scholarly journals Observations of the mesospheric semi-annual oscillation (MSAO) in water vapour by Odin/SMR

2008 ◽  
Vol 8 (21) ◽  
pp. 6527-6540 ◽  
Author(s):  
S. Lossow ◽  
J. Urban ◽  
J. Gumbel ◽  
P. Eriksson ◽  
D. Murtagh
Keyword(s):  
Water Vapour ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Annual Variation ◽  
Equatorial Region ◽  
Peak Amplitude ◽  
Altitude Range ◽  
Double Peak Structure ◽  
Latitude Range ◽  
Mixing Ratios

Abstract. Mesospheric water vapour measurements taken by the SMR instrument aboard the Odin satellite between 2002 and 2006 have been analysed with focus on the mesospheric semi-annual circulation in the tropical and subtropical region. This analysis provides the first complete picture of mesospheric SAO in water vapour, covering altitudes above 80 km where previous studies were limited. Our analysis shows a clear semi-annual variation in the water vapour distribution in the entire altitude range between 65 km and 100 km in the equatorial area. Maxima occur near the equinoxes below 75 km and around the solstices above 80 km. The phase reversal occurs in the small layer in-between, consistent with the downward propagation of the mesospheric SAO in the zonal wind in this altitude range. The SAO amplitude exhibits a double peak structure in the equatorial region, with maxima at about 75 km and 81 km. The observed amplitudes show higher values than an earlier analysis based on UARS/HALOE data. The upper peak amplitude remains relatively constant with latitude. The lower peak amplitude decreases towards higher latitudes, but recovers in the Southern Hemisphere subtropics. On the other hand, the annual variation is much more prominent in the Northern Hemisphere subtropics. Furthermore, higher volume mixing ratios during summer and lower values during winter are observed in the Northern Hemisphere subtropics, as compared to the corresponding latitude range in the Southern Hemisphere.

scholarly journals Observations of the mesospheric semi-annual oscillation (MSAO) in water vapour by Odin/SMR

2008 ◽  
Vol 8 (3) ◽  
pp. 10153-10187
Author(s):  
S. Lossow ◽  
J. Urban ◽  
J. Gumbel ◽  
P. Eriksson ◽  
D. Murtagh
Keyword(s):  
Water Vapour ◽  
Southern Hemisphere ◽  
Annual Variation ◽  
Peak Amplitude ◽  
Altitude Range ◽  
Double Peak Structure ◽  
Latitude Range ◽  
Mixing Ratios ◽  
Peak Structure ◽  
Downward Propagation

Abstract. Mesospheric water vapour measurements taken by the SMR instrument onboard the Odin satellite between 2002 and 2006 have been analysed with focus on the mesospheric semi-annual circulation in the tropical and subtropical region. This analysis provides the first complete picture of mesospheric SAO in water vapour, covering altitudes above 80 km where the only previous study based on UARS/HALOE data was limited. Our analysis shows a clear semi-annual variation in the water vapour distribution in the entire altitude range between 65 km and 100 km in the equatorial area. Maxima occur near the equinoxes below 75 km and around the solstices above 80 km. The phase reversal occurs in the small layer in-between, consistent with the downward propagation of the mesospheric SAO in the zonal wind in this altitude range. The SAO amplitude exhibits a double peak structure, with maxima at about 75 km and 81 km. The observed amplitudes show higher values than the UARS/HALOE amplitudes. The upper peak amplitude remains relatively constant with latitude. The lower peak amplitude decreases towards higher latitudes, but recovers in the Southern Hemisphere subtropics. On the other hand, the annual variation is much more prominent in the northern hemispheric subtropics. Furthermore, higher volume mixing ratios during summer and lower values during winter are observed in the Northern Hemisphere subtropics, as compared to the corresponding latitude range in the Southern Hemisphere.

