 So Nina is joining us from India and she also gave a talk about monsoons last week, thank you so much for that. And she's at the, please remind me of the institution I just lost it at Pune, that's right, at the Indian Institute of Science Education and Research. Thank you so much for stepping in. We're looking forward to your talk. Thanks Judith. Thank you for the opportunity for this talk. So today I'll talk about equitable leave so I think in the first talk itself, we found that how important those are for the tropical predictability. So today I'll talk about the modulation of connectedly coupled Kelvin waves by the NGO or different geographical domain. So my screen is visible right. Yes, it's not yet full screen but it is well visible. Okay. Okay, so what we are looking at here is the symmetric raw by background spectra of OLA in the tropics. So you can see the significant variance associated with the NGO, and, and there is a very large variance associated with what we call Kelvin waves. So those two modes are the most dominant modes of tropical convection and explains a lot of propagating disturbances in the tropics. So here you can see the coherence spectra in OLA and you wait 50. So those also show the convectively coupled nature of these two modes are very pretty. So the first and the second largest modes of tropical variance is explained by these two modes and you're being interested in the time scale, planetary scale be number one to six, and convectively coupled Kelvin waves can what we call is much more like in our way number and shorter spatial scale and higher frequency three to 20 day time scale we can identify that. So the properties of these waves, what how it separates from the NGO is mainly in how the meridional wind component. The NGO is a planetary scale tropical mode of variability and propagate slowly. CCKW is more equitably confined and propagation is much faster, and the shorter spatial scale and higher frequency time scales as we read it. The NGO is known to modulate the CCKW activity several studies have reported that some studies have also indicated that a residue of NGO convective activity over the specific is what initiates the convectively coupled Kelvin waves, which propagates to tropical Pacific and Africa. So, and the synoptic scale and miso scale disturbances activity is also modulated by the NGO up. And likewise, the convective phase of CCKW is also known to modulate the synoptic and miso scale disturbances over the specific Amazonia and Ecuador Africa. So, this does the interaction between these very close by tropical scales of variability is very important. So, here we are looking at the NGO variance and the CCKW variance the Kelvin wave variance. So, we get in oil are you can see that there is significantly large variance associated with the NGO with the one for and the Pacific is a very strong center for CCKW activity, along with the like in general we have very strong activity along the IPCC. You can. One of the earliest studies by Rondi in 2008, they explore the NGO modulation of CCKW or the Indian Ocean domain, and they found that the CCKW convective phase is higher when there is active phase of NGO. They also found to be a slower relatively slower propagation during NGO connectivity active phase, implying the role of connection circulation coupling. So, we are now focusing on total three different geographical domains, the Indian Ocean, the Pacific Ocean and the Atlantic Ocean, and trying to see how the NGO is modulating the CCKW activity in the different geographical domains, along with like trying to understand the face of NGO whether it being the NGO being convictively active, convictively suppressed or the NGO being weak, how the CCKW activity is affected by that. So, let's identify how the CCKW events used the filtered indices for NGO and CCKW over these domains, and based on whether it crosses a threshold for a certain number of days. We can identify the total CCKW events like for three consecutive days if the CCKW index falls less than minus one, then we can call it as a CCKW event and if it occurs together with the NGO index being less than minus one or greater than minus one or with having a very low probability of being 0.5 to minus 0.5, then we categorize it into whether the CCKW is occurring with NGO convictively active state, suppressed state or weak amplitude state. So, this is the basic statistics of CCKW events what we obtained. So, here you can see among the three domains, the highest number of CCKW events are observed over the Pacific. Of which about like 37% of the CCKW events over the Pacific occur when the NGO amplitude is weak. Higher number of events are associated with the NGO convictive active state as compared to the NGO suppressed state. Between the Atlantic and the Indian Ocean, about like 40 to 41% of the CCKW events occur when the NGO amplitude is strong, either being in the convictive suppressed or active state. And similar to the Pacific, you can see that over the Atlantic, there is a greater preference for NGO being