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Title: First extended validation of satellite microwave liquid water path with ship-based observations of marine low clouds

 [1];  [2];  [3];  [4]
  1. Science Systems and Applications Inc., NASA Langley Research Center, Hampton Virginia USA
  2. Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin-Madison, Madison Wisconsin USA
  3. Argonne National Laboratory, Lemont Illinois USA
  4. NASA Langley Research Center, Hampton Virginia USA
Publication Date:
Sponsoring Org.:
OSTI Identifier:
Grant/Contract Number:
FOA-0000885; AC02-06CH11357
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 43; Journal Issue: 12; Related Information: CHORUS Timestamp: 2017-10-23 17:27:48; Journal ID: ISSN 0094-8276
American Geophysical Union
Country of Publication:
United States

Citation Formats

Painemal, David, Greenwald, Thomas, Cadeddu, Maria, and Minnis, Patrick. First extended validation of satellite microwave liquid water path with ship-based observations of marine low clouds. United States: N. p., 2016. Web. doi:10.1002/2016GL069061.
Painemal, David, Greenwald, Thomas, Cadeddu, Maria, & Minnis, Patrick. First extended validation of satellite microwave liquid water path with ship-based observations of marine low clouds. United States. doi:10.1002/2016GL069061.
Painemal, David, Greenwald, Thomas, Cadeddu, Maria, and Minnis, Patrick. 2016. "First extended validation of satellite microwave liquid water path with ship-based observations of marine low clouds". United States. doi:10.1002/2016GL069061.
title = {First extended validation of satellite microwave liquid water path with ship-based observations of marine low clouds},
author = {Painemal, David and Greenwald, Thomas and Cadeddu, Maria and Minnis, Patrick},
abstractNote = {},
doi = {10.1002/2016GL069061},
journal = {Geophysical Research Letters},
number = 12,
volume = 43,
place = {United States},
year = 2016,
month = 6

