Investigation of Birch Pollen Concentrations in Air and It Influencing Factors for the Years 2003-2009 in Latvia

Maģistra darba tēma ir bērza putekšņu koncentrācijas gaisā un to noteicošo faktoru izpēte Latvijā 2003.-2009. gadā. Darbā tiek raksturots, kādā veidā bērza produktivitātes periodiskums, putekšņu sezonas garums un meteoroloģiskie rādītāji (gaisa un augsnes temperatūra, nokrišņu summas, gaisa relatīvais mitrums, vēja virziens un stiprums, gaisa spiediens) ietekmē bērza putekšņu koncentrāciju gaisā. Tiek aprakstītas, raksturotas un analizētas dažādas bērza putekšņu sezonas definīcijas un tās aprēķināšanas metodes. Izteikta gaisa temperatūras ietekme tika konstatēta pirms sezonas vai bērza putekšņu sezonas sākumā, savukārt pārējo meteoroloģisko rādītāju ietekme jūtama visas sezonas garumā. Atslēgas vārdi: aerobioloģija, bērza putekšņu koncentrācija, bērza putekšņu sezona, meteoroloģiskie rādītāji, Latvija.The title of the master thesis is the investigation of birch pollen concentration in the air and its influencing factors in Latvia in the years 2003-2009. The paper describes how the influencing factors (periodicity of birch pollen productivity; length of pollen season; meteorological indices such as air and soil temperature, precipitation, relative humidity, wind speed and direction, atmospheric pressure) impact birch pollen. The definitions of birch pollen seasons and evaluative methods have been described and analysed. The influence of air temperature is stated before and at the beginning of the birch pollen season, however, the influence of the other meteorological indices is felt during the whole birch pollen season. Keywords: aerobiology, birch pollen concentration, birch pollen season, meteorological parameters, Latvia

The Influence of Meteorological Parameters on Birch Pollen Concentration in the Air

Bakalaura darba tēma ir meteoroloģisko rādītāju ietekme uz bērza ziedputekšņu koncentrāciju gaisā. Par pētījuma objektu tika ņemti tieši bērza ziedputekšņi, jo bērzs ir visbīstamākais elpceļu un cita veida alerģijas izraisītājs Latvijas teritorijā. Darbā tiek raksturots kādā veidā meteoroloģiskie rādītāji (temperatūra, nokrišņu daudzums, vēja stiprums un virziens, gaisa spiediens, relatīvais mitrums, mākoņu daudzums) ietekmē ziedputekšņu koncentrāciju. Tiek sniegta jauna interpretācija bērza ziedputekšņu sezonas sākuma datumiem. Darbu veido 5 pamatnodaļas ar 12 apakšnodaļām, ko ilustratīvi papildina 12 attēli un 4 tabulas darba pamatnodaļā un 9 pielikumos. Atslēgvārdi: Aerobioloģija, aerobioloģiskais monitorings, Burkard uztvērējs, ziedputekšņu koncentrācija, ziedputekšņu transports, bērzs, meteoroloģiskie rādītāji.The theme of this Bachelor Paper is „The influence of Meteorological parameters on Birch pollen Concentration in the Air”. Investigation object is birch pollen, because of the fact that birch is the most dangerous founder of the respiratory tract and other types of allergy. The paper describes how the meteorological indices (temperature, wind speed and direction, rainfall, cloudiness, level of humidity) impact birch pollen concentration in the air. The author of the paper worked out the new birch pollen interpretation for the dates of pollination season start. The paper consists of 5 chapters with 12 sub-chapters, 12 figures, 4 tables and 9 appendixes. Key words: Aerobiology, pollen concentration, Burkard pollen trap, pollen transportation, birch, meteorological parameter

Ģeotelpisko un temporālo putekšņu sezonas izmaiņu prognozēšana Eiropā ar statistisko un deterministisko modelēšanu

Promocijas darbs ir pētījums par temporālo un ģeotelpisku putekšņu sezonas prognozēšanu. Pētījuma pirmā daļā, pēc 12 gadu diennakts datiem tika izveidots lokāls modelis diennakts putekšņu prognozēšanai Rīgā ar precizitāti virs 80%. Otrā pētījumā tika izveidots universāls modelis nākamā gada sezonālā putekšņu indeksa prognozēšanai Ziemeļeiropā ar precizitāti līdz 92%. Promocijas darba trešā daļa tika veltīta olīvu putekšņu modeļu ansambļa izveidei Eiropā. Pierādīts, ka sešu modeļu ansamblis darbojas ievērojami labāk par katru atsevišķu modeli. Tika secināts, ka ir iespējams prognozēt putekšņu daudzumu gaisā dažādos temporālos mērogos – pēc meteoroloģiskās situācijas aprēķināt nākamā gada sezonālo putekšņu indeksu un pēc lokālās meteoroloģiskās prognozes datiem, prognozēt diennakts putekšņu koncentrāciju noteiktā vietā.The thesis introduces forecasting of the temporal and geospatial patterns of pollen season in Europe through complex, multi-step transformation of data and parametric statistical analysis. The first part develops a local flowering model for Riga based on 12 years of data and it’s accuracy exceeds 80%. The second model shows regional-scale predictions of seasonal pollen index for the region of Northern Europe is universally applicable to the entire region with accuracy up to 92%. The third part describes an optimised ensemble built over simulations of six forecasting models for olive pollen over Europe in 2014 and it noticeably improves the accuracy of the pollen forecasts generated by the individual models and simple ensembles built over their predictions

