| 21. |
- Koo, J. H., et al.
(författare)
-
Global climatology based on the ACE-FTS version 3.5 dataset: Addition of mesospheric levels and carbon-containing species in the UTLS
- 2017
-
Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier BV. - 0022-4073. ; 186, s. 52-62
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present a new climatology based on, the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) version 3.5 data set from February 2004 to February 2013. This extends the ACE-FTS climatology to include profile information in the mesosphere and carbon-containing species in the upper troposphere and lower stratosphere. Climatologies of 21 species, based on nine years of observations, are calculated, providing the most comprehensive and self-consistent climatology available from limb-viewing satellite measurements. Pressure levels from the upper troposphere to the mesosphere and lower thermosphere are included with similar to 3 to 4 km vertical resolution up to 10(-4) hPa (similar to 105 km). Volume mixing ratio values are filtered prior to the climatology estimation using the ACE-FTS data quality recommendations. The multi-year mean climatology contains zonal mean profiles for monthly and three-monthly (DJF, MAM, JJA, and SON) periods. These are provided with 5-degree spacing in either latitude or equivalent latitude. Also, the local daytime and nighttime distributions are provided separately for nitrogen-containing species, enabling diurnal differences to be investigated. Based on this climatology, examples of typical spatiotemporal patterns for trace gases in the mesosphere and for carbon-containing gases in the upper troposphere and lower stratosphere are discussed. (C) 2016 Elsevier Ltd. All rights reserved.
|
|
| 22. |
- Laeng, A., et al.
(författare)
-
Validation of MIPAS IMK/IAA V5R_O3_224 ozone profiles
- 2014
-
Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 7:11, s. 3971-3987
-
Tidskriftsartikel (refereegranskat)abstract
- We present the results of an extensive validation program of the most recent version of ozone vertical profiles retrieved with the IMK/IAA (Institute for Meteorology and Climate Research/Instituto de Astrofisica de Andalucia) MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) research level 2 processor from version 5 spectral level 1 data. The time period covered corresponds to the reduced spectral resolution period of the MIPAS instrument, i.e., January 2005-April 2012. The comparison with satellite instruments includes all post-2005 satellite limb and occultation sensors that have measured the vertical profiles of tropospheric and stratospheric ozone: ACE-FTS, GOMOS, HALOE, HIRDLS, MLS, OSIRIS, POAM, SAGE II, SCIAMACHY, SMILES, and SMR. In addition, balloon-borne MkIV solar occultation measurements and ground-based Umkehr measurements have been included, as well as two nadir sensors: IASI and SBUV. For each reference data set, bias determination and precision assessment are performed. Better agreement with reference instruments than for the previous data version, V5R_O3_220 (Laeng et al., 2014), is found: the known high bias around the ozone vmr (volume mixing ratio) peak is significantly reduced and the vertical resolution at 35 km has been improved. The agreement with limb and solar occultation reference instruments that have a known small bias vs. ozonesondes is within 7% in the lower and middle stratosphere and 5% in the upper troposphere. Around the ozone vmr peak, the agreement with most of the satellite reference instruments is within 5 %; this bias is as low as 3% for ACE-FTS, MLS, OSIRIS, POAM and SBUV.
|
|
| 23. |
- Lossow, Stefan, 1977, et al.
(författare)
-
Comparison of HDO measurements from Envisat/MIPAS with observations by Odin/SMR and SCISAT/ACE-FTS
- 2011
-
Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 4:9, s. 1855-1874
-
Tidskriftsartikel (refereegranskat)abstract
- Measurements of thermal emission in the mid-infrared by Envisat/MIPAS allow the retrieval of HDO information roughly in the altitude range between 10 km and 50 km. From June 2002 to March 2004 MIPAS performed measurements in the full spectral resolution mode. To assess the quality of the HDO data set obtained during that period comparisons with measurements by Odin/SMR and SCISAT/ACE-FTS were performed. Comparisons were made on profile-to-profile basis as well as using seasonal and monthly averages. All in all the comparisons yield favourable results. The largest deviations between MIPAS and ACE-FTS are observed below 15 km, where relative deviations can occasionally exceed 100%. Despite these deviations in the absolute amount of HDO the latitudinal structures observed by both instruments are consistent in this altitude range. Between 15 km and 20 km there is less good agreement, in particular in the Antarctic during winter and spring. Also in the tropics some deviations are found. Above 20 km there is a high consistency in the structures observed by all three instruments. MIPAS and ACE-FTS typically agree within 10%, with MIPAS mostly showing higher abundances than ACE-FTS. Both data sets show considerably more HDO than SMR. This bias can be explained basically by uncertainties in spectroscopic parameters. Above 40 km, where the MIPAS HDO retrieval reaches its limits, still good agreement with the structures observed by SMR is found for most seasons. This puts some confidence in the MIPAS data at these altitudes.
|
|
| 24. |
- Milz, Mathias, et al.
