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Low Pressure Area
             A low-pressure area, low or depression, is a region where the atmospheric pressure at sea level is lower than that of surrounding locations. Low-pressure systems form under areas of wind divergence which occur in upper levels of the troposphere. The formation process of a low-pressure area is known as cyclogenesis. Within the field of atmospheric dynamics, areas of wind divergence aloft occur in two areas. The first area is on the east side of upper troughs which form half of a Rossby wave within the Westerlies (a trough with large wavelength which extends through the troposphere). A second area of wind divergence aloft occurs ahead of embedded shortwave troughs which are of smaller wavelength. Diverging winds aloft ahead of these troughs cause atmospheric lift within the troposphere below, which lowers surface pressures as upward motion partially counteracts the force of gravity.


Insight and Reflections
  • Today I learned that-- low pressure area is a region where the atmospheric pressure at sea level is lower than that of surrounding locations
  • i will apply my learnings about-- the occurrence of low pressure area.
  • Learning about this phenomena is  important t because-- i will be aware about this phenomena and i can be ready if their will be a typhoon..
  • On a larger scale, I will share my learnings about these phenomena to others-- so that not only me will be aware but also others.
  • I need to know more about-- the effects of this phenomenon to my life.


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El Nino and La Nina




El Nino
          El Nino, an abnormal warming of surface ocean waters in the eastern tropical Pacific, is one part of what's called the Southern Oscillation. The Southern Oscillation is the see-saw pattern of reversing surface air pressure between the eastern and western tropical Pacific; when the surface pressure is high in the eastern tropical Pacific it is low in the western tropical Pacific, and vice-versa. Because the ocean warming and pressure reversals are, for the most part, simultaneous, scientists call this phenomenon the El Nino/Southern Oscillation or ENSO for short. South American fisherman have given this phenomenon the name El Nino, which is Spanish for "The Christ Child" because it comes about the time of the celebration of the birth of the Christ Child-Christmas. 


          To really understand the effects of an El Nino event, compare the normal conditions of the Pacific region and then see what happens during El Nino below.






Normal Condition (Non El Nino)

El Nino Conditions


 Scientists do not really understand how El Nino forms. It is believed that El Nino may have contributed to the 1993 Mississippi and 1995 California floods, drought conditions in South America, Africa and Australia. It is also believed that El Nino contributed to the lack of serious storms such as hurricanes in the North Atlantic which spared states like Florida from serious storm related damage.


Unfortunately not all El Nino's are the same nor does the atmosphere always react in the same way from one El Nino to another. This is why NASA's Earth scientists continue to take part in international efforts to understand El Nino events. Hopefully one day scientists will be able to provide sufficient warning so that we can be better prepared to deal with the damages and changes that El Nino causes in the weather.


La Nina


La Niña is a coupled ocean-atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño-Southern Oscillation climate pattern. During a period of La Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3–5 °C. In the United States, an episode of La Niña is defined as a period of at least 5 months of La Niña conditions. The name La Niña originates from Spanish, meaning "the girl," analogous to El Niño meaning "the boy." La Niña, sometimes informally called "anti-El Niño", is the opposite of El Niño, where the latter corresponds instead to a higher sea surface temperature by a deviation of at least 0.5 °C, and its effects are often the reverse of those of El Niño.



  • Today I learned that El Niño/La Niña-Southern Oscillation, or ENSO, is a quasiperiodic climate pattern that occurs across the tropical Pacific Ocean roughly every five years. The Southern Oscillation refers to variations in the temperature of the surface of the tropical eastern Pacific Ocean (warming and cooling known as El Niño and La Niña respectively) and in air surface pressure in the tropical western Pacific. The two variations are coupled: the warm oceanic phase, El Niño, accompanies high air surface pressure in the western Pacific, while the cold phase, La Niña, accompanies low air surface pressure in the eastern Pacific.[2][3] Mechanisms that cause the oscillation remain under study while La Niña is a coupled ocean-atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño-Southern Oscillation climate pattern. During a period of La Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3–5 °C. In the United States, an episode of La Niña is defined as a period of at least 5 months of La Niña conditions. The name La Niña originates from Spanish, meaning "the girl," analogous to El Niño meaning "the boy."
  • I will apply my learnings about EL NIÑO and LA NIÑA in order for me to be aware about the effects of the EL NIÑO and LA NIÑA.
  • Learning about EL NIÑO and LA NIÑA is important because I can be ready and prepared.
  • On a larger scale I will share my learnings to others for them to know what my learnings about EL NIÑO and LA NIÑA.
  •  I need to learn more about EL NIÑO and LA NIÑA because it is a phenomenon that affects everyone including ME. 




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Tail-End of a Cold Front

Tail-End of a Cold Frontcold front is defined as the leading edge of a cooler mass of air, replacing (at ground level) a warmer mass of air, which lies within a fairly sharp surface trough of low pressure. It forms in the wake of an extra-tropical cyclone,at the leading edge of its cold air advection pattern, which is also known as the cyclone's dry conveyor belt circulation.


Tail-end of a Cold Front is a front boundary of 2 air masses, which is found in a middle latitude. It causes too much rainfall and cloudiness over affected areas.It is in a Northern portion of the country during the Northern Hemisphere in a winter season.


REVIEW: It is defined wherein the cooler mass of air used to replace the warmer mass of air, which results to a lower pressure in that surface. It is a phenomenon wherein it can experience a change in a temperature. Example of this is, when moisture is present in that place, rain can occur along the boundary. It also form a narrow line thunderstorm along the frontal zone.


