Hydrometeorological Hazard

• Hydrometeorology


  The study of the atmospheric and terrestrial phases of the hydrological cycle with emphasis on the interrelationship between them
• Hydrometeorology


  It deals with the transfer of water and energy between land surface and the lower atmosphere
• Processes of the hydrologic cycle


  1. Precipitation

  2. Formation of snow covered mountain tops (not applicable in the Philippines)

  3. Melting of snow and ice (not applicable in the Philippines)

  4. Interception of precipitation by vegetation cover

  5. Storage in land surface depressions

  6. Infiltration of water into soil

  7. Evapotranspiration

  8. Recharge of groundwater

  9. River runoff
• Clouds


  A visible aggregate of small water droplets and/or ice particles in the atmosphere above earth's surface and they form in the atmosphere as a result of condensation of water vapor rising from the surface
• General cloud types

  • Low clouds: Cumulus, Stratus, Stratocumulus, Cumulonimbus
  • Mid Clouds: Altocumulus, Nimbostratus, Altostratus
  • High Clouds: Cirrus, Cirrostratus, Cirrucumulus
• Nimbus

  Refers to rain producing clouds, hence the two general type of rain producing clouds have the word nimbus in it, namely Cumulonimbus (thunderstorm clouds) and Nimbostratus (continuous rain cloud)
• Terrestrial phase of the hydrologic cycle

  1. Infiltration

  2. Surface runoff

  3. Interception of precipitation by vegetation cover

  4. Storage in land surface depressions

  5. Infiltration of water into soil

  6. Evapotranspiration

  7. Recharge of groundwater

  8. River runoff
• Tropical cyclone

  A rotating, organized system of clouds and thunderstorms that originates over the tropical waters
• Tropical cyclones rotate in a counterclockwise direction in the northern hemisphere (conversely, clockwise in the southern hemisphere)
• Every year, an average of 19 tropical cyclones enter the Philippines Area of Responsibility (PAR), and about half (9-10) make landfall in the Philippines
• Thunderstorms

  • They are typical in warm environments like the tropics and may persist for 1 to 2 hours
• Thunderstorm


  A weather condition generally characterize by heavy rain, thunder, lightning and even the possibility of tornado
• How a thunderstorm forms

  1. Moisture

  2. Rising unstable air (air that keeps rising when given a nudge)

  3. A lifting mechanism to provide the "nudge"
• Thunderstorm Life Cycle

  1. Developing stage

  2. Mature stage

  3. Dissipating stage
• Flood

  A natural disaster that occurs when water soaks or overflows normally dry land
• Flash Floods

  Caused by heavy precipitation in a short period of time, usually less than 6 hours
• El Niño


  A significant increase in ocean temperature over the eastern and central Pacific ocean
• Cumulus

  individual dense clouds with sharp outlines, often develop

  vertically
• Stratus

  gray cloud layer with a uniform base which may (if thick enough) produce drizzle
• Stratocumulus

  gray or whitish sheet or layered clouds with regularly arranged small cloud elements
• Cumulonimbus

  the thunderstorm cloud. This is a heavy and dense cloud in the form of a tall tower. The base of the cloud is often dark and produce precipitation. This cloud type also produce hail and tornado.
• Altocumulus

  a sheet of layered clouds composed of rounded masses

  or rolls.
• Nimbostratus

  a dark gray cloud layer covering the sky with continuous falling rain
• Altostratus

  gray cloud sheets of fibrous clouds that totally or partially covers the sky, but thin enough to reveal the sun
• Cirrus

  clouds in the form of white, delicate filaments. They have fibrous and/or silky sheen appearance.
• Cirrostratus

  transparent, whitish veil clouds with a fibrous appearance
• Cirrocumulus

  thin, white sheet or layer of clouds without shading
• Low Clouds

  height of less than 2 km
• Mid Clouds

  height of between 2 km to 7 km
• High Cloud

  height greater than 7 km
• Infiltration

  flow of water through the soil surface
• Surface Runoff

  flow of water over land surfaces