Sciences and Exploration Directorate

Brief Bio


Dr. Cairns was educated in the United Kingdom at Chesterfield School and received an engineering degree from the University of Cambridge before completing a Ph. D. in physics at the Institute of Optics of the University of Rochester. He has worked at NASA Goddard Institute for Space Studies since 1992. His initial work was focused on developing parameterizations of three-dimensional radiation transport through clouds for use in general circulation models (GCMs) and that parameterization continues to be used in the GISS GCM. Since 1996 he has worked on the use of polarimetric remote sensing of the Earth to determine aerosol and cloud properties using ground based and airborne observations and was one of the developers of the airborne Research Scanning Polarimeter (RSP) instrument. The development of the RSP instrument was completed in 1999 and it made its first airborne measurements on a small Cessna survey plane. This sensor has obtained the most accurate polarization measurements of the atmosphere of the Earth ever made and over a broader spectral and angular range than any other polarimeter. The capability of these measurements to accurately retrieve aerosol and cloud properties has been widely recognized and has led to the development and planning of new instruments that attempt to provide similar capabilities. Since 2000 Dr. Cairns has led the integration of the RSP instrument onto five different platforms and supervised seventeen different field deployments from Mexico to the Canadian Arctic. During that time the RSP instrument performed impeccably acquiring more than 2000 hours of remote sensing observations. Dr. Cairns was instrument scientist for the Aerosol Polarimetry Sensor, which was on the NASA Glory mission that failed to reach orbit on 4th March 2011 and crashed into the South Pacific. He was also a member of the science-working groups appointed by NASA Headquarters to define the ACE and PACE missions that were recommended by the Decadal Survey of the National Academy of Sciences.

Research Interests


Polarimetric Calibration

Earth Science: Remote Sensing

Efficient and accurate techniques to calibrate polarimetric instrumentation that can be used in laboratory, field or spaceflight applications.


3D Radiative Transfer

Earth Science: Theory & Modeling

Effects of three-dimensional variability on radiative transfer and inverse modeling methods for retrieval of 3D distributions of clouds and aerosols from multi-angle multi-spectral intensity and polarization measurements.


Inversion of multiple-scattering data

Earth Science: Aerosols

High-dimensional data sets such as those produced by multi-angle multi-spectral intensity and polarimetric measurements require inversion techniques that make optimal use of the available data, whether it be passive only, or include lidar or radar remote sensing observations too. These inverse methods require efficient forward models that also provide the derivatives of the radiation field with respect to the parameters defining the aerosol and cloud fields that are to be retrieved. Efficient analytical methods can use modified vector adding/doubling calculations to implement such forward model capabilities and are currently being tested.


Hyperspectral Observations

Earth Science: Remote Sensing

Atmospheric correction of hyperspectral data and the use of hyperspectral measurements for atmospheric remote sensing. A hyperspectral radiative transfer code with 1 nm spectral resolution has been developed to facilitate the analysis of hyperspectral imaging radiometer data for atmospheric, land and ocean remote sensing.

Positions/Employment


Electro-optical engineer

Schlumberger Electronics - London, UK

May 1986 - October 1986

Development of sensors for use in Boeing fly-by-light program.  Primary task of developing read head for rotational position sensor using Gray code disk.  Also developed automated test equipment for position sensor using stepper motor and computer to do accelerated life testing of the position sensor.


Research Scientist

Columbia University - Morningside, New York, NY 10025

March 1992 - March 2007

Developed Monte Carlo radiative transfer code for the evaluation of a renormalization group approach to the incorporation of three-dimensional radiative transfer effects in a GCM.  Subsequently used ISCCP observations to develop an observationally based climatology of the three-dimensional effects as a function of cloud type.  Subsequently developed hyperspectral radiative transfer code for the analysis of Hyperion and HyperSpecTIR sensor imaging spectrometer observations. Developed airborne polarimetric sensor called the Research Scanning Polarimeter in conjunction with SpecTIR LLC. Updated vector radiative transfer code for the analysis of airborne remote sensing observations.


Senior Research Scientist

NASA GSFC - Goddard Institute for Space Studies, New York, NY 10025

April 2007 - Present

Instrument scientist for Aerosol Polarimetry Sensor on the NASA Glory mission.  Principal Investigator (PI) for operation of the Research Scanning Polarimeter in ARCTAS, RACORO, CalNEX, CARES, DEVOTE, TCAP, PODEX, SEAC4RS and SABOR.

