 In this short section, we shall try to understand about variable infiltration capacity model. Remember the discussions we had about what is a land surface model and what is a hydrologic model. So, in this section, we will try to understand how to install a variable infiltration capacity model used in hydrologic modeling. So, if you are a Windows user, you can activate the Windows sub-system for Linux, which will let the developer to run a Linux environment directly on Windows. So, I am going to assume that you are a Windows sub-user and therefore, if you want to activate the Windows sub-system for Linux, I would suggest you to visit the apps and features and then on to the program and features, turn Windows features on or off, wait while the list loads on. Here, you have to check the Windows sub-system for Linux, so you can search for it and then check it, yes, Windows sub-system for Linux, press ok, now this will start the search for the required files, let us wait for a couple of seconds and once the search is complete, the changes shall be applied and once the requested changes are completed, mostly a reboot shall also be requested. So, again, why are we doing this to activate Windows sub-system for Linux, which will help us in the installation of the VIC model and you know, WSL that is the command, which will enable the required components and which will download the latest Linux kernel, so here you can see that Windows has completed the requested changes, a reboot shall be required, alright. So, you can go for restart now. Now, let us try to learn how to install the variable infiltration capacity model and this section has been created from the beginner point of view. So, firstly to understand more about the variable infiltration capacity model for information and documentation, I would suggest you to visit the particular website here, visit the particular website here, all the details about the model overview that is the VIC model features and what are the land cover and soil information, all the details you will find in the documentation, you can see that towards the left side of the screen, the tabs are given. Say, if you want to go and understand about a Python driver, you can click on the VIC model user guide and once you click on the Python driver, it will take you to the page where in details about building the Python driver are present, okay, right. Also, there are some sample data sets made available, say you are a beginner and you want to check whether VIC has been installed correctly, you can use the sample data sets that are available in the website, global data sets are available, global VIC parameters at 0.5 degree resolution is made available, you can check it and use it for your work, all right. You can see sample data sets, test data sets and so on. Also, details about the forcing data are given, VIC forcing file, remember we discussed about what are a forcing data. So, all in all, I would suggest that if you are interested to use VIC for your research, please visit this site and go through the documentation that is available, okay. So, with respect to VIC, the inputs, processes and outputs are shown here. You can see the inputs, the model needs hydro-meteorological data as an input along with soil map, land cover map, vegetation properties, lake and wetland features, digital elevation model, stream flow data, these are the inputs required and the processes that it can handle is land atmosphere fluxes, water and energy balance, rainfall runoff modeling and reservoir operating rules. The outputs what VIC model can give you are the river discharge, intermediate hydrologic processes and time series for any grid point at any time, okay. Now, here I have underlined digital elevation model. You will learn about what is DEM or digital elevation model as part of module 6. So, you will learn how a DEM can be generated using radar interferometry, okay. So, coming back, what you see here are the sample files which have been downloaded from the website shown, okay. It is titled VIC master. You can see the files here, the samples under SRC, you see a lot of files and if we go back, you can explore the tools present. This was installed and kept in the directory. So, to begin the installation of VIC model, let us first install Ubuntu which is a Linux distribution. So, I have gone to the Microsoft Store to download Ubuntu. The version is also shown here in the screen in front of you and even if you are a beginner at using the Linux environment, the step-by-step guidelines are made available so that it will be easy for you to install and work with VIC model, all right. So, now the installation is commencing. It will take just a few minutes to complete the installation. The installation has been completed. Let us try to understand what to do next, okay. So, let me enter the Unix username and password. Follow a series of steps and try to explain what these commands mean as and when it is being shown on the screen. So, CD stands for change directory command, okay. So, I am changing the directory. LS stands for the command that allows us to view the list of files and folders in a given directory. LS, you can see the entire list of files and folders. CDMNT, we get to mount file systems or devices by mounting and referring to making the file system available, okay. So, I am changing the directory to VIC master, okay. And I am using CDSRC, SRC source. It is a shell built-in command which is used to read and execute the contents of a file. And the source command can load any function file into the current shell script or a command prompt. So, now you see that I am using the command sudo apt get installed build essential, okay. sudo apt get install build essential. The sudo apt get, it is used to download package information from all the configured sources. And in the case of build essential, it will install everything that is required for compiling basic software written in C and C++. sudo apt get install build essential, okay. So, now what I will do is I will try to install some additional packages as well using the update command that is sudo apt get update, there you go, okay. So, you can see that this does not install any new versions of the software, but then it updates the package list for any upgradation, okay, for any upgrades. We need to wait for a couple of seconds for the process to be completed. So, let us wait. What we will do is I will try to use sudo apt get install make, okay. sudo get install. Now, this will update the list of newest version of packages and its dependencies on your system, okay. So, you can see the following new packages will be installed. I am going to use sudo apt get install GCC, okay. sudo apt get install GCC, okay. So, the GCC compiler, it was built under the GNU project and in the current version of all the line-ups distributions, GCC compiler actually comes as a pre-installed package inside the operating system and you can use the this compiler that is GCC compiler to compile C, C++ and a few other object oriented programming languages and you can get to compile the codes on your terminal shell through the GCC compiler on a line-up system, okay. So, again this is going to take a couple of seconds. So, let us wait for that. You can see that it is being unpacked. It is setting up just a couple of seconds and here the steps, the series of steps that are being shown are same as what you need to follow when you are working with Vic for the first time as a Windows user. So, probably you will get to see the same screen when you are trying to work on the same commands in your system. So, now I am going to use sudo apt get install CSH, let me type that down CSH, C shell, okay. Again a couple of seconds, all right, that is completed and now I can type make file. You can see the screen. So, once we have successfully installed the VIC model, we can even check the version, which version of Vic has been installed. So, now you see the screen, it is trying to initialize. Remember, this is for the sample data set that has been downloaded from the website that I showed you for Vic documentation. If you want to run and install Vic for your study region, you can create the forcing data in a particular format for Vic to understand, for it to be compatible with Vic and then you can follow the same process to run the model for your area of interest. It takes a couple of seconds to complete the process, okay. And once it is completed, we can even check the version of Vic that has been installed. Version 4.2.c is installed in the system. Now, as newer versions come up in the near future, you can follow the same steps to install the newer version. So, I would suggest that if you are interested in installing and using Vic for your research applications, please visit the site that was shown, the website that was shown earlier and have a look at the documentation and be updated about the newer versions of Vic model that is being released with time. So, let me hope that you could benefit from this small section and I will meet you in the next class. Thank you.