 So, I'll try to show you today something from the speedy perspective. And I'm trying to analyze NSU-Europe teleconnections with an intermediate complexity model which is developed here by Franco-Malteni and his group. And I've been using it for a certain time and with the help of my collaborators. So my special thanks are going to Cedro Branković, Martin, Fred, Bianca and Paolo. They helped me a lot to analyze this topic. So when I have started with NSU Impact on North Atlantic European region, we didn't know as much as we know now about NSU Impact on Europe. We know that earning a certain oscillation is a strong generator of climate variability all over the world, but there is quite clear impact on North America. But NSU Impact on North Atlantic European region is not an easy task. We know that over the North Atlantic sector there is a large internal variability of the atmosphere and that complicates our investigation. And also we know that Europe is influenced by other phenomena, North Atlantic oscillation, which is much stronger over that part of the world. And there is also interactions with regional seasonal cycle, with chaotic properties and there are a lot of feedbacks. So to analyze NSU signal over the Europe, it's really complicated sometimes. If you try to Google NSU Impact on the world, you will probably find some figures like this. So you may recognize that NSU Impact depends on the polarity of NSU phase. So we have different impact during the El Nino or warm or during La Nina or cold phase. But there is also a difference between seasons. So winter season is quite different than the summer season. But you can recognize here that there is a quite strong and clear impact over the North America and South America, Australia, Africa. And during La Nina, which is the opposite phase of El Nino, we have almost the opposite impact of NSU. But what I'm concerned about is that there is no clear impact over the Europe. We know that El Nino and La Nina's impact is associated with changes in jets, which brings the warm or moist air over the continent. But over the Europe, there is no signal on these maps. So I'm wondering if there is any impact of NSU on Europe. I think that NSU does have an impact on Europe. If that's not true, then it could be quite embarrassing for me because I claimed a lot of time in my papers that there is a certain impact of NSU on Europe. But recently, Met Office put these figures on their website. And you can see that there is a signed impact on this part of Europe during El Nino and La Nina events with weather conditions associated with El Nino and drier conditions associated with La Nina. So I hope or I'm flattering myself that our papers contributed at least a little bit to this figure. But if you look at the temperature impact, then the impact, NSU impact on Europe is not so clear. So you can find that there is a dipole response over the Europe in temperature. But only when strong events are not included in analysis. Sometimes for La Nina temperature impact, the signal is very weak. So we don't have any significant anomalies here. If you look at the local impact of NSU, here on this figure, you may see the temperature anomalies averaged over the northern part of Croatia for two La Ninas. These two La Ninas are almost of the same amplitude. But the first year is associated with extremely warm events, extremely warm conditions over the northern part of Croatia. And the second one is associated with extremely cold. So results are sometimes controversial on regional and on local scale. When all things have started, this is one of the famous results made by Frederick and Miller. And they found in observations that El Nino situations are more connected to cyclonic type of weather over the Europe, while La Nina is associated with more anti-cyclonic type of weather. So there are many observational and modeling studies that showed that there is a detectable NSU signal over the Europe. But it is seasonal dependent. And they mostly investigated winter season, because we know that there is the strongest answer in the Pacific. And there is also possibility of flagged or time-delayed answer impact on Europe, which means that we need to have some slower component of climate system involved, which can memorize the answer anomalies. So what is the physical mechanism from the observed and modeling point of view? We know that propagation of Rosby waves from a region of tropical connection in the Pacific toward the extra tropics can explain that tropospheric pathway of the signal. But there is also some stratospheric link, which means that stratosphere is also sensitive to NSU forcing, and that can contribute to that link from the tropical Pacific to the Europe. But from the modeling point of view, we see that there is some investigations have showed that we need the models with high resolution to obtain good enough NSU signal over the Europe. But on the other hand, some of them showed that we need models with fully resolved stratosphere to get that stratospheric link between tropical Pacific and Europe. But what we did, we tried to model NSU impact on Europe with speed. Speed is ICTPHCM. It is quite simple model, or it is an intermediate complexity model with quite coarse horizontal and vertical resolution. It has only eight layers in vertical, which means that only two of them could be named as stratosphere because the upper layer is at the 30 hectopascals. But what we show that speed is quite so successful used in many of investigations from climate dynamics. And it seems that speed is capable to reproduce NSU impact on Europe as well. So now I will try to explain you how we made our experiments and why we did it in a certain way. So we started with also forcing of European climate investigated with quite long speed simulations. So we produced 35 member ensemble of very long integrations. And after that, we divided that period in El Nino and La Nina years according to Nino 3.4 index. And in tropical Pacific, you may see that there is an average wintertime La Nina with amplitude of minus 1.6. And wintertime El Nino is here with amplitude of 2 degrees. If you look at the speedy precipitation response in tropical Pacific, you may see that in spite of the fact that the amplitude of the forcing for cold and warm and so phase wasn't similar, the response is not the same, which means that here the La Nina response is two times smaller than the response for El Nino. And precipitation maxima