Teaching Experience


Taught a remote sensing course in the Electrical Engineering department of the City College of New York for four years from 1996 to 2000.

Education


March 1992 Ph.D. An investigation of multiple scattering and radiative transfer, University of Rochester, NY.
June 1988 M.S. Optical Engineering, University of Rochester, NY
June 1985 B.A. with 1st Class Honours, Cambridge University, Department of Engineering, Electrical Sciences Tripos, Cambridge, UK.

Professional Societies


American Geophysical Union

1996 - Present


American Meteorological Society

1993 - 2000

Professional Service


Served on ESTO review panels for their ACT and IIP programs.  Also served on numerous NASA science review panels.  Served on AMS Atmospheric Radiation committee and helped to organize 11th Conference on Atmospheric Radiation and the 11th Conference on Cloud Physics, 3-7 June 2002, Ogden, UT.

Awards


NASA Group Achievement Award, INTEX-B field campaign, 2007.
NASA Group Achievement Award, ARCTAS field campaign, 2009.
Certificate of Appreciation from NASA ESTO, 2010.
NASA GSFC Special Act – Individual Award, 2010.
NASA Center Team Award, RACORO field campaign, 2010.
NASA Performance Award for 2009-2010.
NASA Group Achievement Award, The Glory Project Team, 2011.
NASA Group Achievement Award, DEVOTE project team, 2012.
NASA Group Achievement Award, CLARREO mission concept team, 2012.
NASA Performance Award for 2012-2013.
NASA Performance Award for 2013-2014.

Grants



Polarimetric remote sensing of aerosols and clouds: Glory Aerosol Polarimetry Sensor Calibration and Validation - NASA (NNH10ZDA001N-SEAC4RS) - Awarded: 2011-08-01


Dates: 2011-08-01  - 2014-07-31

Coverage: 0.75

Amount $747K

Other Professional Information


Proficient German and French speaker.

Publications


Refereed

Gao, M., B. A. Franz, P.-W. Zhai, et al. K. D. Knobelspiesse, A. M. Sayer, X. Xu, V. Martins, B. Cairns, P. Castellanos, G. Fu, N. Hannadige, O. Hasekamp, Y. Hu, A. Ibrahim, F. S. Patt, A. Puthukkudy, and P. J. Werdell. 2023. Simultaneous retrieval of aerosol and ocean properties from PACE HARP2 with uncertainty assessment using cascading neural network radiative transfer models Atmospheric Measurement Techniques 16 (23): [https://doi.org/10.5194/amt-16-5863-2023]

Hannadige, N. K., P.-W. Zhai, M. Gao, et al. Y. Hu, P. J. Werdell, K. Knobelspiesse, and B. Cairns. 2023. Performance evaluation of three bio-optical models in aerosol and ocean color joint retrievals Atmospheric Measurement Techniques 16 (23): 5749-5770 [10.5194/amt-16-5749-2023]

Tornow, F., A. S. Ackerman, A. M. Fridlind, et al. G. Tselioudis, B. Cairns, D. Painemal, and G. Elsaesser. 2023. On the impact of a dry intrusion driving cloud-regime transitions in a midlatitude cold-air outbreak Journal of the Atmospheric Sciences [10.1175/jas-d-23-0040.1]

Sorooshian, A., M. D. Alexandrov, A. D. Bell, et al. R. Bennett, G. Betito, S. P. Burton, M. E. Buzanowicz, B. Cairns, E. V. Chemyakin, G. Chen, Y. Choi, B. L. Collister, A. L. Cook, A. F. Corral, E. C. Crosbie, B. van Diedenhoven, J. P. DiGangi, G. S. Diskin, S. Dmitrovic, E.-L. Edwards, M. A. Fenn, R. A. Ferrare, D. van Gilst, J. W. Hair, D. B. Harper, M. R. Hilario, C. A. Hostetler, N. Jester, M. Jones, S. Kirschler, M. M. Kleb, J. M. Kusterer, S. Leavor, J. W. Lee, H. Liu, K. McCauley, R. H. Moore, J. Nied, A. Notari, J. B. Nowak, D. Painemal, K. E. Phillips, C. E. Robinson, A. J. Scarino, J. S. Schlosser, S. T. Seaman, C. Seethala, T. J. Shingler, M. A. Shook, K. A. Sinclair, W. L. Smith, D. A. Spangenberg, S. A. Stamnes, K. L. Thornhill, C. Voigt, H. Vömel, A. P. Wasilewski, H. Wang, E. L. Winstead, K. Zeider, X. Zeng, B. Zhang, L. D. Ziemba, and P. Zuidema. 2023. Spatially coordinated airborne data and complementary products for aerosol, gas, cloud, and meteorological studies: the NASA ACTIVATE dataset Earth System Science Data 15 (8): 3419-3472 [10.5194/essd-15-3419-2023]

