Seasonal News: Pollen Dispersal Forecast
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Count on us for the latest information of spring pollen

Every year, Japan Weather Association (JWA) announces countrywide pollen dispersal forecasts from October to April of the following year.

What is the Pollen Dispersal Forecast?

Since 1990, JWA has been announcing cedar pollen dispersal forecasts annually. These forecasts are based on different data sources such as results of pollen dispersal of the previous season, future temperature forecasts, results of field investigations of floral buds, and information from pollen research groups and other cooperating agencies around the country.
The provided information also includes “year-over-year comparison” which shows how much next spring will disperse compared to the previous year, and “the 10-year average comparison” which shows the predicted amount of pollen dispersal compared to that of the last ten years. JWA also provides both “the cedar pollen dispersal front”, and “the pollen peak period”.

Announcement Schedule of Pollen Dispersal Forecast

Pollen Observation Method

Durham’s method is applied to count the number of cedar and/or cypress pollen separately as demonstrated in the following procedure;

(i) Place the Durham-type pollen detector outdoors in a well-ventilated area and leave the slide glass coated with Vaseline for 24 hours.

* This procedure allows the pollen in the air to adhere to the glass slide.

(ii) After 24 hours, collect the glass slide of (i) and apply a drop of the staining solution to the glass slide, then cover with a coverslip.

(iii) Start measurement under a microscope. Count the pollen under the cover glass visually using a counter.

* In 2019, JWA introduced a monitor and connected it to a microscope. This has been helpful in counting the number of pollen images projected on the monitor.

(iv) Convert the amount of pollen under the cover glass measured in (iii) to the number of pollen grains per square centimeter. This value per square centimeter is recorded as the amount of pollen per day.

For more information

Website for Pollen Dispersal Forecast

JWA portal website: Here
*Only available in Japanese.

News page in corporate site of JWA: Here

 

Corporate Use of the Pollen Dispersal Forecasts

For inquiries concerning the use of pollen dispersal forecasts by overseas corporations, please fill out the inquiry form and our staff will get back to you as soon as possible.