is shifted a little bit westward relative to the maxima of SSDs. But what's going on on the global scale? Here you can see the response in the potential high at 200 hectopascals. And you may see composites for La Nina and the La Nino. And you see here that there is a quite strong response over the Pacific and North America, which projects under the P&A pattern. El Nino response is quite linear, which means it is placed over almost the same place, but it is stronger. And there is also precipitation response, which is in line with that geopotential high anomalies. If you look at the Europe, there is a quite weak signal here, but it is still here. If you look more closely to the Europe, you may see that response in mean sea level pressure is stronger for El Nino than for La Nina, but it is spatially linear. It is placed over the same position. And during La Nina, precipitation anomalies are a little bit weaker in La Nina, but you may recognize here during El Nino events that precipitation is increased over the south in Europe and decreased over the northern part of Europe. So after that, we were worrying about influence of other oceans than tropical Pacific. We know that Atlantic is more closer to Europe and that may have some impact. That's why we made another experiment. And this is experiment which is called tropac, because we used the SST anomalies constrained to tropical Pacific. So in control experiment, we have prescribed SST anomalies globally. And in tropac experiment, SST anomalies are constrained only to tropical Pacific. If we look now at the response over the Europe, you may see that for both La Nina and El Nino, the tropac experiment gives really similar results as that control experiment, which is confirmed with spatial correlations, which are quite high and statistically significant, which means that these results, which we obtain in control experiments, we can believe that it really comes from the tropical Pacific. So the influence of the other oceans is not so important in that simulation. So we can summarize that ANSOC has a detectable and statistically significant impact on the North Atlantic European region, which has been confirmed by observational studies and with this modeling point of view with a model of intermediate complexity. So we can remember that El Nino impact during the winter is associated with more cyclonic type of weather over the Europe and with anti-cyclonic type of weather during La Nina events. Now we would like to know what could happen in a warmer climate. So speed is obviously capable to reproduce an ANSO response over the Europe. But in warmer climate, we designed a double CO2 experiment. And we put the CO2 to double values. We took the SST climatology and CIs from a global coupled model. And SST anomalies were the same as in control experiment, which means that the internal variability of SSTs are the same. But the SST and CIs climatology are shifted according to double CO2 concentration. So here you may see that there is, of course, warmer sea surface in that experiment. And CIs is decreased over the polar regions. So what are the results? Here you may see the difference between the double CO2 and the control run. And there is increase in mid-sea level of operation over that part of Europe, and decrease over the southern part, which is also may be seen in precipitation. So in this experiment, in warmer climate, it seems that precipitation over the southern part of Europe will be decreased, which is in quite good accordance with the results performed with the coupled model of higher resolution. So it's really similar. Maybe some amplitudes are not the same, but the pattern is quite similar for both models, which confirmed us that speed is doing quite good job in warmer climate. But what is with ENSO impact in warmer climate? Here you may see that the precipitation for cold and for warm composites in control experiment and in the warmer climate. So you may see that we can expect, at least from the speed perspective, that there will be some increase in precipitation signal over that part of the Atlantic. But I may stress here that the signal is much stronger over the North Atlantic than over the continent. So why is that? If you look at the zonal wind at 200 hectopascals, you may recognize here that the zonal wind over the North Atlantic is increased over this part compared to the control simulation, which means that during the El Niño, the stronger winds means that we have a stronger eviction of warmer and moisture air over the continent, which will produce more abundant precipitation there. So we can conclude now that speed has shown that there is an influence of ENSO North Atlantic European region from winter season to wintertime climate over the Europe. So now we would like to show if there is possibility that ENSO has also a delayed impact on European climate, which means that is it possible that wintertime ENSO somehow could be memorized in some part of the climate system and survive until the next spring. We know that for that we need some slower component of climate system because atmosphere reacts very quickly to some forcing, but also the memory of atmosphere is up to one month. So we cannot expect that ENSO signals survive only in atmosphere for one season or for three months. For that experiment, we performed the experiment with forcing in tropical Pacific to have an ENSO forcing, but we also used the possibility of speedy to activate slab mixed ocean layer in North Atlantic. So in that way, we allowed RC interaction in the North Atlantic. Here you may see the correlation between principal component of first EOF mode of MJ precipitation, which is spring precipitation over the Europe, and JFMSST anomalies. And you may see that variability of spring precipitation in Europe is correlated, is positively and significantly correlated with SSDs in tropical Pacific, which indicated us that tropical Pacific may be a source of variability for the spring precipitation over the Europe as well. If you look now at the other correlations, you may see that there is also correlation between wintertime SSDs in North Pacific and springtime SSDs in North Atlantic. And here is a dipole pattern produced, which means that during the positive ENSO, we have this kind of SSD pattern in North Atlantic. It is also, Nino 3.4 index is correlated to be to mean sea level pressure over that area, and of course, with this zonal wind. Now we may say now that this pattern, SSD