Summing up and consideration of future research needs

1975 ◽  
Vol 189 (1096) ◽  
pp. 479-483
Keyword(s):  
Organochlorine Pesticides ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Organic Pollutants ◽  
Equatorial Region ◽  
The Other ◽  
Future Research ◽  
World Production ◽  
Research Needs ◽  
The World

If there is one thing above all else that this meeting has established it is surely that most of the questions that one may ask regarding organic pollutants and their behaviour in the sea cannot be satisfactorily answered at present. It is only, perhaps, in regard to the persistent organohalogen pesticides, DDT and dieldrin in particular, and PCBs, that one can speak with any assurance. We were persuaded by Professor Goldberg and Dr Portmann that, although the peak input to the oceans in the northern hemisphere may have passed in respect of both DDT and dieldrin, this is not so for the equatorial region and the southern hemisphere; the problem has moved southward and the world production and use of organochlorine pesticides is still increasing. Vigilance must therefore be maintained. The use of PCBs, on the other hand, is being generally phased out.

scholarly journals Climatology and comparison of ozone from ENVISAT/GOMOS and SHADOZ/balloon-sonde observations in the southern tropics

2010 ◽  
Vol 10 (1) ◽  
pp. 1457-1481
Author(s):  
N. Mze ◽  
A. Hauchecorne ◽  
H. Bencherif ◽  
F. Dalaudier ◽  
J.-L. Bertaux
Keyword(s):  
Southern Hemisphere ◽  
Satisfactory Agreement ◽  
Positive Bias ◽  
Altitude Range ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
Stellar Occultation ◽  
Monthly Distribution

Abstract. In this paper, the stellar occultation instrument GOMOS is compared with ozonesondes from the SHADOZ network. We only used nighttime O3 profiles and a requirement selection at 8 Southern Hemisphere stations. 7 years of GOMOS datasets (GOPR 6.0cf and IPF 5.0) and 11 years of balloon-sondes are used in this study. A monthly distribution of GOMOS O3 mixing ratios is performed in the upper-troposphere and in the stratosphere (15–50 km). A comparison with SHADOZ is done in the altitude range from 15 km to 30 km. In the 21–30 km altitude range, a satisfactory agreement is observed between GOMOS and SHADOZ although some differences are observed depending on the station. The range for monthly differences is generally decreasing with increasing height and is within ±15%. It is found that the agreement between GOMOS and SHADOZ degrades below ~20 km. The median differences are nearly within ±5% particularly above 23 km. But a large positive bias is found below 21 km compared to SHADOZ.

scholarly journals Global upper-tropospheric formaldehyde: seasonal cycles observed by the ACE-FTS satellite instrument

2009 ◽  
Vol 9 (1) ◽  
pp. 1051-1095 ◽  
Author(s):  
G. Dufour ◽  
S. Szopa ◽  
M. P. Barkley ◽  
C. D. Boone ◽  
A. Perrin ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Biomass Burning ◽  
Growing Season ◽  
Global Scale ◽  
Tropospheric Chemistry ◽  
Data Set ◽  
Mixing Ratios ◽  
Good Reproduction ◽  
Summer Maximum

Abstract. Seasonally-resolved upper tropospheric profiles of formaldehyde (HCHO) observed by the ACE Fourier transform spectrometer (ACE-FTS) on a near-global scale are presented for the time period from March 2004 to November 2006. Large upper tropospheric HCHO mixing ratios (>150 pptv) are observed during the growing season of the terrestrial biosphere in the Northern Hemisphere and during the biomass burning season in the Southern Hemisphere. The total errors estimated for the retrieved mixing ratios range from 30 to 40% in the upper troposphere and increase in the lower stratosphere. The sampled HCHO concentrations are in satisfactory agreement with previous aircraft and satellite observations with a negative bias (<25%) within observation errors. An overview of the seasonal cycle of the upper tropospheric HCHO is given for different latitudes. A maximum is observed during summer, i.e. during the growing season, in the northern mid- and high latitudes. The influence of biomass burning is visible in HCHO upper tropospheric concentrations during the September-to-October period in the southern tropics and subtropics. Comparisons with two state-of-the-art models (GEOS-Chem and LMDz-INCA) show that the models fail to reproduce the seasonal variations observed in the southern tropics and subtropics but they capture well the variations observed in the Northern Hemisphere (correlation >0.9). Both models underestimate the summer maximum over Europe and Russia and differences in the emissions used for North America result in a good reproduction of the summer maximum by GEOS-Chem but in an underestimate by LMDz-INCA. Globally, GEOS-Chem reproduces well the observations on average over one year but has some difficulties in reproducing the spatial variability of the observations. LMDz-INCA shows significant bias in the Southern Hemisphere, likely related to an underestimation of methane, but better reproduces the temporal and spatial variations. The differences between the models underline the large uncertainties that remain in the emissions of HCHO precursors. Observations of the HCHO upper tropospheric profile provided by the ACE-FTS represent a unique data set for investigating and improving our current understanding of the formaldehyde budget and upper tropospheric chemistry.

