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1

Soil heat flux and air temperature as factors of radon (Rn-222) concentration in the near-ground air layer

Podstawczyńska A., Pawlak W.

Nukleonika

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2016

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Vol. 61, No. 3

231--237

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.

2

An Analysis of Turbulent Heat Fluxes and the Energy Balance During the REFLEX Campaign

Tol Ch. van der, Timmermans W., Corbari Ch., Carrara A., Timmermans J., Su Z.

Acta Geophysica

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2015

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Vol. 63, no. 6

1516--1539

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).

3

Zmienność stężenia radomu (Rn-222) w przygruntowej warstwie powietrza na tle wartości strumienia ciepła glebowego

Podstawczyńska A.

Woda-Środowisko-Obszary Wiejskie

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2012

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T. 12, z. 2

197-206

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.

4

Problemy metodyczne pomiaru strumienia ciepła w glebie - weryfikacja danych względem uzyskanych inną metodą w wielodniowym ciągu pomiarowym

Kossowski J.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2006

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Vol. 15, No. 1

158--167

EN

The linear regression eąuations describing relation of soil heat flux density values in daily course derived from the indirect (combined) method and flux-plates were used for correction of heat flux plate data on a given day. In the case the gaps occur in comparative materials (i.e. from indirect method), the correction problem of heat flux plate data in the multiday series of measures may be solved in the following way: applying the equation from one day (recognised as representative) for other days; by determination of the correction equation on the basis of the data comprised of a few days together, or a set of data from a great number of days during the measurement season. All these conceptions of performance correction of heat flux plate data were examined regarding their usefulness (exactly, the error magnitude obtained using these equations), but only in respect to days and periods without precipitation. It was stated that applying one equation for correction of heat flux plate data in the course of a long (e.g. several months) period is unreasonable (improper). However, the correction using the equation from one day for the other days, as well as the equation obtained from a few days give correct results on condition that the days taken into considcration are not too distant and precipitation is not recorded at this time (the soil physical properties did not undergo any significant changes).

5

Bilans cieplny lasu iglastego w latach o ekstremalnych opadach i jego wieloletnie zmiany w rejonie Bydgoszczy i Wrocławia

Bubnowska J., Gąsiorek E., Łabędzki L., Musiał E.

Woda-Środowisko-Obszary Wiejskie

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2005

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T. 5, z. spec.

69-82

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.

6

Problemy metodyczne pomiaru strumienia ciepła w glebie: weryfikacja danych względem uzyskanych inną metodą

Kossowski J.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2005

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Vol. 14, No. 2

60--71

EN

The results of soil heat flux density measurement using flux plates are as a rule burdened with substantial errors. Therefore, the verification of heat flux plate data is necessary it may be performed by comparing these data to obtained by the other method, recognised a control. In this paper, there is examined the relation between the values of soil heat flux density from plates burried at the depth of 1 cm and these obtained by combined method (i.e. heat storage changes within soil layer 1-20 cm and flux at depth 20 cm determined by gradient method). The ground for the analyses was constituted by the results of measurements carried out on the cultivated field without plants during the selected three days that were characterized by different weather and soil moisture conditions. The regression equations describing relation of soil beat flux density values (mean for one hour) derived from indirect method and flux plates in daily course were determined separately for each day. It was stated that values of the numerical coefficients in these equations differed significantly with regard to different soil moisture (as a consequence, a diverse relation of soil thermal conductivity to heat flux plate one) as well as different contact between soil material and plate. Therefore, if such equations are to be used for the correction of the flux-plates data, they should be applied, as a rule, only this day they were determined for.

7

Problemy metodyczne pomiaru strumienia ciepła w glebie: zastosowanie teorii Philipa

Kossowski J.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2004

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Vol. 13, No. 1

78--87

EN

In the paper some problents connected with measurement of the heat flux density in soil using heat flux plate are presented. Differentiation of the temperature gradient across the plate and in soil layer as well as the relation between values of heat flux front plate and these obtained by temperature gradient method during laboratory experiments are demonstrated. The effect of Philip’s method application to soil heat flux by plate data correction was analyzed on the basis of the data obtained in the laboratory conditions and also during the measurements carried out on the cultivated field without plants. Over the examined days of field investigations it was stated that this correction had effect on errors reduction of daily sum of heat flux into soil from 30-40% to 13% or even to zero.