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Article ; Online: A tropospheric chemistry reanalysis for the years 2005–2012 based on an assimilation of OMI, MLS, TES and MOPITT satellite data

K. Miyazaki / H. J. Eskes / K. Sudo

Atmospheric Chemistry and Physics Discussions, Vol 15, Iss 6, Pp 8687-

2015 Volume 8770

Abstract: We present the results from an eight-year tropospheric chemistry reanalysis for the period 2005–2012 obtained by assimilating multiple retrieval data sets from the OMI, MLS, TES, and MOPITT satellite instruments. The reanalysis calculation was conducted ... ...

Abstract	We present the results from an eight-year tropospheric chemistry reanalysis for the period 2005–2012 obtained by assimilating multiple retrieval data sets from the OMI, MLS, TES, and MOPITT satellite instruments. The reanalysis calculation was conducted using a global chemical transport model and an ensemble Kalman filter technique that simultaneously optimises the chemical concentrations of various species and emissions of several precursors. The optimisation of both the concentration and the emission fields is an efficient method to correct the entire tropospheric profile and its year-to-year variations, and to adjust various tracers chemically linked to the species assimilated. Comparisons against independent aircraft, satellite, and ozonesonde observations demonstrate the quality of the analysed O 3 , NO 2 , and CO concentrations on regional and global scales and for both seasonal and year-to-year variations from the lower troposphere to the lower stratosphere. The data assimilation statistics imply persistent reduction of model error and improved representation of emission variability, but also show that discontinuities in the availability of the measurements lead to a degradation of the reanalysis. The decrease in the number of assimilated measurements increased the ozonesonde minus analysis difference after 2010 and caused spurious variations in the estimated emissions. The Northern/Southern Hemisphere OH ratio was modified considerably due to the multiple species assimilation and became closer to an observational estimate, which played an important role in propagating observational information among various chemical fields and affected the emission estimates. The consistent concentration and emission products provide unique information on year-to-year variations of the atmospheric environment.
Keywords	Environmental sciences ; GE1-350 ; Geography. Anthropology. Recreation ; G
Subject code	333
Language	English
Publishing date	2015-03-01T00:00:00Z
Publisher	Copernicus GmbH
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: A tropospheric chemistry reanalysis for the years 2005–2012 based on an assimilation of OMI, MLS, TES, and MOPITT satellite data

K. Miyazaki / H. J. Eskes / K. Sudo

Atmospheric Chemistry and Physics, Vol 15, Iss 14, Pp 8315-

2015 Volume 8348

Abstract: We present the results from an 8-year tropospheric chemistry reanalysis for the period 2005–2012 obtained by assimilating multiple data sets from the OMI, MLS, TES, and MOPITT satellite instruments. The reanalysis calculation was conducted using a global ...

Abstract	We present the results from an 8-year tropospheric chemistry reanalysis for the period 2005–2012 obtained by assimilating multiple data sets from the OMI, MLS, TES, and MOPITT satellite instruments. The reanalysis calculation was conducted using a global chemical transport model and an ensemble Kalman filter technique that simultaneously optimises the chemical concentrations of various species and emissions of several precursors. The optimisation of both the concentration and the emission fields is an efficient method to correct the entire tropospheric profile and its year-to-year variations, and to adjust various tracers chemically linked to the species assimilated. Comparisons against independent aircraft, satellite, and ozonesonde observations demonstrate the quality of the analysed O 3 , NO 2 , and CO concentrations on regional and global scales and for both seasonal and year-to-year variations from the lower troposphere to the lower stratosphere. The data assimilation statistics imply persistent reduction of model error and improved representation of emission variability, but they also show that discontinuities in the availability of the measurements lead to a degradation of the reanalysis. The decrease in the number of assimilated measurements increased the ozonesonde-minus-analysis difference after 2010 and caused spurious variations in the estimated emissions. The Northern/Southern Hemisphere OH ratio was modified considerably due to the multiple-species assimilation and became closer to an observational estimate, which played an important role in propagating observational information among various chemical fields and affected the emission estimates. The consistent concentration and emission products provide unique information on year-to-year variations in the atmospheric environment.
Keywords	Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	551 ; 333
Language	English
Publishing date	2015-07-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Representativeness errors in comparing chemistry transport and chemistry climate models with satellite UV/Vis tropospheric column retrievals

