GCM Oriented Calipso Cloud Product

 

CALIPSO-GOCCP data have been updated the 29/04/2013 (see the list of changes at the bottom of the page)

A cloud phase diagnosis in GOCCP (and its counterpart in the lidar simulator included in COSP) is now available (Cesana and Chepfer 2013). This diagnosis is independent of temperature and allows to take into account the effects of multiple scattering and attenuation due to the lidar, in the cloud phase partitioning. It is based on the lidar polarization. More details about the method to estimate GOCCP cloud phase are available in Cesana and Chepfer 2013.

A detailed comparison between CALIPSO-GOCCP data and NASA Science Team CALIPSO-ST data has been published in 2012 (Chepfer et al. 2012 JAOT). This study explains the signal to noise correction during day time in GOCCP algorithm and emphasizes the need to use CALIPSO-GOCCP for model studies.

Examples of model evaluation using CALIPSO-GOCCP have been published in GRL: Cesana and Chepfer 2012 (without cloud phase) and Cesana et al. 2012 (with cloud phase).

 

The CALIPSO-GOCCP (GCM Oriented Cloud Calipso Product) is designed to evaluate GCM cloudiness.

CALIPSO-GOCCP contains observational cloud diagnostics fully consistent with the ones simulated by the ensemble "GCM+lidar simulator": it has been built in using the same horizontal and vertical resolutions, and the same cloud detection thresholds. The lidar simulator is part of the CICCS (CFMIP Observation Simulator Package) and can be downloaded on: http://cfmip.metoffice.com/CICCS.html

CALIPSO-GOCCP is used for the CFMIP pilot model intercomparison study, it has been processed at LMD/IPSL with the support of NASA/CNES, ICARE and Climserv.

CALIPSO-GOCCP is derived from Calipso L1/NASA products (NASA Langley ASDC - CALIPSO Data Sets) and contains four types of files:

 

  • 1a) 3D_CloudFraction: monthly/seasonal zonal mean cloud fraction
  • 1b) 3D_CloudFraction_phase: 3D_CloudFraction_phase
  • 1c) 3D_CloudFraction_phase_temp: 3D_CloudFraction_phase_temp
  • 2a) MapLowMidHigh: monthly/seasonal cloud fraction maps at three levels (Low, Mid, High following ISCCP definition)
  • 2b) MapLowMidHighphase: MapLowMidHigh phase
  • 3a) SR_histo: monthly/seasonal diagrams of occurence (z, SR) where SR is the lidar scattering ratio (similar as CFAD for Cloudsat)
  • 3b) SR_histophase: SR_histo phase
  • 4a) Instant_SR : SR(z) along the satellite flight track for each orbit.
  • 4b) Instant_SRphase :Instant_SR phase
  •  

    References:

    - Chepfer H., G. Cesana, D. Winker, B. Getzewich, and M. Vaughan, 2013: Comparison of two different cloud climatologies derived from CALIOP Level 1 observations: the CALIPSO-ST and the CALIPSO-GOCCP, J. Atmos. Ocean. Tech., doi.10.1175/JTECH-D-12-00057.1,[PDF]
    http://journals.ametsoc.org/doi/abs/10.1175/JTECH-D-12-00057.1

    - Cesana G. and H. Chepfer (2013): Evaluation of the cloud water phase in a climate model using CALIPSO-GOCCP, J. Geophys. Res., doi: 10.1002/jgrd.50376 http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50376/abstract

    - Cesana, G., J. E. Kay, H. Chepfer, J. M. English, and G. deBoer (2012), Ubiquitous low-level liquid-containing Arctic clouds: New observations and climate model constraints from CALIPSO-GOCCP, Geophys. Res. Lett, 39, L20804, doi:10.1029/2012GL053385 http://onlinelibrary.wiley.com/doi/10.1029/2012GL053385/abstract

    - Cesana, G., and H. Chepfer (2012), How well do climate models simulate cloud vertical structure? A comparison between CALIPSO-GOCCP satellite observations and CMIP5 models, Geophys. Res. Lett, 39, L20803, doi:10.1029/2012GL053153 http://onlinelibrary.wiley.com/doi/10.1029/2012GL053153/abstract

    - Chepfer,H., S.Bony, D. M. Winker, G. Cesana, JL. Dufresne, P. Minnis, C.J. Stubenrauch, S. Zeng, 2010: "The GCM Oriented CALIPSO Cloud Product (CALIPSO-GOCCP)", J. Geophys. Res., 105, D00H16, doi: 10.1029/2009JD012251, [PDF]
    http://www.agu.org/journals/jd/jd1005/2009JD012251/

