 Our attention, many people's attention, to look into these problems, to look into the questions about the groundwater contributions. How much freshwater discharged to the ocean through the underground systems. So you know, our measurements at the beach very localised but ultimately related to that big questions, big questions that concern in the global hydrological cycle. I know someone's opinion may contradict yours. Where's my friend Alan? It's all about your perspective. Who are we and what is the nature of this reality? Five, four, three, two... What's up everyone? Welcome to Simulation. I'm your host Alan Sajian. We are on site at the beautiful Westlake University in Hangzhou, China. We are now going to be talking about environmental hydrology. We have Dr. Ling Li joining us on the show. Hi, Ling. Hi, Alan. Thank you so much for coming on our show. We really appreciate it. Pleasure. I'm so excited for this episode. For those who don't know Ling's background, he's professor in environmental hydrology at Westlake University School of Engineering, focused on mathematical modeling of complex environmental systems. And you can find the links in the bio below. All right, Ling, let's start things off with one of our favourite questions we like asking our guests. What are your thoughts on the direction of our world? It's such a big question. I don't even know where to start. But I read quite a few news articles about the big event around the world now on BBC reports about the global warming discussions in the UN summit. But prior to that, there were very, very serious protests around the world by the young people. And of course, this is quite related to my research work. Climate change has always been kind of the drive for what we do. So in a way, I was very pleased to see it. But I think the world has been undergoing changes, very rapid changes. I'm not sure all for good. And of course, in China, those changes occur to a much greater extent, also at a much faster pace. I often get asked about what I think about China's and development and even in the scientific research areas. And I use the word fast, always. So that rapid development around the world, I would say, has put so much pressure on our resources and our environment as a whole. Climate change is becoming more and more evident. There is a consensus, I would say, not just within the scientific community, but also in the general public, that this is becoming a big challenge, perhaps the biggest we're facing now, the whole humanity. And so you asked me about the directions of the world. I reckon we are facing this challenge. We have to do something about it. My research, looking at these hydrological processes in various systems, has a lot to do with climate change. And in many ways, we aim to look for ways to better assess the impact and look for ways of dealing with the impact, mitigations or self-adaptations of the systems. Yes. Yes, just yesterday we were talking to Ketchum on the show about sustainable industrialization and circular economics. And this is why I love Westlake. There's so many of these different components, tackling it from a bioengineering and sustainability standpoint, tackling it from an environmental hydrological standpoint, which we're going to unpack today on the show. I really appreciate the focus on taking care of this planet that sustains us. That's such an important, critical part of our life. So how about when you were a kid and how you even got interested in the environment, how you got interested in science, what were those main impact factors that got you interested? It was almost accidental, I would say. I mean, what I had in my mind about environmental science and engineering was quite ecological. I like math and I like physics and I had an idea that the degree program I chose, and that was offered at Tsinghua University, a top engineering university in China, I thought the program was oriented towards ecology more than pollution, problems we did, or I end up doing a lot. So somehow I went to the program with that idea, but it turned out the program wasn't like that at all. I initially lost a little bit of interest in my study with a big focus on the design of water treatment plants and so on. Of course, it's very important and it's a major research field in environmental engineering. We can see my pursuit of that interest to look at ecosystem has been ongoing. So the work I'm doing now, physical processes and so on, has a lot to do with the eco-health of the environment. So ultimately I want to see how water maintain the ecosystems and how the degradation of a coastal wetland may be linked to the change of the flow regimes. It may be linked to sea level rise, but of course through the modifications of perhaps the flow and salt transport or the flow and change of soil conditions such as aeration conditions, which will affect the plant growth and distributions and so on in a coastal wetland. So let's jump into this. So this is big for us to understand because we don't typically think about the ocean land interface and interactions being something that we want to dive deeper into studying. Many people just walk on the beach, but they don't actually think about how the ocean and land interface in a very complex way right at that region and how the hydrological cycle deals with that. So over the last 20 or so years you did your PhD at the University of Western Australia and then you've been specifically, a lot of your time has been at the University of Queensland since 2002 to 2018, so 16 years and you were doing senior lecturing and also then professing directly starting in 2005. Okay, so during that time you were really deep in working on this submarine groundwater discharge and that incorporates oscillating groundwater flow and the circulation driven by tides and waves. So let's start talking about this complex environmental ecosystem and how exactly you've spent the last couple of decades just diving deep