It is very difficult to accurately collect precipitation samples. Before precipitation, the sampler must be covered and only opened after the actual precipitation occurs. Take water samples throughout the entire process of each precipitation (from the start to the end of the precipitation). When collecting samples, one should avoid sources of dirty sand. There should be no tall trees or buildings around the sampler that can block rain or snow to obtain accurate results.
The relative height at which the sampler is placed should be above 1.2 meters.
Each time it starts to rain (snow), immediately place the spare sampler on the stand at the designated sampling point, open the cover to start sampling, and record the start time of sampling. Do not open the lid for sampling before precipitation to prevent the influence of sedimentation.
04 Take samples of the entire process of each precipitation (from the start to the end of the precipitation). If there are several precipitation processes in a day, they can be combined into one sample for determination. If there is continuous rainfall for several days, the precipitation from 8:00 a.m. to 8:00 a.m. the next day can be collected, that is, the 24-hour precipitation sample can be used as one sample for determination.
The collected samples should be transferred into clean and dry polyethylene plastic bottles and sealed for storage. Label and number the sample bottles, and record the sampling location, date, start and end time, and precipitation at the same time.