Meteorology ATPL question

[MarkColeman]

Hi, im having a little trouble with this question:

Q: In the southern hemisphere what wind effect would you expect when flying from a high pressure area towards a low pressure area at FL 100?


A) Headwind with no drift

B) Wind from the left

C) Wind from the right

D) Tailwind with no drift

The answer given is C - wind from the right.

Now, unless i'm way off the mark, the key to answering this question is that the wind blows anticlockwise around a high pressure area in SH, and clockwise around a low?

So if youre flying towards a low, and the wind is coming from the right, then you must be approaching the low from the east? (i'm visualising the wind literally blowing like a clock)

If that is the reasoning behind the answer, then should it not specify in which direction youre flying?

If someone can clear this up for me itd be much appreciated! :ugh:

[Whirlygig]

I might be wrong but I think this is Buys Ballots!!

With your back to the wind in the Southern hemisphere, the low pressure is on your right.

Cheers

Whirls



Awaiting my Met failure result!!!

[MarkColeman]

Ah yeah thats what it is...thanks!

i think ill just go bury my head in the sand now....

[londonmet]

Just remember - from whatever direction you fly towards a low pressure area you'll always have a wind from the right, in the SH.

[ATPMBA]

To solve that problem I drew a high-pressure system and a low-pressure system on a piece of paper along with the aircraft ground track. I set up the pressure patterns as you would find in the Northern Hemisphere. I solved the problem for the north and then reversed my answer for the south.

[YYZ_Instructor]

It doesn't matter which direction you are flying!!!

No matter how you draw it on paper if u draw a line from the centre of the high to the centre of the low the wind will always come in from the right in the southern hemisphere. Draw it in many different positions and you will see that direction has no part in this question. The faster you understand that concept the quicker you will be able to jump these questions and help u focus on the harder ones.

Good Luck! :ok:

[MarkColeman]

heres another one guys:

You are flying over the sea at FL 250 and measure an outside temperature of -50°C. The pressure at sea level is 1023 hPa. What is your approximate true altitude calculated using normal vertical change in temperature with increase in height?

(a) 23230'

(B) 26770

(C)26230

(D) 23770

answer is D....can anyone enlighten me as to how to work out that exact figure?

thanks!

[OW LEE]

FL250 =) 1013 hpa
1013 hpa =) 1023 hpa = +270 ft
Outside temperature at 25270 ft should be -35°C

True Alt= Alt with 1023hpa + 4x (outside t° - Std t°)x alt in thousand ft.
= 25270ft + 4x -50° - (-35°) x 25
= 23770ft
:ok:

[MarkColeman]

thanks mate,

dunno how i missed that formula when i was studying the met book

[captain_rossco]

you're not in the exam right now are you Mark? lol

:ok: