共查询到20条相似文献,搜索用时 125 毫秒
1.
T. AALTO J. HATAKKA I. PAATERO J.-P. TUOVINEN M. AURELA T. LAURILA K. HOLMÉN N. TRIVETT Y. VIISANEN 《Tellus. Series B, Chemical and physical meteorology》2002,54(2):110-126
Diurnal and annual variations of CO2 , O3, SO2 , black carbon and condensation nuclei and their source areas were studied by utilizing air parcel trajectories and tropospheric concentration measurements at a boreal GAW site in Pallas, Finland. The average growth trend of CO2 was about 2.5 ppm yr−1 according to a 4-yr measurement period starting in October 1996. The annual cycle of CO2 showed concentration difference of about 19 ppm between the summer minimum and winter maximum. The diurnal cycle was most pronounced during July and August. The variation between daily minimum and maximum was about 5 ppm. There was a diurnal cycle in aerosol concentrations during spring and summer. Diurnal variation in ozone concentrations was weak. According to trajectory analysis the site was equally affected by continental and marine air masses. During summer the contribution of continental air increased, although the southernmost influences decreased. During daytime in summer the source areas of CO2 were mainly located in the northern parts of the Central Europe, while during winter the sources were more evenly distributed. Ozone showed similar source areas during summer, while during winter, unlike CO2 , high concentrations were observed in air arriving from the sea. Sulfur dioxide sources were more northern (Kola peninsula and further east) and CO2 sources west-weighted in comparison to sources of black carbon. Source areas of black carbon were similar to source areas of aerosols during winter. Aerosol source area distributions showed signs of marine sources during spring and summer. 相似文献
2.
SHINJIRO OHKUBO YOSHIKO KOSUGI SATORU TAKANASHI NAOKO MATSUO MAKOTO TANI ABDUL RAHIM NIK 《Tellus. Series B, Chemical and physical meteorology》2008,60(4):569-582
Ambient CO2 concentration, air temperature and relative humidity were measured intermittently for a 3-year period from the floor to the canopy top of a tropical rainforest in Pasoh, Peninsular Malaysia. Mean diurnal CO2 storage flux ( S c ; μmol m−2 s−1 ) and sensible and latent heat storage fluxes ( Q a and Q w ; W m−2 ) ranged from −12.7 to 3.2 μmol m−2 s−1 , −15 to 27 W m−2 and −10 to 20 W m−2 , respectively. Small differences in diurnal changes were observed in S c and Q a between the driest and wettest periods. Compared with the ranges of mean diurnal CO2 eddy flux (−14.7 to 4.9 μmol m−2 s−1 ), sensible eddy flux (−12 to 169 W m−2 ) and latent eddy flux (0 to 250 W m−2 ), the contribution of CO2 storage flux was especially large. Comparison with summertime data from a temperate Japanese cypress forest suggested a higher contribution of S c in the tropical rainforest, probably mainly due to the difference in nighttime friction velocity at the sites. On the other hand, differences in Q a and Q w were smaller than the difference in S c , probably because of the smaller nighttime sinks/sources of heat and water vapour. 相似文献
3.
WOLFRAM SCHÜßLER ROLF NEUBERT INGEBORG LEVIN NATALIE FISCHER CHRISTIAN SONNTAG 《Tellus. Series B, Chemical and physical meteorology》2000,52(3):909-918
The amounts of microbial and root‐respired CO2 in a maize/winter wheat agricultural system in south western Germany were investigated by measurements of the CO2 mixing ratio and the 13 C/12 C ratio in soil air. CO2 fluxes at the soil surface for the period of investigation (1993–1995) were also determined. Root respired CO2 shows a strong correlation with the plant mass above ground surface of the respective vegetation (R2 ≥0.88); the maximum CO2 release from roots was in August for the maize (2.0±0.5 mmol m−2 h−1 ) and in June for winter wheat (1.5±0.5 mmol m−2 h−1 ). Maximum CO2 production by roots correlate well with the maximum amount of plant root matter. Integrating the CO2 production over the whole growing season and normalizing to the dry root matter yields, the CO2 production per gram dry organic root matter (DORM) of maize was found to be 0.14±0.03 gC (g DORM)−1 . At the sites investigated, root‐produced CO2 contributed (16±4)% for maize, and (24±4)% for winter wheat, respectively, to the total annual CO2 production in the soil (450±50 gC m−2 for maize, 210±30 gC m−2 for winter wheat). 相似文献
4.
