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Why No Cyclone in South Atlantic and South-Eastern Pacific Region?

Vajiram Key says - Because water is too cold
Shankar key says - ITCZ seldom occurs

Found article which support ITCZ option.

http://www.aoml.noaa.gov/hrd/tcfaq/G6.html

Condition for Tropical Cyclone:
High Temperature ~ 26 C -
Low Pressure

It seems both temperature and ITCZ can contribute to Cyclone.
What could be authentic source?

Comments

  • vaji key... link?
    2014- PRE
    2015 - PREPARING
  • As per vajiram , 1&3 is the ans for question oj babur... Bhagwan kare ki upsc bhi agree kare....
  • As per vajiram , 1&3 is the ans for question oj babur... Bhagwan kare ki upsc bhi agree kare....
    I have read it in satish Chandra medieval book.. don't worry... that's the correct answer
  • Equatorial counter current pe Shankar and vaji differ..baki sab same hai dono me..to bhai batao kya hoga iska answer.
  • he has specificaly gvn regions wch r in cold current area so it should b bcz of low temp...nt sure as many ans keys gvn abt ictz
  • Koi geography specialist?
  • sir plz think.. all those regions western margins have cold deserts. because of cold current... which implies sea surface temperature is low there... that's why it is not able to establish low pressure area
  • One of the greatest mistakes is to judge policies and programs by their intentions rather than their results
  • The answer is sure shot, the sea surface temp option.
    I had written this exact point while making notes. See this map.

    https://upload.wikimedia.org/wikipedia/en/4/40/SST_20131220_blended_Global.png

    The sea surface temp are low in western coast of South America and South Atlantic. This hampers development of cyclones.

    ITCZ is a trigger mechanism for hurricane formation, not one of the primary factors.
    CSE 2015. Got in.

    CSE 2016. Hopefully, the hallowed All India Services.
  • I second @INeeDtoGetIn
    For cyclone formation, the most important factor is SST. A cyclone derives its energy from that only, though ITCZ shift is one of the causal conditionality.
  • Correct so SST is final.
    2014- PRE
    2015 - PREPARING

  • 1) In the South Atlantic and South-Eastern Pacific regions in tropical latitudes, cyclone does not originate. What is the reason
    A) Sea surface temperatures are low B) Inter-Tropical Convergence Zone seldom occurs
    C) Coriolis force is too weak D) Absence of land in those regions
    View Answer
    Answer : Sea surface temperatures are low

    http://www.quizzerhub.com/Question/Q3/CC00122121-In-the-South-Atlantic-and-South-Eastern-Pacific-regions-in-tropical-latitudes,-cyclone-does-not-orig.php
    Its ok to fail once but Dont Quit..else how will u taste the sweetness of the success that awaits you if you Quit !
  • As per vajiram , 1&3 is the ans for question oj babur... Bhagwan kare ki upsc bhi agree kare....
    I have read it in satish Chandra medieval book.. don't worry... that's the correct answer
    Sorry Bro . Satish chandra mein mention hai ki Gun powder is of chinese origin and was introduced by chinese in India . Gun powder was usd by Mongols during 12 AD and they were the ones who came to subcintinet with this technology . Babur was known for his artillery and canons . So only option 3 is correct .
  • As per vajiram , 1&3 is the ans for question oj babur... Bhagwan kare ki upsc bhi agree kare....
    I have read it in satish Chandra medieval book.. don't worry... that's the correct answer
    Although even i have marked it 1 and 3. Its wrong as satish chandra says Babur used gun powder and in the very next line he says it was already known to India.Sorry .Pg 139
    Optional hai Geo ,magar ye Geene nahi deta
  • TCFAQ G6) Why doesn't the South Atlantic Ocean experience tropical - http://www.aoml.noaa.gov/hrd/tcfaq/G6.html
  • As per vajiram , 1&3 is the ans for question oj babur... Bhagwan kare ki upsc bhi agree kare....
    I have read it in satish Chandra medieval book.. don't worry... that's the correct answer
    Although even i have marked it 1 and 3. Its wrong as satish chandra says Babur used gun powder and in the very next line he says it was already known to India.Sorry .Pg 139
    Gun Powder question is very famous in my state psc examinations.It is Babur 100%..Ask any history professor you will get to know details...

    Any fool with a bit of luck can find himself born into power.