into understanding that and what can be, especially what we can take away as like a big picture understanding of what's actually happening. Well, you mentioned the beach environment which we go to and enjoy our time there, but it's true a lot of the time we wouldn't go to the beach to think about the groundwater system underneath at all and yet you experience waves, these oceanic oscillations, they are clearly visible and in fact that's part of the fun we have at the beach. And yet for groundwater researchers for long we have pretty much overlooked the impact of these oceanic oscillations on the groundwater system. So the classical view of groundwater flow in the coastal aquifer is based on the assumptions of aesthetic sea levels with these oscillations neglected completely. We looked into this starting from 2006 with a PhD student project. We measured the groundwater flow in the intertidal zone of a beach in a great detail involving measurements of hydraulic head conditions, salinity distributions over many tidal cycles with the tidal oscillations resolved. So that means the measurements were taken at a relatively high frequency, intertidal signals were measured. And from that we pick up of course groundwater responses to the tidal oscillations but more importantly it's the time average effect that we're showing clearly in the measurements meaning when you average the groundwater flow there is a residual current in the result that indicate the tide not only induces oscillations of groundwater flow it produces a persistent flow that drives groundwater circulating through the upper intertidal zone near the beach surface. And of course in terms of salinity measurement we found the presence of a high salinity zone which we call upper saline zone. The importance of this very localized phenomenon, this feature of the system is that it can potentially control the exit conditions of a transport pathway for fresh groundwater but also for what's in that fresh groundwater. A lot of material is coming from the land largely in the soil form. So this localized phenomenon has implications for the determinations of freshwater discharge but also for fluxes of chemicals that are derived from the land because you know groundwater and ocean waters they're very different waters right. So one for example has very low oxygen content and that's groundwater and the other ocean water has relatively high oxygen content. The two mix will create conditions for reactions for chemical reaction. A lot of chemicals in a reduced form in groundwater coming in contact with oxygenated seawater can get oxidized. For example we were talking about ferrous iron being oxidized to ferric iron and precipitate. So you know a lot of reactions can take place because of the mixings induced by the tidally driven flows and of course you know this enhanced dispersions of as well. Yes let's also then dive into the last since now it's been since October of 2018 joining Westlake University as a professor of environmental hydrology and now having seven full-time researchers here at Westlake and you still have students and research fellows at the University of Queensland as well and I actually really enjoyed this understanding of how you're probing that ocean-land interface and interactions because you actually go and do field trips. This is a very fun part to science. I love this part. This is such a beautiful part. It's almost like a holiday on the beach. It's a holiday for you guys. For environmental hydrologists their field trip is literally to the beach and it's so great. So the field work I show you was done by my students and they had three weeks at a beach side near a resort and I think for them it was a holiday but it was a holiday of a lot of hard work. And let's talk about what exactly people will see here in this image that we'll have embedded. So you guys have, what are these rods that are inside of the sand and what are they measuring with this ocean-land interface? So they are, sorry, they were a set of sensors we've put in through these PVC pipes. And they were also samplers that are inserted to different depths of the beach sand within these PVC pipes. So for the sensors we measure the pore-water pressures. We measure also the salinity. We measure for some sensors we were also measuring dissolved oxygens. And in the same time we measure, in the same time we also sample waters for direct measurement of these physical, chemical parameters including even pH. And the aim is to look at the flow. The hydraulic head can be determined based on the measurement of the pore-water pressures and of course the complexity here is the salinity has to be combined in the calculations, has to be combined with the pressures because gravity here is an important drive of the flow but then gravity exists in an environment with variable density. Now it's a bit technical but I guess you can think of buoyancy force as perhaps the analogy here. If you have different density of course the force balance would be different and therefore in the calculation of the hydraulic head the density effect has to be taken into account. Nevertheless with the pressure measurements and the salinity we can calculate the hydraulic head the gradient of the hydraulic head will indicate the flow, the groundwater flow. In this case of course it could be just pore-water mixed pore-water with both freshwater and sea water involved. And the salinity measurement is not trivial. Using electrical conductivity probe sometimes requires a lot of calibrations in that environment and DO measurement is also not trivial. Remember this is in the sand. A lot of these probes they are built for clear water. So indeed in the pipe we had to design measurement chambers at different depths again in order to measure the representative local salinity dissolved oxygens fairly accurately. And of course to ensure the institutional measurements using these sensors these probes we also sample water for independent