K. F. Boersma / G. C. M. Vinken / H. J. Eskes

Geoscientific Model Development Discussions, Vol 8, Iss 9, Pp 7821-

2015 Volume 7877

Abstract: UV/Vis satellite retrievals of trace gas columns of nitrogen dioxide (NO 2 ), sulphur dioxide (SO 2 ), and formaldehyde (HCHO) are useful to test and improve models of atmospheric composition, for data assimilation, air quality hindcasting and ... ...

Abstract	UV/Vis satellite retrievals of trace gas columns of nitrogen dioxide (NO 2 ), sulphur dioxide (SO 2 ), and formaldehyde (HCHO) are useful to test and improve models of atmospheric composition, for data assimilation, air quality hindcasting and forecasting, and to provide top-down constraints on emissions. However, because models and satellite measurements do not represent the exact same geophysical quantities, the process of confronting model fields with satellite measurements is complicated by representativeness errors, which degrade the quality of the comparison beyond contributions from modelling and measurement errors alone. Here we discuss three types of representativeness errors that arise from the act of carrying out a model-satellite comparison: (1) horizontal representativeness errors due to imperfect collocation of the model grid cell and an ensemble of satellite pixels called superobservation, (2) temporal representativeness errors originating mostly from differences in cloud cover between the modelled and observed state, and (3) vertical representativeness errors because of reduced satellite sensitivity towards the surface accompanied with necessary retrieval assumptions on the state of the atmosphere. To minimize the impact of these representativeness errors, we recommend that models and satellite measurements be sampled as consistently as possible, and our paper provides a number of recipes to do so. A practical confrontation of tropospheric NO 2 columns simulated by the TM5 chemistry transport model (CTM) with Ozone Monitoring Instrument (OMI) tropospheric NO 2 retrievals suggests that horizontal representativeness errors, while unavoidable, are limited to within 5–10 % in most cases and of random nature. These errors should be included along with the individual retrieval errors in the overall superobservation error. Temporal sampling errors from mismatches in cloud cover, and, consequently, in photolysis rates, are on the order of 10 % for NO 2 and HCHO, and systematic, but partly avoidable. In the case of air pollution applications where sensitivity down to the ground is required, we recommend that models should be sampled on the same mostly cloud-free days as the satellite retrievals. The most relevant representativeness error is associated with the vertical sensitivity of Ultraviolet-visible (UV/Vis) satellite retrievals. Simple vertical integration of modelled profiles leads to systematically different model columns compared to application of the appropriate averaging kernel. In comparing OMI NO 2 to GEOS-Chem NO 2 simulations, these systematic differences are as large as 15–20 % in summer, but, again, avoidable.
Keywords	Geography (General) ; G1-922
Subject code	290
Language	English
Publishing date	2015-09-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Air quality impacts of COVID-19 lockdown measures detected from space using high spatial resolution observations of multiple trace gases from Sentinel-5P/TROPOMI

P. F. Levelt / D. C. Stein Zweers / I. Aben / M. Bauwens / T. Borsdorff / I. De Smedt / H. J. Eskes / C. Lerot / D. G. Loyola / F. Romahn / T. Stavrakou / N. Theys / M. Van Roozendael / J. P. Veefkind / T. Verhoelst

Atmospheric Chemistry and Physics, Vol 22, Pp 10319-

2022 Volume 10351

Abstract: The aim of this paper is to highlight how TROPOspheric Monitoring Instrument (TROPOMI) trace gas data can best be used and interpreted to understand event-based impacts on air quality from regional to city scales around the globe. For this study, we ... ...

