Comparison of cloud liquid water paths derived from in situ and microwave radiometer data taken during the SHEBA/FIREACE

2001 ◽  
Vol 28 (6) ◽  
pp. 975-978 ◽  
Author(s):  
Bing Lin ◽  
Patrick Minnis ◽  
Alice Fan ◽  
Judith A. Curry ◽  
H. Gerber
Keyword(s):  
Liquid Water ◽  
Microwave Radiometer ◽  
Cloud Liquid Water

scholarly journals Microphysical Processes and Synergistic Interaction between Frontal and Orographic Forcing of Precipitation during the 13 December 2001 IMPROVE-2 Event over the Oregon Cascades

2005 ◽  
Vol 62 (10) ◽  
pp. 3493-3519 ◽  
Author(s):  
Christopher P. Woods ◽  
Mark T. Stoelinga ◽  
John D. Locatelli ◽  
Peter V. Hobbs
Keyword(s):  
Pacific Northwest ◽  
Liquid Water ◽  
Particle Production ◽  
Microwave Radiometer ◽  
Synergistic Interaction ◽  
Orographic Precipitation ◽  
Cyclonic Storm ◽  
Cloud Liquid Water ◽  
Oregon Cascades

Abstract On 13–14 December 2001 a vigorous cyclonic storm passed over the Pacific Northwest, producing heavy orographic precipitation over the Cascade Mountains. This storm was one of several studied during the second field phase of the Improvement of Microphysical Parameterization through Observational Verification Experiment (IMPROVE). A wide variety of in situ and remotely sensed measurements were obtained as this storm passed over the Oregon Cascades. These measurements provided a comprehensive dataset of meteorological state parameters (temperature, pressure, humidity, winds, and vertical air velocity), polarization Doppler radar measurements, and cloud microphysical parameters (cloud liquid water, particle concentrations, size spectra, and imagery). The 13–14 December case was characterized by the passage of a tipped-forward lower-tropospheric front that extended upward to a preceding vigorous upper cold-frontal rainband, which produced clouds up to ∼8–9 km. An important difference between this storm and those studied previously over the Washington Cascades was that the prefrontal low-level airflow over the Oregon Cascades was characterized by strong westerly (as opposed to weak easterly) cross-barrier flow. Consequently, as the upper cold-frontal band passed over the Oregon Cascades there was both strong ice particle production aloft and significant production of liquid water at lower levels in the orographic lifting zone. Airborne in situ measurements, ground-based microwave radiometer measurements, and observations of snow crystals showed the simultaneous presence of high ice crystal concentrations and relatively large values of cloud liquid water aloft, and heavily rimed particles reaching the ground. Analyses indicate that a synergistic interaction occurred between the frontal and orographic precipitation.

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 Retrieval of cloud liquid water distributions from a single scanning microwave radiometer aboard a moving platform – Part 1: Field trial results from the Wakasa Bay experiment

2009 ◽  
Vol 9 (3) ◽  
pp. 12027-12064 ◽  
Author(s):  
D. Huang ◽  
A. Gasiewksi ◽  
W. Wiscombe
Keyword(s):  
Data Collection ◽  
Liquid Water ◽  
Microwave Radiometer ◽  
Three Dimensional ◽  
Observation System ◽  
Mobile Cloud ◽  
The Sea Of Japan ◽  
Inversion Algorithm ◽  
Cloud Liquid Water ◽  
Wakasa Bay

Abstract. Tomographic methods offer a new promise for retrieving three-dimensional distributions of cloud liquid water from path-integrated radiometric measurements by passive sensors. A mobile cloud tomography system using only a single scanning microwave radiometer has many advantages over a fixed system using multiple distinctly-located radiometers, e.g., efficient and flexible data collection. Part 1 (this paper) examines the results from a limited cloud tomography trial carried out during the 2003 AMSR-E validation campaign at Wakasa Bay of the Sea of Japan. During the tomographic test, the Polarimetric Scanning Radiometer (PSR) and Microwave Imaging Radiometer (MIR) aboard the NASA P-3 research aircraft scanned through a system of low-level clouds and thus provided a useful dataset for testing the cloud tomography method. We conduct three retrieval runs with a constrained inversion algorithm using, respectively the PSR, MIR, and combined PSR and MSR data. The liquid water paths calculated from the PSR retrieval are consistent with that from the MIR retrieval. The retrieved cloud field based on the combined data appears to be physically plausible and consistent with the cloud image obtained by a cloud radar. It is unfortunate that there were no in-situ cloud measurements during the experiment that can be used to quantitatively validate the tomographic retrievals. Nevertheless, we find that some vertically-uniform clouds appear at high altitudes in the retrieved fields where the radar image shows clear sky. This is likely due to flawed data collection geometry, which, in turn, is determined by the radiometer scan strategy, and aircraft altitude and moving speed. This sets the stage for Part 2 of this study that aims at possible improvements of the mobile cloud tomography approach by a group of sensitivity studies using observation system simulation experiments.