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1002/2016GL069061

Citation Metrics:
Cited by: 1work
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  • Cloud effective radii (r{sub e}) and cloud liquid water path (LWP) are derived from ISCCP spatially sampled satellite data and validated with ground-based pyranometer and microwave radiometer measurements taken on San Nicolas Island during the 1987 FIRE IFO. Values of r{sub e} derived from the ISCCP data are also compared to values retrieved by a hybrid method that uses the combination of LWP derived from microwave measurement and optical thickness derived from GOES data. The results show that there is significant variability in cloud properties over a 100 km x 80 km area and that the values at San Nicolasmore » Island are not necessarily representative of the surrounding cloud field. On the other hand, even though there were large spatial variations in optical depth, the r{sub e} values remained relatively constant (with {rho} {<=} 2-3 {mu}m in most cases) in the marine stratocumulus. Furthermore, values of r{sub e} derived from the upper portion of the cloud generally are representative of the entire stratiform cloud. When LWP values are less than 100 g m{sup {minus}2}, then LWP values derived from ISCCP data agree well with those values estimated from ground-based microwave measurements. In most cases LWP differences were less than 20 gm{sup {minus}2}. However, when LWP values become large (e.g., {>=}200 g m{sup {minus}2}), then relative differences may be as large as 50%-100%. There are two reasons for this discrepancy in the large LWP clouds: (1) larger vertical inhomogeneities in precipitating clouds and (2) sampling errors on days of high spatial variability of cloud optical thicknesses. Variations of r{sub e} in stratiform clouds may indicate drizzle: clouds with droplet sizes larger than 15 {mu}m appear to be associated with drizzling, while those less than 10 {mu}m are indicative of nonprecipitating clouds. Differences in r{sub e} values between the GOES and ISCCP datasets are found to be 0.16 {plus_minus} 0.98 {mu}m.« less
  • In this paper the authors present an analysis of the integrated liquid water content and precipitation characteristics of stratiform clouds using data from the Nimbus 7 Scanning Multichannel Microwave Radiometer (SMMR) for January 1979, over the North Atlantic Ocean (40{degree}-60{degree}N). Concurrent analysis of the SMMR data with the US Air Force 3-Dimensional Nephanalysis (3DNEPH) allows the interpretation of the SMMR-derived liquid water paths and precipitation characteristics in terms of cloud type, cloud fraction, and cloud height. Combining the initialized analyses from the European Center for Medium-Range Weather Forecasting with the 3DNEPH enables vertical temperature and humidity profiles to be incorporatedmore » into the retrievals. The interpretation and presentation of results are guided by their implications for the parameterization of liquid water content of layer clouds in large-scale atmospheric models. The average liquid water paths for middle and low clouds were determined to be 115 and 102 g m{sup {minus}2}, respectively, with a maximum value of 1,070 g m{sup {minus}2}. Analysis of the liquid water path as a function of temperature showed that clouds with average temperature below 246 K had little liquid water and were inferred to be predominantly crystalline. Liquid water paths of 350 g m{sup {minus}2} and 500 g m{sup {minus}2} for middle and low clouds, respectively, were determined to be average thresholds for the onset of precipitation. Maximum rain rates for these clouds were determined to be 7 mm h{sup {minus}1}. The autoconversion of cloud water to rain water was determined to occur at a rate of 0.001 s{sup {minus}1}.« less
  • Published estimates of cloud liquid water path (LWP) from satellite-measured microwave radiation show little agreement, even about the relative magnitudes of LWP in the tropics and midlatitudes. To understand these differences and to obtain more reliable estimate, optical and microwave LWP retrieval methods are compared using the International Satellite Cloud Climatology Project (ISCCP) and special sensor microwave/imager (SSM/I) data. Errors in microwave LWP retrieval associated with uncertainties in surface, atmosphere, and cloud properties are assessed. Sea surface temperature may not produce great LWP errors, if accurate contemporaneous measurements are used in the retrieval. An uncertainty of estimated near-surface wind speedmore » as high as 2 m/s produces uncertainty in LWP of about 5 mg/sq cm. Cloud liquid water temperature has only a small effect on LWP retrievals (rms errors less than 2 mg/sq cm), if errors in the temperature are less than 5 C; however, such errors can produce spurious variations of LWP with latitude and season. Errors in atmospheric column water vapor (CWV) are strongly coupled with errors in LWP (for some retrieval methods) causing errors as large as 30 mg/sq cm. Because microwave radiation is much less sensitive to clouds with small LWP (less than 7 mg/sq cm) than visible wavelength radiation, the microwave results are very sensitive to the process used to separate clear and cloudy conditions. Different cloud detection sensitivities in different microwave retrieval methods bias estimated LWP values.« less
  • We present a new methodology for retrieving liquid water path over land using satellite microwave observations. As input, the technique exploits the Advanced Microwave Scanning Radiometer for earth observing plan (EOS) (AMSR-E) polarization-difference signals at 37 and 89 GHz. Regression analysis performed on model simulations indicates that over variable atmospheric and surface conditions the polarization-difference signals can be simply parameterized in terms of the surface emissivity polarization difference ({Delta}{var_epsilon}), surface temperature, liquid water path (LWP), and precipitable water vapor (PWV). The resulting polarization-difference parameterization (PDP) enables fast and direct (noniterative) retrievals of LWP with minimal requirements for ancillary data. Single-more » and dual-channel retrieval methods are described and demonstrated. Data gridding is used to reduce the effects of instrumental noise. The methodology is demonstrated using AMSR-E observations over the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site during a six day period in November and December, 2003. Single- and dual-channel retrieval results mostly agree with ground-based microwave retrievals of LWP to within approximately 0.04 mm.« less
  • A new method to retrieve cloud liquid water path using 23.8 and 31.4 GHz microwave radiometer brightness temperature measurements is developed. This method does not depend on climatological estimates of either the mean radiating temperature of the atmosphere T{sub mr} or the mean cloud liquid water temperature T{sub cloud}. Rather, T{sub mr} is estimated from surface temperature and relative humidity measurements, while T{sub cloud} is estimated using millimeter-wave cloud radar data, together with atmospheric temperature profiles obtained from either radiosonde or rapid update cycle (RUC) model output. Simulations demonstrate that the new retrieval method significantly reduces the biases in themore » liquid water path estimates that are apparent in a site-specific retrieval based on monthly stratified, local climatology. An analysis of the liquid water path estimates produced by the two retrievals over four case study days illustrates trends and retrieval performances consistent with the model simulations.« less