Abstract	The aim of this paper is to highlight how TROPOspheric Monitoring Instrument (TROPOMI) trace gas data can best be used and interpreted to understand event-based impacts on air quality from regional to city scales around the globe. For this study, we present the observed changes in the atmospheric column amounts of five trace gases (NO 2 , SO 2 , CO, HCHO, and CHOCHO) detected by the Sentinel-5P TROPOMI instrument and driven by reductions in anthropogenic emissions due to COVID-19 lockdown measures in 2020. We report clear COVID-19-related decreases in TROPOMI NO 2 column amounts on all continents. For megacities, reductions in column amounts of tropospheric NO 2 range between 14 % and 63 %. For China and India, supported by NO 2 observations, where the primary source of anthropogenic SO 2 is coal-fired power generation, we were able to detect sector-specific emission changes using the SO 2 data. For HCHO and CHOCHO, we consistently observe anthropogenic changes in 2-week-averaged column amounts over China and India during the early phases of the lockdown periods. That these variations over such a short timescale are detectable from space is due to the high resolution and improved sensitivity of the TROPOMI instrument. For CO, we observe a small reduction over China, which is in concert with the other trace gas reductions observed during lockdown; however, large interannual differences prevent firm conclusions from being drawn. The joint analysis of COVID-19-lockdown-driven reductions in satellite-observed trace gas column amounts using the latest operational and scientific retrieval techniques for five species concomitantly is unprecedented. However, the meteorologically and seasonally driven variability of the five trace gases does not allow for drawing fully quantitative conclusions on the reduction in anthropogenic emissions based on TROPOMI observations alone. We anticipate that in future the combined use of inverse modeling techniques with the high spatial resolution data from S5P/TROPOMI for all observed ...
Keywords	Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	550 ; 520
Language	English
Publishing date	2022-08-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Biomass burning combustion efficiency observed from space using measurements of CO and NO 2 by the TROPOspheric Monitoring Instrument (TROPOMI)

I. R. van der Velde / G. R. van der Werf / S. Houweling / H. J. Eskes / J. P. Veefkind / T. Borsdorff / I. Aben

Atmospheric Chemistry and Physics, Vol 21, Pp 597-

2021 Volume 616

Abstract: The global fire emission inventories depend on ground and airborne measurements of species-specific emission factors (EFs), which translate dry matter losses due to fires to actual trace gas and aerosol emissions. The EFs of nitrogen oxides (NO x ) and ... ...

Abstract	The global fire emission inventories depend on ground and airborne measurements of species-specific emission factors (EFs), which translate dry matter losses due to fires to actual trace gas and aerosol emissions. The EFs of nitrogen oxides (NO x ) and carbon monoxide (CO) can function as a proxy for combustion efficiency to distinguish flaming from smoldering combustion. The uncertainties in these EFs remain large as they are limited by the spatial and temporal representativeness of the measurements. The global coverage of satellite observations has the advantage of filling this gap, making these measurements highly complementary to ground-based or airborne data. We present a new analysis of biomass burning pollutants using space-borne data to investigate the spatiotemporal efficiency of fire combustion. Column measurements of nitrogen dioxide and carbon monoxide ( X NO 2 and X CO ) from the TROPOspheric Monitoring Instrument (TROPOMI) are used to quantify the relative atmospheric enhancements of these species over different fire-prone regions around the world. We find spatial and temporal patterns in the Δ X NO 2 ∕ Δ X CO ratio that point to distinct differences in biomass burning behavior. Such differences are induced by the burning phase of the fire (e.g., high-temperature flaming vs. low-temperature smoldering combustion) and burning practice (e.g., the combustion of logs, coarse woody debris and soil organic matter vs. the combustion of fine fuels such as savanna grasses). The sampling techniques and the signal-to-noise ratio of the retrieved Δ X NO 2 ∕ Δ X CO signals were quantified with WRF-Chem experiments and showed similar distinct differences in combustion types. The TROPOMI measurements show that the fraction of surface smoldering combustion is much larger for the boreal forest fires in the upper Northern Hemisphere and peatland fires in Indonesia. These types of fires cause a much larger increase (3 to 6 times) in Δ X CO relative to Δ X NO 2 than elsewhere in the world. The high spatial and ...
Keywords	Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	550
Language	English
Publishing date	2021-01-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Global NO x emission estimates derived from an assimilation of OMI tropospheric NO 2 columns

