Thu, 11 Mar 2010
METROCAST | 




SA REGIONAL




GLOBAL




INFORMATION




You are in: Weather > SA regional > Ecucation


SEA TEMP DIFFERENCES AROUND CT

Ever wondered why the ocean temperatures are so cold at Clifton and the Atlantic coastline beaches in summer, while at the same time the waters in False Bay are warm in comparison ?

Actually it is rather a simple explanation. During summer, the dominant wind direction is SE, i.e., the trade winds that blow from the SE towards the NW. The dominant South Easterly wind direction has two consequences :

However, let's first look at the action that the wind performs on the ocean surface. Without getting too theoretical, it is is sufficient to know that when wind blows over an ocean surface, a stress is induced on the ocean surface. In short, this means the wind "pushes" or "pulls" the surface layers of the water along with it. Hence, if we apply this to the Cape Town situation in summer the two consequences are :

  1. FALSE BAY

    The direct action of the SE wind is to pile up the warm surface waters along the Peninsula beaches such as Fish Hoek and Muizenberg. Hence water temperatures in summer approach the 22°C (72°F) mark.

  2. ATLANTIC COASTLINE BEACHES

    Just the opposite occurs here. The strong SE winds pull all the warm water AWAY from the coast. However, this water has to be replaced. In realitity the warm surface waters are replaced by very cold water from great depths along the Cape Peninsula. This water is usually in the realms of 10-14°C (50-57°F) and is known as "upwelled" water, for it has been "upwelled" from greater depths. This cold water is nutrient rich and is usually very clear and blue. So, the next time you wander off down to Clifton and the water is crystal clear, you can bet your bottom Dollar that it is going to be freezing.....If you think that this is cold, try swimming in the great Lakes of the USA in summer......

Keep in mind that the cold water is the result of the SE wind that has blown over the surface of the ocean for sometime. So whenever the SouthEaster has been howling, you can be guarenteed that the Atlantic coastline beaches are going to have freezing waters....but then the hot bods make up for that shortfall !!!!!


Click to view a larger image
showing the effect of the SE wind
on ocean temperatures

[ back ]

Search
Goodstuff



Goodstuff
ALEXANDER BAY 27/16
ALLDAYS 37/20
BEAUFORT WEST 32/17
BELA-BELA 34/18
BETHLEHEM 28/11
BISHO 31/20
BLOEMFONTEIN 32/16
CALVINIA 30/15
CAPE ST LUCIA 29/23
CAPE TOWN 23/17
CLANWILLIAM 29/17
DE AAR 33/18
DURBAN 29/21
EAST LONDON 30/23
ERMELO 28/12
FAURESMITH 33/18
FICKSBURG 28/13
GEORGE 25/19
GRAAF-REINETT 31/19
GRAHAMSTOWN 30/22
HERMANUS 25/19
JOHANNESBURG 30/14
JOUBERTINA 25/20
KIMBERLEY 34/20
KLERKSDORP 34/17
KOMATIPOORT 30/19
KROONSTAD 33/15
LADYSMITH 27/10
LANGEBAAN 25/18
LEPHALALE 34/20
LYDENBURG 28/14
MAFIKENG 36/19
MUSINA 38/21
NELSPRUIT 29/15
NEWCASTLE 29/12
OUDTSHOORN 28/18
PAARL 28/17
PHALABORWA 35/20
PIETERMARITZBURG 28/16
PLETTENBERG BAY 23/20
POLOKWANE 33/19
PORT ALFRED 29/23
PORT ELIZABETH 28/23
PORT ST JOHNS 28/19
POTCHEFSTROOM 33/15
PRETORIA 31/17
QUEENSTOWN 30/16
RICHARDS BAY 29/24
ROBERTSON 28/17
RUSTENBURG 32/17
SASOLBURG 33/14
SKUKUZA 32/19
SOWETO 30/15
SPRINGBOK 33/15
STILBAAI 25/20
SUTHERLAND 29/14
TZANEEN 33/19
ULUNDI 30/19
UMTATA 30/15
UPINGTON 38/23
VEREENIGING 32/14
VREDENDAL 28/17
VRYBURG 35/19
WELKOM 34/16
WITBANK 30/14
WORCESTER 28/16

 

| DISCLAIMER | FEEDBACK | ABOUT US | ADVERTISING | CONTACTS | SERVICES & PRODUCTS |

©COPYRIGHT 1995-2008, CUSTOMWEATHER,INC
San Francisco, California, USA
Your use of this site constitutes your acceptance of
the LEGAL RESTRICTIONS AND TERMS OF USE