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1

A multi-layer box model of carbon dynamics in soil

Kuc T.

Nukleonika

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2005

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Vol. 50, nr 2

49-55

EN

Abstract A multi-layer box model (MLB) for quantification of carbon fluxes between soil and atmosphere has been developed. In the model, soil carbon reservoir is represented by two boxes: fast decomposition box (FDB) and slow decomposition box (SDB), characterised by substantially different turnover time (TT) of carbon compounds. Each box has an internal structure (sub-compartments) accounting for carbon deposited in consecutive time intervals. The rate of decomposition of carbon compounds in each sub-compartment is proportional to the carbon content. With the aid of the MLB model and the 14C signature of carbon dioxide, the fluxes entering and leaving the boxes, turnover time of carbon in each box, and the ratio of mass of carbon in the slow and fast box (Ms/Mf) were calculated. The MBL model yields the turnover time of carbon in the FDB (TTf) ca. 14 for typical investigated soils of temperate climate ecosystems. The calculated contribution of the CO2 flux originating from the slow box (Fs) to the total CO2 flux into the atmosphere ranges from 12% to 22%. These values are in agreement with experimental observations at different locations. Assuming that the input flux of carbon (Fin) to the soil system is doubled within the period of 100 years, the soil buffering capacity for excess carbon predicted by the MLB model for typical soil parameters may vary in the range between 26% and 52%. The highest values are obtained for soils characterised by long TTf, and well developed old carbon pool.

2

Carbon dynamics in soil recorded by 14C: model calculations

Kuc T., Gorczyca Z., Kapusta M.

Geochronometria

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2004

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Vol. 23

45-50

EN

Time records of 14CO2 from soil respiration collected in the years 1998 to 2003 on sites representing different ecosystems (mixed wood, agricultural field and grassland, southern Poland), were analysed by use of MLB model built for this purpose. The modelled turnover time (TT) is maximum 22 yr for the agriculturally cultivated soil and only 14 yr for soil under grassland and mixed forest. About 22% of an old component of 1500 yr was admixed to the agriculturally cultivated soil while it was only 12% under mixed forest. Estimated ratio of carbon content in slow and in fast decomposition boxes varies from 22 to 40 in southern Poland pointing to slow decomposing organic compounds as the major pool of carbon in soil. The lowest ratio was observed for soil of low proportion of organics content in mixed forest, and the highest for grassland of well developed soil profile. D14C time records for not cultivated soils (under grassland and mixed forest) showed higher values than local atmospheric CO2, moreover 14CO2 from the mixed forest soil respiration remarkable exceeded "clean air" reference level for Central Europe.

3

Opracowanie modeli średniego obszarowego stężenia i powtarzalności ponadnormatywnych stężeń pyłu i SO2 dla oceny zagrożenia miast polskich występowaniem stanów smogowych

Sztyler A.

Archiwum Ochrony Środowiska

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1999

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Vol. 25, no. 2

29-44

PL

Praca przedstawia próbę opracowania modeli umożliwiających porównanie narażenia mieszkańców miast na wysokie stany zanieczyszczenia powietrza (sytuacje smogowe). Modele bazują na współczynnikach proporcjonalności B i y uniwersalizujących obliczenia (na całym terytorium kraju) odpowiednio średnich obszarowych stężeń pyłu i SO2 przy użyciu modelu skrzynkowego (box-model) i częstości występowania epizodów smogowych na podstawie matematycznego modelu częstości. Wartości ilorazu średniej standardowej różnicy zmierzonych i obliczonych stężeń i średniego stężenia zanieczyszczeń (pył i SO2) wynosi znacznie poniżej jedności, a zatem modele można uznać za dobre. Ich fizyczną poprawność i dokładność można zwiększyć przez wprowadzenie bardziej poprawnych danych wejściowych dotyczących emisji ze źródeł obszarowych, stężeń mierzonych w ujednoliconym systemie monitoringowym, a także dodatkowych danych meteorologicznych, np. temperatury i wilgotności względnej powietrza.

EN

The aim of the paper was to develop the tools for the quantitative estimation of dust-sulphur smog episodes frequancy in Polish towns. They consist of two simple models approximating the area mean concentrations and above-standard concentration frequancy. The models are based on proportionality coefficients B and Y determining the all-purpose box-model and frequancy distribution model, respectively, for entire territory of Poland. The models can be regarded as good. Accuracy, sensitiveness and physical clarity of models approach can be improved by introducing more correct data on area emission amount concentrations measured at methodologically uniform air monitoring system and additional meteorological factors e.g. relative humidity.