K. Sudo / H. J. Eskes / K. Miyazaki

Atmospheric Chemistry and Physics, Vol 12, Iss 5, Pp 2263-

2012 Volume 2288

Abstract: A data assimilation system has been developed to estimate global nitrogen oxides (NO x ) emissions using OMI tropospheric NO 2 columns (DOMINO product) and a global chemical transport model (CTM), the Chemical Atmospheric GCM for Study of Atmospheric ... ...

Abstract	A data assimilation system has been developed to estimate global nitrogen oxides (NO x ) emissions using OMI tropospheric NO 2 columns (DOMINO product) and a global chemical transport model (CTM), the Chemical Atmospheric GCM for Study of Atmospheric Environment and Radiative Forcing (CHASER). The data assimilation system, based on an ensemble Kalman filter approach, was applied to optimize daily NO x emissions with a horizontal resolution of 2.8° during the years 2005 and 2006. The background error covariance estimated from the ensemble CTM forecasts explicitly represents non-direct relationships between the emissions and tropospheric columns caused by atmospheric transport and chemical processes. In comparison to the a priori emissions based on bottom-up inventories, the optimized emissions were higher over eastern China, the eastern United States, southern Africa, and central-western Europe, suggesting that the anthropogenic emissions are mostly underestimated in the inventories. In addition, the seasonality of the estimated emissions differed from that of the a priori emission over several biomass burning regions, with a large increase over Southeast Asia in April and over South America in October. The data assimilation results were validated against independent data: SCIAMACHY tropospheric NO 2 columns and vertical NO 2 profiles obtained from aircraft and lidar measurements. The emission correction greatly improved the agreement between the simulated and observed NO 2 fields; this implies that the data assimilation system efficiently derives NO x emissions from concentration observations. We also demonstrated that biases in the satellite retrieval and model settings used in the data assimilation largely affect the magnitude of estimated emissions. These dependences should be carefully considered for better understanding NO x sources from top-down approaches.
Keywords	Environmental sciences ; GE1-350 ; Geography. Anthropology. Recreation ; G ; DOAJ:Environmental Sciences ; DOAJ:Earth and Environmental Sciences
Subject code	290
Publishing date	2012-03-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Global lightning NO x production estimated by an assimilation of multiple satellite data sets

K. Miyazaki / H. J. Eskes / K. Sudo / C. Zhang

Atmospheric Chemistry and Physics, Vol 14, Iss 7, Pp 3277-

2014 Volume 3305

Abstract: The global source of lightning-produced NO x (LNO x ) is estimated by assimilating observations of NO 2 , O 3 , HNO 3 , and CO measured by multiple satellite measurements into a chemical transport model. Included are observations from the Ozone ... ...

Abstract	The global source of lightning-produced NO x (LNO x ) is estimated by assimilating observations of NO 2 , O 3 , HNO 3 , and CO measured by multiple satellite measurements into a chemical transport model. Included are observations from the Ozone Monitoring Instrument (OMI), Microwave Limb Sounder (MLS), Tropospheric Emission Spectrometer (TES), and Measurements of Pollution in the Troposphere (MOPITT) instruments. The assimilation of multiple chemical data sets with different vertical sensitivity profiles provides comprehensive constraints on the global LNO x source while improving the representations of the entire chemical system affecting atmospheric NO x , including surface emissions and inflows from the stratosphere. The annual global LNO x source amount and NO production efficiency are estimated at 6.3 Tg N yr −1 and 310 mol NO flash −1 , respectively. Sensitivity studies with perturbed satellite data sets, model and data assimilation settings lead to an error estimate of about 1.4 Tg N yr −1 on this global LNO x source. These estimates are significantly different from those estimated from a parameter inversion that optimizes only the LNO x source from NO 2 observations alone, which may lead to an overestimate of the source adjustment. The total LNO x source is predominantly corrected by the assimilation of OMI NO 2 observations, while TES and MLS observations add important constraints on the vertical source profile. The results indicate that the widely used lightning parameterization based on the C-shape assumption underestimates the source in the upper troposphere and overestimates the peak source height by up to about 1 km over land and the tropical western Pacific. Adjustments are larger over ocean than over land, suggesting that the cloud height dependence is too weak over the ocean in the Price and Rind (1992) approach. The significantly improved agreement between the analyzed ozone fields and independent observations gives confidence in the performance of the LNO x source estimation.
Keywords	Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	290
Language	English
Publishing date	2014-04-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Global NO x emission estimates derived from an assimilation of OMI tropospheric NO 2 columns

