scholarly journals Cloud ice water content retrieved from the CALIOP space-based lidar

2012 ◽  
Vol 39 (5) ◽  
pp. n/a-n/a ◽  
Author(s):  
Melody Avery ◽  
David Winker ◽  
Andrew Heymsfield ◽  
Mark Vaughan ◽  
Stuart Young ◽  
...  
Keyword(s):  
Water Content ◽  
Ice Water Content ◽  
Cloud Ice ◽  
Ice Water

scholarly journals Changes in the shape of cloud ice water content vertical structure due to aerosol variations

2016 ◽  
Vol 16 (10) ◽  
pp. 6091-6105 ◽  
Author(s):  
Steven T. Massie ◽  
Julien Delanoë ◽  
Charles G. Bardeen ◽  
Jonathan H. Jiang ◽  
Lei Huang
Keyword(s):  
Water Content ◽  
Vertical Structure ◽  
Distribution Functions ◽  
Ozone Monitoring Instrument ◽  
Modis Aod ◽  
Ice Water Content ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Cloud Ice ◽  
Ice Water ◽  
Derivatives Of

Abstract. Changes in the shape of cloud ice water content (IWC) vertical structure due to variations in Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depths (AODs), Ozone Monitoring Instrument (OMI) absorptive aerosol optical depths (AAODs), and Microwave Limb Sounder (MLS) CO (an absorptive aerosol proxy) at 215 hPa are calculated in the Tropics during 2007–2010 based upon an analysis of DARDAR IWC profiles for deep convective clouds. DARDAR profiles are a joint retrieval of CloudSat-CALIPSO data. Analysis is performed for 12 separate regions over land and ocean, and carried out applying MODIS AOD fields that attempt to correct for 3-D cloud adjacency effects. The 3-D cloud adjacency effects have a small impact upon our particular calculations of aerosol–cloud indirect effects. IWC profiles are averaged for three AOD bins individually for the 12 regions. The IWC average profiles are also normalized to unity at 5 km altitude in order to study changes in the shape of the average IWC profiles as AOD increases. Derivatives of the IWC average profiles, and derivatives of the IWC shape profiles, in percent change per 0.1 change in MODIS AOD units, are calculated separately for each region. Means of altitude-specific probability distribution functions, which include both ocean and land IWC shape regional derivatives, are modest, near 5 %, and positive to the 2σ level between 11 and 15 km altitude. Similar analyses are carried out for three AAOD and three CO bins. On average, the vertical profiles of the means of the derivatives based upon the profile shapes over land and ocean are smaller for the profiles binned according to AAOD and CO values, than for the MODIS AODs, which include both scattering and absorptive aerosol. This difference in character supports the assertion that absorptive aerosol can inhibit cloud development.

scholarly journals Changes in the shape of cloud ice water content vertical structure due to aerosol variations

2016 ◽  
Author(s):  
Steven T. Massie ◽  
Julien Delanoe ◽  
Charles G. Bardeen
Keyword(s):  
Water Content ◽  
Vertical Structure ◽  
Distribution Functions ◽  
Convective Clouds ◽  
Modis Aod ◽  
Ice Water Content ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Cloud Ice ◽  
Ice Water ◽  
Derivatives Of

Abstract. Changes in the shape of cloud ice water content vertical structure due to aerosol variations are calculated in the Tropics during 2007–2010 based upon an analysis of DARDAR ice water content (IWC) profiles for deep convective clouds. DARDAR profiles are a joint retrieval of CloudSat-CALIPSO data. Our analysis is performed for 12 separate regions over land and ocean, and carried out applying Moderate-Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) fields that attempt to correct for 3D cloud adjacency effects. The 3D cloud adjacency effects have a small impact upon our calculations of aerosol-cloud indirect effects. IWC profiles are averaged for three AOD bins individually for the 12 regions. The IWC average profiles are also normalized to unity at 5 km altitude in order to study changes in the shape of the average IWC profiles as AOD increases. Derivatives of the IWC average profiles, and derivatives of the IWC shape profiles, in percent change per 0.1 change in MODIS AOD units, are calculated separately for each region. Means of altitude-specific probability distribution functions, which include both ocean and land IWC shape regional derivatives, are modest, near 5 %, and positive to the 2σ level between 11 and 15 km altitude.

scholarly journals Diagnosing the average spatio-temporal impact of convective systems – Part 1: A methodology for evaluating climate models

2013 ◽  
Vol 13 (23) ◽  
pp. 12043-12058 ◽  
Author(s):  
M. S. Johnston ◽  
S. Eliasson ◽  
P. Eriksson ◽  
R. M. Forbes ◽  
K. Wyser ◽  
...  
Keyword(s):  
Water Content ◽  
Outgoing Longwave Radiation ◽  
Longwave Radiation ◽  
Cloud Fraction ◽  
Convective Systems ◽  
Ice Water Content ◽  
The Mean ◽  
Spatio Temporal ◽  
Cloud Ice ◽  
Ice Water