    - Cesana, G., H. Chepfer, 2009: "The GCM Oriented CALIPSO Cloud Product (CALIPSO-GOCCP)", poster, [PDF]

    - Chepfer,H., S. Bony, D. M. Winker, M. Chiriaco, J.-L. Dufresne, and G. Seze, 2008: "Use of CALIPSO lidar observations to evaluate the cloudiness simulated by a climate model", Geophys. Res. Lett., vol. 35, L15704, doi: 10.1029/2008GL034207, [PDF]
    http://www.agu.org/journals/gl/gl0815/2008GL034207/

     

    Informations and updates:
    Please send us an e-mail if you download data, so that we can keep you inform of CALIPSO-GOCCP updates.
    Mail to: goccp@lmd.polytechnique.fr

     


     

    1a) 3D_CloudFraction

    - 3D_CloudFraction file contains the following monthly (or seasonal) fractions in longitude/latitude/altitude boxes: cloud fraction, clearfraction, and uncertain fraction. The sum of this fraction in a longitude/latitude/altitude box is equal to 1 (The file contains also an information on the fully attenuated point. The way to calculate this fraction is not fixed yet)

    - The following figure is an example of what you can do with the CALIPSO-GOCCP 3D_CloudFraction DATA for the period JJA 2006-2009 (a) (c) (d) and JFM 2007-2009 (b).

    3d_cloudfraction_jja06-09_avg_cfmip2bis.png

     

    File contents:

    Size: 6.4Mo

    Dimensions:

  • longitude= 96 / 144 / 180 / 360
  • latitude = 72 / 72 / 90 / 180
  • altitude = 40
  • nv = 2
  • time = 1
  • Variables :

  • longitude(longitude)
  • latitude(latitude)
  • alt_mid(altitude)
  • alt_bound(nv,altitude)
  • time(time)
  • clcalipso(time,altitude,latitude,longitude)
  • clrcalipso(time,altitude,latitude,longitude)
  • uncalipso(time,altitude,latitude,longitude)
  •  


     

    1b) 3D_CloudFraction_phase

    - The name of the 3D cloud fraction phase files begin with 3D_CloudFraction_Phase330m_* and contain liquid/ice/undefined-Phase cloud fractions and the relative percentage of ice in cloud with respect to the total condensate.

    - CF3D Phase: Cloud phase vertical distribution observed by CALIPSO-GOCCP in JFM. Ice cloud fraction (left column), liquid (center) cloud fraction, and ice fraction with respect to the total condensate (right).

    CF3D_Phase_CFMIP-OBS.png

     

    New Variables :

  • clcalipso_liq(time,altitude,latitude,longitude)
  • clcalipso_ice(time,altitude,latitude,longitude)
  • clcalipso_un(time,altitude,latitude,longitude)
  • clcalipso_RPIC(time,altitude,latitude,longitude)
  •  


     

    1c) 3D_CloudFraction_phase_temp

    - There are also 3D_CloudFraction_Temp330m_* files that contain cloud fractions for all clouds and for liquid/ice clouds as a function of the temperature instead of height and for each longitude/latitude grid box. The temperature bins and ranged every 3°C. The temperature is taken from GMAO data (Global Modeling and Assimilation Office, Bey et al., 2001), which is part of CALIPSO level 1 ancillary data. For each CALIOP level 1 profile, we interpolate the GMAO temperature over the 480m-vertical levels of CALIPSO-GOCCP, and use it as the cloudy pixel temperature.

    - Cloud temperature distribution annual mean observed by CALIPSO-GOCCP for 2012: a) Total cloud fraction, b) Ice cloud fraction, c) liquid cloud fraction and d) Relative percentage of ice with respect to the total condensate.

    CF3DTEMP.png

     

    New Variables :

  • cltemp(time,altitude,latitude,longitude)
  • cltemp_liq(time,altitude,latitude,longitude)
  • cltemp_ice(time,altitude,latitude,longitude)
  • cltemp_phase(time,altitude,latitude,longitude)
  •  

    Ftp CMOR data access:

  • 3D_CloudFraction_2x2xL40 !! Use this grid for the CMIP5/CFMIP-2 experiment. !!
  • 3D_CloudFraction_3.5x2.5xL40
  • 3D_CloudFraction_2.5x2.5xL40
  • 3D_CloudFraction_1x1xL40 !! Use this grid ONLY for the GEWEX Cloud Assessment. !!
  •  

    Ftp data access:

