[Gwo And Global Angular Momentum]

Thanks for the interesting update BF.

I don't know how this may affect things, but I reckon that the stratospheric vortex has more than reformed since the severe disruption in January. Looking at the mean zonal winds we are now running above average for this time of year throughout the whole height of the stratosphere. Does have any bearing on your thoughts?

c

[Gwo And Global Angular Momentum]

Yes thanks to both GP anb BF.

This explains very well why (apart from the initial split) the MMW has not led to the blocking some of us would have preferred. The low angular momentum (perhaps from a more diffuse downwelling of stratospheric negative wind anomalies due to the persistant westerly QBO) coinciding with a weak La Nina state have contrived to prevent northern blocking patterns that every mid range forecast even seemed to suggest.

This to me makes perfect sense with what we have seen on the ground and is another illustration of why we need all the troposheric fastors to be favourable to achieve maximum benefit from a SSW.

c

[Gwo And Global Angular Momentum]

Promising posts thanks GP and BF. I will keep an eye on the potential vorticity charts in the next few days to see how they change. So for those who can look further than the short term variable model outputs still a lot to look forward to with some potential wintry weather possible into March. I didn't think this SSW would give up that easily without something more to show so fingers crossed!

c

[Gwo And Global Angular Momentum]

That slightly tricky to answer. Lets try to answer the second question first.

Fast, zonally oriented Rossby wave dispersion occurs in phase 5. (Amplified Jet)

An extended Pacific Ocean jet stream and southward shifted storm track is observed in phase 7 (strong flat jet over the pacific)

A retracted Pacific Ocean jet stream is a key feature in the total field is observed in phase 3 (Weak pacific jet)

Phase 1 has enhanced subtropical jets and closed lows in the subtropics.

Angular momentum being added usually results in a stronger jetstream I think.

As for how angular momentum is measured and what level then I think it is from the winds at all levels up to 10hPa with those at the jet stream level being important.

GP will probably have a few more details.

Thanks for your reply BF.

So at present we would like to see the GWO in phases 1-2 which supports higher latitude blocking.

Do other teleconnection factors such as MJO phase and ENSO state affect angular momentum?

C

[Gwo And Global Angular Momentum]

Thanks for that good read BF. I think that you have just made global angular momentum as easy to understand as I have seen but that does stir me into wanting to know more!

Is the angular momentum measured at sea level or cumulatively throughout the whole troposphere?

Also, do we get greater levels of angular momentum in flat jet or greater amplified jet scenarios, or is this more dependent on the track of the jet and subsequent surface troughs, across land masses and mountain ranges?

Regards and a Happy New Year.

c