    But earning it for yourself, that takes work.
  • As per vajiram , 1&3 is the ans for question oj babur... Bhagwan kare ki upsc bhi agree kare....
    I have read it in satish Chandra medieval book.. don't worry... that's the correct answer
    Although even i have marked it 1 and 3. Its wrong as satish chandra says Babur used gun powder and in the very next line he says it was already known to India.Sorry .Pg 139
    Gun Powder question is very famous in my state psc examinations.It is Babur 100%..Ask any history professor you will get to know details...

    panipat battle was the first battle where it was used and it was the main reason for babar success and ibrahim lodhi had no answer for that!!

  • edited August 2015
    As per vajiram , 1&3 is the ans for question oj babur... Bhagwan kare ki upsc bhi agree kare....
    I have read it in satish Chandra medieval book.. don't worry... that's the correct answer
    Although even i have marked it 1 and 3. Its wrong as satish chandra says Babur used gun powder and in the very next line he says it was already known to India.Sorry .Pg 139
    Gun Powder question is very famous in my state psc examinations.It is Babur 100%..Ask any history professor you will get to know details...

    panipat battle was the first battle where it was used and it was the main reason for babar success and ibrahim lodhi had no answer for that!!


    https://en.wikipedia.org/wiki/History_of_gunpowder
  • I agree with Vajiram on C. Equatorial Current. Also, it is because of low temperatures the ITCZ wont shift farther from equator in south as compared to North.

    ITCZ is a combined effect of the angle of insolation and the temperatures of the region. The ITCZ is checked proper by the cold waters of the south.

    In a way low temperatures is the mother of all affecting the phenomenon like - ITCZ, cyclones,

    I also agree with Vajiram key on Tax/GDP ratio. It could mean a hell lot of things. We cannot say if the GDP is increasing or decreasing with the decrease in the Tax to GDP ratio. So economy can wither be growing or decreasing. As for the second option I think fall in tax to GDP ratio will reflect increase in equitable distribution for Raise in GDP

    That the equatorial current will flow towards east with respect to earth because earth is rotating towards east is the most idiotic logic applied by many coaching centres. It is like saying you are pushing a block on a surface and another block on top of the block being pushed will move faster than the block which is the cause of the motion.

  • edited August 2015
    Why it does not occur will come second , first tell why it occurs , ???
    what is the most imp condition of its occurrence in only tropical sea???

    Why it occurs only around august in indian ocean , why not in June or july ???

    Water is hot even in June , but why not in June ???

    Any one who knows these question can ans why it doesn't occur in south Atlantic ocean ,

    thanks , jis ko jo lega laga lo apne apne hisaab se ;)) ;))
    It is not the eyes that are blind but the heart
  • Now this says the prime reason as land distribution. Option d. Haha all options seems correct for this question

    The eastern South Pacific is just about as void of activity as the South Atlantic, due largely to the ITCZ also having a tendency to stay near or north of the equator, and to climatalogically cool sea surface temperatures. Of course, one can then ask why are these factors aligned in such a way, which would make for a very long answer - the short version is they are all the result of the shapes, sizes, and distribution of continents and ocean basins, together with the character of the landform surfaces, and the Earth's tilted rotation axis and not quite circular orbit around the sun.
    Read more at http://www.wral.com/weather/blogpost/1672862/#vom86BIiYJteCumH.99
  • The most important factor for tropical cyclone, from where it derives its energy is convection currents. The convection currents are possible only if there is intense heating. Low temperature is the most important factor for a anticyclonic region. Please go through cyclogenesis from any standard source. No heating = No cyclone.

    Even if something like ITCZ occurs to the south of tropics in Southern Hemisphere, Cyclones can still not form, Why? because ITCZ is also called a region of doldrums where cyclogenesis doesnt happen, instead of intensifying the convection currents, the region just gets filled up(sentence from Phy Geo NCERT). Cyclones always form a little north or south of ITCZ.

    Land doesnt matter, (read extra tropical cyclones from Phy Geo NCERT). Extra tropical cyclones happen over high latitudes in Northern hemisphere and are generated over land or ocean. Whereas in tropics, cyclones only happen over water bodies. So land is not necessarily a pre condition for formation of cyclones.

    Coriolis force is not weak as south pacific/atlantic is near poles.

