 Here is wintertime and so impact on spring European climate. Mostly these results are obtained in collaborations with my dear colleagues, one of them here. And many thanks goes to them as well to the Franco-Multeney, because I used speedy as my main tool to investigate and so impact on European climate. So my talk, out of my talk is like this. First in the introduction part, I will explain you some winter and so forcing and our results about wintertime and so impact on European climate. Then I will explain your motivation to study that time lag, the wintertime and so to springtime European climate study. I will explain you shortly experiment design and also results about delayed and so impact. And as conclusion, I will provide you some kind of physical mechanism of that delayed and so impact. So we know that tropical oceans are strong generator of climate variability all over the world. I'm particularly interested in SOT anomalies in tropical Pacific and in Aesophases, both La Nina and El Nino and their impact on European climate variability. On this picture, we may see El Nino precipitation impact over the globe. And you see that the impact over the sun region in the world is quite clear, particularly over the Pacific North American pattern over the Australia. But if you look at the European region, there is quite weak signal. It is not easy to extract and so signal from the other influences over that part of the world. We know that North Atlantic European region is associated with large internal variability of the atmosphere. And there is also some other phenomena that might even have stronger impact on European climate like we know that North Atlantic oscillation has strong impact on this area. Tropical Pacific, particularly the Nino 3.4 region, is quite away from the Europe. And interactions with regional seasonal cycle, aquatic properties, complexity of a lot of feedbacks, they may mask and so impact over the Europe. But what we did in our experiment, one of the first experiment was to create large ensemble of speedy simulations. It was quite long simulations, and we tried to easily answer signal over the northern hemisphere. Here you can see the composites for La Nina and El Nino events for 100 hectopascals go potential high. And you see that the response of the Pacific North American region is quite strong. What is also the truth for the model is that the signal is symmetric, which means that action centers over the P&A region for La Nina and El Nino oppose over the more or less over the similar places, which may not be the true for the observations. But that's what we got with speedy. Also what we obtained for P&A region that the strength of the response is proportional to the strength of the forcing. If you look over the Europe, you may see that there is quite weak signal over the mainly over the North Atlantic. But at least we obtained that for El Nino, there is decreased anomalies and for La Nina increased anomalies, which is in quite good correspondence with some other studies, both modeling and observational studies. And it is which is also in line with the results of Frederick and Miller, who obtained that for the European climate, El Nino events are related more to a cyclonic type of weather and opposite for La Nina. So our speedy gives more or less good results even over the Europe. So what was the motivation to analyze time delay and some impact over the Europe? First, we obtained that concurrent ENSO impact was obtained in many modeling and observational studies. But there are also some studies that were indicated some time delay than ENSO impact. And that spring precipitation anomalies sometimes is even stronger than wintertime spring precipitation anomaly associated with ENSO. Then there were some quite big progress in understanding of observed and modulate ENSO impact have been made. And also, dynamical ENSO predictions have been improved. So if we found some correlation between wintertime ENSO and springtime response over the Europe, that might have an impact on seasonal predictions, hopefully. So what we made. Experimental design, we used observational data for precipitation as climate research. You will need to prove data. And then sea level pressure from Hadley Center. And we need SSTs and CI's climatology as input forcing for speedy model. Modulated data, we performed several targeted experiments. One of them is control experiment, which is based on 20 member ensemble of speedy simulations forced with observed globally prescribed SST in global oceans. Then we have mixed experiment, which means that we have SST forcing in tropical Indian and tropical Pacific Ocean. But also, we prescribed a slab ocean layer in North Atlantic to allow air sea interaction over that part. After that, we have mixed winter ENSO, which is the similar experiment like this one. But we limited SST forcing to the winter season, which is more or less extended winter from October to March. And also, mixed summer ENSO experiment with SST forcing prescribed in only during the summer part of the year. And here, there are some of results over the North Atlantic European region. So first, we may see that during the GFM season, which is winter season, we have La Nina and El Nino response, which is quite similar to that what Frederick and Miller obtained based on their observational study. And for La Nina, there is increased density level pressure. And during El Nino, it decreased, which is more or less cyclonic type of weather. Precipitation anomalies are in quite good accordance with density level pressure as they should be. So we have increased precipitation during El Nino years over the southern part of the Europe, while the strongest signal is over the Atlantic. The signal is quite symmetrical. But what we obtained over the Europe is that the amplitude of the response doesn't depend on the amplitude of the forcing. Because when we try to do composites based on strong ENSO events and moderate ENSO events, we didn't get much difference in amplitude of the response. So obviously, at least in speedy and in observation, we have concurrent ENSO influence on northern Atlantic European region. So the question is, is it possible that wintertime ENSO has an impact on springtime climate over the Europe? Here you may see the first EOF of AMJ precipitation for crew and for control experiment with speedy. They're quite similar. And we see that there is increased variability of the AMJ precipitation over the southern parts of Europe. So our question is, how tropical Pacific SST influences AMJ precipitation over these parts of the world? It could be done by contemporaneous impact, which means that springtime SSTs in tropical Pacific forces somehow springtime precipitation. There is also the possibility of time delayed, which means that wintertime ENSO has an impact on springtime precipitation over the Europe. So what we did to try to