Stamnes, S., M. Jones, J. G. Allen, et al. E. Chemyakin, A. Bell, J. Chowdhary, X. Liu, S. P. Burton, B. Van Diedenhoven, O. Hasekamp, J. Hair, Y. Hu, C. Hostetler, R. Ferrare, K. Stamnes, and B. Cairns. 2023. The PACE-MAPP algorithm: Simultaneous aerosol and ocean polarimeter products using coupled atmosphere-ocean vector radiative transfer Frontiers in Remote Sensing 4 [10.3389/frsen.2023.1174672]

Gao, M., K. Knobelspiesse, B. A. Franz, et al. P.-W. Zhai, B. Cairns, X. Xu, and J. V. Martins. 2023. The impact and estimation of uncertainty correlation for multi-angle polarimetric remote sensing of aerosols and ocean color Atmospheric Measurement Techniques 16 (8): 2067–2087 [https://doi.org/10.5194/amt-16-2067-2023]

Lenhardt, E. D., L. Gao, J. Redemann, et al. F. Xu, S. P. Burton, B. Cairns, I. Chang, R. A. Ferrare, C. A. Hostetler, P. E. Saide, C. Howes, Y. Shinozuka, S. Stamnes, M. Kacarab, A. Dobracki, J. Wong, S. Freitag, and A. Nenes. 2023. Use of lidar aerosol extinction and backscatter coefficients to estimate cloud condensation nuclei (CCN) concentrations in the southeast Atlantic Atmospheric Measurement Techniques 16 (7): 2037-2054 [10.5194/amt-16-2037-2023]

Li, X.-Y., H. Wang, J. Chen, et al. S. Endo, S. Kirschler, C. Voigt, E. Crosbie, L. D. Ziemba, D. Painemal, B. Cairns, J. W. Hair, A. F. Corral, C. Robinson, H. Dadashazar, A. Sorooshian, G. Chen, R. A. Ferrare, M. M. Kleb, H. Liu, R. Moore, A. J. Scarino, M. A. Shook, T. J. Shingler, K. L. Thornhill, F. Tornow, H. Xiao, and X. Zeng. 2023. Large-Eddy Simulations of Marine Boundary Layer Clouds Associated with Cold-Air Outbreaks during the ACTIVATE Campaign. Part II: Aerosol–Meteorology–Cloud Interaction Journal of the Atmospheric Sciences 80 (4): 1025-1045 [10.1175/jas-d-21-0324.1]

Sayer, A. M., L. Lelli, B. Cairns, et al. B. van Diedenhoven, A. Ibrahim, K. D. Knobelspiesse, S. Korkin, and P. J. Werdell. 2023. The CHROMA cloud-top pressure retrieval algorithm for the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite mission Atmospheric Measurement Techniques 16 (4): 969-996 [10.5194/amt-16-969-2023]

Nied, J., M. Jones, S. Seaman, et al. T. Shingler, J. Hair, B. Cairns, D. V. Gilst, A. Bucholtz, S. Schmidt, S. Chellappan, P. Zuidema, B. Van Diedenhoven, A. Sorooshian, and S. Stamnes. 2023. A cloud detection neural network for above-aircraft clouds using airborne cameras Frontiers in Remote Sensing 4 [10.3389/frsen.2023.1118745]

van Diedenhoven, B., O. P. Hasekamp, B. Cairns, et al. G. L. Schuster, S. Stamnes, M. Shook, and L. Ziemba. 2022. Remote sensing of aerosol water fraction, dry size distribution and soluble fraction using multi-angle, multi-spectral polarimetry Atmospheric Measurement Techniques 15 (24): 7411-7434 [10.5194/amt-15-7411-2022]

