Global assessment of AMSR-E and MODIS cloud liquid water path retrievals in warm oceanic clouds

removed, in a global mean sense, by adiabatic correction; however, large regional differences remained. Most notably, MODIS showed strong overestimations at high latitudes, which we traced to 3‐D effects in plane‐parallel visible‐near‐infrared retrievals over heterogeneous clouds at low Sun. In the tropics or subtropics, AMSR‐E‐MODIS differences also depended on cloud type, with MODIS overestimating in stratiform clouds and underestimating in cumuliform clouds, resulting in large‐scale coherent bias patterns where marine Sc transitioned into trade wind Cu. We noted similar geographic variations in Wentz cloud temperature errors and MODIS 1.6–3.7 mm droplet effective radius differences, suggesting that microwave retrieval errors due to cloud absorption uncertainties, and visible near‐infrared retrieval errors due to cloud vertical stratification might have contributed to the observed liquid water path bias patterns. Finally, cloud‐rain partitioning was found to introduce a systematic low bias in Wentz retrievals above 180 g m −2 as the microwave algorithm erroneously assigned an increasing portion of the liquid water content of thicker nonprecipitating clouds to rain.

[1]  Roger Davies,et al.  Anisotropy of water cloud reflectance: A comparison of measurements and 1D theory , 2004 .

[2]  Steven Platnick,et al.  Estimate of the impact of absorbing aerosol over cloud on the MODIS retrievals of cloud optical thickness and effective radius using two independent retrievals of liquid water path , 2009 .

[3]  Jerome Riedi,et al.  Case study of inhomogeneous cloud parameter retrieval from MODIS data , 2005 .

[4]  R. Wood,et al.  Spatial variability of liquid water path in marine low cloud : The importance of mesoscale cellular convection , 2006 .

[5]  Christopher W. Fairall,et al.  Ship-based liquid water path estimates in marine stratocumulus , 2005 .

[6]  Fuzhong Weng,et al.  Impact of the Vertical Variation of Cloud Droplet Size on the Estimation of Cloud Liquid Water Path and Rain Detection , 2007 .

[7]  Alexander Marshak,et al.  View angle dependence of cloud optical thicknesses retrieved by Moderate Resolution Imaging Spectroradiometer (MODIS) , 2007 .

[8]  M. King,et al.  Determination of the Optical Thickness and Effective Particle Radius of Clouds from Reflected Solar Radiation Measurements. Part II: Marine Stratocumulus Observations , 1991 .

[9]  Roger Davies,et al.  Comparison of Microwave and Optical Cloud Water Path Estimates From TMI, MODIS, and MISR , 2007 .

[10]  Ralf Bennartz,et al.  Global assessment of marine boundary layer cloud droplet number concentration from satellite , 2007 .

[11]  R. Davies,et al.  Observational evidence of plane parallel model biases: Apparent dependence of cloud optical depth on solar zenith angle , 1996 .

[12]  Harshvardhan,et al.  Correction to “Global assessment of marine boundary layer cloud droplet number concentration from satellite” , 2007 .

[13]  S. Bony,et al.  Marine boundary layer clouds at the heart of tropical cloud feedback uncertainties in climate models , 2005 .

[14]  Damien Lafont,et al.  Subpixel fractional cloud cover and inhomogeneity effects on microwave beam-filling error , 2004 .

[15]  Robert Wood,et al.  Studying the vertical variation of cloud droplet effective radius using ship and space-borne remote sensing data , 2008 .

[16]  David M. Winker,et al.  Influence of Subpixel-Scale Cloud-Top Structure on Reflectances from Overcast Stratiform Cloud Layers , 1998 .

[17]  Cloud inhomogeneity from MODIS Lazaros 0 reopoulosi 2 and , 2004 .

[18]  Zhanqing Li,et al.  Retrieving vertical profiles of water‐cloud droplet effective radius: Algorithm modification and preliminary application , 2003 .

[19]  Marie Doutriaux-Boucher,et al.  A comparison of cloud droplet radii measured from space , 2005, IEEE Transactions on Geoscience and Remote Sensing.

[20]  Alexander Marshak,et al.  The Potential for Improved Boundary Layer Cloud Optical Depth Retrievals from the Multiple Directions of MISR , 2008 .

[21]  M. King,et al.  Determination of the optical thickness and effective particle radius of clouds from reflected solar , 1990 .

[22]  Roy W. Spencer,et al.  SSM/I Rain Retrievals within a Unified All-Weather Ocean Algorithm , 1998 .

[23]  Sundar A. Christopher,et al.  Evaluating specific error characteristics of microwave‐derived cloud liquid water products , 2007 .

[24]  B. Stevens.  ATMOSPHERIC MOIST CONVECTION , 2005 .

[25]  Ralf Bennartz,et al.  Vertical structure of stratiform marine boundary layer clouds and its impact on cloud albedo , 2007 .

[26]  F. Wentz,et al.  Intercalibrated Passive Microwave Rain Products from the Unified Microwave Ocean Retrieval Algorithm (UMORA) , 2008 .

[27]  P. Levelt,et al.  Aerosols and surface UV products from Ozone Monitoring Instrument observations: An overview , 2007 .

[28]  W. Paul Menzel,et al.  The MODIS cloud products: algorithms and examples from Terra , 2003, IEEE Trans. Geosci. Remote. Sens..

[29]  Shepard A. Clough,et al.  Thin Liquid Water Clouds: Their Importance and Our Challenge , 2007 .

[30]  Jim Haywood,et al.  The effect of overlying absorbing aerosol layers on remote sensing retrievals of cloud effective radius and cloud optical depth , 2004 .

[31]  Steven Platnick,et al.  Impact of three‐dimensional radiative effects on satellite retrievals of cloud droplet sizes , 2006 .

[32]  Norman G. Loeb,et al.  Inference of Marine Stratus Cloud Optical Depths from Satellite Measurements: Does 1D Theory Apply? , 1998 .

[33]  Christopher W. O'Dell,et al.  Cloud Liquid Water Path from Satellite-Based Passive Microwave Observations: A New Climatology over the Global Oceans , 2008 .

[34]  Robert F. Cahalan,et al.  The albedo of fractal stratocumulus clouds , 1994 .

[35]  A. Marshak,et al.  Statistical Analysis of the Uncertainties in Cloud Optical Depth Retrievals Caused by Three-Dimensional Radiative Effects , 2001 .

[36]  Christian D. Kummerow,et al.  Multisensor satellite observations of aerosol effects on warm clouds , 2008 .

[37]  Joyce Chou,et al.  Cloud liquid water path comparisons from passive microwave and solar reflectance satellite measurements : Assessment of sub-field-of-view cloud effects in microwave retrievals , 1997 .

[38]  F. Wentz.  A well‐calibrated ocean algorithm for special sensor microwave / imager , 1997 .

[39]  Guangyu Zhao,et al.  Cloud fraction errors for trade wind cumuli from EOS‐Terra instruments , 2006 .

[40]  Ákos Horváth,et al.  Cloud‐fraction‐dependent bias in satellite liquid water path retrievals of shallow, non‐precipitating marine clouds , 2007 .