Demographic Base Model: Earth's 8,124,500,000 population is mapped across 24 standard solar UTC longitude offsets. Major population centers (East Asia UTC+8 ~1.65B, South Asia UTC+5.5 ~1.52B, Europe & West Africa UTC+0/+1 ~950M, Americas UTC-3 to -8 ~1.02B) create massive diurnal waves as the planet rotates.
Time-Use Survey Integration: Probability distributions are parameterized from the American Time Use Survey (ATUS), Eurostat Harmonised European Time Use Surveys (HETUS), and UN Statistics Division time-use studies.
Mathematical Formulation: For any global UTC minute $t \in [0, 1439]$, the total synchronous population $S_a(t)$ for activity $a$ is calculated by integrating across all timezones $z$:
S_a(t) = \sum_{z \in Z} P_z \cdot f_a((t + \text{offset}_z) \pmod{1440}, D)
where $P_z$ is the timezone population, $f_a$ is the smoothed probability kernel for activity $a$ at local solar time, and $D$ is the day-type coefficient.