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.

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 An integrated approach toward the incorporation of clouds in the temperature retrievals from microwave measurements

2014 ◽  
Vol 7 (6) ◽  
pp. 1619-1628 ◽  
Author(s):  
F. Navas-Guzmán ◽  
O. Stähli ◽  
N. Kämpfer
Keyword(s):  
Liquid Water ◽  
Microwave Radiometer ◽  
Integrated Approach ◽  
Liquid Water Content ◽  
Cloud Base ◽  
Temperature Profiles ◽  
Tropospheric Temperature ◽  
Inversion Algorithm ◽  
Instrumental Approach

Abstract. In this paper, we address the characterization of clouds and its inclusion in microwave retrievals in order to study its effect on tropospheric temperature profiles measured by TEMPERA radiometer. TEMPERA is the first ground-based microwave radiometer that makes it possible to obtain temperature profiles in the troposphere and stratosphere at the same time. In order to characterize the clouds a multi-instrumental approach has been adopted. Cloud base altitudes were detected using ceilometer measurements while the integrated liquid water was measured by TROWARA radiometer. Both instruments are co-located with TEMPERA in Bern (Switzerland). Using this information and a constant Liquid Water Content value inside the cloud a liquid profile is provided to characterize the clouds in the inversion algorithm. Microwave temperature profiles have been obtained incorporating this water liquid profile in the inversion algorithm and also without considering the clouds, in order to assess its effect on the retrievals. The results have been compared with the temperature profiles from radiosondes which are launched twice a day at the aerological station of MeteoSwiss in Payerne (40 km W of Bern). Almost 1 year of data have been analysed and 60 non-precipitating cloud cases were studied. The statistical analysis carried out over all the cases evidenced that temperature retrievals improved in most of the cases when clouds were incorporated in the inversion algorithm.

Wakasa Bay: An AMSR Precipitation Validation Campaign

2007 ◽  
Vol 88 (4) ◽  
pp. 551-558 ◽  
Author(s):  
Elena S. Lobl ◽  
Kazumasa Aonashi ◽  
Brian Griffith ◽  
Christian Kummerow ◽  
Guosheng Liu ◽  
...  
Keyword(s):  
Environmental Science ◽  
Science And Technology ◽  
Microwave Radiometer ◽  
The Sea Of Japan ◽  
Convective Systems ◽  
Earth Observing System ◽  
Mesoscale Convective ◽  
Technology Corporation ◽  
Wakasa Bay ◽  
Microwave Radiometers

The “ Wakasa Bay Experiment” was conducted in order to refine error models for oceanic precipitation from the Advanced Microwave Sounding Radiometer-Earth Observing System (AMSR-E) measurements and to develop algorithms for snowfall. The NASA P-3 aircraft was equipped with microwave radiometers, covering a frequency range of 10.7–340 GHz, and radars at 13.4, 35.6, and 94 GHz, and was deployed to Yokota Air Base in Japan for flights from 14 January to 3 February 2003. For four flight days (27–30 January) a Gulfstream II aircraft provided by Core Research for Environmental Science and Technology (CREST), carrying an extensive cloud physics payload and a two-frequency (23.8 and 31.4 GHz) microwave radiometer, joined the P-3 for coordinated flights. The Gulfstream II aircraft was part of the “Winter Mesoscale Convective Systems Observations over the Sea of Japan in 2003” (“WMO-03”) field campaign sponsored by Japan Science and Technology Corporation (JST). Extensive data were taken, which addressed all of the experimental objectives. The data obtained with the NASA P-3 are available at the National Snow and Ice Data Center (NSIDC), and they are available free of charge to all interested researchers.

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