Abstract. An earlier method to determine the mean response of upper-tropospheric water to localised deep convective systems (DC systems) is improved and applied to the EC-Earth climate model. Following Zelinka and Hartmann (2009), several fields related to moist processes and radiation from various satellites are composited with respect to the local maxima in rain rate to determine their spatio-temporal evolution with deep convection in the central Pacific Ocean. Major improvements to the earlier study are the isolation of DC systems in time so as to prevent multiple sampling of the same event, and a revised definition of the mean background state that allows for better characterisation of the DC-system-induced anomalies. The observed DC systems in this study propagate westward at ~4 m s−1. Both the upper-tropospheric relative humidity and the outgoing longwave radiation are substantially perturbed over a broad horizontal extent and for periods >30 h. The cloud fraction anomaly is fairly constant with height but small maximum can be seen around 200 hPa. The cloud ice water content anomaly is mostly confined to pressures greater than 150 hPa and reaches its maximum around 450 hPa, a few hours after the peak convection. Consistent with the large increase in upper-tropospheric cloud ice water content, albedo increases dramatically and persists about 30 h after peak convection. Applying the compositing technique to EC-Earth allows an assessment of the model representation of DC systems. The model captures the large-scale responses, most notably for outgoing longwave radiation, but there are a number of important differences. DC systems appear to propagate eastward in the model, suggesting a strong link to Kelvin waves instead of equatorial Rossby waves. The diurnal cycle in the model is more pronounced and appears to trigger new convection further to the west each time. Finally, the modelled ice water content anomaly peaks at pressures greater than 500 hPa and in the upper troposphere between 250 hPa and 500 hPa, there is less ice than the observations and it does not persist as long after peak convection. The modelled upper-tropospheric cloud fraction anomaly, however, is of a comparable magnitude and exhibits a similar longevity as the observations.

scholarly journals UARS/MLS Cloud Ice Measurements: Implications for H2O Transport near the Tropopause

2005 ◽  
Vol 62 (2) ◽  
pp. 518-530 ◽  
Author(s):  
D. L. Wu ◽  
W. G. Read ◽  
A. E. Dessler ◽  
S. C. Sherwood ◽  
J. H. Jiang
Keyword(s):  
Water Content ◽  
Total Water ◽  
Ice Clouds ◽  
Clear Sky ◽  
Ice Water Content ◽  
Satellite Microwave ◽  
Cold Point ◽  
Cloud Ice ◽  
Ice Water

Abstract A technique for detecting large hydrometeors at high altitudes is described here and applied to the Upper Atmosphere Research Satellite/Microwave Limb Sounder (UARS/MLS) 203-GHz radiance measurements at tangent pressures between 200 and 46 hPa. At these tangent pressures the radiances remain optically thin and cloudy-sky radiances are brighter than normal clear-sky cases. Unlike infrared/visible cloud observations, the 203-GHz radiances can penetrate most ice clouds and are sensitive to ice crystals of convective origin. Rough ice water content (IWC) retrievals are made near the tropopause using estimated size distributions from in situ convective studies. The seasonal mean IWC observed at 100 hPa reaches vapor-equivalent 20 ppmv or more over convective centers, dominating the total water content. Convectively lofted ice, therefore, appears to be hydrologically significant at the tropical cold point. IWC is well correlated spatially with relative humidity with respect to ice (RHi) at 100 hPa during both the dry (January–March) and moist (July–September) periods.

Analytical Solutions to the Stochastic Kinetic Equation for Liquid and Ice Particle Size Spectra. Part I: Small-Size Fraction

2008 ◽  
Vol 65 (7) ◽  
pp. 2025-2043 ◽  
Author(s):  
Vitaly I. Khvorostyanov ◽  
Judith A. Curry
Keyword(s):  
Water Content ◽  
Analytical Solutions ◽  
Climate Models ◽  
Size Fraction ◽  
Size Spectra ◽  
Cloud Liquid Water ◽  
Gamma Distributions ◽  
Ice Water Content ◽  
Cloud Ice ◽  
Ice Water

Abstract The kinetic equation of stochastic condensation for cloud drop size spectra is extended to account for crystalline clouds and also to include the accretion–aggregation process. The size spectra are separated into small and large size fractions that correspond to cloud drops (ice) and rain (snow). In Part I of this two-part paper, analytical solutions are derived for the small-size fractions of the spectra that correspond to cloud drops and cloud ice particles that can be identified with cloud liquid water or cloud ice water content, and used in bulk microphysical schemes employed in cloud and climate models. Solutions for the small-size fraction have the form of generalized gamma distributions. Simple analytical expressions are found for parameters of the gamma distributions that are functions of quantities that are available in cloud and climate models: liquid or ice water content and its vertical gradient, mean particle radius or concentration, and supersaturation or vertical velocities. Equations for the gamma distribution parameters provide an explanation of the dependence of the observed spectra on atmospheric dynamics, cloud temperature, and cloud liquid water or ice water content. The results are illustrated with example calculations for a crystalline cloud. The analytical solutions and expressions for the parameters presented here can be used for parameterization of the small-size fraction size spectra in liquid and crystalline clouds and related quantities (e.g., optical properties, lidar, and radar reflectivities).

