TITLE

Use of a Lidar Forward Model for Global Comparisons of Cloud Fraction between the ICESat Lidar and the ECMWF Model

AUTHOR(S)
Wilkinson, Jonathan M.; Hogan, Robin J.; Illingworth, Anthony J.; Benedetti, Angela
PUB. DATE
October 2008
SOURCE
Monthly Weather Review;Oct2008, Vol. 136 Issue 10, p3742
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The performance of the European Centre for Medium-Range Weather Forecasts (ECMWF) model in simulating clouds is evaluated using observations by the Geoscience Laser Altimeter System lidar on the Ice, Cloud, and Land Elevation Satellite (ICESat). To account for lidar attenuation in the comparison, model variables are used to simulate the attenuated backscatter using a lidar forward model. This generates a new model cloud fraction that can then be fairly compared with the ICESat lidar. The lidar forward model and ICESat comparison is performed over 15 days (equivalent to 226 orbits of Earth, or roughly 9 million km) of data. The model is assessed by cloud fraction statistics, skill scores, and its ability to simulate lidar backscatter. The results show that the model generally simulates the occurrence and location of clouds well but overestimates the mean amount when present of the ice cloud by around 10%, particularly in the tropics. The skill of the model is slightly better over the land than over the sea. The model also has some problems representing the amount when present in tropical boundary layer cloud, particularly over land, where there is an underestimate by as much as 15%. Calculations of backscatter reveal that the ECMWF model predicts the lidar backscatter to within 5% on average, for a lidar ratio of 20 sr, apart from in thick ice clouds. Sensitivity tests show that realistic variations in extinction-to-backscatter ratio and effective radius affect the forward modeled mean cloud fraction by no more than 10%.
ACCESSION #
34783209

 

Related Articles

  • A lidar method for determining internal wave characteristics. Dolin, L.; Dolina, I.; Savel'ev, V. // Izvestiya, Atmospheric & Oceanic Physics;Jul2012, Vol. 48 Issue 4, p444 

    An analytical model of lidar imaging of pycnoclinic internal waves (IWs) is developed. The IW image is shown to represent a superposition of two images: reflective and shadow. The former reflects perturbations in the profile of the light backscattering coefficient in the IW field, and the latter...

  • Dynamic Adjustment in a Numerically Simulated Mesoscale Convective System: Impact of the Velocity Field. de Lima Nascimento, Ernani; Droegemeier, Kelvin K. // Journal of the Atmospheric Sciences;Sep2006, Vol. 63 Issue 9, p2246 

    An identical twin methodology is applied to a three-dimensional cloud model to study the dynamics of adjustment in deep convective storms. The principal goal is to diagnose how mass and velocity fields mutually adjust in order to better understand the relative information content (value) of...

  • Aerosol extinction to backscatter ratio derived from passive satellite measurements. Bréon, F. -M. // Atmospheric Chemistry & Physics Discussions;2013, Vol. 13 Issue 1, p2351 

    Spaceborne reflectance measurements from the POLDER instrument are used to study the specific directional signature close to the backscatter direction. The data analysis makes it possible to derive the extinction to backscatter ratio (EBR) which is the invert of the scattering phase function for...

  • A new method for retrieval of the extinction coefficient of water clouds by using the tail of the CALIOP signal. J. Li; Hu, Y.; J. Huang; Stamnes, K.; Yi, Y.; Stamnes, S. // Atmospheric Chemistry & Physics;2011, Vol. 11 Issue 6, p2903 

    A method is developed based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) level 1 attenuated backscatter profile data for deriving the mean extinction coefficient of water droplets close to cloud top. The method is applicable to low level (cloud top <2 km),...

  • A simulated future atmospheric observation database including ATOVS, ASCAT, and DWL. Becker, Bernd Dieter; Roquet, Herve // Bulletin of the American Meteorological Society;Oct96, Vol. 77 Issue 10, p2277 

    Discusses the creation of a database for the study of the impact of Doppler wind lidar data on numerical weather prediction in Observation System Simulation Experiments. Advanced TIROS Operational Vertical Sounder; Required current wind observation coverage; Elements of the database.

  • Sensitivity Study of Cloud-Resolving Convective Simulations with WRF Using Two Bulk Microphysical Parameterizations: Ice-Phase Microphysics versus Sedimentation Effects. Hong, Song-You; Sunny Lim, Kyo-Sun; Kim, Ju-Hye; Jade Lim, Jeong-Ock; Dudhia, Jimy // Journal of Applied Meteorology & Climatology;Jan2009, Vol. 48 Issue 1, p61 

    This study examines the relative importance of ice-phase microphysics and sedimentation velocity for hydrometeors in bulk microphysics schemes. The two bulk microphysics schemes having the same number of prognostic water substances, the Weather Research and Forecasting (WRF) Single-Moment...

  • The Airborne Demonstrator for the Direct-Detection Doppler Wind Lidar ALADIN on ADM-Aeolus. Part I: Instrument Design and Comparison to Satellite Instrument. Reitebuch, Oliver; Lemmerz, Christian; Nagel, Engelbert; Paffrath, Ulrike; Durand, Yannig; Endemann, Martin; Fabre, Frederic; Chaloupy, Marc // Journal of Atmospheric & Oceanic Technology;Dec2009, Vol. 26 Issue 12, p2501 

    The global observation of profiles of the atmospheric wind speed is the highest-priority unmet need for global numerical weather prediction. Satellite Doppler lidar is the most promising candidate to meet the requirements on global wind profile observations with high vertical resolution,...

  • Predictability of Tropical Pacific Decadal Variability in an Intermediate Model. Karspeck, Alicia R.; Seager, Richard; Cane, Mark A. // Journal of Climate;Jul2004, Vol. 17 Issue 14, p2842 

    The Zebiak–Cane (ZC) model for simulation of the El Niño–Southern Oscillation is shown to be capable of producing sequences of variability that exhibit shifts in the time-mean state of the eastern equatorial Pacific that resemble observations of tropical Pacific decadal...

  • Adaptive Observations: A Feasibility Study.  // Monthly Weather Review;May99, Vol. 127 Issue 5, p743 

    The feasibility of the recently proposed concept of adaptive observations is tested on a typical case of poorly forecast North Atlantic cyclogenesis. Only numerical tools are employed, no special observations. Although based on simulated data, this study addresses both theoretical and...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics