Studies for the Odin sub-millimetre radiometer: III. Performance simulations

Merino, F.; Murtagh, Donal; Ridal, Martin; Eriksson, Patrick; Baron, Philippe; Ricaud, Philippe; Noë, J. de La

doi:10.1139/p01-154

Cited by 31 publications

(26 citation statements)

References 6 publications

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“…Another characteristic of the observations is, as the result of the 2 months periodic local-time precession of the ISS, semidiurnal and diurnal variations of mesospheric winds such as those induced by tides are captured in the observations. Figure 4 (left panel) shows the vertical resolution of the retrieved wind profiles and the measurement responses, i.e., the sum of the averaging kernel rows (Merino et al, 2002) that indicate the altitudes of good measurement sensitivity. Good sensitivity (defined as where the measurement response ranges from 0.9 to 1.1) is found from 25 to 70 km (20-0.05 hPa) and from 25 to 80 km (20-0.01 hPa) for the O 3 and HCl line retrievals, respectively.…”

Section: Measurement Methodsmentioning

confidence: 99%

Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010

et al. 2013

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Abstract. Although the links between stratospheric dynamics, climate and weather have been demonstrated, direct observations of stratospheric winds are lacking, in particular at altitudes above 30 km. We report observations of winds between 8 and 0.01 hPa (~35–80 km) from October 2009 to April 2010 by the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the International Space Station. The altitude range covers the region between 35–60 km where previous space-borne wind instruments show a lack of sensitivity. Both zonal and meridional wind components were obtained, though not simultaneously, in the latitude range from 30° S to 55° N and with a single profile precision of 7–9 m s–1 between 8 and 0.6 hPa and better than 20 m s–1 at altitudes above. The vertical resolution is 5–7 km except in the upper part of the retrieval range (10 km at 0.01 hPa). In the region between 1–0.05 hPa, an absolute value of the mean difference < 2 m s–1 is found between SMILES profiles retrieved from different spectroscopic lines and instrumental settings. Good agreement (absolute value of the mean difference of ~2 m s–1) is also found with the European Centre for Medium-Range Weather Forecasts (ECMWF) analysis in most of the stratosphere except for the zonal winds over the equator (difference > 5 m s−1). In the mesosphere, SMILES and ECMWF zonal winds exhibit large differences (> 20 m s–1), especially in the tropics. We illustrate our results by showing daily and monthly zonal wind variations, namely the semi-annual oscillation in the tropics and reversals of the flow direction between 50–55° N during sudden stratospheric warmings. The daily comparison with ECMWF winds reveals that in the beginning of February, a significantly stronger zonal westward flow is measured in the tropics at 2 hPa compared to the flow computed in the analysis (difference of ~20 m s–1). The results show that the comparison between SMILES and ECMWF winds is not only relevant for the quality assessment of the new SMILES winds, but it also provides insights on the quality of the ECMWF winds themselves. Although the instrument was not specifically designed for measuring winds, the results demonstrate that space-borne sub-mm wave radiometers have the potential to provide good quality data for improving the stratospheric winds in atmospheric models.

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Section: Measurement Methodsmentioning

confidence: 99%

Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010

et al. 2013

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“…Murtagh et al (2002) give an overview of Odin's atmospheric mission, and the performance of the SMR instrument regarding its standard stratospheric and mesospheric retrievals is summarised by Merino et al (2002). The measurements used for these retrievals and the most relevant technical details are presented in Ekström et al (2007) and Eriksson et al (2007).…”

Section: Odin-smrmentioning

confidence: 99%

Overview and sample applications of SMILES and Odin-SMR retrievals of upper tropospheric humidity and cloud ice mass

Eriksson

Rydberg²,

Sagawa

et al. 2014

Atmos. Chem. Phys.

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Abstract. Retrievals of cloud ice mass and humidity from the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) and the Odin-SMR (Sub-Millimetre Radiometer) limb sounder are presented and example applications of the data are given. SMILES data give an unprecedented view of the diurnal variation of cloud ice mass. Mean regional diurnal cycles are reported and compared to some global climate models. Some improvements in the models regarding diurnal timing and relative amplitude were noted, but the models' mean ice mass around 250 hPa is still low compared to the observations. The influence of the ENSO (El Niño-Southern Oscillation) state on the upper troposphere is demonstrated using 12 years of Odin-SMR data.The same retrieval scheme is applied for both sensors, and gives low systematic differences between the two data sets. A special feature of this Bayesian retrieval scheme, of Monte Carlo integration type, is that values are produced for all measurements but for some atmospheric states retrieved values only reflect a priori assumptions. However, this "allweather" capability allows a direct statistical comparison to model data, in contrast to many other satellite data sets. Another strength of the retrievals is the detailed treatment of "beam filling" that otherwise would cause large systematic biases for these passive cloud ice mass retrievals.The main retrieval inputs are spectra around 635/525 GHz from tangent altitudes below 8/9 km for SMILES/Odin-SMR, respectively. For both sensors, the data cover the upper troposphere between 30 • S and 30 • N. Humidity is reported as both relative humidity and volume mixing ratio. The vertical coverage of SMILES is restricted to a single layer, while Odin-SMR gives some profiling capability between 300 and 150 hPa. Ice mass is given as the partial ice water path above 260 hPa, but for Odin-SMR ice water content, estimates are also provided. Besides a smaller contrast between most dry and wet cases, the agreement with Aura MLS (Microwave Limb Sounder) humidity data is good. In terms of tropical mean humidity, all three data sets agree within 3.5 %RHi. Mean ice mass is about a factor of 2 lower compared to CloudSat. This deviation is caused by the fact that different particle size distributions are assumed, combined with saturation and a priori influences in the SMILES and Odin-SMR data.

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“…This study compares the IMK-IAA ozone data with the observations of halogen occultation experiment (HALOE) on the upper atmosphere research satellite (UARS) (Russell et al, 1993) and sub-millimetre radiometer (SMR) on ODIN (Urban et al, 2004;Murtagh et al, 2002;Merino et al, 2002). The HALOE/UARS ozone profiles have been validated already.…”

Section: Introductionmentioning

confidence: 97%

Comparisons of MIPAS/ENVISAT ozone profiles with SMR/ODIN and HALOE/UARS observations

Wang

Stiller

Clarmann

et al. 2005

Advances in Space Research

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Studies for the Odin sub-millimetre radiometer: III. Performance simulations

Cited by 31 publications

References 6 publications

Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010

Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010

Overview and sample applications of SMILES and Odin-SMR retrievals of upper tropospheric humidity and cloud ice mass

Comparisons of MIPAS/ENVISAT ozone profiles with SMR/ODIN and HALOE/UARS observations

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