measurements to validate the measurements the data of these sensors collected by these sensors. And the measurement was taken over the tidal periods. In fact I think we did it for one particular field campaign we actually took the measurement over a period of three weeks covering the spring and neap cycle. So very intensive, very intensive. But then these measurements provide a picture of how the local flow processes involving recycling sea waters and then fresh water discharge. The discharge of water coming from the land to the oceans and even circulations of sea water in the lower south waterway driven by the density gradients have these three different kind of flow regimes interact. So I think it's necessary and indeed our measurement our initial measurement is involving a lot of hard work at the end kind of provide the pictures of that complex groundwater flow systems. Yes yes I like how you call this a global hydrological cycle that's happening I like how you showed me this really good gif that was being in that we can embed here where it's as though when the two meet this ocean land interface there's so much complexity happening there and you can you can simulate out what the tide from the ocean is doing to that ocean land relationship and you can you can see how there's this there's the formation of this saline plume that occurs and you can see how there's this meeting this meeting zone of the freshwater that meets the ocean water and the complex geo biogeochemical reaction that's occurring right there and that zone and how even further there's also this other really cool asset that you were showing me that we can embed here where there's a there's the relationship of these these groundwater aquifers that also interplay at these ocean land interfaces where there's actually an even small earthquakes have a lot to deal with the way that the fractures occur from the aquifers that enable the groundwater to come up deep aquifers that we're talking about yet and how it it's so fascinating how it literally it you also taught me this this phrase catchment hydrology and that there's these these gorgeous like like freshwater in catchment plumes that occur in normally like completely more saline a saline area areas and the grass was called kogan kogan grass it's a freshwater species yeah yeah so you know I guess we talked about how a beach groundwater system can be complicated by tide waves and lately we looked at the impact of the temperature differences between ocean water and coastal ground waters and of course we previously studied how even the beach morphology the shape of the beach can also influence how the groundwater flow in the near Shazam but the complexity of the groundwater system itself is also in that the aquifer may involve multiple units not just one shallow aquifer as we just talked about yes may not just be simply a sandy aquifer with the beach has been you know the seawall boundary underneath they may be confining aquifers confining units and and the confining units may be recharged by a remote source right from a distant area you you said catchment of course it's a very important concept in hydrology because it tells where the water comes from and quite often in catchment hydrology when we do water balance we assume the groundwater system has the same the shallow groundwater system has the same catchment as the surface water for a lot of hydrological system or for a lot of river basin this is possibly quite true but as I showed you right you know the field side we had in the Jansu province in a reclaimed land area next to the coast basically north of Shanghai north of Shanghai that system clearly is impacted by not only recharge from the local area but also a remote water source which goes through this deep groundwater aquifer with a leakage right wow that goes up into worlds to the local surface aquifer and potentially also discharged directly to the ocean as well and that will change the traditional view hydrological view based on you know the classical catchment water balance here we took an additional water could be large amount discharging to the oceans yes I think it you know and deep aquifers and catchment hydrology is one of one of potentially many other complexities of the ocean land interface yeah the the hydrogeology itself can be very complex right and and again that's the challenge and yet we we have to resolve this in order to quantify how much groundwater actually discharged to the oceans it is an important question because this effect our estimate of the return flow of water from the land to the oceans currently the estimate is is largely based on a river discharge groundwater contribution is assumed to be fairly small but will have more paper published in nature in 1996 attracted our attentions many people's attention to look into this problems to look into the questions about the groundwater contributions how much fresh water discharged to the ocean through the underground systems yes so you know our measurements at the beach very localized but ultimately related to that big questions big questions that concerning the global hydrological cycles why should you care about the water cycle the water cycle is a vital component of life the fact that we have water on this planet that is located in just this perfect habitable zone around the star that gives us water for life is that we're made of life that's so many that water sustains us that we drink every single day that the water cycle itself the hydrological cycle itself is so important for us to study to get these amounts for us so let's let's actually explain this exact amount so that right now it's approximated that 40,000 cubic kilometers of water is exchanged between the rivers and the ocean globally annually is an approximation but that's not taking into account the groundwater that could these deep aquifers all of these other potential styles of ocean land interface and so for us to get the true picture of