Tropical Depression
tropical depression is an organized system of clouds and thunderstorms with a defined, closed surface circulation and maximum sustained winds of less than 34 knots (39 mph). It has no eye and does not typically have the organization or the spiral shape of more powerful storms. However, it is already a low-pressure system, hence the name "depression".The practice of the Philippines is to name tropical depressions from their own naming convention when the depressions are within the Philippines' area of responsibility.


Insight and Reflections
  • Today I learned that-- is a front boundary of 2 air masses, which is found in a middle latitude. It causes too much rainfall and cloudiness over affected areas.
  • i will apply my learnings about-- the occurrence of tropical depression weather it will have rainy weather or not.
  • Learning about this phenomena is  important t because-- i will be aware about this phenomena.
  • On a larger scale, I will share my learnings about these phenomena to others-- so that not only me will be aware but also others.
  • I need to know more about-- the effects of this phenomenon to my life.

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Monsoon


Monsoon
Every summer, southern Asia and especially India, is drenched by rain that comes from moist air masses that move in from the Indian Ocean to the south. These rains, and the air masses that bring them, are known as monsoons.

However, the term monsoon refers not only to the summer rains but to the entire cycle that consists of both summer moist onshore winds and rain from the south as well as the offshore dry winter winds that blow from the continent to the Indian Ocean.

The Arabic word for season, mawsin, is the origin of the word monsoon due to their annual appearance. Although the precise cause of the monsoons is not fully understood, no one disputes that air pressure is one of the primary factors. In the summer, a high pressure area lies over the Indian Ocean while a low exists over the Asian continent. The air masses move from the high pressure over the ocean to the low over the continent, bringing moisture-laden air to south Asia.

During winter, the process is reversed and a low sits over the Indian Ocean while a high lies over the Tibetan plateau so air flows down the Himalaya and south to the ocean. The migration of trade winds and westerlies also contributes to the monsoons.

Smaller monsoons take place in equatorial Africa, northern Australia, and, to a lesser extent, in the southwestern United States.

Almost half of the world's population lives in areas affected by the monsoons of Asia and most of these people are subsistence farmers, so the coming and goings of the monsoon are vital to their livelihood to grow food to feed themselves. Too much or two little rain from the monsoon can mean disaster in the form of famine or flood.

The wet monsoons, which begins almost suddenly in June, are especially important to India, Bangladesh, and Myanmar (Burma). They are responsible for almost 90 percent of India's water supply. The rains usually last until September.





Insights and Reflections


Today I learned that--  Monsoons, or rainy seasons, are a shift in wind direction which causes excessive rainfall in many parts of the world including Asia
I will apply my learnings about-- the occurrence of monsoon rains so that i will aware about the seasonal rains.
Learning about this phenomena is  important t because-- i will be aware about this phenomena.
On a larger scale, I will share my learnings about these phenomena to others-- so that not only me will be aware but also others.
I need to know more about-- the effects of this phenomenon to my life.



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Intertropical Convergence Zone (ITCZ)


Intertropical Convergence Zone (ITCZ)
          The Intertropical Convergence Zone (ITCZ) is the region that circles the Earth, near the equator, where the trade winds of the Northern and Southern Hemispheres come together. Also known by sailors as doldrums. It was originally identified from the 1920s to the 1940s as the Intertropical Front (ITF), but after the recognition in the 1940s and 1950s of the significance of wind field convergence in tropical weather production, the term "ITCZ" was then applied. When it lies near the equator, it is called the near-equatorial through. The ITCZ appears as a band of clouds, usually thunderstorms, that circle the globe near the equator. In the Northern Hemisphere, the trade winds move in a southwestern direction from the northeast, while in the Southern Hemisphere, they move northwestward from the southeast.





South Pacific Convergence Zone (SPCZ)
          The South Pacific Convergenze Zone (SPCZ) is a reverse-oriented, or west-northwest to east-southeast aligned, trough extending from the west Pacific warm pool southeastwards towards French Polynesia. It lies just south of the Equator during the Southern Hemisphere warm season, but can be more extratropical in nature, especially east of the International Date Line. It is considered the largest and most important piece of the ITCZ, and has the least dependence upon heating from a nearby land mass during the summer than any other portion of the monsoon trough.




Effects on weather
          It may affect  the amount of rainfall in many equatorial nations resulting on the wet and dry seasons of the tropics. Longer term changes in the ITCZ may cause severe droughts or flooding in nearby area. In some cases, the ITCZ may become narrow, then, it can be interpreted as a front along the leading edge of the equatorial air. Within the ITCZ, the average are slight. Early sailors named this belt of calm "the doldrums" because of the inactivity and stagnation they found themselves in after days of no wind.




Insight and Reflections


Today I learned that-- monsoon rains are geographical phenomena caused by ciclic air movements changing with the time of year, and some of them are results of the seasonal shifts of the ITCZ and great seasonal temperatue and humidity differences between areas.
I will apply my learnings about-- the occurence of monsoon rains in the Philippines to be aware of its effects to my life.
Learning about these phenomena is important, because-- I will be aware and alert to the effects of this phenomenon.
On a larger scale, I will share my learnings about these phenomena to others-- so that, not only me is the one who can prepare and be responsible for incoming bad weathers, but also others and as a result i will be a model to others.
I need to know more about-- the effects of this phenomenon that may affect my daily lives.
BE AWARE AND RESPONSIBLE =)

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