pattern, is serves as a link between the wintertime ENSO and springtime European climate in that way that this SSD pattern survived until the next spring and then produces the anomalies in sea level pressure and also in zonal wind. Increased zonal wind in this area means increased advection of moisture over the continent, which produces the increased precipitation over the continent in spring. So now if we compare the modulate, the results from the speedy and from the observed composites, you may see that mean sea level pressure obtained in El Nino and for speedy and for hardly mean sea level pressure are quite similar. The same is true for La Nina events. So speedy produces quite similar results to the observed mean sea level pressure pattern during the spring. These composites are based on wintertime ENSO index, which means that we categorized the years according to wintertime ENSO index but looked at the springtime response. So now we can conclude that at least based on speedy simulations, springtime climate over the Europe is influenced by ENSO as delayed ENSO influence, which means that wintertime ENSO produces some AMJ anomalies over the Europe. But there is also contemporaneous ENSO influence, which means that springtime ENSO entropical Pacific may force springtime climate over the Europe as well. To distinguish these two impacts, we performed another two experiments. The first one is the mix of winter ENSO experiment. In this experiment, we prescribed SST forcing in tropical Pacific only during the winter, allowing that wintertime ENSO forcing. And we also activated mixed layer in North Atlantic. And the other experiment is the mixed summer ENSO experiment where we allowed SST forcing in tropical Pacific only during the summer, which means only during the spring summer, which means that there is no chance that we have delayed ENSO impact on spring or summer. Now, if we look at the composites for these two experiments, for summer SST forcing in tropical Pacific, we obtained this response in precipitation. But when we have winter SST, the response is quite different. So the precipitation is increased over the Europe when we have wintertime SSTs in tropical Pacific. If we now look at the contour experiment, we see that in contour experiment, we have continuous SST forcing in both winter and summer. There is also the continuous response over the European continent. In contrast to this one where there is a negative anomalies between positive, if we look at the crew precipitation, which are more or less observed precipitation over the continental part of Europe, you may see that this result for wintertime SST forcing in tropical Pacific is more similar to that for crew data, which means if we have SST anomalies during the winter in tropical Pacific, which means that we allow ENSO forcing during the winter, that we obtain more realistic response. So that delayed ENSO impact from wintertime to the springtime is really important. So at the beginning of this talk, I told you that some studies have showed that we need resolved stratosphere to obtain realistic ENSO impact on Europe. So what is going on in the stratosphere in Speedy? We know that Speedy has really crude representation of stratosphere with only two layers in the model. But if we looked at the temperature response for El Niño minus La Niña composites, you may recognize that during the winter, there is a warming in polar stratosphere over the Northern Hemisphere, which is in line with other results observed as well as modeling results. In the same time, you may see that there is a northern annular mode response in zonal wind over the Northern Hemisphere, which is campaigned with warming in polar stratosphere. So it seems that Speedy in stratosphere is quite consistent with some other models and with the observations. After that, we performed some idealized ENSO forcing with daily data to analyze persistence of ENSO signal in both in stratosphere and at the surface. So here you may see some results for temperature index, which is average temperature over that polar cap. And there is also some zonal wind index, which measures the strength of the zonal wind anomalies. And here we may see that ENSO signal is quite persistent in stratosphere. And it is also persistent in zonal wind. And although the forcing was prescribed in that way, that it is constant in January and February, the signal is still here during the march. And we showed also that based on calculated heat flux, that there is increasing incoming heat flux, which precedes the strongest polar warming, which makes that heat flux is responsible for that static polar warming in Speedy. So is this heat flux into the polar at 100 hectares? And 500 hectares. Into the regionally, into the polar cap? Yes. So now we have also the vertical cross sections for results with no slab ocean layer and with slab ocean layer in North Atlantic. In previous slides, I show you that we detected North Atlantic as importantly between tropical Pacific in winter and North Atlantic European climate in spring. So here you may see that if there is no ENSO, if there is ENSO forcing during the winter, but with no slab ocean layer, we have response both in stratosphere and in the lower part of troposphere. But if we have activated slab ocean layer in North Atlantic, this signal lasts for a longer time and survives until even the May. It may be also seen here in the Zonal Wind Index. So for the winter time ENSO impact on spring time European climate, it's important to have active North Atlantic. So partially, this delayed response is up to the persistence of the signaling stratosphere. But also the North Atlantic is that link which allows delayed ENSO impact on European climate. So now we can see how does an ENSO impact looks like from the speedist perspective. So we know that during the winter there is a tropical Pacific SST anomalies, which of course has an impact on tropical atmosphere producing rosby waves and also through the stratospheric link that the signal comes to the mid-latitude atmosphere over the Europe with cyclonic type of weather connected to ENSO events. And through the air-sea interaction, there is some North Atlantic SST anomalies which is connected with tropical Pacific through the atmospheric bridge, which is called after the law and that. And after that, due to sea air interaction in that North Atlantic area, there is also mid-latitude atmospheric response in spring time. And thank you.