Occurence of Ragweed Plants and Pollen in Latvia

Ragweed poses a health and an agricultural risk that need to be assessed in Latvia by determining the growth of ragweed plants and pollen transported from local sources and neighboring countries. It has been stated that the northern border for the growth of ragweed exists at the 55o latitude north and Latvia is situated between the 55 and 58° latitude north. This study investigates the collection of ragweed plants during field studies of other plants (1970- 2007) and pollen collected from aerobiological monitoring in Riga starting from 2003. Ragweed is classified as an invasive plant species and was found growing alongside main transportation routes (railways and roads) in Latvia. The most harmful species, A. artemisiifolia, represented 84% of all the ragweed plants, followed by 9% of A. trifida and 5% of A. psilostachya. Field studies in 2007 that located ragweed were repeated, but no plants were found in the same locations in 2011. Herbariums have revealed that ragweed plants have flowered between the middle of July until September. Aerobiological studies have revealed ragweed pollen during the day within a two weeks period between late August and the start of September that suggests pollen from local sources. The pollen concentration only reached a concentration of 2-3 grains/m3 over the two weeks period starting in August. Ragweed pollen is presently not a threat in Latvia, but more studies need to be conducted to follow any changes over time

A statistical model for predicting the inter-annual variability of birchpollen abundance in Northern and North-Eastern Europe

The paper suggests amethodology for predicting next-year seasonal pollen index (SPI, a sumof daily-mean pollen concentrations)over large regions and demonstrates its performance for birch in Northern andNorth-Eastern Europe. Astatistical model is constructed using meteorological, geophysical and biological characteristics of the previous year).A cluster analysis of multi-annual data of European Aeroallergen Network (EAN) revealed several large regions inEurope, where the observed SPI exhibits similar patterns of the multi-annual variability.We built the model for thenorthern cluster of stations, which covers Finland, Sweden, Baltic States, part of Belarus, and, probably, Russia andNorway,where the lack of data did not allow for conclusive analysis. The constructed modelwas capable of predictingthe SPI with correlation coefficient reaching up to 0.9 for somestations, odds ratio is infinitely high for 50% of sites insidethe region and the fraction of prediction fallingwithin factor of 2 from observations, stays within 40–70%. In particular,model successfully reproduced both the bi-annual cycle of the SPI and years when this cycle breaks down

Multi-model ensemble simulations of olive pollen distribution in Europe in 2014

A 6-models strong European ensemble of Copernicus Atmospheric Monitoring Service (CAMS) was run through the season of 2014 computing the olive pollen dispersion in Europe. The simulations have been compared with observations in 6 countries, members of the European Aeroallergen Network. Analysis was performed for individual models, the ensemble mean and median, and for a dynamically optimized combination of the ensemble members obtained via fusion of the model predictions with observations. The models, generally reproducing the olive season of 2014, showed noticeable deviations from both observations and each other. In particular, the season start was reported too early, by 8 days but for some models the error mounted to almost two weeks. For the season end, the disagreement between the models and the observations varied from a nearly perfect match up to two weeks too late. A series of sensitivity studies performed to understand the origin of the disagreements revealed crucial role of ambient temperature, especially systematic biases in its representation by meteorological models. A simple correction to the heat sum threshold eliminated the season shift but its validity in other years remains to be checked. The short-term features of the concentration time series were reproduced better suggesting that the precipitation events and cold/warm spells, as well as the large-scale transport were represented rather well. Ensemble averaging led to more robust results. The best skill scores were obtained with data fusion, which used the previous-days observations to identify the optimal weighting coefficients of the individual model forecasts. Such combinations were tested for the forecasting period up to 4 days and shown to remain nearly optimal throughout the whole period

MACC regional multi-model ensemble simulations of birch pollen dispersion in Europe

This paper presents the first ensemble modelling experiment in relation to birch pollen in Europe. The seven-model European ensemble of MACC-ENS, tested in trial simulations over the flowering season of 2010, was run through the flowering season of 2013. The simulations have been compared with observations in 11 countries, all members of the European Aeroallergen Network, for both individual models and the ensemble mean and median. It is shown that the models successfully reproduced the timing of the very late season of 2013, generally within a couple of days from the observed start of the season. The end of the season was generally predicted later than observed, by 5 days or more, which is a known feature of the source term used in the study. Absolute pollen concentrations during the season were somewhat underestimated in the southern part of the birch habitat. In the northern part of Europe, a record-low pollen season was strongly overestimated by all models. The median of the multi-model ensemble demonstrated robust performance, successfully eliminating the impact of outliers, which was particularly useful since for most models this was the first experience of pollen forecasting