Numerical simulation of the global atmospheric circulation is one of the main tools to understand the formation and dynamic behaviors of global climate, and it is also a great challenge to port and optimize such a complex application onto large scale heterogeneous platforms. Tend_lin is the hot spot of the dynamic core of IAP AGCM-4 (the 4th generation of IAP atmospheric general circulation model), and it has a low compute-to-communication ratio. The paper ports Tend_lin to SunWay Taihulight (a large scale heterogeneous computing platform) using two different parallel application programming interfaces. The paper introduces how to parallelize the program using a data-driven parallel application programming interface AceMesh, the task parallelization method of computation loops and MPI communication, how to relax the sharing of the communication resources, and the task mapping diffe- rences between a single-level task graph and a nested task graph. The experimental results show that AceMesh can attain more than 2 times speedups compared with the OpenACC version when using 16 to 1 024 processes. The paper analyzes and explains the reasons of the performance improvement.