Retrieval of cloud liquid water using the special sensor microwave imager (SSM/I)

Weng, Fuzhong; Grody, Norman C.

doi:10.1029/94jd02304

Cited by 239 publications

(160 citation statements)

References 16 publications

(13 reference statements)

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“…We also show the inferred liquid water path from the SSMI satellite instrument (Weng and Grody, 1994;Greenwald et al, 1993) and from the MODIS satellite instrument (Platnick et al, 2003). We note that the liquid water path for the LMD-Z model was not available as a separate diagnostic, and hence we plot the Weng and Grody (1993) and by (b) Greenwald et al (1993) and (c) as inferred from the MODIS instrument for T>260 • (Platnick et al, 2003).…”

Section: Resultsmentioning

confidence: 99%

Model intercomparison of indirect aerosol effects

et al. 2006

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Abstract. Modeled differences in predicted effects are increasingly used to help quantify the uncertainty of these effects. Here, we examine modeled differences in the aerosol indirect effect in a series of experiments that help to quantify how and why model-predicted aerosol indirect forcing varies between models. The experiments start with an experiment in which aerosol concentrations, the parameterization of droplet concentrations and the autoconversion scheme are all specified and end with an experiment that examines the predicted aerosol indirect forcing when only aerosol sources are specified. Although there are large differences in the predicted liquid water path among the models, the predicted aerosol first indirect effect for the first experiment is rather similar, about −0.6 Wm −2 to −0.7 Wm −2 . Changes to the autoconversion scheme can lead to large changes in the liquid water path of the models and to the response of the liquid water path to changes in aerosols. Adding an autoconversion scheme that depends on the droplet concentration caused a larger (negative) change in net outgoing shortwave radiation compared to the 1st indirect effect, and the increase varied from only 22% to more than a factor of three. The change in net shortwave forcing in the models due to varying the autoconversion scheme depends on the liquid water content of the clouds as well as their predicted droplet concentrations, and both increases and decreases in the net shortwave forcing can occur when autoconversion schemes are changed. The parameterization of cloud fraction within models is not sensitive to the aerosol concentration, and, therefore, the response of the modeled cloud fraction within the present models appears to be smaller than that which would be associated Correspondence to: J. E. Penner (penner@umich.edu) with model "noise". The prediction of aerosol concentrations, given a fixed set of sources, leads to some of the largest differences in the predicted aerosol indirect radiative forcing among the models, with values of cloud forcing ranging from −0.3 Wm −2 to −1.4 Wm −2 . Thus, this aspect of modeling requires significant improvement in order to improve the prediction of aerosol indirect effects.

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Section: Resultsmentioning

confidence: 99%

Model intercomparison of indirect aerosol effects

et al. 2006

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“…Global annual mean results from present-day simulations and observations. Shown are total cloud fraction (CLDTOT, %) and high cloud fraction (CLDHGH, %) compared to ISCCP data (Rossow and Schiffer, 1999), MODIS data (Platnick et al, 2003) and HIRS data (Wylie et al, 2005); shortwave cloud forcing (SWCF, W m −2 ), long-wave cloud forcing (LWCF, W m −2 ), whole-sky shortwave (FSNT, W m −2 ) and long-wave (FLNT, W m −2 ) net radiative fluxes at the top of the atmosphere, clear-sky shortwave (FSNTC, W m −2 ) and longwave (FLNTC, W m −2 ) radiative fluxes at the top of the atmosphere compared to ERBE data (Kiehl and Trenberth, 1997) and CERES data (Loeb et al 2009); liquid water path (LWP; g m −2 ) compared to SSM/I oceans data (Greenwald et al, 1993;Weng and Grody, 1994) and ISCCP data (Han et al, 1994); ice water path (IWP, g m −2 ) compared to CloudSat data (Li et al, 2012); column-integrated grid-mean cloud droplet number concentration (CDNUMC, 10 10 m −2 ) compared to MODIS data (Table 4 in Barahona et al, 2014); column-integrated grid-mean ice crystal number concentration (CDNUMI, 10 6 m −2 ), convective (PRECC, mm d −1 ) and large-scale (PRECL, mm d −1 ) and total precipitation rate (PRECT, mm d −1 ) compared to Global Precipitation Climatology Project data set (Adler et al, 2003 (Wielicki et al, 1996). Units are shown in the upper right corner.…”

Section: Model Evaluationsmentioning

confidence: 99%

Effects of pre-existing ice crystals on cirrus clouds and comparison between different ice nucleation parameterizations with the Community Atmosphere Model (CAM5)