  • 3D_CloudFraction_2x2xL40 !! Use this grid for the CMIP5/CFMIP-2 experiment. !!
  • 3D_CloudFraction_3.5x2.5xL40
  • 3D_CloudFraction_2.5x2.5xL40
  • 3D_CloudFraction_1x1xL40 !! Use this grid ONLY for the GEWEX Cloud Assessment. !!
  • 3D_CloudFraction_obsolete
  •  

    Matlab routine: 3D_CloudFraction

     


     

    2a) MapLowMidHigh

    - MapLowMidHigh file contains maps of Low-Mid-High cloud fractions, total cloud fraction and clear fraction:

  • Low level clouds :     P° < 680 hPa                   z < 3.2 km          (Hydrostatic equilibrium)
  • Mid level clouds :     680 hPa < P° < 440 hPa        3.2 km < z < 6.5 km
  • High level clouds :   P° > 440 hPa                    z > 6.5 km     
  • - The total cloud/clear fraction (called cltcalipso for cloud and clccalipso for clear) enable to know the cloud/clear fraction present in a longitude/latitude column.

    - The following figure is an example of what you can do with the CALIPSO-GOCCP MapLowMidHigh DATA for the period JJA 2006-2009.

     

    maplowmidhigh_jja06-09_avg_cfmip2bis.png

     

    File contents:

    Size: 140ko

    Dimensions:

  • longitude= 96 / 144 / 180 / 360
  • latitude = 72 / 72 / 90 / 180
  • toplvl = 3
  • time = 1
  • Variables :

  • longitude(longitude)
  • latitude(latitude)
  • toplvl(toplvl)
  • time(time)
  • cllcalipso(time,latitude,longitude)
  • clmcalipso(time,latitude,longitude)
  • clhcalipso(time,latitude,longitude)
  • cltcalipso(time,latitude,longitude)
  • clccalipso(time,latitude,longitude)
  •  


     

    2b) MapLowMidHighphase

    - The name of the cloud phase map files begin with MapLowMidHigh_Phase330m_*. They contain:

  • liquid/ice/undefined-Phase of low/mid/high/total cloud covers.
  • Another variable which is the relative percentage of ice in cloud with respect to the total condensate for low/mid/high/total level
  • - Map Phase: Ice and Liquid cloud maps observed by CALIPSO-GOCCP in JFM: Liquid cloud covers observed (a-c) and Ice cloud covers observed (g-i) at high, mid, low altitudes.

     

    Map_Phase_CFMIP-OBS.png

     

    New Variables :

  • cllcalipso_liq(time,latitude,longitude)
  • cllcalipso_ice(time,latitude,longitude)
  • cllcalipso_un(time,latitude,longitude)
  • cllcalipso_RPIC(time,latitude,longitude)
  • clmcalipso_liq(time,latitude,longitude)
  • clmcalipso_ice(time,latitude,longitude)
  • clmcalipso_un(time,latitude,longitude)
  • clmcalipso_RPIC(time,latitude,longitude)
  • clhcalipso_liq(time,latitude,longitude)
  • clhcalipso_ice(time,latitude,longitude)
  • clhcalipso_un(time,latitude,longitude)
  • clhcalipso_RPIC(time,latitude,longitude)
  • cltcalipso_liq(time,latitude,longitude)
  • cltcalipso_ice(time,latitude,longitude)
  • cltcalipso_un(time,latitude,longitude)
  • cltcalipso_RPIC(time,latitude,longitude)
  •  

    Ftp CMOR data access:

  • MapLowMidHigh_2x2xL40 !! Use this grid for the CMIP5/CFMIP-2 experiment. !!
  • MapLowMidHigh_3.5x2.5xL40
  • MapLowMidHigh_2.5x2.5xL40
  • MapLowMidHigh_1x1xL40 !! Use this grid ONLY for the GEWEX Cloud Assessment. !!
  •  

    Ftp data access:

  • MapLowMidHigh_2x2xL40 !! Use this grid for the CMIP5/CFMIP-2 experiment. !!
  • MapLowMidHigh_3.5x2.5xL40
  • MapLowMidHigh_2.5x2.5xL40
  • MapLowMidHigh_1x1xL40 !! Use this grid ONLY for the GEWEX Cloud Assessment. !!
  • MapLowMidHigh_obsolete
  •  

    Matlab routine: MapLowMidHigh

     


     

    3a) SR_histograms

    - SR_histo file contains the number of points encontered in each SR bin (= cfad_lidarsr532_Occ & cfad_lidarsr532_Occ2).

    - The 19 SR interval boundaries are : -888,-777,-776,0, 0.01, 1.2, 3, 5, 7, 10, 15, 20, 25, 30, 40, 50, 60, 80, 10000.