scholarly journals Tomographic retrieval of cloud liquid water fields from a single scanning microwave radiometer aboard a moving platform – Part 1: Field trial results from the Wakasa Bay experiment

2010 ◽  
Vol 10 (14) ◽  
pp. 6685-6697 ◽  
Author(s):  
D. Huang ◽  
A. J. Gasiewski ◽  
W. Wiscombe
Keyword(s):  
Data Collection ◽  
Liquid Water ◽  
Microwave Radiometer ◽  
Three Dimensional ◽  
Mobile Systems ◽  
Observation System ◽  
The Sea Of Japan ◽  
Inversion Algorithm ◽  
Cloud Liquid Water ◽  
Wakasa Bay

Abstract. Tomographic methods offer great potential for retrieving three-dimensional spatial distributions of cloud liquid water from radiometric observations by passive microwave sensors. Fixed tomographic systems require multiple radiometers, while mobile systems can use just a single radiometer. Part 1 (this paper) examines the results from a limited cloud tomography trial with a single-radiometer airborne system carried out as part of the 2003 AMSR-E validation campaign over Wakasa Bay of the Sea of Japan. During this trial, the Polarimetric Scanning Radiometer (PSR) and Microwave Imaging Radiometer (MIR) aboard the NASA P-3 research aircraft provided a useful dataset for testing the cloud tomography method over a system of low-level clouds. We do tomographic retrievals with a constrained inversion algorithm using three configurations: PSR, MIR, and combined PSR and MIR data. The liquid water paths from the PSR retrieval are consistent with those from the MIR retrieval. The retrieved cloud field based on the combined data appears to be physically plausible and consistent with the cloud image obtained by a cloud radar. We find that some vertically-uniform clouds appear at high altitudes in the retrieved field where the radar shows clear sky. This is likely due to the sub-optimal data collection strategy. This sets the stage for Part 2 of this study that aims to define optimal data collection strategies using observation system simulation experiments.

scholarly journals Tomographic retrieval of cloud liquid water fields from a single scanning microwave radiometer aboard a moving platform – Part 2: Observation system simulation experiments

2010 ◽  
Vol 10 (14) ◽  
pp. 6699-6709 ◽  
Author(s):  
D. Huang ◽  
A. Gasiewski ◽  
W. Wiscombe
Keyword(s):  
Liquid Water ◽  
System Simulation ◽  
Microwave Radiometer ◽  
Retrieval Algorithm ◽  
Observation System ◽  
Total Variation Regularization ◽  
L1 Norm ◽  
Simulation Experiments ◽  
Cloud Liquid Water ◽  
L2 Norm

Abstract. Part 1 of this research concluded that many conditions of the 2003 Wakasa Bay experiment were not optimal for the purpose of tomographic retrieval. Part 2 (this paper) then aims to find possible improvements to the mobile cloud tomography method using observation system simulation experiments. We demonstrate that the incorporation of the L1 norm total variation regularization in the tomographic retrieval algorithm better reproduces discontinuous structures than the widely used L2 norm Tikhonov regularization. The simulation experiments reveal that a typical ground-based mobile setup substantially outperforms an airborne one because the ground-based setup usually moves slower and has greater contrast in microwave brightness between clouds and the background. It is shown that, as expected, the error in the cloud tomography retrievals increases monotonically with both the radiometer noise level and the uncertainty in the estimate of background brightness temperature. It is also revealed that a lower speed of platform motion or a faster scanning radiometer results in more scan cycles and more overlap between the swaths of successive scan cycles, both of which help to improve the retrieval accuracy. The last factor examined is aircraft height. It is found that the optimal aircraft height is 0.5 to 1.0 km above the cloud top. To summarize, this research demonstrates the feasibility of tomographically retrieving the spatial structure of cloud liquid water using current microwave radiometric technology and provides several general guidelines to improve future field-based studies of cloud tomography.

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