Parameterization of ice fall speeds in midlatitude cirrus: Results from SPartICus

Mishra, Subhashree; Mitchell, David L.; Turner, David D.; Lawson, R. Paul

doi:10.1002/2013jd020602

Cited by 27 publications

(50 citation statements)

References 62 publications

(107 reference statements)

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“…Mitchell et al, 2011;Mishra et al, 2014;Luebke et al, 2016). In the occurrence of a bi-modal shape in in situ measurements, the D05 parameterization naturally tends to reproduce the concentration in large particles due to their strong weight on D m and IWC.…”

Section: Reproducibility Of Psds By D05mentioning

confidence: 99%

Ice crystal number concentration estimates from lidar-radar satellite remote sensing. Part 1: Method and evaluation

Sourdeval¹,

Gryspeerdt²,

Krämer³

et al. 2018

Preprint

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Abstract. The number concentration of cloud particles is a key quantity for understanding aerosol-cloud interactions and describing clouds in climate and numerical weather prediction models. In contrast with recent advances for liquid clouds, few observational constraints exist on the ice crystal number concentration (N i ). This study investigates how combined lidar-radar measurements can be used to provide satellite estimates of N i , using a methodology that constrains moments of a parameterized particle size distribution (PSD). The operational liDAR-raDAR (DARDAR) product serves as an existing base for this method, 5 which focuses on ice clouds with temperatures T c < -30°C.Theoretical considerations demonstrate the capability for accurate retrievals of N i , apart from a possible bias in the concentration in small crystals when T c -50°C, due to the assumption of a monomodal PSD shape in the current method. This is verified by comparing satellite estimates to co-incident in situ measurements, which additionally demonstrates the sufficient sensitivity of lidar-radar observations to N i . Following these results, satellite estimates of N i are evaluated in the context of a 10 case study and a preliminary climatological analysis based on 10 years of global data. Despite of a lack of other large-scale references, this evaluation shows a reasonable physical consistency in N i spatial distribution patterns. Notably, increases in N i are found towards cold temperatures and, more significantly, in the presence of strong updraughts, such as those related to convective or orographic uplifts. Further evaluation and improvements of this method are necessary but these results already constitute a first encouraging step towards large-scale observational constraints for N i . Part two of this series uses this new 15 dataset to examine the controls on N i .

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Section: Reproducibility Of Psds By D05mentioning

confidence: 99%

Ice crystal number concentration estimates from lidar-radar satellite remote sensing. Part 1: Method and evaluation

Sourdeval¹,

Gryspeerdt²,

Krämer³

et al. 2018

Preprint

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“…Regarding SPARTICUS, the data set described in Mishra et al (2014) was used, and the TC4 data is described in Mitchell et al (2011). Details regarding field measurements, the flights analyzed and the microphysical processing are described in these articles.…”

mentioning

confidence: 99%

“…The PSD effective diameter was determined from the measured PSD as described in Mishra et al (2014), but in essence is given as De = (3/2) IWC/(ρi APSD), where ρi is the density of bulk ice (0.917 g cm -3 ). The PSD extinction efficiencyQext was determined in a manner analogous toQabs.…”

mentioning

confidence: 99%

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CALIPSO observations of the dependence of homo- and heterogeneous ice nucleation in cirrus clouds on latitude, season and surface condition

Mitchell

Avery

Erfani

2016

Preprint

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Abstract. There are two fundamental mechanisms through which cirrus clouds form; homo-and heterogeneous ice nucleation (henceforth hom and het). The relative contribution of each mechanism to ice crystal production often determines the microphysical and radiative properties of a cirrus cloud. A new satellite remote sensing method is described in this study to estimate cirrus cloud ice particle number concentration and the relative contribution of hom and het to cirrus cloud formation as a function of altitude, latitude, season and surface type (e.g. land vs. 532 nm cirrus cloud centroid altitude and temperature, the cirrus cloud ice particle number concentration, effective diameter, layer-average ice water content and visible optical depth. Using a conservative criterion for hom cirrus, on average, the sampled cirrus clouds formed through hom occur about 43% of the time in the Arctic and 50% of the time in the Antarctic, and during winter at mid-latitudes in the Northern Hemisphere, hom cirrus occur 37% of the time. Elsewhere (and during other seasons in the Northern Hemisphere mid-latitudes), this hom cirrus fraction is 25 lower. Processes that could potentially explain these observations are discussed, as well as the potential relevancy of these results to ice nucleation studies, climate modeling and jet-stream dynamics.

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“…The optical properties of ice clouds (and atmospheric gases and aerosols) needed as input to the MC-UniK are based on data collected during ARM's 2010 Small Particles in Cirrus (SPARTICUS) field campaign (Mishra et al, 2014;Muhlbauer et al, 2014;Jackson et al, 2015). The aircraft measurements were collected in the vicinity of the groundbased measurements made at the SGP site.…”

Section: Optical Propertiesmentioning

confidence: 99%

Disk and circumsolar radiances in the presence of ice clouds

et al. 2017

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Abstract. The impact of ice clouds on solar disk and circumsolar radiances is investigated using a Monte Carlo radiative transfer model. The monochromatic direct and diffuse radiances are simulated at angles of 0 to 8 • from the center of the sun. Input data for the model are derived from measurements conducted during the 2010 Small Particles in Cirrus (SPAR-TICUS) campaign together with state-of-the-art databases of optical properties of ice crystals and aerosols. For selected cases, the simulated radiances are compared with groundbased radiance measurements obtained by the Sun and Aureole Measurements (SAM) instrument.First, the sensitivity of the radiances to the ice cloud properties and aerosol optical thickness is addressed. The angular dependence of the disk and circumsolar radiances is found to be most sensitive to assumptions about ice crystal roughness (or, more generally, non-ideal features of ice crystals) and size distribution, with ice crystal habit playing a somewhat smaller role. Second, in comparisons with SAM data, the ice cloud optical thickness is adjusted for each case so that the simulated radiances agree closely (i.e., within 3 %) with the measured disk radiances. Circumsolar radiances at angles larger than ≈ 3 • are systematically underestimated when assuming smooth ice crystals, whereas the agreement with the measurements is better when rough ice crystals are assumed. Our results suggest that it may well be possible to infer the particle roughness directly from ground-based SAM measurements. In addition, the results show the necessity of correcting the ground-based measurements of direct radiation for the presence of diffuse radiation in the instrument's field of view, in particular in the presence of ice clouds.

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Parameterization of ice fall speeds in midlatitude cirrus: Results from SPartICus

Cited by 27 publications

References 62 publications

Ice crystal number concentration estimates from lidar-radar satellite remote sensing. Part 1: Method and evaluation

Ice crystal number concentration estimates from lidar-radar satellite remote sensing. Part 1: Method and evaluation

CALIPSO observations of the dependence of homo- and heterogeneous ice nucleation in cirrus clouds on latitude, season and surface condition

Disk and circumsolar radiances in the presence of ice clouds

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