(författare)
-
Validation of water vapour profiles (version 13) retrieved by the IMK/IAA scientific retrieval processor based on full resolution spectra measured by MIPAS on board Envisat
- 2009
-
Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 2:2, s. 379-399
-
Tidskriftsartikel (refereegranskat)abstract
- Vertical profiles of stratospheric water vapour measured by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) with the full resolution mode between September 2002 and March 2004 and retrieved with the IMK/IAA scientific retrieval processor were compared to a number of independent measurements in order to estimate the bias and to validate the existing precision estimates of the MIPAS data. The estimated precision for MIPAS is 5 to 10% in the stratosphere, depending on altitude, latitude, and season. The independent instruments were: the Halogen Occultation Experiment (HALOE), the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS), the Improved Limb Atmospheric Spectrometer-II (ILAS-II), the Polar Ozone and Aerosol Measurement (POAM III) instrument, the Middle Atmospheric Water Vapour Radiometer (MIAWARA), the Michelson Interferometer for Passive Atmospheric Sounding, balloon-borne version (MIPAS-B), the Airborne Microwave Stratospheric Observing System(AMSOS), the Fluorescent Stratospheric Hygrometer for Balloon (FLASH-B), the NOAA frostpoint hygrometer, and the Fast In Situ Hygrometer (FISH). For the in-situ measurements and the ground based, air- and balloon borne remote sensing instruments, the measurements are restricted to central and northern Europe. The comparisons to satellite-borne instruments are predominantly at mid- to high latitudes on both hemispheres. In the stratosphere there is no clear indicationof a bias in MIPAS data, because the independent measurements in some cases are drier and in some cases are moister than the MIPAS measurements. Compared to the infrared measurements of MIPAS, measurements in the ultraviolet and visible have a tendency to be high, whereas microwave measurements have a tendency to be low. Theresults of chi2-based precision validation are somewhat controversial among the comparison estimates. However, for comparison instruments whose error budget also includes errors due to uncertainties in spectrally interfering species and where good coincidences were found, the chi2 values found are in the expected range or even below. This suggests that there is no evidence of systematically underestimated MIPAS random errors.
|
|
| 25. |
- Rahpoe, N., et al.
(författare)
-
Relative drifts and biases between six ozone limb satellite measurements from the last decade
- 2015
-
Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 8:10, s. 4369-4381
-
Tidskriftsartikel (refereegranskat)abstract
- As part of European Space Agency's (ESA) climate change initiative, high vertical resolution ozone profiles from three instruments all aboard ESA's Envisat (GOMOS, MIPAS, SCIAMACHY) and ESA's third party missions (OSIRIS, SMR, ACE-FTS) are to be combined in order to create an essential climate variable data record for the last decade. A prerequisite before combining data is the examination of differences and drifts between the data sets. In this paper, we present a detailed analysis of ozone profile differences based on pairwise collocated measurements, including the evolution of the differences with time. Such a diagnosis is helpful to identify strengths and weaknesses of each data set that may vary in time and introduce uncertainties in long-term trend estimates. The analysis reveals that the relative drift between the sensors is not statistically significant for most pairs of instruments. The relative drift values can be used to estimate the added uncertainty in physical trends. The added drift uncertainty is estimated at about 3 % decade-1 (1s). Larger differences and variability in the differences are found in the lowermost stratosphere (below 20 km) and in the mesosphere.
|
|
| 26. |
|
|
| 27. |
- Sandqvist, Aa, et al.
(författare)
-
Odin spectral line observations of Sgr A and Sgr B2 at submm wavelengths and in the 118-GHz band
- 2006
-
Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 54, s. 72-76
-
Tidskriftsartikel (refereegranskat)abstract
- Since its launch in 2001, the Odin satellite has been observing the Galactic Centre Sgr A Complex (CND, +20 and +50 km s-1 Clouds) as well as the nearby star formation region, Sgr B2, a number of times. Observations have been made in the 118-119 GHz and 486-581 GHz bands. A limited mapping of the Sgr A Complex in the H162O line has been performed and new observations of the H182O line took place in 2006. In the 118-119 GHz band, a strong line of HC3N (J = 13 - 12) has been detected at a number of positions - sensitive upper limits have been obtained for the O2 (11 - 10) and the SiC (3Π2, J = 3 - 2) lines. Towards Sgr B2, submm observations have yielded absorption profles of H162O, H182O, H172O, NH3, and 15NH3.
|
|
| 28. |
- Wang, D.Y., et al.
