Remote sensing of multiple cloud layer heights using multi-angular measurements

被引:22
作者
Sinclair, Kenneth [1 ,2 ]
van Diedenhoven, Bastiaan [2 ,3 ]
Cairns, Brian [2 ]
Yorks, John [4 ]
Wasilewski, Andrzej [5 ]
McGill, Matthew [4 ]
机构
[1] Columbia Univ, Dept Earth & Environm Engn, New York, NY 10025 USA
[2] NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA
[3] Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA
[4] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA
[5] Trinnovim LLC, New York, NY USA
关键词
REFLECTANCE MEASUREMENTS; VERTICAL STRUCTURE; POLARIMETER; RETRIEVALS; SIZE;
D O I
10.5194/amt-10-2361-2017
中图分类号
P4 [大气科学(气象学)];
学科分类号
0706 ; 070601 ;
摘要
Cloud top height (CTH) affects the radiative properties of clouds. Improved CTH observations will allow for improved parameterizations in large-scale models and accurate information on CTH is also important when studying variations in freezing point and cloud microphysics. NASA's airborne Research Scanning Polarimeter (RSP) is able to measure cloud top height using a novel multi-angular contrast approach. For the determination of CTH, a set of consecutive nadir reflectances is selected and the cross correlations between this set and collocated sets at other viewing angles are calculated for a range of assumed cloud top heights, yielding a correlation profile. Under the assumption that cloud reflectances are isotropic, local peaks in the correlation profile indicate cloud layers. This technique can be applied to every RSP footprint and we demonstrate that detection of multiple peaks in the correlation profile allows retrieval of heights of multiple cloud layers within single RSP footprints. This paper provides an in-depth description of the architecture and performance of the RSP's CTH retrieval technique using data obtained during the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC(4)RS) campaign. RSP-retrieved cloud heights are evaluated using collocated data from the Cloud Physics Lidar (CPL). The method's accuracy associated with the magnitude of correlation, optical thickness, cloud thickness and cloud height are explored. The technique is applied to measurements at a wavelength of 670 and 1880 nm and their combination. The 1880 nm band is virtually insensitive to the lower troposphere due to strong water vapor absorption. It is found that each band is well suitable for retrieving heights of cloud layers with optical thicknesses above about 0.1 and that RSP cloud layer height retrievals more accurately correspond to CPL cloud middle than cloud top. It is also found that the 1880 nm band yields the most accurate results for clouds at middle and high altitudes (4.0 to 17 km), while the 670 nm band is most accurate at low and middle altitudes (1.0-13.0 km). The dual band performs best over the broadest range and is suitable for accurately retrieving cloud layer heights between 1.0 and 16.0 km. Generally, the accuracy of the retrieved cloud top heights increases with increasing correlation value. Improved accuracy is achieved by using customized filtering techniques for each band with the most significant improvements occurring in the primary layer retrievals. RSP is able to measure a primary layer CTH with a median error of about 0.5 km when compared to CPL. For multilayered scenes, the second and third layer heights are determined median errors of about 1.5 and 2.0-2.5 km, respectively.
引用
收藏
页码:2361 / 2375
页数:15
相关论文
共 37 条
[1]   Polarized view of supercooled liquid water clouds [J].
Alexandrov, Mikhail D. ;
Cairns, Brian ;
van Diedenhoven, Bastiaan ;
Ackerman, Andrew S. ;
Wasilewski, Andrzej P. ;
McGill, Matthew J. ;
Yorks, John E. ;
Hlavka, Dennis L. ;
Platnick, Steven E. ;
Arnold, G. Thomas .
REMOTE SENSING OF ENVIRONMENT, 2016, 181 :96-110
[2]   Liquid water cloud properties during the Polarimeter Definition Experiment (PODEX) [J].
Alexandrov, Mikhail D. ;
Cairns, Brian ;
Wasilewski, Andrzej P. ;
Ackerman, Andrew S. ;
McGill, Matthew J. ;
Yorks, John E. ;
Hlavka, Dennis L. ;
Platnick, Steven E. ;
Arnold, G. Thomas ;
van Diedenhoven, Bastiaan ;
Chowdhary, Jacek ;
Ottaviani, Matteo ;
Knobelspiesse, Kirk D. .
REMOTE SENSING OF ENVIRONMENT, 2015, 169 :20-36
[3]   Accuracy assessments of cloud droplet size retrievals from polarized reflectance measurements by the research scanning polarimeter [J].
Alexandrov, Mikhail D. ;
Cairns, Brian ;
Emde, Claudia ;
Ackerman, Andrew S. ;
van Diedenhoven, Bastiaan .
REMOTE SENSING OF ENVIRONMENT, 2012, 125 :92-111
[4]   Cloud detection and derivation of cloud properties from POLDER [J].
Buriez, JC ;
Vanbauce, C ;
Parol, F ;
Goloub, P ;
Herman, M ;
Bonnel, B ;
Fouquart, Y ;
Couvert, P ;
Seze, G .
INTERNATIONAL JOURNAL OF REMOTE SENSING, 1997, 18 (13) :2785-2813
[5]   The research scanning polarimeter: Calibration and ground-based measurements [J].
Cairns, B ;
Russell, EE ;
Travis, LD .
POLARIZATION: MEASUREMENT, ANALYSIS, AND REMOTE SENSING II, 1999, 3754 :186-196
[6]  
Cairns B., 2013, RSP SEAC4RS CAMPAIGN
[7]  
Collins W.D., 1994, The Chemistry of the Atmosphere: Its Impact on Global Change, edited by, P207
[8]  
DINER DJ, 1999, D11399 JPL
[9]   Synergy of stereo cloud top height and ORAC optimal estimation cloud retrieval: evaluation and application to AATSR [J].
Fisher, Daniel ;
Poulsen, Caroline A. ;
Thomas, Gareth E. ;
Muller, Jan-Peter .
ATMOSPHERIC MEASUREMENT TECHNIQUES, 2016, 9 (03) :909-928
[10]   The time-space exchangeability of satellite retrieved relations between cloud top temperature and particle effective radius [J].
Lensky, I. M. ;
Rosenfeld, D. .
ATMOSPHERIC CHEMISTRY AND PHYSICS, 2006, 6 :2887-2894