scholarly journals Climatology and comparison of ozone from ENVISAT/GOMOS and SHADOZ/balloon-sonde observations in the southern tropics

2010 ◽  
Vol 10 (16) ◽  
pp. 8025-8035 ◽  
Author(s):  
N. Mze ◽  
A. Hauchecorne ◽  
H. Bencherif ◽  
F. Dalaudier ◽  
J.-L. Bertaux
Keyword(s):  
Southern Hemisphere ◽  
Satisfactory Agreement ◽  
Positive Bias ◽  
Altitude Range ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
Stellar Occultation ◽  
Monthly Distribution ◽  
Made In

Abstract. In this paper, the stellar occultation instrument GOMOS is compared with ozonesondes from the SHADOZ network. We only used nighttime O3 profiles and selected 8 Southern Hemisphere stations. 7 years of GOMOS datasets (GOPR 6.0cf and IPF 5.0) and 11 years of balloon-sondes are used in this study. A monthly distribution of GOMOS O3 mixing ratios was performed in the upper-troposphere and in the stratosphere (15–50 km). A comparison with SHADOZ was made in the altitude range between 15 km and 30 km. In the 21–30 km altitude range, a satisfactory agreement was observed between GOMOS and SHADOZ, although some differences were observed depending on the station. The range for monthly differences generally decreases with increasing height and is within ±15%. It was found that the agreement between GOMOS and SHADOZ declines below ~20 km. The median differences are almost within ±5%, particularly above 23 km. But a large positive bias was found below 21 km, in comparison to SHADOZ.

scholarly journals Global marine plankton functional type biomass distributions: <i>Phaeocystis</i> sp.

2012 ◽  
Vol 5 (1) ◽  
pp. 405-443
Author(s):  
M. Vogt ◽  
C. O'Brien ◽  
J. Peloquin ◽  
V. Schoemann ◽  
E. Breton ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Spherical Geometry ◽  
Specific Cell ◽  
Carbon Conversion ◽  
Latitude Range ◽  
Abundance Data ◽  
The North ◽  
Carbon Biomass ◽  
Cell Biomass

Abstract. The planktonic haptophyte Phaeocystis has been suggested to play a fundamental role in the global biogeochemical cycling of carbon and sulphur, but little is known about its global biomass distribution. We have collected global microscopy data of the genus Phaeocystis and converted abundance data to carbon biomass using species-specific carbon conversion factors. Microscopic counts of single-celled and colonial Phaeocystis were obtained both through the mining of online databases and by accepting direct submissions (both published and unpublished) from Phaeocystis specialists. We recorded abundance data from a total of 1595 depth-resolved stations sampled between 1955–2009. The quality-controlled dataset includes 5057 counts of individual Phaeocystis cells resolved to species level and information regarding life-stages from 3526 samples. 83% of stations were located in the Northern Hemisphere while 17% were located in the Southern Hemisphere. Most data were located in the latitude range of 50–70° N. While the seasonal distribution of Northern Hemisphere data was well-balanced, Southern Hemisphere data was biased towards summer months. Mean species- and form-specific cell diameters were determined from previously published studies. Cell diameters were used to calculate the cellular biovolume of Phaeocystis cells, assuming spherical geometry. Cell biomass was calculated using a carbon conversion factor for Prymnesiophytes (Menden-Deuer and Lessard, 2000). For colonies, the number of cells per colony was derived from the colony volume. Cell numbers were then converted to carbon concentrations. An estimation of colonial mucus carbon was included a posteriori, assuming a mean colony size for each species. Carbon content per cell ranged from 9 pg (single-celled Phaeocystis antarctica) to 29 pg (colonial Phaeocystis globosa). Non-zero Phaeocystis cell biomasses (without mucus carbon) range from 2.9 × 10−5 μg l−1 to 5.4 × 103 μg l−1, with a mean of 45.7 μg l−1 and a median of 3.0 μg l−1. Highest biomasses occur in the Southern Ocean below 70° S (up to 783.9 μg l−1), and in the North Atlantic around 50° N (up to 5.4 × 103 μg l−1). The original and gridded data can be downloaded from PANGAEA, http://doi.pangaea.de/10.1594/PANGAEA.779101.

