I would like to retrieve water leaving reflectance from sentinel-2/MSIL1C data e.g. S2A_MSIL1C_20200510T054641_N0209_R048_T43SDT_20200513T075357 from this scene. How to do that in SNAP-7 version of the software?
You can use the C2RCC operator. You need to have installed the S3TBX. it will show up in the menu at
Optical / Thematic Water Processing / C2RCC. Beside water leaving reflectance it provides chl and tsm and other things.