that aspect of our water cycle is a critical way for us to realize the planet that we actually live in and on and how if we get a more clear understanding of our reality that's one of the most important things for us to do yeah science yeah I think your interpretation is actually fairly accurate almost accurate the 40,000 cubic kilometers as the annual amount of the water exchange between land and oceans the estimate is largely based on river discharge assuming the groundwater contribution is small but I think it is an open questions as to how much you know water is returned from the land to the ocean through the groundwater system still not resolved and it's important to have a good constraint on that figure I think we need to know more accurately what is the amount of water exchange between the land and oceans because it is the amount of water vapor flux the net flux from the ocean to from over oceans to over land roughly it's it's it's a large percentage it's 35% of the precipitation on the continent and you can imagine you know what we see in the river what we see in the catchment you know is quite driven by that flux so we need to know how much it is more accurately at the moment as already mentioned the estimate is only based on river discharge it water is also well water vapor is a greenhouse gas water vapor transport provides a key feedback mechanism for the climate for the climate change and hydrological cycle changes and therefore it is also for that reason we need to quantify the net flux more accurately because potentially you know if we underestimate this flux you can see that it means we have underestimate the role played by water vapor at a very large scale the global scale right so perhaps that also means we have under estimate the feedback played by water vapors as a way either to modify the climate systems both in terms of positive or negative feedbacks you know for a lot of reason we really need to have a better a better estimate of this net flux water exchange between the land and oceans yes especially the net fluxes yeah I'm surprised by how small of a volume the hydrological cycle right now is predicted to be compared to the entire volume of the earth of the earth okay but water mainly exists on justice in this let's say surface areas or near surface areas above and below yeah so and that's also where all the live forms okay so the majority of the live forms exist exactly so let's let's put it this way the surface of the planet being 70% water and 30% land or so and if you just take into account just the surface of the planet I believe 40,000 cubic kilometers is actually pretty substantial in comparison to just the surface as in 40,000 cubic kilometers being a part of the hydrological cycle annually is actually quite a bit regarding just the surface you can do it you can do a conversion of that so if we divide that volume by the surface area you get some kind of equivalent either evaporation or precipitations and then perhaps we can see how so it'd be somewhere around well but let's let me give you another way of looking at the significance of that figure that 40,000 cubic kilometers of water is equivalent very close to 35% of the precipitations on the continent yes you said which is very very important that's a very important figure just to make sure that this point is being communicated because it's such a profound one so okay the earth's volume is over a trillion cubic kilometers but I'm not sure what percent of that volume is on the surface let's just say only 5% maybe or even less it depends on the surface probably what you well what you define as the near-surface the near-surface area right if it is I guess I said five kilometers okay five or ten kilometers above and below yes okay we can I guess some calculation would have would it be 95% or 99% is located in the actual inner mantle and outer mantle core cool yeah yeah and even even the deep crust yeah deep crust okay so okay so that let's let's just say and someone can help us in the comments below and tell us about these numbers but let's just say that it's somewhere around 95 or 99% of the volume yeah okay so I ran the calculation a trillion divided by 95 or so is 10 billion so it's still significant even if it's 99 if you're divided by 98 still 10 billion so then 10 billion of the kilometers cubic kilometers of the planet are located on the surface or the edge surface area I think the volume comparison is not very meaningful and it might even because if you look at yeah if you well I mean even if it is I think it is still small but this ratio doesn't mean much at all when you look at the hydrological processes for example you know flow overland flow and then to the rivers generating flood and so on all these processes happen essentially on the land surface so then how do you calculate the volume of that area right it's a very small volume what what I'm saying is if you look at what happened on the land surface as as the key hydrological processes right when you have rainfall take in place it generate overland flow flow that take the water to the rivers and then of course water flowing the rivers which might generate flood and so on right this all these processes occur on the land surface essentially right within a very very small volume of space so the volume comparison I think it's not particularly useful of course you can argue that you know the the activity take place not just on the land surface there will be water going through the soil and and reach the groundwater and then you know somehow there will be some flow activity also underneath and of course you know you also can think about the rain as a process rainfall and precipitation rainfall and also evaporation as a process that takes place in the atmosphere as well but remember at the end right the the the key processes occur on the land surface so I don't think the volume comparison is particularly meaningful it is very true that this large amount of water