in the active state, the CCKW activity is more when the NGO being in the active state but such a big difference is not observed or it's more kind of an opposite preference over the Indian Ocean domain. So, there are differences in the CCKW activity over the different domains that is one important factor. And there is differences between or just preference for the NGO state whether it is convictively active, suppressed or whether NGO is in general weak. So, we'll try to explore the dynamical features associated with these Kelvin waves over the three domains. So, this is the composites based on the different events, whatever we have identified. And this is based on unfiltered OLR and wind anomalies and overlaid on top of it is like the convective phase of spacetime filtered CCKW or just to indicate that the other presence is there. So, based on the events like around those events, whatever we have identified, there's the pattern. And we can see that the CCKW pattern is discernible in the unfiltered anomalies when the NGO is weak. So when the NGO signal is there, it kind of overpowers the pattern in the unfiltered anomalies. That's the reason we cannot make out the Kelvin wave structure there. But we can clearly see that the method captures the CCKW events and associated NGO events. So, let's move on to look at how the main spatial temporal structure of the CCKW evolves along with the NGO active suppressed and weak states. And this is done by a lead light composite of those events. So, we can see the CCKW propagation in all the three cases. The main difference what we can say is that the CCKW propagates more eastward, it's more evident in the whole molar diagrams, that more eastward the propagation when the NGO is connectively active. So, the observed higher amplitude of CCKW and the NGO amplitude is strong, clearly indicates that there is some linear interaction between the NGO and the CCKW. So, this is over the Indian Ocean. Now, we move to the Pacific Ocean. So, here we can see there is a officultural structure of the Kelvin waves as it moves eastward. And the CCKW structure during week, NGO amplitude is similar to that of the theoretical Kelvin wave and there's a negligible marital wind component associated with it. And now we move on to the Atlantic. So, things are a little bit different over the Atlantic. The spatial and temporal scales of CCKW is different, it's shorter spatial scale and higher temporal scale CCKW are found over the Atlantic. And it propagates the CCKW convective events propagates slower when the NGO is a convectively active over all the three domains not here. So, we will summarize on the phase speed of this way so the three domains for the different NGO active suppressed and weak faces. So, we can see here that in general there is a faster propagation of Kelvin waves over the Atlantic as compared to the other two domains and comparing between the NGO active suppressed and weak phases in general when the NGO is weak. There is a faster propagation and there is a difference in the phase speed during NGO active and suppressed state. So, what could be the possible factors which might be influencing the CCKW phase propagation. One could be the differences in the convection circulation coupling strength over the different domains and over the different states associated with the NGO. There could be the differences in the vertical structure of the waves itself. And third factor we examine is the gross moist stability over the different domains. So, we'll see how these are related to the CCKW phase speed or the three domains. So, first we are looking at the coherent spectra of convection and circulation, low level convection and circulation so it is a good metric for quantifying the convection circulation coupling in the wave number frequency space. So, we have used the coherent square values and averaged over the CCKW times scale at each pressure levels and that is what is indicated. The larger coherence is observed. So, these are the set of states which is corresponding to the strong NGO amplitude which is associated with the larger coherence values, which indicates more stronger coupling and the convection circulation coupling is weak when the NGO amplitude is weak. So, there is some role of the NGO amplitude or there is some influence of NGO amplitude and the total convection circulation coupling and the phase speed of the waves. So, it doesn't really explain like why there is variation in phase speed across the different domains. And then we're going to the next factor we are examining is the vertical structure of CCKW. So, we are looking at the relationship between phase speed and vertical structure is given by this relation and you can see this is in the temperature anomalies associated with the CCKW and in the Indian Ocean as well as the Pacific Ocean. So, you can see the strong second baroclinic vertical structure, which with a very significant tilt, and it is much larger over the Indian Ocean domain than that over the Pacific. But over the Atlantic we don't observe