    - In the simulator outputs, the three first interval boxes (-888,-777,-776 to 0) do not have their counterpart in the simulator outputs, they are associated to the following situation:

  • First box (SR=-888) corresponds to pixels located below the surface elevation.
  • Second box (SR=-777) corresponds to pixels rejected.
  • Third box (-776<SR<0) corresponds to noisy pixels.
  • - SR_histo is defined for each longitude/latitude/altitude box.

    - The following figures are examples of what you can do with the CALIPSO-GOCCP SR_histo DATA for the period JJA 2006-2009:

     

  • The first graphic is a representation of the SR histograms as a function of the altitude.
  • sr_histo_jja_cfmip2_avgbis.png

     

  • We can use the SR_histo CALIPSO-GOCCP data on particular regions such as the graphic below.
  • sr_histo_jja_region_cfmip2_avgbis.png

     

  • On the third graphic, the cloud fraction is rebuilt from the SR_histovalues. Thus, we can chose the treshold of SR and follow the evolutionof the optically thicker or thinner clouds.
  • There is some differences between this method and the cloud fractionderived from 3D_CloudFraction files. Indeed, in the 3D_cloudFraction files we introduce a treshold called DeltaAtb which is equal to : atb - atbmol, during the calculation of the cloud fraction.The aim of the DeltaAtb is to reduce the noise in the stratosphere. This treshold has been set to 2.5E-03 km-1.sr-1. So, in the3D_CloudFraction files a cloudy point has to be higher than the cloudy treshold but also higher than the DeltaAtb treshold, whereas inthe SR_histo files the DeltaAtb treshold is not used.
  • 3dcf_srhist_jja_cfmip2_avgbis.png

     

    File contents:

    Size: 33Mo

    Dimensions:

  • longitude= 96 / 144 / 180 / 360
  • latitude = 72 / 72 / 90 / 180
  • altitude = 40
  • nv = 2
  • box = 15
  • box2 = 3
  • time = 1
  • Variables :

  • longitude(longitude)
  • latitude(latitude)
  • alt_mid(altitude)
  • alt_bound(nv,altitude)
  • srbox_mid(box)
  • srbox_mid2(box2)
  • srbox_bound(nv,box)
  • srbox_bound2(nv,box2)
  • time(time)
  • cfad_lidarsr532_Occ(time,box,altitude,latitude,longitude)
  • cfad_lidarsr532_Occ2(time,box2,altitude,latitude,longitude)
  •  


     

    3b) SR_histograms phase

    - The name of the SR_histo phase files begin with SR_histo_Phase330m_* and contain liquid/ice/undefined-Phase SR histograms of clouds.

    - SR histograms Phase : Seasonal two-dimensional histograms of scattering ratio and height from CALIPSO-GOCCP Arctic (70-82 N, ocean-only) observations. a) SON liquid-containing cloud, b) DJF liquid-containing cloud, c) MAM liquid-containing cloud, d) JJA liquid-containing cloud, e-h) as in a-d) but for ice-dominated cloud, i-l) as in a-d) but for unclassified cloud:

    SR_histo_Phase_CFMIP-OBS.png

     

    New Variables :

  • cfad_lidarsr532_liq(time,box,altitude,latitude,longitude)
  • cfad_lidarsr532_ice(time,box,altitude,latitude,longitude)
  • cfad_lidarsr532_un(time,box,altitude,latitude,longitude)
  •  

    Ftp CMOR data access:

  • SR_histo_2x2xL40 !! Use this grid for the CMIP5/CFMIP-2 experiment. !!
  • SR_histo_3.5x2.5xL40
  • SR_histo_2.5x2.5xL40
  • SR_histo_1x1xL40 !! Use this grid ONLY for the GEWEX Cloud Assessment. !!
  •  

    Ftp data access:

  • SR_histo_2x2xL40 !! Use this grid for the CMIP5/CFMIP-2 experiment. !!
  • SR_histo_3.5x2.5xL40
  • SR_histo_2.5x2.5xL40
  • SR_histo_1x1xL40 !! Use this grid ONLY for the GEWEX Cloud Assessment. !!
  • SR_histo_obsolete
  •  

    Matlab routine: SR_histo

     


     

    4a) Instant_SR_CR_DR

    - Instant_SR_CR_DR file contains the scattering ratio (SR), Color Ratio (CR) and Depolarization Ratio (DR) average over the 40 vertical levels of the CFMIP grid. The horizontal day track resolution is 330m (about 60000 points).

