Numerical weather models at MeteoSwiss have long us current measurements for forecasts. This was not the case for pollen forecasts until now. The reason for this was that no current pollen measurements were available; instead, pollen was count by hand under a microscope. The pollen data was only available 2-9 days after the survey – too late for direct use in the numerical pollen forecast.
With the introduction of the
national automatic pollen measuring network
The situation has chang fundamentally. 15 stations in Switzerland measure pollen in real time. This data is automatically sent to MeteoSwiss, where it can be access in less than an hour.
But how do you get the pollen forecast model to use this data sensibly? The forecast model COSMO-ART (COnsortium for Small-scale MOdeling – Aerosols and Reactive Trace gases) calculates the weather and pollen load for hundrs of thousands of grid points, which are to be correct using our 15 station measurements.
Let’s take a look at how ART works: An important part is phenology, i.e. how a plant develops over the course of the year. The periods in which the plants flower are calculat using the temperature trend in spring. Warm portugal phone number library weather encourages plants to flower early, and cooler temperatures cause them to flower late. However, it is not possible to prict exactly when flowers will start – errors of a few days are quite common. This means that the pollen forecast can be incorrect during the flowering period, which is a sensitive time for people with allergies.
Figure 1: Percentage of birch trees ready to bloom in the numerical pollen forecast model on March 28. The darker the green, the higher the percentage of existing birch trees ready to bloom. White means that the birch trees are not yet blooming. (Source: MeteoSwiss)
Real-time data corrects forecast
This is where the real-time data comes in. It is us campaign idea promote gifts for wding to correctly calculate the onset of flowering. If a station reports significant pollen concentrations and the phenology in the model is lagging behind, the phenology in the model is adjust accordingly. In the same way, if flowering is prict too early in the model, the real-time data awb directory can be us to correct it. Figure 1 shows the current, adjust phenology field for birch pollen.
However, the real-time data is also us in another place in the model. Because the plants do not bloom to the same extent every year, the pollen count also fluctuates accordingly. There are also other uncertainties in the model, such as in the plant distribution but also in the prict weather. The ratio between real-time data and model data from the last five days is now us to increase or decrease the amount of pollen releas.
start of the birch pollen season
The birch pollen season has already begun on the southern side of the Alps, and the first birch pollen has also been register on the northern side of the Alps. Like the hazel and alder, the birch is also blooming early this year. On average, the period with strong birch pollen count lasts around four weeks.
On the
MeteoSwiss website
(Figure 2) as well as in the MeteoSwiss app, the future development of birch pollen pollution can be follow in detail in space and time. The pollen concentrations close to the ground are shown. Thanks to the small mesh size of 1.1 kilometers, the large and also the middle Alpine valleys are well resolv. Birch pollen concentrations are expect to increase over the course of the day today.