exchange drive the major hydrological processes on the land surface yes which is what you see happening in the rivers in the catchments everywhere at different scales as well yes so yes yeah it is important yeah yeah yeah this was actually really enlightening for me to dive into that and hopefully for other people as well because we typically don't think of the diameter of the planet the volume of the planet we don't typically think about what amount of the the volume of the planet is actually only along the land surface as well as the ocean volume and then we don't think about what volume is moved in the hydrological cycle globally annually either and so these things are very interesting to try and picture what 40,000 cubic kilometers looks like that's moving in a hydrological cycle across the planet every single year and these are all very interesting ways of perceiving something that just seems to be not important but is actually critical to understanding our ecology so there's of course like you were explaining as well all of the other components that actually go into environmental hydrology and understanding the ocean land relationship is in the interface is so cool and how you guys go on the field trips to be able to start analyzing this is so neat I really want you to also explain how there's more to this that meets the eye again so when we look at dams so we had this example with that we were talking about earlier before we started with the three gorgeous dam in China which I believe was was producing the most energy out of all the dams on in the planet and was recently replaced by one that borders Brazil and Panama and so I mean in the numbers are crazy 100 terawatt hours per year wow and so we don't typically think about how when you put a dam down how it affects the ecology of the area and so teach us about how putting a dam here in China at the Yangtze River how that created environmental hydrological changes okay now building a dam can potentially also affect the processes at the ocean land interface because the flow will be modified by the dam operation as well but we haven't really looked into that effect yet I was involved in a project looking at how three gorgeous dam operation may influence wetland systems in two major lakes downstream Dongting Lake and Poyang Lake so the operation of the dam involving different discharge patterns or manipulation of the river discharge prior to and after the rain season can regulate cause significant changes of the flow in the rivers downstream the two effect of these prior to the rain season the dam will discharge more water than usual to kind of empathy the reservoir to some extent to increase its flood mitigation capacity to increase the storage and that occur of course prior to the rain season upstream but that rain season comes later than the rain the rainfall downstream downstream on the eastern side you know this whole area is affected by the eastern Asia monsoon all right which comes from the Pacific so it rains first for example in Poyang Lake around May or late May or June but it the rain affected by that monsoon system takes place upstream of the three gorgeous dams July or late June and therefore this time lack men when the reservoir discharge more water this kind of overlap with heavy rainfall in the lake area of Poyang so potentially the discharge can cause flooding or can worsen the flooding in the Poyang Lake area okay this is the blocking effect we think that can happen because of the regulations of the dam on the rivers it turned out this effect is rather minor based on our analysis of the data existing data but the second effect is after the the rain season the dam start to store more water so by reducing the discharge to raise the water level in the reservoir for hydropower generations and that means it will you know it will reduce the discharge and it will lower the river water levels at the lake at the lake mouth this lowered water level in the river can induce can increase the drainage of the lake water to the rivers causing potentially a dry conditions a drought we found based on the data analysis about a meter of you know overjoin or lowering of the lake water levels because of that effect so this is quite significant this could impact on the wetland systems in the project i was involved in our ecologist indeed found a trend of these wetland turning into dry land so you know it is quite amazing that the impact can be so visible and manifested in such a way in such short period of time and and i think it does give us a warning of running to this kind of unexpected problems uh because of the engineering work it happens i think quite often uh we we can easily overlook this impact uh totally yeah when we design you know the engineering project and and so on totally i have to say you know um the three gorgeous dam overall of course has also produced positive effect for example the power generation you've mentioned compared to burning fossil fuels yeah but there's a next there's a next step of sustainable energy advancement that we're going to get to yeah because there's significant you can't just put a dam this is a really again just a very important way of viewing it we were talking about this again yesterday with catch and just you can't think that if you're going to dump wastewater into a river that it's going to have no downstream effects but you got to know that it's going to have downstream effects everything's interconnected same thing oh let's build a dam here well it's going to have ecological and hydrological effects on the environment not only at where you put the dam but also downstream it's going to have effects and so humans thinking with this indigenous principle of seven generations out how is my dam placement here going to affect the environment seven generations down the line it's just a crucial way of thinking yeah i think it goes back to almost you know our initial discussion about uh what we're facing now