scholarly journals A global climatology of tropospheric and stratospheric ozone derived from Aura OMI and MLS measurements

2011 ◽  
Vol 11 (6) ◽  
pp. 17879-17911 ◽  
Author(s):  
J. R. Ziemke ◽  
S. Chandra ◽  
G. Labow ◽  
P. K. Bhartia ◽  
L. Froidevaux ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Tropospheric Ozone ◽  
Stratospheric Ozone ◽  
Ozone Monitoring Instrument ◽  
Mean Values ◽  
Latitude Range ◽  
The Pacific ◽  
The Pacific Ocean

Abstract. A global climatology of tropospheric and stratospheric column ozone is derived by combining six years of Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone measurements for the period October 2004 through December 2010. The OMI/MLS tropospheric ozone climatology exhibits large temporal and spatial variability which includes ozone accumulation zones in the tropical south Atlantic year-round and in the subtropical Mediterranean/Asia region in summer months. High levels of tropospheric ozone in the Northern Hemisphere also persist in mid-latitudes over the Eastern North American and Asian continents extending eastward over the Pacific Ocean. For stratospheric ozone climatology from MLS, largest ozone abundance lies in the Northern Hemisphere in the latitude range 70° N–80° N in February–April and in the Southern Hemisphere around 40° S–50° S during months August–October. The largest stratospheric ozone abundances in the Northern Hemisphere lie over North America and Eastern Asia extending eastward across the Pacific Ocean and in the Southern Hemisphere south of Australia extending eastward across the dateline. With the advent of many newly developing 3-D chemistry and transport models it is advantageous to have such a dataset for evaluating the performance of the models in relation to dynamical and photochemical processes controlling the ozone distributions in the troposphere and stratosphere. The OMI/MLS ozone gridded climatology data, both calculated mean values and RMS uncertainties are made available to the science community via the NASA total ozone mapping spectrometer (TOMS) website http://toms.gsfc.nasa.gov.

scholarly journals Zonal asymmetries in middle atmospheric ozone and water vapour derived from Odin satellite data 2001–2010

2011 ◽  
Vol 11 (2) ◽  
pp. 4167-4198 ◽  
Author(s):  
A. Gabriel ◽  
H. Körnich ◽  
S. Lossow ◽  
D. H. W. Peters ◽  
J. Urban ◽  
...  
Keyword(s):  
Water Vapour ◽  
Southern Hemisphere ◽  
Satellite Data ◽  
Stationary Wave ◽  
Atmospheric Ozone ◽  
Tracer Transport ◽  
Meridional Transport ◽  
Mixing Processes ◽  
Double Peak Structure ◽  
Wave Patterns

Abstract. Based on Odin satellite data 2001–2010 we investigate stationary wave patterns in middle atmospheric ozone (O3) and water vapour (H2O) as indicated by their seasonal long-term means of the zonally asymmetric components O3* = O3-[O3] and H2O* = H2O-[H2O] ([O3], [H2O]: zonal means). At mid- and polar latitudes of Northern and Southern Hemisphere, we find a pronounced wave one pattern in both constituents. In the Northern Hemisphere, the wave one patterns increase during autumn, maintain their strength during winter and decay during spring, with maximum amplitudes of about 10–20% of zonal mean values. During winter, the wave one in stratospheric O3* is characterized by a maximum over North Pacific/Aleutians and a minimum over North Atlantic/Northern Europe and by a double-peak structure with enhanced amplitude in the lower and in the upper stratosphere. The wave one in H2O* extends from lower stratosphere to upper mesosphere with a westward shift in phase with increasing height including a jump in phase at upper stratosphere altitudes. In the Southern Hemisphere, similar wave one patterns occur during southern spring when the polar vortex breaks down. Based on a simplified tracer transport approach we explain these wave patterns as a first-order result of zonal asymmetries in mean meridional transport by geostrophically balanced winds, which were derived from combined temperature profiles of Odin, and ECMWF (European Centre of Medium-Range Weather Forecasts) Reanalysis data (ERA Interim). Further influences which may contribute to the stationary wave patterns, e.g. eddy mixing processes or temperature-dependent chemistry, are discussed.

scholarly journals Hydrogen cyanide in the upper troposphere: GEM-AQ simulation and comparison with ACE-FTS observations