that it is more kind of a first baroclinic vertical structure, and there is a higher vertical scale, which is consistent with what we observe as the higher phase speed over the Atlantic Ocean, Atlantic domain. So, this indicates that the vertical structure of the waves over the three different geographical domains is different, which can have an influence on the phase speed. But it doesn't really like to have an idea about like why how it is different for the different NGO states. So, third factor we are looking at is the normalised growth GMS or gross moist stability index which is used as a metric for measuring the NGO moist mode. So, you can use it for the tropical other tropical moist modes as well. So, we check the NGMS values, the vertical component of NGMS is calculated and we can see the vertical component of NGMS is having a very strong relationship with the phase speed. So, it's for the different NGO states over the Indian Ocean Pacific Ocean and the Atlantic Ocean are indicated by these dots. And you can see that there is a strong relationship between the phase speed of these waves over the different domains for the different NGO states and the value of the vertical component. So, lower the value or less positive the value of the NGMS indicates slower phase speed of the waves and it means that it can be used as a measure of a metric for the NGMS and CCKW phase speed variation over the different domains as well as for different NGO states. So, this is one of the studies which we are exploring and soon to be submitted. And summarize, we have looked at the CCKW convective phase variation, how it is influenced by the different NGO phases over the Indian Ocean Pacific Ocean and the Atlantic Ocean. Amplitude and phase speed of the CCKW both get modulated by the NGO activity. CCKW convective phase propagation is slower when the NGO is convectively active and among the factors we have examined the vertical structure that is connected to circulation subcoupling and the NGMS and it is NGMS is found to have a strong linear relationship with CCKW phase for the different NGO states over the different domains and stronger connection circulation coupling is observed when the NGO is active. There are also differences in phase speed and differences in spatio-tentral scales over the domain such as CCKW is a dispersive disturbance and NGMS might be a useful metric for assessing the properties of CCKW and climate models are just like we use it for the NGO. So, I think I'll stop here. Thank you. Thank you very much for this detailed view on the relationship between NGO and CCKW. So I have a question, would you tell us a bit about the implications for predictability over the Indian component in these different phases? Predictability, sorry, I forgot. Predictability over the Indian component in those different phases. Okay, so the activity, the convective Kelvin wave activity over the Indian Ocean is quite strong and there is a difference as compared to the Atlantic and the Pacific as to when it is like over the suppressed state it is more active, the convective coupled Kelvin waves is more active. So on sub seasonal to seasonal timescale, I think this would have like importance in terms of like how this small scale to like next larger scale variance is distributed like so if you can understand how the NGO is influencing the CCKW downstream and into like synoptic or miso scale disturbances, I think that is very crucial for the like you know organization of like what we have convective systems over the Indian Ocean which is very crucial for the Indian subcontinent. Thanks very much. Anish. You know, it was very interesting. Especially the other connection between NGO CCKW and NGMS like the instability coming from moisture mode right. So, the question was related to the Pacific versus the Atlantic and the NGMS plot you had towards the end I think. So here, I was wondering how strong is the coupling between convection and dynamics in the Pacific versus Atlantic because the NGO itself, the convective part of the NGO signal stops around the date line right. In one way, it does propagate through the East Pacific and Atlantic. Does the convective signal of the CCKWs over the Atlantic. Does the strength of that resemble what's over the Pacific. So the convection circulation coupling over the Atlantic and Pacific, we don't see much difference. Like it's, it's there like you know that a strong coupling over the Pacific and the Atlantic for the CCKW, but not for the NGO. So, how like this is something which we will have to explore further to get a clearer idea about like how the CCKW is influenced is different over these two domains the and how it is influenced by the convection circulation coupling. Thanks very much. Thanks. Other questions. Yes. I don't see any hand right now. Can I check if Sergei is back. So, I am. Oh, you are. Oh, that's great. All right. So, are you ready. Prepare to give you a talk now. Okay, so before Sergei goes, let's, let's thank Nina again. Thanks so much for this. Thank you. Thank you.