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EN
A unique, highly time-resolved, and synchronous three-year dataset of near-surface atmospheric radon-222 as well as soil heat flux and air temperature measurements at two sites (rural and urban) in Central Poland are investigated. The recognition of temporal variability of Rn-222 and selected meteorological variables in the urban and rural areas served to create two statistical models for estimation of this radionuclide concentration at 2 m a.g.l. The description of the relationships between the variables for individual months was established on the basis of an exponential function and an exponential function with time derivative of predictor to account for the hysteresis issue. The model with time derivative provided better results. The weakest fitting of modelled data to empirical ones is observed for the winter months. During subsequent seasons, air temperature as well as QG-driven (soil heat flux) models exhibited very high agreement with the empirical data (MBE, RMSE, MAE, and ‘index of agreement’ by Willmott were used to evaluate the models). A restriction in the use of QG for Rn-222 concentration was observed only in winter in the case of snow cover occurrence, which reduces the daily QG variability. A unique, highly time-resolved, and synchronous three-year dataset of near-surface atmospheric radon-222 as well as soil heat flux and air temperature measurements at two sites (rural and urban) in Central Poland are investigated. The recognition of temporal variability of Rn-222 and selected meteorological variables in the urban and rural areas served to create two statistical models for estimation of this radionuclide concentration at 2 m a.g.l. The description of the relationships between the variables for individual months was established on the basis of an exponential function and an exponential function with time derivative of predictor to account for the hysteresis issue. The model with time derivative provided better results. The weakest fitting of modelled data to empirical ones is observed for the winter months. During subsequent seasons, air temperature as well as QG-driven (soil heat flux) models exhibited very high agreement with the empirical data (MBE, RMSE, MAE, and ‘index of agreement’ by Willmott were used to evaluate the models). A restriction in the use of QG for Rn-222 concentration was observed only in winter in the case of snow cover occurrence, which reduces the daily QG variability.
EN
Three eddy covariance stations were installed at the Barrax experimental farm during the Land-Atmosphere Exchanges (REFLEX) airborne training and measurement campaign to provide ground truth data of energy balance fluxes and vertical temperature and wind profiles. The energy balance closure ratio (EBR) was 105% for a homogeneous camelina site, 86% at a sparse reforestation site, and 73% for a vineyard. We hypothesize that the lower closure in the last site was related to the limited fetch. Incorporating a vertical gradient of soil thermal properties decreased the RMSE of the energy balance at the camelina site by 16 W m-2. At the camelina site, eddy covariance estimates of sensible and latent heat fluxes could be reproduced well using mean vertical profiles of wind and temperature, provided that the Monin-Obukhov length is known. Measured surface temperature and sensible heat fluxes suggested high excess resistance for heat (kB-1 = 17).
PL
Celem opracowania jest znalezienie związku między stężeniem radonu (ρRn-222), rejestrowanym w powietrzu 2 m nad gruntem, i strumieniem ciepła glebowego (QG). Pomiary ρRn-222 wykonywano co 1 godz. za pomocą automatycznej komory jonizacyjnej Alpha GUARDR PQ2000 Pro. Synchronicznie do stężenia radonu w latach 2008-2010 mierzono QG za pomocą czujnika typu HFP01 Heat Flux Plate firmy Cambell Scientific Ltd. w centrum Łodzi oraz na stacji zamiejskiej Ciosny (teren rolniczy, 25 km na połnoc od Łodzi). Badane zmienne cechuje quasi-synchroniczny przebieg dobowy z maksimum w godzinach nocnych i minimum w godzinach popołudniowych. Związek ρRn-222 i QG opisano modelem funkcji eksponencjalnej. Na stacji Ciosny miesiące od III do XI cechują się bardzo wysokim stopniem dopasowania danych modelowanych do danych pomiarowych stężenia radonu w świetle indeksu zgodności Willmotta. Dla stacji w Łodzi uzyskano gorsze rezultaty, stosując model ρRn-222 w którym wykorzystuje się strumień ciepła glebowego.
EN
The aim of the study was to find the relationship between radon (Rn-222) concentration and soil heat flux. Atmospheric concentration of radon was measured continuously (in 60-min intervals) at a height of 2 m above the ground using AlphaGUARD® PQ2000PRO (ionization chamber) at urban (city center of Łódź) and rural (Ciosny, 25 km north of Łódź) site in the period 2008-2010. Simultaneously, soil heat flux (QG) was measured by means of HFP01 Heat Flux Plate, Campbell Scientific Ltd. The diurnal pattern of Rn-222 concentration was revealed with a maximum in the early morning and a minimum in the afternoon. In general, the diurnal variation of near-surface Rn-222 concentration varied approximately in phase with the soil heat flux. The exponential function model was used to estimate a daily course of radon concentration on the basis of soil heat flux values in particular months. The period from March to November was characterised by a good agreement between the observed and model-predicted Rn-222 concentration ("index of agreement" by Willmott was used to evaluate the model). Measured Rn-222 concentrations in the rural station Ciosny fitted better to model data than those from the urban station in the city center of Łódź.
PL
Zmiany klimatu, szczególnie widoczne w ostatnich dekadach XX w., mają duży wpływ na działalność gospodarczą człowieka. Bilans cieplny powierzchni czynnej jest jednym z czynników wpływających na ostateczny stan klimatu. Wpływ ten jest również widoczny w przebiegu zmian poszczególnych składowych bilansu cieplnego lasu iglastego. W pracy przedstawiono badania nad zmianami składowych bilansu cieplnego lasu iglastego w okresie wegetacyjnym tego ekosystemu (III-X), w latach o maksymalnych i minimalnych sumach opadów, na przykładzie Wrocławia (w wieloleciu 1964-2000) oraz Bydgoszczy (w wieloleciu 1945-2003).
EN
Climate changes, particularly visible in the last decades of the XXth century have paramount influence on human economic activity. Heat balance is one of the factors affecting the climate. That impact is noticeable when variations in heat balance components are examined e. g. in coniferous forest. This paper presents analyses of these variations during the growing season (III-X) in the years with maximal and minimal precipitation sums. The study shows also the changes in heat balance components in Wrocław-Swojec in the years 1964-2000 and in Bydgoszcz in the years 1945-2003.
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