By HEATHER D. GRAVEN † BRITTON B. STEPHENS THOMAS P. GUILDERSON TERESA L. CAMPOS DAVID S. SCHIMEL J. ELLIOTT CAMPBELL RALPH F. KEELING 《Tellus. Series B, Chemical and physical meteorology》2009,61(3):536-546
Measurements of Δ14 C in atmospheric CO2 are an effective method of separating CO2 additions from fossil fuel and biospheric sources or sinks of CO2 . We illustrate this technique with vertical profiles of CO2 and Δ14 C analysed in whole air flask samples collected above Colorado, USA in May and July 2004. Comparison of lower tropospheric composition to cleaner air at higher altitudes (>5 km) revealed considerable additions from respiration in the morning in both urban and rural locations. Afternoon concentrations were mainly governed by fossil fuel emissions and boundary layer depth, also showing net biospheric CO2 uptake in some cases. We estimate local industrial CO2 :CO emission ratios using in situ measurements of CO concentration. Ratios are found to vary by 100% and average 57 mole CO2 :1 mole CO, higher than expected from emissions inventories. Uncertainty in CO2 from different sources was ±1.1 to ±4.1 ppm for addition or uptake of −4.6 to 55.8 ppm, limited by Δ14 C measurement precision and uncertainty in background Δ14 C and CO2 levels. 相似文献
5.
Hiroshi A. Takahashi Eiichi Konohira Tetsuya Hiyama Masayo Minami Toshio Nakamura Naohiro Yoshida 《Tellus. Series B, Chemical and physical meteorology》2002,54(2):97-109
Diurnal variation in the atmospheric CO2 concentration and the carbon isotopic composition (Δ14 C and δ13 C) was measured in a forest in an urban area on 9 February 1999. The carbon isotope approach used in the present study differentiated between the quantitative contributions from anthropogenic and biogenic CO2 sources in the urban atmosphere. The anthropogenic (fossil fuel) and biogenic (soil respiration) contributions was estimated, and they ranged from 1 to 16% and from 2 to 8% of the total atmospheric CO2 . The diurnal variation of the anthropogenic CO2 was the major cause of the total atmospheric CO2 variation, while the biogenic CO2 remained relatively constant throughout the day. Estimating the contribution of soil respired CO2 provided the mean residence time of soil respired CO2 within the forest atmosphere. 相似文献
6.
Long‐range transport of anthropogenic and biogenic CO2 to a remote site in the Arctic is studied. A limited area, off‐line, Eulerian atmospheric transport model is used, and the results are compared to the observed CO2 concentration at the "Ny‐Alesund International Arctic Research and Monitoring Facility". Inventories of anthropogenic CO2 emissions and estimates of biogenic CO2 emissions are used to investigate the respective impact of these emissions on Arctic CO2 variations during 4 winter months. A direct comparison of the modelled and observed concentrations reveals remarkably good timing in the modelled variations as compared to the observed variations for most of the time. The correlation of observed versus modelled CO2 concentration is significant at the 95% confidence level. The biogenic and the anthropogenic CO2 emissions are shown to have approximately equal influence on Arctic CO2 variations during winter. Europe is found to be the dominant source of anthropogenic CO2 at the monitoring station, while Siberia and Northern America have little influence on Arctic CO2 , during the months studied. These results contradict Engardt and Holmén whose results indicate that the lower‐Ob region in western Siberia has a large impact on Arctic CO2 . 相似文献
7.
