Evaluation of ice cloud representation in the ECMWF and UK Met Office models using CloudSat and CALIPSO data

Delanoë, Julien; Hogan, Robin J.; Forbes, R. M.; Bodas‐Salcedo, Alejandro; Stein, Thorwald H. M.

doi:10.1002/qj.882

Cited by 60 publications

(78 citation statements)

References 33 publications

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“…8d-f show that HiGEM produces higher mean reflectivity from fewer clouds when compared to ERAI-which may indicate more precipitation being produced by the convection scheme in HiGEM than ERAI, though still not capturing the observed distributions. It has previously been shown that the ERAI cloud scheme fails to represent ice water content distribution in the −20 to 0 • C range, which can be reconciled with the underestimate of reflectivity in ERAI at upper levels (see Delanoë et al 2011) It is clear from the transects in Fig. 8 that in the CloudSat composite ETC, significant precipitation can occur both north and south of the axis of propagation, whilst precipitation in both HiGEM and ERAI mostly occurs towards the south, particularly in ERAI-an important finding in the context of the influence of latent heating in ETCs.…”

Section: Cloudsat Composite Storm Structurementioning

confidence: 93%

Using satellite and reanalysis data to evaluate the representation of latent heating in extratropical cyclones in a climate model

et al. 2016

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exhibit biases in cloud structure, with more clouds at lower altitudes than those observed in ISCCP in the warm conveyor belt region. As a result, latent heat release in ERAI is concentrated at lower altitudes. CloudSat indicates that much precipitation may be produced at too low an altitude in both HiGEM and ERAI, particularly ERAI, and neither capture observed variability in precipitation intensity. The potential vorticity structure in composite extratropical cyclones in HiGEM and ERAI is also compared. A more pronounced tropopause ridge evolves in HiGEM on the leading edge of the composite as compared to ERAI. One future area of research to be addressed is what impact these biases in the representation of latent heating have on climate projections produced by HiGEM. The biases found in ERAI indicate caution is required when using reanalyses to study cloud features and precipitation processes in extratropical cyclones or using reanalysis to evaluate climate models' ability to represent their structure.

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Section: Cloudsat Composite Storm Structurementioning

confidence: 93%

Using satellite and reanalysis data to evaluate the representation of latent heating in extratropical cyclones in a climate model

et al. 2016

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“…There have been past comparisons of the ECMWF ice water content product to satellite measurements of cloud ice content (Li et al, 2007;Waliser et al, 2009;Wu et al, 2009;Delanoë et al, 2011). They show that while the ice content may be under-estimated, there is at least good spatial agreement between ECMWF and the satellite measurements.…”

Section: A New Ice-flux-based Parametrisation (Iceflux)mentioning

confidence: 99%

Using cloud ice flux to parametrise large-scale lightning

et al. 2014

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Abstract.Lightning is an important natural source of nitrogen oxide especially in the middle and upper troposphere. Hence, it is essential to represent lightning in chemistry transport and coupled chemistry-climate models. Using ERA-Interim meteorological reanalysis data we compare the lightning flash density distributions produced using several existing lightning parametrisations, as well as a new parametrisation developed on the basis of upward cloud ice flux at 440 hPa. The use of ice flux forms a link to the non-inductive charging mechanism of thunderstorms. Spatial and temporal distributions of lightning flash density are compared to tropical and subtropical observations for 2007-2011 from the Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission (TRMM) satellite. The well-used lightning flash parametrisation based on cloud-top height has large biases but the derived annual total flash density has a better spatial correlation with the LIS observations than other existing parametrisations. A comparison of flash density simulated by the different schemes shows that the cloud-top height parametrisation has many more instances of moderate flash densities and fewer low and high extremes compared to the other parametrisations. Other studies in the literature have shown that this feature of the cloud-top height parametrisation is in contrast to lightning observations over certain regions. Our new ice flux parametrisation shows a clear improvement over all the existing parametrisations with lower root mean square errors (RMSEs) and better spatial correlations with the observations for distributions of annual total, and seasonal and interannual variations. The greatest improvement with the new parametrisation is a more realistic representation of the zonal distribution with a better balance between tropical and subtropical lightning flash estimates. The new parametrisation is appropriate for testing in chemistry transport and chemistry-climate models that use a lightning parametrisation.

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“…A key input to the retrieval algorithm is an observational error covariance matrix, which includes both instrument and forward-model errors Hogan, 2008, 2010). The resulting DARDAR (for li-DAR + raDAR) products contain the profiles of the ice cloud related parameters on a 60 m vertical grid, which have been used in a number of studies (Bardeen et al, 2013;Battaglia and Delanoë, 2013;Ceccaldi et al, 2013;Delanoë et al, 2011Delanoë et al, , 2013Deng et al, 2013;Eliasson et al, 2012;Gayet et al, 2014;Huang et al, 2012;Jouan et al, 2012Jouan et al, , 2014Mason et al, 2014;Stein et al, 2011a, b).…”

Section: Cloudsat Geometrical Profiling Product (Geoprof)mentioning

confidence: 99%

Ice water content vertical profiles of high-level clouds: classification and impact on radiative fluxes

2015

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Abstract. In this article, we discuss the shape of ice water content (IWC) vertical profiles in high ice clouds and its effect on their radiative properties, both in short-and in long-wave bands (SW and LW). Based on the analysis of collocated satellite data, we propose a minimal set of primitive shapes (rectangular, isosceles trapezoid, lower and upper triangle), which represents the IWC profiles sufficiently well. About 75 % of all high-level ice clouds (P < 440 hPa) have an ice water path (IWP) smaller than 100 g m −2 , with a 10 % smaller contribution from single layer clouds. Most IWC profiles (80 %) can be represented by a rectangular or isosceles trapezoid shape. However, with increasing IWP, the number of lower triangle profiles (IWC rises towards cloud base) increases, reaching up to 40 % for IWP values greater than 300 g m −2 . The number of upper triangle profiles (IWC rises towards cloud top) is in general small and decreases with IWP, with the maximum occurrence of 15 % in cases of IWP less than 10 g m −2 . We propose a statistical classification of the IWC shapes using IWP as a single parameter. We have estimated the radiative effects of clouds with the same IWP and with different IWC profile shapes for five typical atmospheric scenarios and over a broad range of IWP, cloud height, cloud vertical extent, and effective ice crystal diameter (De). We explain changes in outgoing LW fluxes at the top of the atmosphere (TOA) by the cloud thermal radiance while differences in TOA SW fluxes relate to the De vertical profile within the cloud. Absolute differences in net TOA and surface fluxes associated with these parameterized IWC profiles instead of assuming constant IWC profiles are in general of the order of 1-2 W m −2 : they are negligible for clouds with IWP < 30 g m −2 , but may reach 2 W m −2 for clouds with IWP > 300 W m −2 .

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Evaluation of ice cloud representation in the ECMWF and UK Met Office models using CloudSat and CALIPSO data

Cited by 60 publications

References 33 publications

Using satellite and reanalysis data to evaluate the representation of latent heating in extratropical cyclones in a climate model

Using satellite and reanalysis data to evaluate the representation of latent heating in extratropical cyclones in a climate model

Using cloud ice flux to parametrise large-scale lightning

Ice water content vertical profiles of high-level clouds: classification and impact on radiative fluxes

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