwaves, cold spells and
many more
• Most popular hydrometeorological hazards and most of the time gives the most
damages: (tropical cyclone, thunderstorms. Tornadoes and waterspouts, flash floods,
flood, storm surge, lightning, and downburst)
1. Tropical Cyclone/Cyclone
ITCZ- Inter Tropical Convergence Zone
○ An intense low pressure system which is characterized by strong spiral winds
towards the center called the "Eye" in a counter-clockwise flow in the Northern
Hemisphere
○ Tropical cylcones are formed by the meeting of cold air and warm air
○ Always starts with low pressure area (LPA)
○ A cyclone has an eye, eye wall and rain bands.
○ Eye – very peaceful; halos no weather disturbances; diameter can range up to 20-
65km; weak winds; warm temperature; sky is very clear as if there is no weather
disturbance; short lived
○ Eye wall – where winds are the strongest; rotating wind column or rotating air
column; can grow up to 15km above the sea level; strength of wind develops as
time passes by and while it gets stronger nabubuo yung different types of cyclones
cumulonimbus clouds that contains heavy rains; very dangerous/catastrophic; with
rotating strong wind column; where different types of cyclone are formed; hihina if
tatama sa big masses of land forms like mountain ranges
○ Rain bands – strips of normal clouds with average power of rotating wind column;
natitirang hangin sa outermost regions; konting rotating air column nalang
○ 4 TYPES OF TROPICAL CYCLONE (different types of cylones are dependent on its
wind speed)
i. Tropical Depression – its eye wall has a rotating wind speed up to 62kph
ii. Tropical Storm – it has a wind speed of 63-118kph
iii. Typhoon – it has a wind speed of greater than 118kph; north-west pacific
1. A large powerful and violent tropical cyclone
2. LPA rotating counter clockwise and containing rising warm air that
forms over warm water in the western pacific ocean
3. Called a hurricane when formed in the atlantic ocean, called a cyclone
when formed in the Indian ocean and Wili-wily in australia
iv. Super Typhoon – it has a wind speed exceeding 220kph
○ Why do Tropical Cyclones Form?
▪ To cool down the surface of the earth
▪ Balances heat and cold temperature because of the existence of tropical
cyclones
○ What are the importance of Tropical Cyclones?
▪ Because of this we are able to balance the heat and coldness of the Earth
▪ Tropical cyclones gives us water/ tropical Cyclones is one source of water
▪ Dams are highly dependent on the tropical cyclones
▪ Reduces drought
▪ Waters plants trees and other vegetation
▪ Tropical cyclones form as a result of the atmosphere's natural tendency to
maintain equilibrium by redistributing heat through winds from the
equatorial regions to the polar regions, this mechanism prevents the ares
from becoming too hot and too cold.
○ How do Tropical Cyclones Form?
▪ At least one part of the ocean where the temperature is 26.5°C or higher;
nasisinagan ng sun and may warm winds or warm air sa gilid from the
tropical areas
▪ Water molecules will go up as warm air, then this will meet the cold airs sa
taas which is galing sa polar regions
▪ Warm air continues to go up because of evaporation, then may convergent
winds or latitude winds that are also hot (no convergent winds, no tropical
, 7/14/2021 OneNote
cyclone)
▪ Condensation happens then clouds are formed, converging winds are still
blowing
▪ Clouds can form and rise to ~10km in the troposphere; condensation
magkaka clouds bc nagsama wamr and cold air (low pressure area)
▪ As time passes magiging malaking cumulonimbus which brings heavy rains
(Tropical Depression) here is where the rotating winds are formed which is
called tropical depression.
▪ Magiging Tropical Storm na; may powerful winds sa taas then sa baba may
malaking cumulonimbus clouds; then magkakainit sa gilid so kahit wala nang
convergent winds okay lang.
▪ From tropical storm magiging Typhoon; lalakas yung rotating winds then
lalaki pa yung cumolonimbus clouds; magsisimula nang magsama yung
clouds at rotating winds
▪ From tyhpoon to super typhoon
▪ Coreolis Effect – sumasabay sa ikot ng Earth yung ikot ng Typhoon
○ Tropical cyclones are formed by the meeting of cold and warm air
○ Conditions for a cyclone
1. Large, still, warm ocean area with temperatue above 26.5C
2. deep
3. Converging winds/latitude winds
4. Has o have moisture
5. Clouds for and rise to –10km in the troposphere (low pressure area)
○ Whate are the effects of tropical cyclones?
▪ Strong winds
• Costs the most damage
• Winds slows down on landfalls
▪ Storm surge
• Unusual increase in sea water level way above thepredicted
astronomical tide level
• Can have slow speed which is dangerous
▪ Heavy/torrential rains
• Actually occurs in tropical cyclones of lower intensity
• The lower intensity the more rains it gives
Mesures in mitigating the destructive effect of typhoon
○ Determining areas prone to typhoon-related disasters
▪ Typhoons sometimes follows a certain path
▪ Fujiwara effect – typhoons na nag uu-turn
○ Implementing legislation involving land use planning, zoning, and building
standards.
▪ "typhoon simulation" that can help prevent hazards
○ Weather forecasting and monitoring.
▪ PAG-ASA (Philippine atmospheric geophysical astronomical services
administration)
▪ Signal 1 – tropical cyclone winds are at 30-60km/h
▪ Signal 2 – tropical cyclone winds of 61 –118km/h (tropical depression)
▪ Signal 3 – tropical cyclone winds of more than 121-170km/h (tropical storm
or typhoon)
▪ Signal 4 & 5 – super typhoon
○ Effective public typhoon warning systems.
▪
2. Thunderstorms
○ Violent transcent type of weather disturbance associated with thousands of meters
of tall cumulonimbus clouds which useually involves lightning, thunder, heavy
rainfall, gust of winds and occasionally tornadoes and hail.
○ Thunder storms often occur in the equatorial regions at any time of the day (based
on observation it happens more on in the afternoon)
○ Specific elements
▪ Lightning
▪ Thunder
▪ Heavy rainfall
▪ Tornado (posibbly)
▪ Gust of winds (rotating but not fully rotating like a tropical cyclone)
▪ Hail (sometimes)for thw formation of thunderstorms are:
• Moisture (water vapor) which must be readily available
• An unstable, rapidly rising mass of warm air
• A strong upward current of air to forcw moisture to higher, colder
levels of the atmosphere.
○ 3 requirements
1. Cumulus cloud stage/developing stage (3-5 miles height
i. "developing stage"
ii. Begins with the upward draft of a cumulus clouds due to the continuous up-
draft (warm air goes up) and supply of moisture (from transpiration or any
water from the surface of the earth)
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