Google Earth Engine（GEE）——用for双循环进行逐月数据下载以北京市为例

本次所用的函数：ee.ImageCollection

filter(filter)

Apply a filter to this collection.对这个集合应用一个过滤器。

Returns the filtered collection.

Arguments:

this:collection (Collection):

The Collection instance.

filter (Filter):

A filter to apply to this collection.

Returns: Collection

ee.Filter

ee.Filter.calendarRange(start, end, field)

Returns a filter that passes if the object's timestamp falls within the given range of a calendar field. The `month`, `day_of_year`, `day_of_month`, and `day_of_week` are 1-based. Times are assumed to be in UTC. Weeks are assumed to begin on Monday as day 1. If `end` < `start` then this tests for `value` >= `start` O