walker circulation

[windycity]

im trying to make sure i have this right. Since we were experiencing a weak la nina , the walker circulation was stronger. Now that it looks like neutral conditions, the wc is there fore weaking? Will it continue to do so as we enter el nino maybe next year? The easternly trade winds have seemed to be a dominate feature this year so wondered if i had it right. Thanks!!

[Aquawind]

Here is the latest discussion..

http://www.bom.gov.au/climate/tropnote/tropnote.shtml

Australian and Indonesian longitudes have thus been the broad focus of tropical convection. Accordingly, most indicators suggest an enhanced Walker Circulation centred over the Maritime Continent region in recent months.

http://www.bom.gov.au/lam/climate/level ... elnino.htm

Paul

[windycity]

thanks! and if it weakens, could that be indicative of a el nino next year?

[benny]

In a sense you could also infer the displaced walker circulation this year from looking at the low-level anomalies on the equator:
http://www.cpc.ncep.noaa.gov/products/a ... 850a_c.gif

Basically there is a net divergence at the surface around 150w (where the blues (elys) changes to reds (wlys))... there pretty much has to be upper subsidence compensating for all that surface divergence... in a sense that is a representation of the walker circulation for the epac portion. As far as next year goes... El Nino averages once every three years.. last one was the winter of 04-05.. not unrealistic to guess 07-08...

[Aquawind]

Well looking at the graphics representing the Walker in El Nino versus Typical.. The Easterly Trades clearly weaken and switch to a ~westerly during the El Nino.

http://www.bom.gov.au/lam/climate/level ... o.htm#four

Paul

[benny]

Basically in the central equatorial pacific they have been stronger than average.. while in the eastern portion they have been weaker than average... the central pacific is where the strongest El Nino signal is. The strong trades occuring now w of 150w is a classic La Nina signal. Usually when La Nina weakens you can see some sort of westerlies impinging eastward from the WestPac but none have really done that for a long time. In more plain English... the westerly trades have to weaken west of the dateline and closer to Austraila probably for an El Nino to have any chance of forming.

[windycity]

thankyou !!! that makes sence, and i wanted to make sure i had it right.!!