scholarly journals Determination of Cloud Liquid Water Path over the Oceans from Special Sensor Microwave/Imager (SSM/I) Data Using Neural Networks

1998 ◽  
Vol 37 (8) ◽  
pp. 832-844 ◽  
Author(s):  
Thomas Jung ◽  
Eberhard Ruprecht ◽  
Friedrich Wagner
Keyword(s):  
Neural Networks ◽  
Liquid Water ◽  
Liquid Water Path ◽  
Cloud Liquid Water ◽  
Water Path ◽  
Microwave Imager ◽  
Cloud Liquid Water Path

scholarly journals Cloud Liquid Water Path from Satellite-Based Passive Microwave Observations: A New Climatology over the Global Oceans

2008 ◽  
Vol 21 (8) ◽  
pp. 1721-1739 ◽  
Author(s):  
Christopher W. O’Dell ◽  
Frank J. Wentz ◽  
Ralf Bennartz
Keyword(s):  
Liquid Water ◽  
Systematic Errors ◽  
Cloud Water ◽  
Liquid Water Path ◽  
Cloud Liquid Water ◽  
Water Path ◽  
Microwave Imager ◽  
Cloud Liquid Water Path ◽  
The Tropics ◽  
Global Oceans

Abstract This work describes a new climatology of cloud liquid water path (LWP), termed the University of Wisconsin (UWisc) climatology, derived from 18 yr of satellite-based passive microwave observations over the global oceans. The climatology is based on a modern retrieval methodology applied consistently to the Special Sensor Microwave Imager (SSM/I), the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI), and the Advanced Microwave Scanning Radiometer (AMSR) for Earth Observing System (EOS) (AMSR-E) microwave sensors on eight different satellite platforms, beginning in 1988 and continuing through 2005. It goes beyond previously published climatologies by explicitly solving for the diurnal cycle of cloud liquid water by providing statistical error estimates, and includes a detailed discussion of possible systematic errors. A novel methodology for constructing the climatology is used in which a mean monthly diurnal cycle as well as monthly means of the liquid water path are derived simultaneously from the data on a 1° grid; the methodology also produces statistical errors for these quantities, which decrease toward the end of the time record as the number of observations increases. The derived diurnal cycles are consistent with previous findings in the tropics, but are also derived for higher latitudes and contain more information than in previous studies. The new climatology exhibits differences with previous observationally based climatologies and is found to be more consistent with the 40-yr ECMWF Re-Analysis (ERA-40) than are the previous climatologies. Potential systematic errors of the order of 15%–30% or higher exist in the LWP climatology. A previously unexplored source of systematic error is caused by the assumption that all microwave-based retrievals of LWP must make regarding the partitioning of cloud water and rainwater, which cannot be determined using microwave observations alone. The potentially large systematic errors that result may hamper the usefulness of microwave-based climatologies of both cloud liquid water and especially rain rate, particularly in certain regions of the tropics and midlatitudes where the separation of rain from liquid cloud water is most critical.

scholarly journals An Uncertainty Data Set for Passive Microwave Satellite Observations of Warm Cloud Liquid Water Path

2018 ◽  
Vol 123 (7) ◽  
pp. 3668-3687 ◽  
Author(s):  
Thomas J. Greenwald ◽  
Ralf Bennartz ◽  
Matthew Lebsock ◽  
João Teixeira
Keyword(s):  
Liquid Water ◽  
Satellite Observations ◽  
Passive Microwave ◽  
Liquid Water Path ◽  
Data Set ◽  
Cloud Liquid Water ◽  
Water Path ◽  
Warm Cloud ◽  
Cloud Liquid Water Path

scholarly journals A new retrieval for cloud liquid water path using a ground-based microwave radiometer and measurements of cloud temperature

2001 ◽  
Vol 106 (D13) ◽  
pp. 14485-14500 ◽  
Author(s):  
James C. Liljegren ◽  
Eugene E. Clothiaux ◽  
Gerald G. Mace ◽  
Seiji Kato ◽  
Xiquan Dong
Keyword(s):  
Liquid Water ◽  
Microwave Radiometer ◽  
Liquid Water Path ◽  
Cloud Liquid Water ◽  
Water Path ◽  
Cloud Temperature ◽  
Cloud Liquid Water Path

scholarly journals Climatology of Warm Boundary Layer Clouds at the ARM SGP Site and Their Comparison to Models

2004 ◽  
Vol 17 (24) ◽  
pp. 4760-4782 ◽  
Author(s):  
Manajit Sengupta ◽  
Eugene E. Clothiaux ◽  
Thomas P. Ackerman
Keyword(s):  
Liquid Water ◽  
Solar Flux ◽  
Cloud Base ◽  
Liquid Water Path ◽  
Cloud Liquid Water ◽  
Water Path ◽  
Cloud Forcing ◽  
Cloud Liquid Water Path ◽  
Ecmwf Model ◽  
Cloud Thickness

Abstract A 4-yr climatology (1997–2000) of warm boundary layer cloud properties is developed for the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Program Southern Great Plains (SGP) site. Parameters in the climatology include cloud liquid water path, cloud-base height, and surface solar flux. These parameters are retrieved from measurements produced by a dual-channel microwave radiometer, a millimeter-wave cloud radar, a micropulse lidar, a Belfort ceilometer, shortwave radiometers, and atmospheric temperature profiles amalgamated from multiple sources, including radiosondes. While no significant interannual differences are observed in the datasets, there are diurnal variations with nighttime liquid water paths consistently higher than daytime values. The summer months of June, July, and August have the lowest liquid water paths and the highest cloud-base heights. Model outputs of cloud liquid water paths from the European Centre for Medium-Range Weather Forecasts (ECMWF) model and the Eta Model for 104 model output location time series (MOLTS) stations in the environs of the SGP central facility are compared to observations. The ECMWF and MOLTS median liquid water paths are greater than 3 times the observed values. The MOLTS data show lower liquid water paths in summer, which is consistent with observations, while the ECMWF data exhibit the opposite tendency. A parameterization of normalized cloud forcing that requires only cloud liquid water path and solar zenith angle is developed from the observations. The parameterization, which has a correlation coefficient of 0.81 with the observations, provides estimates of surface solar flux that are comparable to values obtained from explicit radiative transfer calculations based on plane-parallel theory. This parameterization is used to estimate the impact on the surface solar flux of differences in the liquid water paths between models and observations. Overall, there is a low bias of 50% in modeled normalized cloud forcing resulting from the excess liquid water paths in the two models. Splitting the liquid water path into two components, cloud thickness and liquid water content, shows that the higher liquid water paths in the model outputs are primarily a result of higher liquid water contents, although cloud thickness may a play a role, especially for the ECMWF model results.

scholarly journals Retrieval and characterization of cloud liquid water path using airborne passive microwave data during INDOEX

2001 ◽  
Vol 106 (D22) ◽  
pp. 28719-28730 ◽  
Author(s):  
Guosheng Liu ◽  
Judith A. Curry ◽  
Julie A. Haggerty ◽  
Yunfei Fu
Keyword(s):  
Liquid Water ◽  
Passive Microwave ◽  
Liquid Water Path ◽  
Cloud Liquid Water ◽  
Water Path ◽  
Cloud Liquid Water Path ◽  
Microwave Data
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