    Answer is low sea temp

  • edited May 2016

    As per UPSC ans is ITCZ seldom occurs.. all explanation corresponds to sea surface temp here except that noaa link. I am finding it difficult to understand, can some one with geography optional explain ITCZ phenomenon and how this explains the question? NCERT dont' explain it much and this noaa link is talking too much technicalities. @ mrintech @ Maverick33 @Inspector_Steel

    @Captain_Peroxide
    I marked answer as Low Sea Temp.. I m just trying to explain what u r asking.

    ITCZ=>Trade winds converge here.(N &S)+low pressure as both converging air rises

    Wind Shear=>change in movement of wind in short distance of time in normal parlance known as spreading of air which occur due to downdraft of air(subsidence of air and spread of air afterwards.It may be upward direction also but it will be of spreading type not converging type which is required for cyclone formation)

    Why Atlantic and SouthEast Pacific have no ITCZ=>ITCZ movement depends on various factor among the few are land and heat. Since there is no land in Southern Atlantic and South East Pacific regions+sea temperature is also not that high due to 1.cold currents 2.Not enclosed as Indian Ocean(hottest ocean)+Lack of ITCZ(also affects wind shear as it is a low pressure zone if it is missing then a subsidence zone would take its place.)

    If u check image it shows Southern Indian Ocean and South West Pacific oceans do have cyclones in Southern Hemisphere the reason is land+warmth of the oceans








    Hence UPSC answer focuses on the primary reasons for formation of cyclones in which ITCZ suits the most as it explains both parts ie.Wind Shear & Sea Surface Temp which are required for Cyclone formation so ITCZ is most appropriate option.
  • edited May 2016

    As per UPSC ans is ITCZ seldom occurs.. all explanation corresponds to sea surface temp here except that noaa link. I am finding it difficult to understand, can some one with geography optional explain ITCZ phenomenon and how this explains the question? NCERT dont' explain it much and this noaa link is talking too much technicalities. @mrintech @Maverick33 @Inspector_Steel

    @Captain_Peroxide bhai.. Cyclogenesis ke liye there are few conditions which needs to be fulfilled..

    The primary criteria being High Sea Surface Temp. (>~26.5) ( reason being, obviously, high evaporation rate and high surface air temp. thus making it lighter and creating low pressure); So if SST is less than this then forget about a tropical cyclone, as anything less can't sustain such a large heat-exchange system.

    image

    Now, for a moment forget about the UPSC question.. And look the SST map of global ocean, you will see Eastern margins of oceans have less temp. than western margins, due to cold currents/upwelling. So you would conclude that, chances of cyclones originating in eastern margins is very less.. (though east northern pacific- around mexico, do originate few cyclones - looks like Californian current isn't very strong)
    *This still doesn't explain why Western margin of South Atlantic lacks Cyclogenesis!

    image


    But SST was the basic prerequisite for Cyclone development.. The next important criteria is there has to be a low pressure area around which surface air converges... This can be fulfilled by i) Presence of ITCZ ii) Front that has moved from mid latitudes towards tropics iii) Presence of tropical waves (it is bit complex so no need to understand)
    When cyclone originates in our Bay of Bengal, it is due to the ITCZ passing over it towards north with the corresponding movement of Sun.

    Alone ITCZ and SST still can't guarantee a tropical cyclone.. Cause if ITCZ is passing over Equator, absence of Coriolis force will allow the surface air to fill the low pressure region without giving the rotational feature which is very essential for cyclone development.. As no Coriolis, no deflection, and thus no circular rotational movement of surface air and so NO sustainability of Low Pressure system.. Thus ITCZ has to be away from equator.. And this is what happens in case of Western South Atlantic and Eastern Pacific!
    Now see the map of ITCZ + SST and you could easily guess regions where cyclone is not feasible..

    image


    One other factor which also affects cyclone formation is Wind Shear... That is : When speed of winds vary across vertical or horizontal distance..
    As cyclonic system needs to be develop vertically, especially the eye wall which develops till around tropopause to properly sustain the latent heat exchange system., If there is vertical wind shear, it will move higher parts of this eye wall disproportionately compared to lower part and thus tearing apart the vertical development and cyclone will die out.. This is also an important region why East coast of Brazil/Western South Atlantic don't have cyclones as there is very high wind shear..

    Excuse the highly resolved images, couldn't get to resize and thought it's helpful to visualize.

    Cse 16,17,18 : Interview*
  • So you mean to say that both are responsible surface sea temp and movement of itcz
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