Technical Note: An assessment of the accuracy of the RTTOV fast radiative transfer model using IASI data

Matricardi, Marco

doi:10.5194/acp-9-6899-2009

Cited by 46 publications

(46 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This result has been documented in a number of unpublished presentations made during the second workshop of the EUMETSAT IASI Sounding Science Working Group (ISSWG-2) and in several papers published in the open literature, e.g. see Shephard et al (2009);Matricardi (2009) ;Masiello et al (2009).…”

Section: Introductionmentioning

confidence: 93%

“…In this case simulations were performed using the RTTOV (Matricardi et al (2004)) forward model and input fields obtained from the ECMWF short-range forecasts. Shephard et al (2009) and Matricardi (2009) have suggested that the radiance bias at 667 cm −1 could be caused by Published by Copernicus Publications on behalf of the European Geosciences Union. incorrect specification of the temperature profile in the upper stratosphere.…”

Section: Introductionmentioning

confidence: 99%

“…It is important to stress how the biases at 667 cm −1 do not display any day-night cycle (see e.g. Matricardi (2009)). However, as exemplified in Fig.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The use of IASI data to identify systematic errors in the ECMWF forecasts of temperature in the upper stratosphere

2011

Self Cite

View full text Add to dashboard Cite

Abstract. Since data from the Infrared Atmospheric Sounding Interferometer (IASI) became available in 2007, a number of papers have appeared in the literature which have reported relatively large discrepancies between IASI spectra and forward calculations in the centre of the CO 2 Q-branch at 667 cm −1 . In this paper we show that these discrepancies are primarily due to errors in the temperature profiles used in the forward calculations. In particular, we have used forecasts of temperature profiles from the European Centre for MediumRange Weather Forecasts (ECMWF) to demonstrate that, for the case study considered in this paper, these profiles are affected by systematic errors of the order of ≈10 K at the level of the stratopause. To derive the magnitude and the spatial location of the systematic errors in the temperature profile, we have carried out forward/inverse calculations for a number of clear-sky, daytime, IASI tropical soundings over the sea. The forward calculations have been performed using atmospheric state vectors which have been obtained either from the direct inversion of the IASI radiances or from space-time co-located profiles derived from radiosonde observations and from the ECMWF model. To rule out any effect due to the accuracy of the forward model, we have performed the forward calculations using two independent models. The sensitivity of the temperature biases to the variability of the CO 2 profile and to spectroscopy errors has also been studied.

show abstract

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The use of IASI data to identify systematic errors in the ECMWF forecasts of temperature in the upper stratosphere

2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…The RTTOV algorithm is described in detail in Saunders et al (1999) and Matricardi et al (2004). The overall accuracy of RTTOV has been addressed using IASI data in Matricardi (2009). The RTTOV software is available free of charge on request from NWP-SAF at http://research.metoffice.gov.uk/ research/interproj/nwpsaf/rtm/rtm/rttov9.html.…”

Section: Sofridmentioning

confidence: 99%

Retrieval of MetOp-A/IASI CO profiles and validation with MOZAIC data

et al. 2012

Self Cite

View full text Add to dashboard Cite

Abstract. The IASI (Infrared Atmospheric Sounding Interferometer) nadir-looking thermal infrared sounder onboard MetOp-A enables the monitoring of atmospheric constituents on a global scale. This paper presents a quality assessment of IASI CO profiles retrieved by the two different retrieval algorithms SOFRID and FORLI, by an intercomparison with airborne in-situ CO profiles from the MOZAIC program for the and upper tropospheric partial column (480-225 hPa) comparisons as well as profile comparisons are made. The retrieval errors of the IASI products are less than 21 % in the lower troposphere and less than 10 % in the upper troposphere. A statistical analysis shows similar correlation coefficients for the two retrieval algorithms and smoothed MOZAIC of r ∼ 0.8 and r ∼ 0.7 in the lower and upper troposphere respectively. Comparison with smoothed MOZAIC data of the temporal variation of the CO profiles at the airports of Frankfurt and Windhoek demonstrates that the IASI products are able to capture the seasonal variability at these sites. At Frankfurt SOFRID (respectively FORLI) is positively biased by 10.5 % (13.0 %) compared to smoothed MOZAIC in the upper (lower) troposphere, and the limited sensitivity of the IASI instrument to the boundary layer when thermal contrast is low is identified. At Windhoek, the impact of the vegetation fires in Southern Africa from July to November is captured by both SOFRID and FORLI, with an overestimation of the CO background values (fire maxima) by SOFRID (FORLI) by 12.8 % (10 %). Profile comparisons at Frankfurt and Windhoek show that the largest discrepancies are found between the two IASI products and MOZAIC for the nighttime retrievals.

show abstract

“…Brightness temperatures corresponding to the modeled atmospheric profiles were calculated using the RTTOV v9.3 radiative transfer code (Saunders et al 1999;Matricardi et al 2004;Matricardi 2009) (Bodas-Salcedo et al 2011). The nadir-view top of the atmosphere radiance in HIRS chs.…”

Section: Calculation Of Simulated Brightness Temperaturesmentioning

confidence: 99%

Climate Model–Simulated Diurnal Cycles in HIRS Clear-Sky Brightness Temperatures

2012

View full text Add to dashboard Cite

Clear-sky brightness temperature measurements from the High-Resolution Infrared Radiation Sounder (HIRS) are simulated with two climate models via a radiative transfer code. The models are sampled along the HIRS orbit paths to derive diurnal climatologies of simulated brightness temperature analogous to an existing climatology based on HIRS observations. Simulated and observed climatologies are compared to assess model performance and the robustness of the observed climatology.Over land, there is good agreement between simulations and observations, with particularly high consistency for the tropospheric temperature channels. Diurnal cycles in the middle-and upper-tropospheric water vapor channels are weak in both simulations and observations, but the simulated diurnal brightness temperature ranges are smaller than are observed with different phase and there are also intermodel differences. Over sea, the absence of diurnal variability in the models' sea surface temperatures causes an underestimate of the small diurnal cycles measured in the troposphere.The simulated and observed climatologies imply similar diurnal sampling biases in the HIRS record for the tropospheric temperature channels, but for the upper-tropospheric water vapor channel, differences in the contributions of the 24-and 12-hourly diurnal harmonics lead to differences in the implied bias. Comparison of diurnal cycles derived from HIRS-like and full model sampling suggests that the HIRS measurements are sufficient to fully constrain the diurnal behavior.Overall, the results suggest that recent climate models well represent the major processes driving the diurnal behavior of clear-sky brightness temperature in the HIRS channels. This encourages further studies of observed and simulated climate trends over the HIRS era.

show abstract

Technical Note: An assessment of the accuracy of the RTTOV fast radiative transfer model using IASI data

Cited by 46 publications

References 27 publications

The use of IASI data to identify systematic errors in the ECMWF forecasts of temperature in the upper stratosphere

The use of IASI data to identify systematic errors in the ECMWF forecasts of temperature in the upper stratosphere

Retrieval of MetOp-A/IASI CO profiles and validation with MOZAIC data

Climate Model–Simulated Diurnal Cycles in HIRS Clear-Sky Brightness Temperatures

Contact Info

Product

Resources

About