By NATCHAYA PINGINTHA MONIQUE Y. LECLERC JOHN P. BEASLEY Jr. GENGSHENG ZHANG CHUCKREE SENTHONG 《Tellus. Series B, Chemical and physical meteorology》2010,62(1):47-58
This paper uses a refined soil gradient method to estimate soil CO2 efflux. Six different models are used to determine the relative gas diffusion coefficient (ξ). A weighted harmonic averaging is used to estimate the soil CO2 diffusion coefficient, yielding a better estimate of soil CO2 efflux. The resulting soil CO2 efflux results are then compared to the soil CO2 efflux measured with a soil chamber. Depending on the choice of ξ model used, the estimated soil CO2 efflux using the gradient method reasonably approximates the efflux obtained using the soil chamber method. In addition, the estimated soil CO2 efflux obtained by this improved method is well described by an exponential function of soil temperature at a depth of 0.05 m with the temperature sensitivity ( Q 10 ) of 1.81 and a linear function of soil moisture at a depth of 0.12 m, in general agreement with previous findings. These results suggest that the gradient method is a practical cost-effective means to measure soil CO2 emissions. Results from the present study suggest that the gradient method can be used successfully to measure soil CO2 efflux provided that proper attention is paid to the judicious use of the proper diffusion coefficient. 相似文献
8.
VINCENT E. LARSON HANS VOLKMER 《Tellus. Series B, Chemical and physical meteorology》2008,60(4):525-536
The net flux of carbon dioxide (CO2 ) from the land surface into the atmospheric boundary layer has a diurnal cycle. Drawdown of CO2 occurs during daytime photosynthesis, and return of CO2 to the atmosphere occurs during night. Even when the net diurnal-average surface flux vanishes, the diurnal-average profile of atmospheric CO2 mixing ratio is usually not vertically uniform. This is because of the diurnal rectifier effect, by which atmospheric vertical transport and the surface flux conspire to produce a surplus of CO2 near the ground and a deficit aloft.
This paper constructs an idealized, 1-D, eddy-diffusivity model of the rectifier effect and provides an analytic series solution. When non-dimensionalized, the intensity of the rectifier effect is related solely to a single 'rectifier parameter'. Given this model's governing equation and boundary conditions, we prove that the existence of the rectifier effect is related to the correlation of CO2 gradient and transport, and also to the day–night symmetry of transport.
The rectifier-induced near-surface CO2 surplus ought to be included in inverse calculations that use near-surface CO2 mixing ratio to infer land–surface sources and sinks of carbon. Such inverse modeling is facilitated by our model's simplicity. To illustrate, we use a 1-D inverse calculation to infer the amplitude of diurnal CO2 surface flux. 相似文献
This paper constructs an idealized, 1-D, eddy-diffusivity model of the rectifier effect and provides an analytic series solution. When non-dimensionalized, the intensity of the rectifier effect is related solely to a single 'rectifier parameter'. Given this model's governing equation and boundary conditions, we prove that the existence of the rectifier effect is related to the correlation of CO
The rectifier-induced near-surface CO
9.
A recent build-up of atmospheric CO2 over Europe. Part 1: observed signals and possible explanations
By MICHEL RAMONET PHILIPPE CIAIS TUULA AALTO CÉLINE AULAGNIER FRÉDÉRIC CHEVALLIER DOMENICO CIPRIANO THOMAS J. CONWAY LASZLO HASZPRA VICTOR KAZAN FRANK MEINHARDT JEAN-DANIEL PARIS MARTINA SCHMIDT PETER SIMMONDS IRÈNE XUEREF-RÉMY JAROSLAW N. NECKI 《Tellus. Series B, Chemical and physical meteorology》2010,62(1):1-13
We analysed interannual and decadal changes in the atmospheric CO2 concentration gradient (ΔCO2 ) between Europe and the Atlantic Ocean over the period 1995–2007. Fourteen measurement stations are used, with Mace-Head being used to define background conditions. The variability of ΔCO2 reflects fossil fuel emissions and natural sinks activity over Europe, as well as atmospheric transport variability. The mean ΔCO2 increased by 1–2 ppm at Eastern European stations (∼30% growth), between 1990–1995 and 2000–2005. This built up of CO2 over the continent is predominantly a winter signal. If the observed increase of ΔCO2 is explained by changes in ecosystem fluxes, a loss of about 0.46 Pg C per year would be required during 2000–2005. Even if severe droughts have impacted Western Europe in 2003 and 2005, a sustained CO2 loss of that magnitude is unlikely to be true. We sought alternative explanations for the observed CO2 build-up into transport changes and into regional redistribution of fossil fuel CO2 emissions. Boundary layer heights becoming shallower can only explain 32% of the variance of the signal. Regional changes of emissions may explain up to 27% of the build-up. More insights are given in the Aulagnier et al. companion paper. 相似文献
10.