(författare)
-
Validation of nitric acid retrieved by the IMK-IAA processor from MIPAS/ENVISAT measurements
- 2007
-
Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 7, s. 721-738
-
Tidskriftsartikel (refereegranskat)abstract
- The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard the ENVISAT satellite provides profiles of temperature and various trace-gases from limb-viewing mid-infrared emission measurements. The stratospheric nitric acid (HNO(3)) from September 2002 to March 2004 was retrieved from the MIPAS observations using the science-oriented data processor developed at the Institut fur Meteorologie und Klimaforschung (IMK), which is complemented by the component of non-local thermodynamic equilibrium (non-LTE) treatment from the Instituto de Astrofisica de Andalucia (IAA). The IMK-IAA research product, different from the ESA operational product, is validated in this paper by comparison with a number of reference data sets. Individual HNO3 profiles of the IMK-IAA MIPAS show good agreement with those of the balloon-borne version of MIPAS (MIPAS-B) and the infrared spectrometer MkIV, with small differences of less than 0.5 ppbv throughout the entire altitude range up to about 38 km, and below 0.2 ppbv above 30 km. However, the degree of consistency is largely affected by their temporal and spatial coincidence, and differences of 1 to 2 ppbv may be observed between 22 and 26 km at high latitudes near the vortex boundary, due to large horizontal inhomogeneity of HNO(3). Statistical comparisons of MIPAS IMK-IAA HNO(3) VMRs with respect to those of satellite measurements of Odin/SMR, ILAS-II, ACE-FTS, as well as the MIPAS ESA product show good consistency. The mean differences are generally +/- 0.5 ppbv and standard deviations of the differences are of 0.5 to 1.5 ppbv. The maximum differences are 2.0 ppbv around 20 to 25 km. This gives confidence in the general reliability of MIPAS HNO(3) VMR data and the other three satellite data sets.
|
|
| 29. |
- Carleer, M. R., et al.
(författare)
-
Validation of water vapour profiles from the Atmospheric Chemistry Experiment (ACE)
- 2008
-
Ingår i: Atmospheric Chemistry and Physics Discussion: An Interactive Open Access Journal of the European Geosciences Union. ; 8:2, s. 4499-4559
-
Tidskriftsartikel (refereegranskat)abstract
- The Atmospheric Chemistry Experiment (ACE) mission was launched in August 2003 to sound the atmosphere by solar occultation. Water vapour (H2O), one of the most important molecules for climate and atmospheric chemistry, is one of the key species provided by the two principal instruments, the infrared Fourier Transform Spectrometer (ACE-FTS) and the MAESTRO UV-Visible spectrometer (ACE-MAESTRO). The first instrument performs measurements on several lines in the 1362–2137 cm−1 range, from which vertically resolved H2O concentration profiles are retrieved, from 7 to 90 km altitude. ACE-MAESTRO measures profiles using the water absorption band in the near infrared part of the spectrum at 926.0–969.7 nm. This paper presents a comprehensive validation of the ACE-FTS profiles. We have compared the H2O volume mixing ratio profiles with space-borne (SAGE II, HALOE, POAM III, MIPAS, SMR) observations and measurements from balloon-borne frostpoint hygrometers and a ground based lidar. We show that the ACE-FTS measurements provide H2O profiles with small retrieval uncertainties in the stratosphere (better than 5% from 15 to 70 km, gradually increasing above). The situation is unclear in the upper troposphere, due mainly to the high variability of the water vapour volume mixing ratio in this region. A new water vapour data product from the ACE-MAESTRO (Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) is also presented and initial comparisons with ACE-FTS are discussed.
|
|
| 30. |
- Jones, A., et al.
(författare)
-
Technical Note: A trace gas climatology derived from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) data set
- 2012
-
Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 12:11, s. 5207-5220
-
Tidskriftsartikel (refereegranskat)abstract
- The Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS) aboard the Canadian satellite SCISAT (launched in August 2003) was designed to investigate the composition of the upper troposphere, stratosphere, and mesosphere. ACE-FTS utilizes solar occultation to measure temperature and pressure as well as vertical profiles of over thirty chemical species including O-3, H2O, CH4, N2O, CO, NO, NO2, N2O5, HNO3, HCl, ClONO2, CCl3F, CCl2F2, and HF. Global coverage for each species is obtained approximately over a three month period and measurements are made with a vertical resolution of typically 3-4 km. A quality-controlled climatology has been created for each of these 14 baseline species, where individual profiles are averaged over the period of February 2004 to February 2009. Measurements used are from the ACE-FTS version 2.2 data set including updates for O-3 and N2O5. The climatological fields are provided on a monthly and three-monthly basis (DJF, MAM, JJA, SON) at 5 degree latitude and equivalent latitude spacing and on 28 pressure surfaces (26 of which are defined by the Stratospheric Processes And their Role in Climate (SPARC) Chemistry-Climate Model Validation Activity). The ACE-FTS climatological data set is available through the ACE website.
|
|