K. Sudo / H. J. Eskes / K. Miyazaki

Atmospheric Chemistry and Physics Discussions, Vol 11, Iss 12, Pp 31523-

2011 Volume 31583

Abstract: A data assimilation system has been developed to estimate global nitrogen oxides (NO x ) emissions using OMI tropospheric NO 2 columns (DOMINO product) and a global chemical transport model (CTM), CHASER. The data assimilation system, based on an ... ...

Abstract	A data assimilation system has been developed to estimate global nitrogen oxides (NO x ) emissions using OMI tropospheric NO 2 columns (DOMINO product) and a global chemical transport model (CTM), CHASER. The data assimilation system, based on an ensemble Kalman filter approach, was applied to optimize daily NO x emissions with a horizontal resolution of 2.8° during the years 2005 and 2006. The background error covariance estimated from the ensemble CTM forecasts explicitly represents non-direct relationships between the emissions and tropospheric columns caused by atmospheric transport and chemical processes. In comparison to the a priori emissions based on bottom-up inventories, the optimized emissions were higher over Eastern China, the Eastern United States, Southern Africa, and Central-Western Europe, suggesting that the anthropogenic emissions are mostly underestimated in the inventories. In addition, the seasonality of the estimated emissions differed from that of the a priori emission over several biomass burning regions, with a large increase over Southeast Asia in April and over South America in October. The data assimilation results were validated against independent data: SCIAMACHY tropospheric NO 2 columns and vertical NO 2 profiles obtained from aircraft and lidar measurements. The emission correction greatly improved the agreement between the simulated and observed NO 2 fields; this implies that the data assimilation system efficiently derives NO x emissions from concentration observations. We also demonstrated that biases in the satellite retrieval and model settings used in the data assimilation largely affect the magnitude of estimated emissions. These dependences should be carefully considered for better understanding NO x sources from top-down approaches.
Keywords	Environmental sciences ; GE1-350 ; Geography. Anthropology. Recreation ; G ; DOAJ:Environmental Sciences ; DOAJ:Earth and Environmental Sciences ; Geophysics. Cosmic physics ; QC801-809
Subject code	290
Language	English
Publishing date	2011-12-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Extended and refined multi sensor reanalysis of total ozone for the period 1970–2012

R. J. van der A / M. A. F. Allaart / H. J. Eskes

Atmospheric Measurement Techniques Discussions, Vol 8, Iss 3, Pp 3283-

2015 Volume 3319

Abstract: The ozone multi-sensor reanalysis (MSR) is a multi-decadal ozone column data record constructed using all available ozone column satellite datasets, surface Brewer and Dobson observations and a data assimilation technique with detailed error modelling. ... ...