    - The longitude, latitude, hour and SE are saved in the instantaneous files too.

    instant_srcrdr_20070101_nightbis.png

     

    File contents:

    Size: about 10Mo

    Dimensions:

  • altitude = 40
  • it = about 60000
  • Variables :

  • longitude(it)
  • latitude(it)
  • altitude(altitude)
  • heure(it)
  • SE(it) (Surface_Elevation)
  • instant_SR(it,altitude)
  • instant_CR(it,altitude)
  • instant_DR(it,altitude)
  •  


     

    4b) Instant_SR_CR_DR phase

    -The cloud phase mask has been added to the existing instant_SR_CR_DR files (instant_Phase variable).

    - Instant Cloud Phase: Cloud phase mask CALIPSO-GOCCP for a CALIPSO orbit, January 1st 2007 during night time (latitude between 72°13 and -58°93; longitude between 173°85 and -4°86).

    instant_Phase_CFMIP-OBS.png

     

  • instant_Cloud(it,altitude)
  • instant_Phase(it,altitude)
  • ATB(it,altitude)
  • ATB_mol(it,altitude)
  • ATB_per(it,altitude)
  • ATB_par(it,altitude)
  • TEMP(it,altitude)
  •  

    Ftp data access: instant_SR_CR_DR

     

    Matlab routine: instant_SRCRDR

     


     

    Update of the 29/04/2013 ==> cloud phase diagnosis

    The list of changes is summarized here after:

    Main changes:

  • In addition to monthly night/day/avg files, daily night/day/avg files (in the daily folder) and yearly files (in the same folder as the monthly files) are now available.
  • The processing period has been extended from june 2006 to december 2012.
  • Cloud phase diagnosis have been added in 3D_CloudFraction, MapLowMidHigh, SR_histo and instant_SR files.
  •  

    New Cloud Phase files:

  • MapLowMidHigh_Phase contain liquid, ice and undefined low/mid/high/tot cloud covers
  • 3D_CloudFraction_Phase contain liquid, ice and undefined vertical cloud fractions
  • 3D_CloudFraction_Temp contain liquid, ice and undefined cloud fractions as a function of the temperature instead of the height
  • SR_histo_Phase contain liquid, ice and undefined histograms of SR
  • instant_SR_CR_DR contain new variables: cloud phase mask, total ATB, perpendicular ATB, parallel ATB, molecular ATB and Temperature. The name of the instant_SR_CR_DR has been changed. It is built such as the CALIPSO level1 orbit files.
  •  

    Update of the 01/2012 ==> CMOR data available

    The list of changes is summarized here after:

  • CMOR data available.
  •  

    Update of the 23/03/2011 ==> CALIPSO-GOCCP version 2.1

     

    The list of changes is summarized here after:

  • improve DAY TIME Signal to Noise Ratio correction:
  • Major changes in "MapLowMidHigh" and "3D_CloudFraction" files (AVG,DAY & "climato" files).
  • Correction of fake detections above 8km, during DAY TIME,in "instant_SR" variable:
  • changes in "SR_histo" DAY/AVG TIME files and "SR_histo_climato" files.
  • Add Color Ratio and Depolarization Ratio in instant_SR files:
  • Name of instant_SR files becomes instant_SR_CR_DR.
  • Color Ratio variable is called "instant_CR", Depolarization Ratio is called "instant_DR".
  • New variables in "SR_histo" files:
  • The previous "cfad_lidarsr532_Occ" variable has been splitted into 2 different variables:
  • the variable "cfad_lidarsr532_Occ" contains (lon,lat,alt,srbox[0 to 10e5]) (= positive bins of SR).
  • the variable "cfad_lidarsr532_Occ2" contains (lon,lat,alt,srbox[-888 to 0]) (= negative bins of SR e.g. negative values, rejected values and surface values).
  • The altitude description has been changed in:
  • "3D_CloudFraction", "SR_histo", "instant_SR_CR_DR" and "climato" files:
  • "alt_mid(40x1)" contains the altitude of the middle of the layer.
  • "alt_bound(40x2)" contains the altitude of the top of the layer and the altitude of the bottom of the layer.
  • The SRbox description has been changed in:
  • "SR_histo" and SR_histo_climato" files:
  • "srbox_mid(15x1)" contains the value of the middle of the SR bin.
  • "srbox_mid2(3x1)" : same as srbox_mid for negative value of SR bin.
  • "srbox_bound(15x2)" contains the higher value of the SR bin and the lower value of the SR bin.
  • "srbox_bound2(3x2)": same as srbox_bound for negative value of SR bin.