Alexandrov, M. D., A. Marshak, B. Cairns, and A. S. Ackerman. 2022. Markovian Statistical Model of Cloud Optical Thickness. Part I: Theory and Examples Journal of the Atmospheric Sciences 79 (12): 3315-3332 [10.1175/jas-d-22-0125.1]

Gao, M., K. Knobelspiesse, B. Franz, et al. P.-W. Zhai, A. Sayer, A. Ibrahim, B. Cairns, O. Hasekamp, Y. Hu, V. Martins, J. Werdell, and X. Xu. 2022. Effective uncertainty quantification for multi-angle polarimetric aerosol remote sensing over ocean Atmos. Meas. Tech. 15 (16): 4859–4879 [10.5194/amt-15-4859-2022]

Kato, S., T. J. Thorsen, S.-H. Ham, et al. N. G. Loeb, R. A. Ferrare, D. M. Winker, H. Barker, G. L. Stephens, S. Schmidt, K. G. Meyer, and B. Cairns. 2022. Effect of Spectral Variability of Aerosol Optical Properties on Direct Aerosol Radiative Effect Frontiers in Remote Sensing 3 [10.3389/frsen.2022.904505]

Fu, D., L. Di Girolamo, R. M. Rauber, et al. G. M. McFarquhar, S. W. Nesbitt, J. Loveridge, Y. Hong, B. van Diedenhoven, B. Cairns, M. D. Alexandrov, P. Lawson, S. Woods, S. Tanelli, S. Schmidt, C. Hostetler, and A. J. Scarino. 2022. An evaluation of the liquid cloud droplet effective radius derived from MODIS, airborne remote sensing, and in situ measurements from CAMP<sup>2</sup>Ex Atmospheric Chemistry and Physics 22 (12): 8259-8285 [10.5194/acp-22-8259-2022]

Tornow, F., A. S. Ackerman, A. M. Fridlind, et al. B. Cairns, E. C. Crosbie, S. Kirschler, R. H. Moore, D. Painemal, C. E. Robinson, C. Seethala, M. A. Shook, C. Voigt, E. L. Winstead, L. D. Ziemba, P. Zuidema, and A. Sorooshian. 2022. Dilution of Boundary Layer Cloud Condensation Nucleus Concentrations by Free Tropospheric Entrainment During Marine Cold Air Outbreaks Geophysical Research Letters 49 (11): [10.1029/2022gl098444]

Liu, L., G. L. Schuster, H. Moosmüller, et al. S. Stamnes, B. Cairns, and J. Chowdhary. 2022. Optical properties of morphologically complex black carbon aerosols: Effects of coatings Journal of Quantitative Spectroscopy and Radiative Transfer 281 108080 [10.1016/j.jqsrt.2022.108080]

Gao, M., K. Knobelspiesse, B. A. Franz, et al. P.-W. Zhai, V. Martins, S. P. Burton, B. Cairns, R. Ferrare, M. A. Fenn, O. Hasekamp, Y. Hu, A. Ibrahim, A. M. Sayer, P. J. Werdell, and X. Xu. 2021. Adaptive Data Screening for Multi-Angle Polarimetric Aerosol and Ocean Color Remote Sensing Accelerated by Deep Learning Frontiers in Remote Sensing 2 [10.3389/frsen.2021.757832]

Alexandrov, M. D., C. Emde, B. Van Diedenhoven, and B. Cairns. 2021. Application of Radon Transform to Multi-Angle Measurements Made by the Research Scanning Polarimeter: A New Approach to Cloud Tomography. Part I: Theory and Tests on Simulated Data Frontiers in Remote Sensing 2 [10.3389/frsen.2021.791130]

Li, X.-Y., H. Wang, J. Chen, et al. S. Endo, G. George, B. Cairns, S. Chellappan, X. Zeng, S. Kirschler, C. Voigt, A. Sorooshian, E. Crosbie, G. Chen, R. A. Ferrare, W. I. Gustafson, J. W. Hair, M. M. Kleb, H. Liu, R. Moore, D. Painemal, C. Robinson, A. J. Scarino, M. Shook, T. J. Shingler, K. L. Thornhill, F. Tornow, H. Xiao, L. D. Ziemba, and P. Zuidema. 2021. Large-eddy simulations of marine boundary-layer clouds associated with cold air outbreaks during the ACTIVATE campaign– part 1: Case setup and sensitivities to large-scale forcings Journal of the Atmospheric Sciences [10.1175/jas-d-21-0123.1]

