An application emulator is a suite of programs that, when run, exhibits computational and data access patterns that resemble the patterns observed in a particular type of application. We will construct two application emulators motivated by loosely synchronous adaptive applications and by data exploration and data fusion applications. As described earlier, application emulators will be used to validate the HLAM/PetaSIM modeling process. We will use the application emulators to produce application and machine specifications at varying levels of granularity and then use PetaSIM to estimate performance obtained on selected current and future architectures. We believe that our application emulators address some of the key applications targeted at future very-high end architectures. The application emulators will be shared with the performance modeling community. We believe that general availability of application emulators will help the community focus attention on crucial application classes.