J.-D. PARIS P. CIAIS P. NÉDÉLEC M. RAMONET B. D. BELAN M. YU. ARSHINOV G. S. GOLITSYN I. GRANBERG A. STOHL G. CAYEZ G. ATHIER F. BOUMARD J.-M. COUSIN 《Tellus. Series B, Chemical and physical meteorology》2008,60(4):551-568
Two airborne campaigns were carried out to measure the tropospheric concentrations and variability of CO2 , CO and O3 over Siberia. In order to quantify the influence of remote and regional natural and anthropogenic sources, we analysed a total of 52 vertical profiles of these species collected in April and September 2006, every ∼200 km and up to 7 km altitude. CO2 and CO concentrations were high in April 2006 (respectively 385–390 ppm CO2 and 160–200 ppb CO) compared to background values. CO concentrations up to 220 ppb were recorded above 3.5 km over eastern Siberia, with enhancements in 500–1000 m thick layers. The presence of CO enriched air masses resulted from a quick frontal uplift of a polluted air mass exposed to northern China anthropogenic emissions and to fire emissions in northern Mongolia. A dominant Asian origin for CO above 4 km (71.0%) contrasted with a dominant European origin below this altitude (70.9%) was deduced both from a transport model analysis, and from the contrasted ΔCO/ΔCO2 ratio vertical distribution. In September 2006, a significant O3 depletion (∼–30 ppb) was repeatedly observed in the boundary layer, as diagnosed from virtual potential temperature profiles and CO2 gradients, compared to the free troposphere aloft, suggestive of a strong O3 deposition over Siberian forests. 相似文献
11.
K. M. STRASSMANN F. JOOS G. FISCHER 《Tellus. Series B, Chemical and physical meteorology》2008,60(4):583-603
The impact of land use on the global carbon cycle and climate is assessed. The Bern carbon cycle-climate model was used with land use maps from HYDE3.0 for 1700 to 2000 A.D. and from post-SRES scenarios for this century. Cropland and pasture expansion each cause about half of the simulated net carbon emissions of 188 Gt C over the industrial period and 1.1 Gt C yr−1 in the 1990s, implying a residual terrestrial sink of 113 Gt C and of 1.8 Gt C yr−1 , respectively. Direct CO2 emissions due to land conversion as simulated in book-keeping models dominate carbon fluxes due to land use in the past. They are, however, mitigated by 25% through the feedback of increased atmospheric CO2 stimulating uptake. CO2 stimulated sinks are largely lost when natural lands are converted. Past land use change has eliminated potential future carbon sinks equivalent to emissions of 80–150 Gt C over this century. They represent a commitment of past land use change, which accounts for 70% of the future land use flux in the scenarios considered. Pre-industrial land use emissions are estimated to 45 Gt C at most, implying a maximum change in Holocene atmospheric CO2 of 3 ppm. This is not compatible with the hypothesis that early anthropogenic CO2 emissions prevented a new glacial period. 相似文献
12.
By LAUREN ELMEGREEN RAFELSKI STEPHEN C. PIPER RALPH F. KEELING 《Tellus. Series B, Chemical and physical meteorology》2009,61(5):718-731
The buildup of atmospheric CO2 since 1958 is surprisingly well explained by the simple premise that 57% of the industrial emissions (fossil fuel burning and cement manufacture) has remained airborne. This premise accounts well for the rise both before and after 1980 despite a decrease in the growth rate of fossil fuel CO2 emissions, which occurred at that time, and by itself should have caused the airborne fraction to decrease. In contrast, the buildup prior to 1958 was not simply proportional to cumulative fossil fuel emissions, and notably included a period during the 1940s when CO2 growth stalled despite continued fossil fuel emissions. Here we show that the constancy of the airborne fraction since 1958 can be in part explained by decadal variations in global land air temperature, which caused a warming-induced release of CO2 from the land biosphere to the atmosphere. We also show that the 1940s plateau may be related to these decadal temperature variations. Furthermore, we show that there is a close connection between the phenomenology producing CO2 variability on multidecadal and El Niño timescales. 相似文献
13.