2009 ◽  
Vol 9 (13) ◽  
pp. 4301-4313 ◽  
Author(s):  
A. Lupu ◽  
J. W. Kaminski ◽  
L. Neary ◽  
J. C. McConnell ◽  
K. Toyota ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Atmospheric Chemistry ◽  
Hydrogen Cyanide ◽  
Boreal Summer ◽  
Air Quality Model ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
The Tropics

Abstract. We investigate the spatial and temporal distribution of hydrogen cyanide (HCN) in the upper troposphere through numerical simulations and comparison with observations from a space-based instrument. To perform the simulations, we used the Global Environmental Multiscale Air Quality model (GEM-AQ), which is based on the three-dimensional global multiscale model developed by the Meteorological Service of Canada for operational weather forecasting. The model was run for the period 2004–2006 on a 1.5°×1.5° global grid with 28 hybrid vertical levels from the surface up to 10 hPa. Objective analysis data from the Canadian Meteorological Centre were used to update the meteorological fields every 24 h. Fire emission fluxes of gas species were generated by using year-specific inventories of carbon emissions with 8-day temporal resolution from the Global Fire Emission Database (GFED) version 2. The model output is compared with HCN profiles measured by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) instrument onboard the Canadian SCISAT-1 satellite. High values of up to a few ppbv are observed in the tropics in the Southern Hemisphere; the enhancement in HCN volume mixing ratios in the upper troposphere is most prominent in October. Low upper-tropospheric mixing ratios of less than 100 pptv are mostly recorded at middle and high latitudes in the Southern Hemisphere in May–July. Mixing ratios in Northern Hemisphere peak in the boreal summer. The amplitude of the seasonal variation is less pronounced than in the Southern Hemisphere. The comparison with the satellite data shows that in the upper troposphere GEM-AQ performs well globally for all seasons, except at northern high and middle latitudes in summer, where the model has a large negative bias, and in the tropics in winter and spring, where it exhibits large positive bias. This may reflect inaccurate emissions or possible inaccuracies in the emission profile. The model is able to explain most of the observed variability in the upper troposphere HCN field, including the interannual variations in the observed mixing ratio. A complementary comparison with daily total columns of HCN from two middle latitude ground-based stations in Northern Japan for the same simulation period shows that the model captures the observed seasonal variation and also points to an underestimation of model emissions in the Northern Hemisphere in the summer. The estimated average global emission equals 1.3 Tg N yr−1. The average atmospheric burden is 0.53 Tg N, and the corresponding lifetime is 4.9 months.

scholarly journals Intercomparison of ILAS-II version 1.4 and version 2 target parameters with MIPAS-Envisat measurements

2008 ◽  
Vol 8 (4) ◽  
pp. 825-843 ◽  
Author(s):  
A. Griesfeller ◽  
T. von Clarmann ◽  
J. Griesfeller ◽  
M. Höpfner ◽  
M. Milz ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Data Quality ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Quality Evaluation ◽  
Mixing Ratios ◽  
The Mean ◽  
Mean Differences

Abstract. This paper assesses the mean differences between the two ILAS-II data versions (1.4 and 2) by comparing them with MIPAS measurements made between May and October 2003. For comparison with ILAS-II results, MIPAS data processed at the Institut für Meteorologie und Klimaforschung, Karlsruhe, Germany (IMK) in cooperation with the Instituto de Astrofísica de Andalucía (IAA) in Granada, Spain, were used. The coincidence criteria of ±300 km in space and ±12 h in time for H2O, N2O, and CH4 and the coincidence criteria of ±300 km in space and ±6 h in time for ClONO2, O3, and HNO3 were used. The ILAS-II data were separated into sunrise (= Northern Hemisphere) and sunset (= Southern Hemisphere). For the sunrise data, a clear improvement from version 1.4 to version 2 was observed for H2O, CH4, ClONO2, and O3. In particular, the ILAS-II version 1.4 mixing ratios of H2O and CH4 were unrealistically small, and those of ClONO2 above altitudes of 30 km unrealistically large. For N2O and HNO3, there were no large differences between the two versions. Contrary to the Northern Hemisphere, where some exceptional profiles deviated significantly from known climatology, no such outlying profiles were found in the Southern Hemisphere for both versions. Generally, the ILAS-II version 2 data were in better agreement with the MIPAS data than the version 1.4, and are recommended for quantitative analysis in the stratosphere. For H2O data in the Southern Hemisphere, further data quality evaluation is necessary.

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