2015

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Abstract. In order to improve the treatment of ice nucleation in a more realistic manner in the Community Atmosphere Model version 5.3 (CAM5.3), the effects of pre-existing ice crystals on ice nucleation in cirrus clouds are considered. In addition, by considering the in-cloud variability in ice saturation ratio, homogeneous nucleation takes place spatially only in a portion of the cirrus cloud rather than in the whole area of the cirrus cloud. Compared to observations, the ice number concentrations and the probability distributions of ice number concentration are both improved with the updated treatment. The pre-existing ice crystals significantly reduce ice number concentrations in cirrus clouds, especially at mid-to high latitudes in the upper troposphere (by a factor of ∼ 10). Furthermore, the contribution of heterogeneous ice nucleation to cirrus ice crystal number increases considerably.Besides the default ice nucleation parameterization of Liu and Penner (2005, hereafter LP) in CAM5.3, two other ice nucleation parameterizations of Barahona and Nenes (2009, hereafter BN) and Kärcher et al. (2006, hereafter KL) are implemented in CAM5.3 for the comparison. In-cloud ice crystal number concentration, percentage contribution from heterogeneous ice nucleation to total ice crystal number, and pre-existing ice effects simulated by the three ice nucleation parameterizations have similar patterns in the simulations with present-day aerosol emissions. However, the change (present-day minus pre-industrial times) in global annual mean column ice number concentration from the KL parameterization (3.24 × 10 6 m −2 ) is less than that from the LP (8.46 × 10 6 m −2 ) and BN (5.62 × 10 6 m −2 ) parameterizations. As a result, the experiment using the KL parameterization predicts a much smaller anthropogenic aerosol longwave indirect forcing (0.24 W m −2 ) than that using the LP (0.46 W m −2 ) and BN (0.39 W m −2 ) parameterizations.

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“…Numbers denote rain rates at the 95th percentile. [Greenwald et al, 1993;Weng and Grody, 1994;Ferraro et al, 1996] and NVAP for the years 1988-1999 [Engelen and Stephens, 1999]. Both data are restricted to oceans.…”

Section: Impacts Of the Optimized Convection On The Global Circulatiomentioning

confidence: 99%

Uncertainty quantification and parameter tuning in the CAM5 Zhang‐McFarlane convection scheme and impact of improved convection on the global circulation and climate

et al. 2013

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[1] In this study, we applied an uncertainty quantification (UQ) technique to improve convective precipitation in the global climate model, the Community Atmosphere Model version 5 (CAM5), in which the convective and stratiform precipitation partitioning is very different from observational estimates. We examined the sensitivity of precipitation and circulation to several key parameters in the Zhang-McFarlane deep convection scheme in CAM5, using a stochastic importance-sampling algorithm that can progressively converge to optimal parameter values. The impact of improved deep convection on the global circulation and climate was subsequently evaluated. Our results show that the simulated convective precipitation is most sensitive to the parameters of the convective available potential energy consumption time scale, parcel fractional mass entrainment rate, and maximum downdraft mass flux fraction. Using the optimal parameters constrained by the observed Tropical Rainfall Measuring Mission, convective precipitation improves the simulation of convective to stratiform precipitation ratio and rain-rate spectrum remarkably. When convection is suppressed, precipitation tends to be more confined to the regions with strong atmospheric convergence. As the optimal parameters are used, positive impacts on some aspects of the atmospheric circulation and climate, including reduction of the double Intertropical Convergence Zone, improved East Asian monsoon precipitation, and improved annual cycles of the cross-equatorial jets, are found as a result of the vertical and horizontal redistribution of latent heat release from the revised parameterization. Positive impacts of the optimal parameters derived from the 2 simulations are found to transfer to the 1 simulations to some extent. Citation: Yang, B. et al. (2013), Uncertainty quantification and parameter tuning in the CAM5 Zhang-McFarlane convection scheme and impact of improved convection on the global circulation and climate,

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Retrieval of cloud liquid water using the special sensor microwave imager (SSM/I)

Cited by 239 publications

References 16 publications

Model intercomparison of indirect aerosol effects

Model intercomparison of indirect aerosol effects

Effects of pre-existing ice crystals on cirrus clouds and comparison between different ice nucleation parameterizations with the Community Atmosphere Model (CAM5)

Uncertainty quantification and parameter tuning in the CAM5 Zhang‐McFarlane convection scheme and impact of improved convection on the global circulation and climate

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