Suppose, each document has a following data
{ some_other_fields, seasonal_data: [{ day_of_year: 1, sales: 3 }, { day_of_year: 2, sales: 5 } ] } <
{ some_other_fields, seasonal_data: [{ day_of_year: 1, sales: 3 }, { day_of_year: 2, sales: 5 } ] }