Consider the following statements regarding Pacific Decadal Oscillatio...
Explanation:
The Pacific Decadal Oscillation (PDO) is a long-term climate pattern that occurs in the Pacific Ocean. It is characterized by fluctuations in sea surface temperatures and atmospheric pressure over the northern Pacific Ocean. The PDO has two phases - positive and negative - which can last for several decades.
Statement 1: It is a long-term ocean fluctuation of the Pacific Ocean.
This statement is correct. The PDO is a long-term climate pattern that affects the Pacific Ocean. It is not a short-term phenomenon but rather a fluctuation that can persist for several decades. The PDO is influenced by a variety of factors, including ocean currents, wind patterns, and atmospheric pressure.
Statement 2: During the positive phase of this oscillation, the west Pacific Ocean becomes warm and the eastern part becomes cool.
This statement is incorrect. During the positive phase of the PDO, the opposite occurs - the eastern part of the Pacific Ocean becomes warm, while the western part becomes cool. This pattern is often referred to as the "warm phase" of the PDO. It is characterized by a weakening of the trade winds, which allows warm water to pool in the eastern Pacific. This can have significant impacts on weather patterns and climate conditions around the world.
During the negative phase of the PDO, the opposite pattern occurs. The eastern Pacific becomes cooler, while the western Pacific becomes warmer. This pattern is often referred to as the "cool phase" of the PDO. It is associated with stronger trade winds, which can push warm water towards the western Pacific.
In conclusion, the correct answer is option A - only statement 1 is correct. The PDO is a long-term ocean fluctuation of the Pacific Ocean, but during the positive phase, the western Pacific becomes cool and the eastern part becomes warm.
Consider the following statements regarding Pacific Decadal Oscillatio...
A recent study revealed that a cyclical event called the Pacific Decadal Oscillation (PDO) that repeats every 20-30 years, could make cyclones that originate near the Equator more frequent in the coming years.
- It is a long-term ocean fluctuation of the Pacific Ocean.
- The term PDO was coined in about 1996 by Steven Hare at the University of Washington.
- It can be known only after several years of measuring ocean temperatures and their interaction with the atmosphere.
- The PDO waxes and wanes approximately every 20 to 30 years.
- From ocean surface topography data, together with other ocean and atmospheric data, scientists can determine whether we are in a ‘cool’ phase or a ‘warm’ phase.
- Cool phase: It is characterized by a cool wedge of lower than normal sea-surface heights/ocean temperatures in the eastern equatorial Pacific and a warm horseshoe pattern of higher than normal sea-surface heights connecting the north, west and southern Pacific.
- Warm' or 'positive' phase: In this the west Pacific Ocean becomes cool and the wedge in the east warms.
How does this affect climate?
- The change in location of the cold and warm water masses alters the path of the jet stream.
- The jet stream in the northern hemisphere delivers storms across the United States.
Hence only statement 1 is correct.