Painemal, D., D. Spangenberg, W. L. Smith, et al. P. Minnis, B. Cairns, R. H. Moore, E. Crosbie, C. Robinson, K. L. Thornhill, E. L. Winstead, and L. Ziemba. 2021. Evaluation of satellite retrievals of liquid clouds from the GOES-13 imager and MODIS over the midlatitude North Atlantic during the NAAMES campaign Atmospheric Measurement Techniques 14 (10): 6633-6646 [10.5194/amt-14-6633-2021]

Hu, Y., X. Lu, P.-W. Zhai, et al. C. A. Hostetler, J. W. Hair, B. Cairns, W. Sun, S. Stamnes, A. Omar, R. Baize, G. Videen, J. Mace, D. T. McCoy, I. L. McCoy, and R. Wood. 2021. Liquid Phase Cloud Microphysical Property Estimates From CALIPSO Measurements Frontiers in Remote Sensing 2 [10.3389/frsen.2021.724615]

Stamnes, S., R. Baize, P. Bontempi, et al. B. Cairns, E. Chemyakin, Y.-J. Choi, J. Chowdhary, Y. Hu, M. Jeong, K.-I. Kang, S. S. Kim, X. Liu, R. Loughman, D. MacDonnell, M. P. McCormick, B. Moon, A. Omar, C. M. Roithmayr, C. K. Sim, W. Sun, B. van Diedenhoven, G. Videen, and A. Wasilewski. 2021. Simultaneous Aerosol and Ocean Properties From the PolCube CubeSat Polarimeter Frontiers in Remote Sensing 2 [10.3389/frsen.2021.709040]

Chemyakin, E., S. Stamnes, S. P. Burton, et al. X. Liu, C. Hostetler, R. Ferrare, B. Cairns, and O. Dubovik. 2021. Improved Lorenz-Mie Look-Up Table for Lidar and Polarimeter Retrievals Frontiers in Remote Sensing 2 [10.3389/frsen.2021.711106]

Gao, M., B. A. Franz, K. Knobelspiesse, et al. P.-W. Zhai, V. Martins, S. Burton, B. Cairns, R. Ferrare, J. Gales, O. Hasekamp, Y. Hu, A. Ibrahim, B. McBride, A. Puthukkudy, P. J. Werdell, and X. Xu. 2021. Efficient multi-angle polarimetric inversion of aerosols and oceancolor powered by a deep neural network forward model Atmospheric Measurement Techniques 14 (6): 4083–4110 [https://doi.org/10.5194/amt-14-4083-2021]

Xu, F., L. Gao, J. Redemann, et al. C. Flynn, W. R. Espinosa, A. M. Da Silva, S. Stamnes, S. Burton, X. Liu, R. Ferrare, B. Cairns, and O. Dubovik. 2021. A Combined Lidar-Polarimeter Inversion Approach for Aerosol Remote Sensing Over Ocean Frontiers in Remote Sensing 2 (2):

Sinclair, K., B. van Diedenhoven, B. Cairns, et al. M. Alexandrov, A. M. Dzambo, and T. L’Ecuyer. 2021. Inference of Precipitation in Warm Stratiform Clouds using Remotely Sensed Observations of the Cloud Top Droplet Size Distribution Geophysical Research Letters [10.1029/2021gl092547]

Dzambo, A. M., T. L'Ecuyer, K. Sinclair, et al. B. van Diedenhoven, S. Gupta, G. McFarquhar, J. R. O'Brien, B. Cairns, A. P. Wasilewski, and M. Alexandrov. 2021. Joint cloud water path and rainwater path retrievals from airborne ORACLES observations Atmospheric Chemistry and Physics 21 (7): 5513-5532 [10.5194/acp-21-5513-2021]

Corral, A. F., R. A. Braun, B. Cairns, et al. V. A. Gorooh, H. Liu, L. Ma, A. H. Mardi, D. Painemal, S. Stamnes, B. van Diedenhoven, H. Wang, Y. Yang, B. Zhang, and A. Sorooshian. 2021. An Overview of Atmospheric Features Over the Western North Atlantic Ocean and North American East Coast – Part 1: Analysis of Aerosols, Gases, and Wet Deposition Chemistry Journal of Geophysical Research: Atmospheres 126 (4): [10.1029/2020jd032592]