uh the whole humanity right things change so rapidly we have developed all these technologies uh that enable human being to manipulate the nature so much i mean in the life science we start to manipulate life imagine how frightening that is but of course you know let's say in in my field you know not just the rivers but many other hydrological system have been our coastline for example has been modified significantly by humans our urban development along the coast in australia you know this is perhaps um the the the worst if i use the word example because 85 percent of the population live along the coast yeah so it made most changes that pop that's to the nature that statistic along the coastline essentially that statistic might be true across the planet yeah it might be 85 percent of people live along coast on the planet yeah that proportion probably yeah it's it's quite so um so you i mean you see this kind of modifications by us everywhere and i we literally live on the region of the world potentially almost nine out of ten of us live on the region of the world that you study so damn closely the ocean land interaction yeah depending on these statistics right if it is that such a majority of people do live in this region let's say eight out of ten people live coastly um within 60 or so miles of the coast then it becomes even more and more important for us to become more and more vigilant and and scientifically um uh advanced around our understanding of the ocean land interaction and relationship the hydrological cycle around those areas and uh also how to um decrease our fossil fuel consumption and increase our uh sustainable industrialization so that we can solve this biggest challenge that the planet is facing around how humans are our anthropomorph how humans are anthropogenically affecting the ecosystem that we reside in and we you know you've been listing all of these different ways that you're exploring this and understanding it and i really am just just deeply fascinated with this as well will you give us um two other thoughts that i want to ask you about or you know when we saw this graphic in grade school most of us saw this water cycle graphic that you have a precipitation that occurs from the clouds and then you have the water that flows from the mountains and from the river ocean to the ocean and then in the ocean the sunlight evaporate water the sunlight evaporates water which then rises and then that move to the land to the land and it's such a beautiful childhood but in a way it is that simple and it is that important as well like these big cycles um so um you know the net flux again is essentially um the key characteristic of that cycle as well the net flux is the word yeah the net flux is the amount globally that is being moved in the water from over the oceans yeah from over the oceans the net flux is is the water cycle movement the amount of water that's being moved from uh from the ocean over the land yeah my goodness 40 000 cubic kilometers right now is what we uh think is the number and it could potentially be much more and affected by could be could be more could be more and it could be but we don't know how much more that's and it could be affected by the um the deep aquifers and um and so many other uh aspects that we're still understanding yeah net flux what a cool two word okay what a cool use those words all the time net flux two words net flux and then water cycle of the water yeah yeah i like that a lot yeah this is an important environmental hydrological concept net flux yeah yeah i love that i love that this is this has been so enlightening i want to ask you also about um how you guys are using um computer modeling and the mathematical modeling um with simulations and with uh trying to see if uh can we potentially make like a digital twin of the planet earth and then and then see the uh hydrological cycle happening on that digital twin and then and then run um our calculations like throw different um variables and situations at it and try and and unpack and um how are you guys using simulations and mathematical modeling now for for my work um uh we uh we built uh mathematical models uh fairly well based uh because these models uh are based on the actual processes uh so the flow processes or the mass transport involving salinity uh salt solute uh and for the scale we're looking at um solving these models these equations uh is challenging can be time consuming but uh it's durable so uh the result i show you um you know was based on the field side we measure so at that scale i think mathematical models are very well based or process based mathematical models um can be developed to assist uh our understanding uh our investigation of these processes uh and the phenomena and so on but you also um ask about how we might do this on a global scale uh they are models i tell you they are models uh combining um uh atmospheric processes uh land hydrological processes and even uh ocean circulations uh really comprehensive models and uh and that uh you know also um aiming to assist our study of uh the hydrological cycles and so on uh and of course climate change or climate simulations uh but these the problem with these models um is that the resolutions uh it's impossible to resolve for example uh the small scale processes and characteristics of the system we were looking at uh we are looking at uh and therefore these models have to develop some kind of parameterization of the small scale processes in the large-scale model of formulations uh and the question of course then is how valid uh or how detailed the parameter the parameterization uh need to be uh for example a lot of land surface models for the hydrological processes uh are simply just based on water balance for the whole catchment some could even be bigger than a sub catchment and it doesn't resolve flows in the rivers um it doesn't resolve particularly the topography of the catchment and so on it can't uh computationally