meteorology , and -degrees N and semi permanent low pressures tend to form at S,

ID: 294680 • Letter: M

Question

meteorology

, and -degrees N and semi permanent low pressures tend to form at S, while semi permanent High pressures tend to form at degrees N and S 1.) - and 2.)are cells of generally vertical air movement in the atmosphere, in belts around the Earth. 3.) In the atmosphere, where air currents converge in the borders of Hadley cells will form. These shift north and south with the seasons 4.) Surface ocean currents are wind-driven, and form large scale in the oceans. -degrees to he nght of the However, large scale VERTICAL movement of water is? surface wind in the northern hemisphere. This is call ?? ed an current. 5.) What is the difference between ZONAL and MERIDIONAL flow in the jet stream? What is it called when the flow cuts off (and what are cut-off ridges and troughs called)? 6) Briefly describe EL NINO, LA NINA. Why is it important to monitor these TE 7.) Define size: a. Micro- b. Mes0- c. Synoptic- d. Planetary "Remember (ties into last week):

Explanation / Answer

When flow cuts off in a jet stream, means air of polar origin is cut off from the main subpolar belt of low pressure and cold air, either cut off low (cyclonic) or cut off high (anticyclonic) air circulation pattern develop. Both follow normal track of depressions. A cut off low begins as a trough and a cut off high begins as a ridge. In both the cases the circulation is blocked, associated with disturbed weather conditions, thunderstorms.

6. El Nino and La Nina both are manifestation of ocean – atmosphere coupling and phases of El Nino Southern Oscilaton (ENSO) .

El Nino is the warm phase of ENSO, where warm water pools in eastern Pacific equatorial rim and cold water resides in the Western Pacific.

While La Nina, refer to the normal situation – warm in the west and cold in the east.

El Nino also gives the following effects in the Eastern Pacific – strengthening of trade winds, deeper thermocline, high sea level, floods. Reverse effects are seen in Western Pacific.

Both these events are the most important weather event because these are the largest source of year to year fluctuations in global weather pattern. Not only Pacific, all the other oceanic circulation, monsoon frequency, temperature, wind pattern are largely controlled by these two. Because El Nino causes lower upwelling in Eastern Pacific, the fishery industry is also largely affected. That is why these events are monitored with utmost importance.

7. The size of the scales must be understood in terms of both time and distance, refer to the table.

scale

Time scale

Distance scale

Micro

Seconds to minutes

< 1 km.

Meso

Minutes to hours

1 – 100 km.

Synoptic

Days to weeks

100 – 5000 km.

Planetary

Weeks or longer

1000 – 40000 km,