Abstract	The ozone multi-sensor reanalysis (MSR) is a multi-decadal ozone column data record constructed using all available ozone column satellite datasets, surface Brewer and Dobson observations and a data assimilation technique with detailed error modelling. The result is a high-resolution time series of 6 hourly global ozone column fields and forecast error fields that may be used for ozone trend analyses as well as detailed case studies. The ozone MSR is produced in two steps. First, the latest reprocessed versions of all available ozone column satellite datasets are collected, and are corrected for biases as function of solar zenith angle, viewing angle, time (trend), and stratospheric temperature using Brewer/Dobson ground measurements from the World Ozone and Ultraviolet Radiation Data Centre (WOUDC; http://www.woudc.org/). Subsequently the debiased satellite observations are assimilated within the ozone chemistry and data assimilation model TMDAM driven by meteorological analyses of the European Centre for Medium-Range Weather Forecasts (ECMWF). The MSR2 (MSR version 2) reanalysis upgrade described in this paper consists of an ozone record for the 43 year period 1970–2012. The chemistry-transport model and data assimilation system have been adapted to improve the resolution, error modelling and processing speed. BUV satellite observations have been included for the period 1970–1977. The total record is extended with 13 years compared to the first version of the ozone multi sensor reanalysis, the MSR1. The latest total ozone retrievals of 15 satellite instruments are used: BUV-Nimbus4, TOMS-Nimbus7, TOMS-EP, SBUV-7, -9, -11, -14, -16, -17, -18, -19, GOME, SCIAMACHY, OMI and GOME-2. The resolution of the model runs, assimilation and output is increased from 2° x 3° to 1° x 1°. The analysis is driven by three-hourly meteorology from the ERA-interim reanalysis of ECMWF starting from 1979, and ERA-40 before that date. The chemistry parameterization has been updated. The performance of the MSR2 analysis is studied with the help of observation-minus-forecast (OmF) departures from the data assimilation, by comparisons with the individual station observations and with ozone sondes. The OmF statistics show that the mean bias of the MSR2 analyses is less than 1% with respect to debiased satellite observations after 1979.
Keywords	Meteorology. Climatology ; QC851-999 ; Physics ; QC1-999 ; Science ; Q ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Earthwork. Foundations ; TA715-787
Subject code	290
Language	English
Publishing date	2015-03-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: MAX-DOAS tropospheric nitrogen dioxide column measurements compared with the Lotos-Euros air quality model

T. Vlemmix / H. J. Eskes / A. J. M. Piters / M. Schaap / F. J. Sauter / H. Kelder / P. F. Levelt

Atmospheric Chemistry and Physics, Vol 15, Iss 3, Pp 1313-

2015 Volume 1330

Abstract: A 14-month data set of MAX-DOAS (Multi-Axis Differential Optical Absorption Spectroscopy) tropospheric NO 2 column observations in De Bilt, the Netherlands, has been compared with the regional air quality model Lotos-Euros. The model was run on a 7×7 km ... ...

Abstract	A 14-month data set of MAX-DOAS (Multi-Axis Differential Optical Absorption Spectroscopy) tropospheric NO 2 column observations in De Bilt, the Netherlands, has been compared with the regional air quality model Lotos-Euros. The model was run on a 7×7 km 2 grid, the same resolution as the emission inventory used. A study was performed to assess the effect of clouds on the retrieval accuracy of the MAX-DOAS observations. Good agreement was found between modeled and measured tropospheric NO 2 columns, with an average difference of less than 1% of the average tropospheric column (14.5 · 10 15 molec cm −2 ). The comparisons show little cloud cover dependence after cloud corrections for which ceilometer data were used. Hourly differences between observations and model show a Gaussian behavior with a standard deviation (σ) of 5.5 · 10 15 molec cm −2 . For daily averages of tropospheric NO 2 columns, a correlation of 0.72 was found for all observations, and 0.79 for cloud free conditions. The measured and modeled tropospheric NO 2 columns have an almost identical distribution over the wind direction. A significant difference between model and measurements was found for the average weekly cycle, which shows a much stronger decrease during the weekend for the observations; for the diurnal cycle, the observed range is about twice as large as the modeled range. The results of the comparison demonstrate that averaged over a long time period, the tropospheric NO 2 column observations are representative for a large spatial area despite the fact that they were obtained in an urban region. This makes the MAX-DOAS technique especially suitable for validation of satellite observations and air quality models in urban regions.
Keywords	Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	333
Language	English
Publishing date	2015-02-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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