scholarly journals Evaluation of the Lidar–Radar Cloud Ice Water Content Retrievals Using Collocated in Situ Measurements

2015 ◽  
Vol 54 (10) ◽  
pp. 2087-2097 ◽  
Author(s):  
Sujan Khanal ◽  
Zhien Wang
Keyword(s):  
Remote Sensing ◽  
Water Content ◽  
Cloud Microphysics ◽  
In Situ Measurements ◽  
Ice Water Content ◽  
Flight Level ◽  
The Mean ◽  
Cloud Ice ◽  
Ice Water

AbstractRemote sensing and in situ measurements made during the Colorado Airborne Multiphase Cloud Study, 2010–2011 (CAMPS) with instruments aboard the University of Wyoming King Air aircraft are used to evaluate lidar–radar-retrieved cloud ice water content (IWC). The collocated remote sensing and in situ measurements provide a unique dataset for evaluation studies. Near-flight-level IWC retrieval is compared with an in situ probe: the Colorado closed-path tunable diode laser hygrometer (CLH). Statistical analysis showed that the mean radar–lidar IWC is within 26% of the mean in situ measurements for pure ice clouds and within 9% for liquid-topped mixed-phase clouds. Considering their different measurement techniques and different sample volumes, the comparison shows a statistically good agreement and is close to the measurement uncertainty of the CLH, which is around 20%. It is shown that ice cloud microphysics including ice crystal shape and orientation has a significant impact on IWC retrievals. These results indicate that the vertical profile of the retrieved lidar–radar IWC can be reliably combined with the flight-level measurements made by the in situ probes to provide a more complete picture of the cloud microphysics.

scholarly journals Analysis of geostationary satellite derived cloud parameters associated with high ice water content environments

2016 ◽  
Author(s):  
Adrianus de Laat ◽  
Eric Defer ◽  
Julien Delanoë ◽  
Fabien Dezitter ◽  
Amanda Gounou ◽  
...  
Keyword(s):  
Water Content ◽  
Cloud Parameters ◽  
Cloud Properties ◽  
Infrared Imager ◽  
Aviation Hazards ◽  
Ice Water Content ◽  
Condensed Water ◽  
Convective Cells ◽  
Cloud Ice ◽  
Ice Water

Abstract. We present a newly developed high ice water content mask (High IWC) based on measurements of the cloud physical properties (CPP) algorithm applied to the geostationary Meteosat Second Generation (MSG) Spinning Enhanced Visible and Infrared Imager (SEVIRI). The mask was developed within the European High Altitude Ice Crystals (HAIC) project for detection of upper atmospheric high IWC, which can be a hazard for aviation. Evaluation of the High IWC mask with satellite measurements of active remote sensors of cloud properties (CLOUDSAT/CALIPSO combined in the DARDAR product) shows that the High IWC mask can be fine-tuned for detection of high IWC values > 1 g/m3 in the DARDAR profiles. The best CPP predictors of High IWC were the condensed water path, cloud optical thickness, cloud phase, and cloud top height. The evaluation of the High IWC mask against DARDAR provided some indications that the MSG-CPP High IWC mask is more sensitive to cloud ice or cloud water in the upper part of the cloud, which is relevant for aviation purposes. Biases in the CPP results were also identified, in particular a solar zenith angle (SZA) dependence that reduces the performance of the High IWC mask for SZAs > 60°. Verification statistics show that for the detection of High IWC a trade-off has to be made between better detection of High IWC scenes and more false detections, i.e. scenes identified by the High IWC mask that do not contain IWC > 1 g/m3. However, the large majority of these detections still contain IWC values between 0.1–1 g/m3. Comparison of the High IEC mask against results from the Rapid Developing Thunderstorm (RDT) algorithm applied to the same geostationary SEVIRI data showed that there are similarities and differences with the High IWC mask: the RDT algorithm is very capable of detection young/new convective cells and areas, whereas the High IWC mask appears to be better capable of detecting more mature and ageing convection as well as cirrus remnants. The lack of detailed understanding what causes aviation hazards related to High IWC hampers further tuning of the High IWC mask. Additional evaluation of the High IWC mask against field campaign data should provide more information on the performance of the MSG-CPP High IWC mask and contribute to a better characterization.

Validation of the Aura MLS cloud ice water content measurements

2008 ◽  
Vol 113 (D15) ◽  
Author(s):  
Dong L. Wu ◽  
Jonathan H. Jiang ◽  
William G. Read ◽  
Richard T. Austin ◽  
Cory P. Davis ◽  
...  
Keyword(s):  
Water Content ◽  
Ice Water Content ◽  
Cloud Ice ◽  
Ice Water
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