impossible um and then so this is the problem with the model in terms of uh its formulations um in some cases we know definitely the over simplification um is a problem that can't be resolved within the model itself and then of course also to run these models um they are data required um some of these models do consider different land users um but then of course to run these models you do need to have those data uh they're not necessarily all available worldwide some countries um can have good data set but some don't um so at the end what you will find is that the models these global models they can produce um some kind of prediction uh of course uh if you try to replicate uh observations from the past uh you know the model can be calibrated but you you you find you know often uh the results are subjected to very large degrees of uncertainties and that's the problem yeah I think I mentioned already um it doesn't uh none of the model predict quite accurately the amount of waters uh you know discharged to the ocean from the land uh that is an indication of uh you know problems in these models models are very useful uh models are often you know very useful tools for us to investigate these processes but the the challenge of course is to um develop a sound model um with enough details uh uh you know resolutions uh especially and temporarily to represent the processes uh still within the constraint of assumptions but nevertheless more compatible to the questions uh been addressed uh but then as I said models need to be driven by data uh which can be a problem uh in many applications of these models yes we need structured data for the models to be better and we also need the right computational structure and resources for the proper simulation process of something as complex as a hydrological system I mean this is going to be a massive advancement for us once we figure out how to make a digital twin of the earth and then analyze it and then be able to add specific uh uh tweak specific variables and see what happens or add specific phenomenon like the rise in parts per million of co2 all this type of stuff all these types of digital twin modelings of the planet um a couple quick questions on the way out that we like asking our guests how do you think we can increase collaboration around our world to me collaboration uh happens almost quite naturally um I think you know we may be assisted by good policies uh from funding bodies um from the universities and of course at the national levels good agreement between countries and so on but I would say uh you know science is something that connects people uh and enable them to collaborate almost by its own power that's what I mean by naturally um but I would say good policies uh will enable people to do that better and at Westlake um collaboration is part of uh what we do um is everything basically uh uh starting with uh very very active uh um communication among ourselves we talk to each other all the time exchanging ideas um um yes and and of course uh you know discussing our work and so on uh and that enable within Westlake very cross disciplinary approach to thinking identifying the problems and to formulating approaches to uh to addressing these problems and carrying out the research the actual research uh I mentioned this news and idea session yeah uh chaired by professor Tenshi uh it's it's a fantastic mechanisms and at Westlake we also have good policies to encourage uh you know staff members to collaborate not only within ourselves but also with people outside um it has a lot to do with evaluations of the performance uh you know these uh these days uh university and then individuals uh are so driven by metrics for measuring the performance of academic uh these are not particularly good and in China sometime we try to be so accurate um in allocating uh you know the credit to people in the research that we have to um decide only the first author or the corresponding author will take the credit and no one else that's clearly not very helpful for collaboration so at Westlake we we don't care about that at all we can double or we can triple count the credit I think that's the way to go um yeah especially since on all of these advancements in our world the burden of genius that has been associated with the advancement of our health care advancements or any technological advancements quantum mechanics whatever it is that it's not like just some first author there's there's there's there's a tremendous amount of people that were part that part took in that advancement plus um there may be some sort of like a first author or someone that carried more of the burden but then there's thousands of other people that have continued um pushing that advancement into the world and making it applicable for us some a couple more questions um do you have children I have one son one son how old is your son a 13 and then what would be a skill for your son and other kids that are being born into the world that you think is important for them to know going into the exponential technology age critical thinking I'm worried that kids are now doing so much uh but think less so to me um and and even for my childhood I had time to to think um well it's it's a problem for kids but it's also a problem for adults as well we're becoming so busy um and think less yes so I would say critical thinking is something we need to um emphasize in our educations in our training uh being spoon fed media uh and entertainment rather than uh enabling ourselves to have long periods of focus creativity free association doing nothing yes because you know when you're busy uh yeah well at least days if you go to I have more questions I have more questions if you go to a restaurant you see people just doing things on the mobile phones and so on in the past we probably would just stay there you know like this uh but somehow probably thinking a couple last rapid fire questions to ask what are your thoughts