investigate if that delayed impact is possible, we calculated the correlation between the PC1 of MAJ precipitation, which is actually the measure of springtime variability of precipitation over the Europe with SSTs all over the world. And in tropical Pacific, we obtained the signal which projects on ENSO pattern. So this is the true for the crew data, but also for the control experiment with speedy. There is the MAJ2-JFM correlation. This is the contemporaneous correlation. You see that springtime variability of precipitation over the Europe is strongly connected to wintertime state of SSTs in tropical Pacific, but is not the true for the springtime, which means that the tropical Pacific during the winter has stronger impact than the springtime conditions in tropical Pacific. Excuse me, the correlation's value is about, it is go by 1.1. So here is 1.4. But they're statistically significant because we have quite a long time period. It is up to 1.4. The contour lines is 0.1, yes, 0.1, and 6. Yes. Yes, it's a dish one. Do you think it could be OK? Could be. Could be. You just need to check. So obviously, we have contemporaneous and delayed ENSO impact on precipitation over the Europe. So to focus only to one of them, we performed the winter and summer experiments. So in winter experiment, we allowed only delayed ENSO impact. And in summer experiment, we allowed only contemporaneous spring to spring impact. And what we obtained is presented here for summer ENSO. There, you may see that precipitation is decreased over the central part of the Europe. While in winter ENSO experiment, we have the more or less continuous band of increased precipitation over the Europe. If you look at the cruel precipitation, there are more similarity between this one and this one. The same is true for the control experiment, which give us an indication that for more similar ENSO response, we need winter time and so forth in tropical Pacific. So what is about the physical mechanism of that time delayed? Obviously, we obtained quite similar results between cool and mixed winter ENSO experiment. If we compare mixed winter and mixed summer experiment, then we can conclude that seasonal persistence of ENSO is not the key factor for that delayed impact. Rosby wave propagation mechanism, we cannot explain that because we know Rosby waves are quite quickly come to the Europe. So we need some intermediate physical mechanism. So we need some slower component of the climate system to allow that connection. And what we focused on is the role of North Atlantic. So what we have in our experiments. So mixed winter experiments on the first data left panel, you may see SSDs obtained in slab ocean layer. Obviously, there are some SSD anomaly pattern, which is also obtained in the experiment when we have the SSD forcing during the fall year. And that SSD pattern is quite in accordance with pattern of temperature, surface temperature, and also with the patterns of the temperature on higher levels. So you can see here that at 850 hectopark styles, the temperature pattern is something like here. Minus sea level pressure response to that pattern is in that way that we have decreased sea level pressure over the North Atlantic and just a little part of Western Europe. But as the consequence of such a mean sea level pressure response, we have increased pressure gradient and also increased zonal wind in this area. Increased zonal wind in this area means that there will be also the increased direction from the ocean to the land. And as a result, we obtain increased precipitation over that part of the Europe. So there's a physical mechanism that explains what's going on in our experiments. But there is also the question, what's going on in the same time in the speedy stratosphere? We all know that stratosphere is an important part in extra-tropical teleconnections. So we look at the speedy stratosphere. Actually, speedy doesn't have a real stratosphere, but at least it has some upper parts of the stratosphere. And for zonal wind, there are some composites for El Niño minus La Niña event. And for the zonal winds, we obtained that response projects onto not an annual mode in January, February, March, and April. So that pattern persists quite long. The same we also looked for the temperature. So the temperature response is associated with stratospheric warming during El Niño events. So polar stratosphere warms during El Niño and cooling during La Niña events. Because the slow stuff is very warming, no sudden. No sudden, no, no. They're only monthly means, so. After that, we just defined some indexes that may measure the strength of this pattern and also the strength of this warming. And what we obtained for the experiment where there is no slab ocean layer, you may see that there is some signal in the stratosphere which is persistent. There is also the signal at the surface. The same is true for zonal wind. We see that the stratosphere responds, but also the response over the surface. But if we include slab ocean layer in North Atlantic, then this surface anomalies last longer than in the experiments where there is no slab ocean layer. Which means that really something comes from the North Atlantic ocean. We have signal persistence in stratosphere, but also something from the interaction between the North Atlantic and atmosphere. To check if that it's really true, we also made another idealized experiment with SST-4, with SST-4 put in tropical pacific from January to mid-February. And after that, it was decreased and in March was zero. There was no mixed layer. This experiment was supposed to just to check what is going on in the species stratosphere. And we obtained that we really may see some stratospheric warming associated with SST-4 in tropical pacific. This is also the true for the wind. And we calculated daily meridional heat flux anomaly and obtained that this increased incoming heat flux preceded to the strongest power warming. So the maximum is somewhere here in February. And then the warming, the maximum warming is somewhere in the middle of March or a little bit later. So even speedy has quite simple stratosphere. It also contributes to that time delayed connection between tropical pacific and North Atlantic European region. So as a conclusion, I can provide you this sketch about mechanism. First of all, what we have, we have tropical pacific forcing and through the interaction, we have tropical atmosphere response. And by Rosby wave train and with the contribution of stratosphere, we also have some response in mid-platid atmosphere. Due to air sea interaction, there is SST anomaly pattern in North Atlantic which can persist for some longer time. And due to that SST pattern, we also have increased zonal wind and atmospheric response, which is here found as increased precipitation over the ocean and over this part of the Europe during the spring. So thank you very much.