DRRR

• Layers of Atmosphere


  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
  • Exosphere
• Troposphere


  • Lowest layer of the atmosphere
  • Exposed to natural phenomena and ground activities
  • Extends from earth's surface up to 7-20 km above sea level
  • Composed of water vapor, carbon dioxide, methane, nitrous oxide, and other gases
  • Warmest portion is near the ground
• The atmosphere is the protective layer of gases that acts like an envelope that shields every creature on Earth from the harmful effects of sunlight, particularly the ultraviolet radiation (UV rays)
• The atmosphere keeps the earth's temperature suitable for living things
• Tropical cyclone


  Meteorological term referring to its cyclonic circulation where the strong winds in the Northern Hemisphere circulate counterclockwise and clockwise in the Southern Hemisphere
• Names of tropical cyclones in different regions

  • Hurricane (North Atlantic Ocean)
  • Typhoon (Northwest Pacific Ocean)
  • Severe tropical cyclone (Southeastern Indian and Southwest Pacific Oceans)
  • Severe cyclonic storm (North Indian Ocean)
  • Tropical cyclone (Southwest Indian Ocean)
• Development of a tropical cyclone

  1. Formative stage

  2. Mature stage

  3. Dissipation stage
• Conditions for tropical cyclone formation

  • Formed in tropical oceans
  • Convergence of low altitude winds
  • Latent heat of condensation
  • Coriolis force
• A tropical cyclone weakens during and after its landfall
• The presence of mountains can reduce the strength of tropical cyclones by as much as 50 percent because moisture is scraped off from them
• PAGASA's classification of tropical cyclones based on maximum sustained winds


  • Tropical Depression (≤61 km/h)
  • Tropical Storm (62-88 km/h)
  • Severe Tropical Storm (89-117 km/h)
  • Typhoon (118-220 km/h)
  • Super Typhoon (>220 km/h)
• Elementary schools suspend classes at Signal #2, high schools at Signal #3
• Location of the Philippines

  • Archipelago in the Western Pacific Ocean in Southeast Asia
  • Bound by the East Philippine Sea, West Philippine Sea, Sulu Sea, and Celebes Sea
  • Separated from Taiwan by the Bashi Channel
• The Philippines suffers an annual onslaught of dangerous tropical cyclones because it is located astride the typhoon belt, the area where tropical cyclones mostly develop
• Philippine Area of Responsibility (PAR)

  Predefined geographic region assigned to PAGASA for weather monitoring and forecasting
• Frequency of tropical cyclones in different regions of the Philippines

  • North Luzon: 32% (very frequent)
  • Batanes Group: 25% (very frequent)
  • Southern Bicol, Mindoro, Masbate, Northern Panay, Samar, and Northern Leyte: 19% (frequent)
  • Central Luzon, Northern Bicol, Southern Tagalog Provinces, and NCR: 16% (frequent)
  • Palawan, Southern Panay, Negros, Cebu, Bohol, Northern Mindanao: 10% (less frequent)
  • Central and Southern Mindanao: 1% (rare)
• Common effects of tropical cyclones

  • Flooding
  • Landslides
  • Destruction of infrastructures and the environment
• Roles of PAGASA


  • Maintain nationwide monitoring and forecasting network
  • Research on formation, development, and movement of typhoons
  • Issue bulletins and tropical cyclone warnings (PSWS)
  • Release color-coded rainfall advisories

  
• Public Storm Warning Signal (PSWS)

  Region-specific announcements by PAGASA on the strength and possible impacts of a tropical cyclone
• Precautionary measures before a tropical cyclone

  • Keep updated on weather forecasts
  • Check and repair house
  • Prepare emergency go-bag
  • Harvest crops
  • Move animals to safe places
  • Secure outdoor objects
  • Leave coastal and low-lying areas
• Precautionary measures during a tropical cyclone

  • Stay alert, calm, and indoors
  • Stay with family and pray
  • Tune in to weather advisories
  • Evacuate if needed
• Precautionary measures after a tropical cyclone

  • Check on family members
  • Hire electrician to inspect house
  • Beware of dangerous animals
  • Report fallen/damaged electric posts
  • Wait for typhoon to fully leave before cleaning up
  • Boil tap water before use
• Thunderstorm


  Violent short-lived weather disturbance associated with lightning, thunder, dense clouds, heavy rain/hail, and strong winds
• Formation of thunderstorms


  1. Warm, moist air rises in a large, swift updraft to cooler regions

  2. Moisture condenses to form towering cumulonimbus clouds and precipitation

  3. Columns of cooled air sink earthward, striking the ground with strong downdrafts and horizontal winds
• Beware of dangerous animals such as snakes that may have entered your house during the typhoon. Immediately report to authorities fallen and/or damaged electric posts.
• Stay tuned in for the latest weather report; wait until the typhoon has totally left your place before cleaning and fixing.
• Boil tap water before drinking or using it in cooking. It might be contaminated with microorganisms brought by floodwater.
• Thunderstorm


  A violent short-lived weather disturbance that is almost always associated with lightning, thunder, dense clouds, heavy rain or hail, and strong gusty winds
• How thunderstorms arise


  1. Warm, moist air rises in a large, swift updraft to cooler regions of the atmosphere

  2. Moisture in the updraft condenses to form towering cumulonimbus clouds and precipitation

  3. Columns of cooled air sink earthward, striking the ground with strong downdrafts and horizontal winds

  4. Electrical charges accumulate on cloud particles

  5. Lightning discharges occur when the accumulated electric charge becomes sufficiently large
• Lightning heats the air it passes through so intensely and quickly that shock waves are produced; these shock waves are heard as claps and rolls of thunder.
• Lightning


  • It is a leading cause of injury and death from weather-related hazards
  • Although most lightning victims survive, people struck by lightning often report a variety of long term, debilitating symptoms
• Thunderstorms


  • They can include powerful winds over 50 MPH
  • They can create hail
  • They can cause flash flooding and tornadoes
• Precautionary measures for thunderstorms


  • Find safe shelter or right away
  • When thunder roars, go indoors!
  • Move from outdoors into a building or car
  • Pay attention to alerts and warnings
  • Unplug appliances
  • Do not use landline phones
  • If indoors, avoid running water or using landline phones
• Types of floods


  • River Flood - occurs when water levels rise over the top of river banks
  • Coastal Flood - is the inundation of normally dry land area along the coast with seawater
  • Storm Surge - is an abnormal rise in water level in coastal areas over and above the regular astronomical tide
  • Inland Flooding - flooding that occurs inland or not in a coastal area
• Flash Floods


  • Can be caused by extremely heavy rainfall from thunderstorms, dam or levee breaks, and/or mudslides (debris flow)
  • Urban areas are prone to flooding in short time-spans due to impervious surfaces that do not allow water to infiltrate the ground
• El Niño


  Trade winds weaken, warm water is pushed back east toward the west coast of the Americas
• La Niña


  Trade winds are even stronger than usual, pushing more warm water toward Asia, upwelling increases off the west coast of the Americas bringing cold, nutrient-rich water to the surface
• Types of hydrometeorological hazards

  • Long Term - Sea Level Rise, El Niño, & La Niña
  • Short Term - Typhoons, Thunderstorm, Floods, Storm Surge
• Vector-borne and water-borne diseases

  • Dengue
  • Leptospirosis
  • Typhoid
• Proper Guidelines, Warning, Evacuation