<blockquote>
  <p>Update:</p>
  
  <p>Granted the question has been asked in different form; but the answer
  still escapes me. </p>
  
  <p>At one place I read that locations in question have low sea-surface
  temperature. At another place I read that due to land positions (or
  lack thereof) causes wind to not gather speed.</p>
  
  <p>The answer mentioned in duplicate-suggestion-question are related to
  vertical wind shear. </p>
  
  <p>Plus, my question is which of the following four options would you
  pick and why and why not others.</p>
</blockquote>

<p>This was an MCQ in a recent exam, with only one option being correct:</p>

<ol>
<li>Sea surface temperature are low.</li>
<li>Inter-tropical Convergence Zone seldom occurs.</li>
<li>Coriolis force is too weak.</li>
<li>Absence of land in those regions.</li>
</ol>

<p>I have doubts as:</p>

<p>Sea surface temp are a tad bit lower in those regions. Also, the ITCZ seldom crosses southwards. (Am I wrong?)</p>

<p>Coriolis force is good in 5 degrees to 30-40 degrees. (I think)</p>

<p>Since, there can be only one option true, which one is true?</p>

CC BY-SA 3.0
2017-06-09T09:57:23.917Z
NOT a good question, and I entirely disagree with gansub's answer.  All we can do is definitely rule out 1) and 3).  [This](https://en.wikipedia.org/wiki/Sea_surface_temperature#/media/File:MODIS_sst.png) and [this](https://en.wikipedia.org/wiki/Sea_surface_temperature#/media/File:WorldwideTCpeaks.gif) clearly show SSTs are fine.  Coriolis increases with latitude equally in both hemispheres.
JeopardyTempest
CC BY-SA 3.0
2017-06-09T10:04:06.430Z
However, the ITCZ does not generate many of the Earth's TCs... and in fact [this](https://en.wikipedia.org/wiki/Intertropical_Convergence_Zone#/media/File:ITCZ_january-july.png) graphic suggests it's located similarly in other SHEM basins.  It's responsible for a percentage of storms in other basins... but so are land-caused features like African waves and diurnal convective cycles. That makes 4) just as fair to me (though no less right).  (of course frontal [and monsoon] troughs are a third unmentioned option common for TC generation). Point being, none of those answers look reasonable to me.
JeopardyTempest
CC BY-SA 3.0
2017-06-09T10:06:27.110Z
It's indeed shear.  As to why so much shear, that's really the fundamental question, and don't know off the top of my head, but interested for a more in-depth answer.  If we say there was a lot of shear in the Atlantic basin causing decreased TCs, people want to know why.  It's reasonable to say we don't know... but people don't like that as an explanation, and seasonal forecasts would disappear in smoke (as perhaps they should given their rather low skill and usefulness!) if such a huge factor had no foundational explanation.  The answer may indeed be "it just works out that way"
JeopardyTempest
CC BY-SA 3.0
2017-11-24T22:54:20.063Z
@gansub Did something change that I should be looking at?
JeopardyTempest
<temperature><tropical-cyclone><coriolis><cyclone>
In the South Atlantic and South-Eastern Pacific regions in tropical latitudes, cyclone does not originate. What is the reason?
Anubhav
# In the South Atlantic and South-Eastern Pacific regions in tropical latitudes, cyclone does not originate. What is the reason?

(Asked by: username_0 on 2015-09-03)

> Update:
>
> Granted the question has been asked in different form; but the answer
> still escapes me.
>
> At one place I read that locations in question have low sea-surface
> temperature. At another place I read that due to land positions (or
> lack thereof) causes wind to not gather speed.
>
> The answer mentioned in duplicate-suggestion-question are related to
> vertical wind shear.
>
> Plus, my question is which of the following four options would you
> pick and why and why not others.

This was an MCQ in a recent exam, with only one option being correct:

1. Sea surface temperature are low.
2. Inter-tropical Convergence Zone seldom occurs.
3. Coriolis force is too weak.
4. Absence of land in those regions.

I have doubts as:

Sea surface temp are a tad bit lower in those regions. Also, the ITCZ seldom crosses southwards. (Am I wrong?)

Coriolis force is good in 5 degrees to 30-40 degrees. (I think)

Since, there can be only one option true, which one is true?

**Tags:** temperature, tropical-cyclone, coriolis, cyclone

> **Comments:**
> **username_1**: NOT a good question, and I entirely disagree with gansub's answer.  All we can do is definitely rule out 1) and 3).  [This](https://en.wikipedia.org/wiki/Sea_surface_temperature#/media/File:MODIS_sst.png) and [this](https://en.wikipedia.org/wiki/Sea_surface_temperature#/media/File:WorldwideTCpeaks.gif) clearly show SSTs are fine.  Coriolis increases with latitude equally in both hemispheres.  
> **username_1**: However, the ITCZ does not generate many of the Earth's TCs... and in fact [this](https://en.wikipedia.org/wiki/Intertropical_Convergence_Zone#/media/File:ITCZ_january-july.png) graphic suggests it's located similarly in other SHEM basins.  It's responsible for a percentage of storms in other basins... but so are land-caused features like African waves and diurnal convective cycles. That makes 4) just as fair to me (though no less right).  (of course frontal [and monsoon] troughs are a third unmentioned option common for TC generation). Point being, none of those answers look reasonable to me.  
> **username_1**: It's indeed shear.  As to why so much shear, that's really the fundamental question, and don't know off the top of my head, but interested for a more in-depth answer.  If we say there was a lot of shear in the Atlantic basin causing decreased TCs, people want to know why.  It's reasonable to say we don't know... but people don't like that as an explanation, and seasonal forecasts would disappear in smoke (as perhaps they should given their rather low skill and usefulness!) if such a huge factor had no foundational explanation.  The answer may indeed be "it just works out that way"  
> **username_1**: @gansub Did something change that I should be looking at?  

---

## 0 answers