G.K. PLATTNER F. JOOS T. F. STOCKER O. MARCHAL 《Tellus. Series B, Chemical and physical meteorology》2001,53(5):564-592
Global warming simulations are performed with a coupled climate model of reduced complexity to investigate global warming–marine carbon cycle feedbacks. The model is forced by emissions of CO2 and other greenhouse agents from scenarios recently developed by the Intergovernmental Panel on Climate Change and by CO2 stabilization profiles. The uptake of atmospheric CO2 by the ocean is reduced between 7 to 10% by year 2100 compared to simulations without global warming. The reduction is of similar size in the Southern Ocean and in low‐latitude regions (32.5°S‐32.5°N) until 2100, whereas low‐latitude regions dominate on longer time scales. In the North Atlantic the CO2 uptake is enhanced, unless the Atlantic thermohaline circulation completely collapses. At high latitudes, biologically mediated changes enhance ocean CO2 uptake, whereas in low‐latitude regions the situation is reversed. Different implementations of the marine biosphere yield a range of 5 to 16% for the total reduction in oceanic CO2 uptake until year 2100. Modeled oceanic O2 inventories are significantly reduced in global warming simulations. This suggests that the terrestrial carbon sink deduced from atmospheric O2 /N2 observations is potentially overestimated if the oceanic loss of O2 to the atmosphere is not considered. 相似文献
14.
HIDEKAZU MATSUEDA HISAYUKI YOSHIKAWA INOUE MASAO ISHII 《Tellus. Series B, Chemical and physical meteorology》2002,54(1):1-21
Abstract The spatial and temporal variations of atmospheric CO2 at 8–13 km from April 1993 to April 1999 were observed by measuring CO2 mixing ratios in samples collected biweekly from a commercial airliner between Australia and Japan. The CO2 growth rate showed a considerable interannual variation, with a maximum of about 3 ppm yr−1 during late 1997. This variation is related to the El Niño/Southern Oscillation (ENSO) events. A year-to-year change related to the ENSO events was also found in the latitudinal distribution pattern of the CO2 annual mean between 30°N and 30°S. The averaged CO2 seasonal cycle in the Northern Hemisphere gradually decayed toward the equator, and a relatively complicated variation with a double seasonal maximum appeared in the Southern Hemisphere. A significant yearly change of the seasonal cycle pattern was observed in the Southern Hemisphere. The impact of a tropical biomass-burning injection on the upper tropospheric CO2 was estimated on the basis of the CO data from the same airliner observation. 相似文献
15.
LAURENT BOPP OLIVIER AUMONT SAUVEUR BELVISO PATRICK MONFRAY 《Tellus. Series B, Chemical and physical meteorology》2003,55(1):11-22
Dimethyl sulfide (DMS) is a biogenic compound produced in sea-surface water and outgased to the atmosphere. Once in the atmosphere, DMS is a significant source of cloud condensation nuclei in the unpolluted marine atmosphere. It has been postulated that climate may be partly modulated by variations in DMS production through a DMS-cloud condensation nuclei-albedo feedback. We present here a modelled estimation of the response of DMS sea-water concentrations and DMS fluxes to climate change, following previous work on marine DMS modeling ( Aumont et al., 2002 ) and on the global warming impact on marine biology ( Bopp et al., 2001 ). An atmosphere–ocean general circulation model (GCM) was coupled to a marine biogeochemical scheme and used without flux correction to simulate climate response to increased greenhouse gases (a 1% increase per year in atmospheric CO2 until it has doubled). The predicted global distribution of DMS at 1 × CO2 compares reasonably well with observations; however, in the high latitudes, very elevated concentrations of DMS due to spring and summer blooms of Phaeocystis can not be reproduced. At 2 × CO2 , the model estimates a small increase of global DMS flux to the atmosphere (+2%) but with large spatial heterogeneities (from −15% to +30% for the zonal mean). Mechanisms affecting DMS fluxes are changes in (1) marine biological productivity, (2) relative abundance of phytoplankton species and (3) wind intensity. The mean DMS flux perturbation we simulate represents a small negative feedback on global warming; however, the large regional changes may significantly impact regional temperature and precipitation patterns. 相似文献
16.
