Current Events

1
Current Events

• IMMIGRATION!!!!!
• McDonalds All-American Game Wed. Night!!
• Ships collide in Gulf - M/V Rokya 1 and USS
  McCampbell (DDG 85)

2
Weather / Storm Avoidance
3
Objectives

• Know basic weather phenomena, including fronts
• Know the relationship between wind and current in
  a wind-driven current system
• Know the earths major wind and current systems
• Know the characteristics of tropical storms Be
  able to determine the most dangerous and least
  dangerous (navigable) semicircles associated with
  a tropical storm

4
Overview

• Weather the state of the Earths atmosphere
• SPECIFICALLY
• Air Flow The circulation of air about the
  planet caused by temperature differentials.
• Pressure Areas The relationship between
  temperature and pressure and wind.
• Fronts The transition zone or interface between
  two air masses of different densities.

5
Air Flow

• Forces that define air flow
• 1. Pressure
• 2. Earths Rotation (Coriolis Effect)
• 3. Friction from the surface of the earth

6
Weather Elements
TEMPERATURE
PRESSURE
WINDS
HUMIDITY
CLOUDS
PRECIPITATION
7
Temperature

• Temperature the amount heat in the atmosphere.
• Causes
• The Earths daily rotation about its axis
• The Earths annual revolution about the sun
• Effects
• The uneven heating and cooling of the Earths
  surface results in air flow about the planet.

8
Wind

• Wind The horizontal movement of the atmosphere
• Causes
• Temperature differentials
• Coriolis Effect
• Maritime significance
• Result in areas of High and Low pressure.

9
(No Transcript)
10
Pressure

• Atmospheric Pressure The weight of the
  atmosphere.
• Causes
• Divergence and convergence of air
• Changes in Altitude/Depth
• Maritime significance
• High/Low pressure systems
• High (H) - caused by diverging winds rotate
  clockwise
• Low (L) - caused by converging winds rotate
  counter-clockwise

11
High Pressure System Air Flow
12
Low Pressure System Air Flow
13
Weather Fronts

• Front a zone of transition between air masses
• High and Low pressure systems travel from the
  areas where they are created.
• When air masses meet, they compete for
  dominance.
• The boundary zone between these two masses is
  known as a front.

14
Cold Front

• When a cold air mass displaces a warm air mass by
  vigorously forcing it up.
• Move fast, 15-35 kts
• Weather deteriorates rapidly
• Possible severe thunderstorms
• Wind will shift (from northerly to southerly in
  N. Hemisphere)
• A fall in pressure will precede the front

15
Warm Front

• When a warm air mass displaces a cold air mass.
• Warm air slides over cold air
• Move slowly, 10-20 kts
• Weather deteriorates gradually
• Southerly winds (in Northern Hemisphere)
• Steady fall in pressure

16
Frontal Passage
17
Occluded Front

• Occurs when a cold front completely lifts a warm
  front off earths surface
• Mix of cold/warm front weather patterns
• Large area of precipitation, clouds and fog
• Severe weather

18
(No Transcript)
19
Basic Weather Phenomena

• Clouds
• Fog
• Tropical storms/hurricanes/typhoons

20
Clouds

• Clouds condensed water droplets or ice
  crystals suspended over the
  surface of the earth
• Causes of clouds
• Clouds are formed by the cooling of saturated air
  by the ocean or land surface beneath.
• Basic Types of Clouds
• Cirrushigh, wispy
• Cumuluslow to high, puffy, indicates unstable
  conditions
• Stratuslow-level, layered

21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
Coastal Fog

• Fog a cloud that touches the surface of the
  earth.
• Causes of clouds/fog
• Clouds are formed by the cooling of saturated air
  by the ocean or land surface beneath.
• Prediction of fog
• If the difference between air temperature and dew
  point is less than 2F, fog may result.

25
Current Systems

• Atlantic Currents
• North Equatorial Starts northward of Cape Verde
  Islands and flows westward. Flows in vicinity of
  northeast trade winds.
• South Equatorial Starts off W. coast of Africa
  and flows westward. Flows in vicinity of
  southeast trade winds.
• Gulf Stream Flows along the east coast of N.
  America.

26
Current Systems

• Pacific Ocean Currents
• N. Equatorialflows westward in area of northeast
  trade winds.
• S. Equatorialflows westward in vicinity of
  southeast trade winds.
• Japan Currentsimilar to Gulf Stream. Carries
  large quantity of warm water to higher latitudes.
  Originates north of Taiwan and flows northeast
  past Japan.

27
Tropical Storms

• Cyclonesstorm with strong winds rotating about a
  low pressure center
• Rotate counterclockwise in N. Hemisphere
• Rotate clockwise in S. Hemisphere
• A.K.A hurricane, typhoon, willy-willy

28
Tropical Storms

• Extratropical Cyclone
• Non-tropical origin
• 500-2500 nm in diameter
• Cold core
• Rarely has eye or calm center
• Generally less intense than tropical storm
• Moves E/NE in N. Hemisphere
• Classifications
• Gale Warning (34-47 kts)
• Storm Warning (48 kts)

29
Tropical Storms

• Tropical Cyclones
• Tropical origin
• 100-800 nm in diameter
• Calm eye
• Moves W/NW in N. Hemisphere
• Classifications
• Tropical Depression (0-33 kts)
• Tropical Storm (34-63 kts)
• Hurricane (64 kts)

30
(No Transcript)
31
Semicircles of a Hurricane

• Dangerous Semicircle
• Wind direction and direction of storm movement
  are the same, producing heaviest rain, strongest
  wind, and highest seas.
• To the right of the hurricanes path in the
  Northern Hemisphere.
• Less Dangerous (Navigable) Semicircle
• To the left of path of forward motion

32
Semicircles of a Hurricane
33
Hurricane Evasion Techniques

• Avoid, if possible
• Do not cross forcasted path of the hurricane
  (crossing the T)
• In N. Hemisphere
• In dangerous semicircle bring true wind on stbd
  bow make as much headway as possible
• In navigable semicircle bring true wind on stbd
  quarter, make as much headway as possible
• In storms path bring true wind onto stbd
  quarter (160R) and hold course until in navigable
  semicircle

34
(No Transcript)
35
Weather Prediction

• Broadcast WEAX Messages
• High Seas Warnings
• Offshore Marine Forecasts
• Coastal Marine Forecasts
• OPAREA Forecasts
• OTSR (Optimum Track Ship Routing)
• Tailored track recommendations

36
Heavy Weather ActionsInport

• Keep informed of weather conditions
• Possibility of getting underway
• Run additional mooring lines
• Secure topside equipment is secured

37
Heavy Weather ActionsUnderway

• Keep CO informed of changes in atmospheric
  conditions
• Secure weatherdecks!!!
• Ensure topside equipment is secured
• Ensure all internal spaces are secured/keep crew
  apprised

38
QUESTIONS?
39
Study Questions

• Workbook Appendix A
• Section 1 3, 6, 9-10
• Section 2 2-4