on the meaning of life I don't know I've been thinking about that as well seriously so um I don't have an answer but I think it's a questions we all have deep in our mind and our heart so I think sometimes that kind of questions can drive you to some kind of belief because at the end I don't think myself or science can help me to acquire that kind of question answers to the question I think one of the most important things to do is to have more people around the world asking themselves that question what is the point of life what is the point of this grand human experience what is the nature of this reality that we're in what is the unique gift that I can bring forward into the world and if we forget to ask that question forget to ask children to think about those questions but at the personal level when you talk about values and so on of course we all have our value but then I don't think that itself will give you the the answers to the question you just asked what is life right or what is the meaning of life so um yeah I don't have an answer for myself that's why I think some belief religious belief can help with that I um uh you know I'm I'm a person who's very keen to seek answers to that question uh very very keen like it's yeah totally yeah and um last three we got to do these fast because we have uh we have to run what is the role of love in our world interesting questions now you know in in China we have a word called Yuan Fen or destiny now it's if I just interpret it yeah it could mean that it's a special relationship so uh to me uh you can talk about how uh you know at at one level of course let's say between wife and husband um that love is special that relationship is special but love of course can be um broader much broader than that but I also think you know it's a special relationship um you know like what you have um as a special relationship with your work that's also love uh and of course even with colleagues with this university and so on I would say that's also love um in substance maybe that special relationship carries a lot of um uh you know common values common goals and share responsibility to achieve something together and of course uh on the way great enjoyment shared by both parties or even more parties uh that's what I think what love is or the rule it's a special relationship with all these ingredients uh yes do you think this is a simulation even our reality reality uh uh I think we we manipulate how to say it if you use the word simulation I think that that is kind of meaningful in a way because the reality is what we perceive so we already intervene the real reality if there is one um I would say using simulation is perhaps not a bad word not completely wrong put it that way and simulation trying to relate this almost to my word I would say it's kind of accurate because when I try to simulate the the processes for example right they seem to be rules I have applied strictly but the result the simulation result right could be subjected to errors uh you know at the very low level but it could be subjected to even the very basis of the models I'm not trying to challenge those conservation laws but certainly for a lot of models we also need to conceptualize how the system may function what's involved right and I'll say our perceptions our understanding of the reality is a bit like that it's a modeling process uh perhaps with some truth uh in it but taking science as an example right they are hypothesis uh hypotheses tested but even from the history we know tested only within constraint of whatever technology at the time whatever capacity we have whatever knowledge we have at the time so I would say simulation is perhaps not a bad word to describe it yeah yeah and last question is what do you think is the most beautiful thing in the world most beautiful thing um I see beauties in a lot of things but the most beautiful one like I even appreciate the beauty of waters and so on in in different ways but the most beautiful thing maybe we can go back to the word love a special relationship you develop with a lot of things including the family of course um so yeah it could be because you ask for one single beauty and the most I would say love but love interpret in you know that very general way it's a it's a special relationship you have uh oh you develop with you know the family but also what you do and and and so on and the nature of course we have a beautiful relationship with the nature yeah I mean thank you so much for maybe this special relationship of course yeah from the interview from this uh you know encounters and absolutely yeah thank you so much for coming on our show Lingon for teaching us about environmental hydrology it's been fascinating thank you so enlightening thank you thank you everyone for tuning in we greatly appreciate it we'd love to hear your thoughts in the comments below in the episode let us know what you're thinking have more conversations with your friends families co-workers people online on social media about environmental hydrology about the relationship between the ocean land interface and interactions about this idea of groundwater discharge about the global hydrological cycle in general the analysis of these return flows about all the different things that we talked about catchment hydrology about dams about how to maximize our prosperity on the planet with our environment all together and also support the artists the entrepreneurs the organizations the leaders around the world that you believe in support them and help them grow you can support simulation our links are below help us continue doing cool things like coming on site to west lake university and interviewing great people like Ling and go and build the future everyone manifest your dreams into the world we love you very much thank you for tuning in and we'll see you soon peace that's a wrap good job that was awesome that was such a fun that was such a fun car okay same for me