Climate sensitivity to cloud optical properties 总被引:1,自引:0,他引:1
A radiative–convective model was developed to investigate the sensitivity of climate to cloud optical properties and the related feedback processes. This model demonstrates that the Earth's surface temperature increases with cloud optical depth when the clouds are very thin but decreases with cloud optical depth when the cloud shortwave (solar) radiative forcing is larger than the cloud longwave (terrestrial) radiative forcing. When clouds are included in the model, the magnitude of the greenhouse effect due to a doubling of the CO2 concentration varies with the cloudoptical depth: the thicker the clouds, the weaker the greenhouse warming. In addition, a small variation in the cloud droplet size has a larger impact on the equilibrium state temperature in the lower atmosphere than the warming caused by a doubling of the CO2 concentration: a 2% increase in the average cloud droplet size per degree increase in temperature doubles the warming caused by the doubling of the CO2 concentration. These findings suggest that physically reliable correlations between the cloud droplet size and macrophysical meteorological variables such as temperature, wind and water vapor fields are needed on a global climate scale to assess the climate impact of increases in greenhouse gases. 相似文献
17.
18.
基于连续的植被指数(NDVI)、气温和降水数据,提取了1982—2009年青藏高原典型台站邻近区域的植物返青期以及0℃和5℃旬均温始期的时序数据,分析了其时空变化特征,探讨了青藏高原冬、春季的气温、降水变化对植物返青期的影响。结果表明:1) 青藏高原典型台站邻近区域植物返青期多年平均值在东西向和南北向上存在显著差异;1982—2009年间,青藏高原典型台站邻近区域植物返青期整体呈提前趋势。2) 青藏高原典型台站0℃和5℃旬均温始期整体呈提前趋势,5℃旬均温始期提前趋势更为显著。3) 青藏高原植物返青期随着冬、春季气温升高和降水增加而提前。与降水相比,返青期与气温的相关程度更高。冬季气温比春季气温对植物返青期的影响更大。 相似文献
19.
By TOBIAS NAEGLER 《Tellus. Series B, Chemical and physical meteorology》2009,61(2):372-384
Oceanic excess radiocarbon data is widely used as a constraint for air–sea gas exchange. However, recent estimates of the global mean piston velocity 〈 k 〉 from Naegler et al., Krakauer et al., Sweeney et al. and Müller et al. differ substantially despite the fact that they all are based on excess radiocarbon data from the GLODAP data base. Here I show that these estimates of 〈 k 〉 can be reconciled if first, the changing oceanic radiocarbon inventory due to net uptake of CO2 is taken into account; second, if realistic reconstructions of sea surface Δ14 C are used and third, if 〈 k 〉 is consistently reported with or without normalization to a Schmidt number of 660. These corrections applied, unnormalized estimates of 〈 k 〉 from these studies range between 15.1 and 18.2 cm h−1 . However, none of these estimates can be regarded as the only correct value for 〈 k 〉 . I thus propose to use the 'average' of the corrected values of 〈 k 〉 presented here (16.5 ± 3.2 cm h−1 ) as the best available estimate of the global mean unnormalized piston velocity 〈 k 〉 , resulting in a gross ocean-to-atmosphere CO2 flux of 76 ± 15 PgC yr−1 for the mid-1990s. 相似文献
20.
By C. AULAGNIER P. RAYNER P. CIAIS R. VAUTARD L. RIVIER M. RAMONET 《Tellus. Series B, Chemical and physical meteorology》2010,62(1):14-25
In this issue, Ramonet et al. revealed a positive trend in European, atmospheric CO2 concentrations relative to a marine, North Atlantic reference baseline, for the years 2001–2006. The observed build up mainly occurred during the cold season where it reaches a 0.8 ppm yr−1 at low-altitude stations to a 0.3 ppm yr−1 at mid-altitude stations. We explore the cause of this build-up using the mesoscale model CHIMERE. We first model the observed trends, using interannually varying fluxes and transport, then suppress the interannual variability in fluxes or aspects of transport to elucidate the cause. The run with no interannual variability in fluxes still matches observed trends suggesting that transport is the major cause. Separate runs varying either boundary layer height or winds show that changes in boundary layer height explain the trends at low-altitude stations within the continents while changes in wind regimes drive changes elsewhere. 相似文献