Redemann, J., R. Wood, P. Zuidema, et al. S. J. Doherty, B. Luna, S. E. LeBlanc, M. S. Diamond, Y. Shinozuka, I. Y. Chang, R. Ueyama, L. Pfister, J.-M. Ryoo, A. N. Dobracki, A. M. da Silva, K. M. Longo, M. S. Kacenelenbogen, C. J. Flynn, K. Pistone, N. M. Knox, S. J. Piketh, J. M. Haywood, P. Formenti, M. Mallet, P. Stier, A. S. Ackerman, S. E. Bauer, A. M. Fridlind, G. R. Carmichael, P. E. Saide, G. A. Ferrada, S. G. Howell, S. Freitag, B. Cairns, B. N. Holben, K. D. Knobelspiesse, S. Tanelli, T. S. L'Ecuyer, A. M. Dzambo, O. O. Sy, G. M. McFarquhar, M. R. Poellot, S. Gupta, J. R. O'Brien, A. Nenes, M. E. Kacarab, J. P. Wong, J. D. Small-Griswold, K. L. Thornhill, D. Noone, J. R. Podolske, K. S. Schmidt, P. Pilewskie, H. Chen, S. P. Cochrane, A. J. Sedlacek, T. J. Lang, E. Stith, M. Segal-Rozenhaimer, R. A. Ferrare, S. P. Burton, C. A. Hostetler, D. J. Diner, S. E. Platnick, J. S. Myers, K. G. Meyer, D. A. Spangenberg, H. Maring, and L. Gao. 2021. An overview of the ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) project: aerosol-cloud-radiation interactions in the Southeast Atlantic basin Atmospheric Chemistry and Physics [10.5194/acp-21-1507-2021]

Hannadige, N. K., P.-W. Zhai, M. Gao, et al. B. A. Franz, Y. Hu, K. Knobelspiesse, J. Werdell, A. Ibrahim, B. Cairns, and O. P. Hasekamp. 2021. Atmospheric correction over the ocean for hyperspectral radiometers using multi-angle polarimetric retrievals Optics Express 29 (3): 4504 [10.1364/oe.408467]

Quaas, J., A. Arola, B. Cairns, et al. M. Christensen, H. Deneke, A. M. Ekman, G. Feingold, A. M. Fridlind, E. Gryspeerdt, O. Hasekamp, Z. Li, A. Lipponen, P.-L. Ma, J. Mülmenstädt, A. Nenes, J. E. Penner, D. Rosenfeld, R. Schrödner, K. Sinclair, O. Sourdeval, P. Stier, M. Tesche, B. van Diedenhoven, and M. Wendisch. 2020. Constraining the Twomey effect from satellite observations: issues and perspectives Atmospheric Chemistry and Physics 20 (23): 15079-15099 [10.5194/acp-20-15079-2020]

Adebiyi, A. A., P. Zuidema, I. Chang, S. P. Burton, and B. Cairns. 2020. Mid-level clouds are frequent above the southeast Atlantic stratocumulus clouds Atmospheric Chemistry and Physics 20 (18): 11025-11043 [10.5194/acp-20-11025-2020]

Knobelspiesse, K., H. M. Barbosa, C. Bradley, et al. C. Bruegge, B. Cairns, G. Chen, J. Chowdhary, A. Cook, A. Di Noia, B. van Diedenhoven, D. J. Diner, R. Ferrare, G. Fu, M. Gao, M. Garay, J. Hair, D. Harper, G. van Harten, O. Hasekamp, M. Helmlinger, C. Hostetler, O. Kalashnikova, A. Kupchock, K. Longo De Freitas, H. Maring, J. V. Martins, B. McBride, M. McGill, K. Norlin, A. Puthukkudy, B. Rheingans, J. Rietjens, F. C. Seidel, A. da Silva, M. Smit, S. Stamnes, Q. Tan, S. Val, A. Wasilewski, F. Xu, X. Xu, and J. Yorks. 2020. The Aerosol Characterization from Polarimeter and Lidar (ACEPOL) airborne field campaign Earth System Science Data 12 (3): 2183-2208 [10.5194/essd-12-2183-2020]

Dzambo, A. M., T. L'Ecuyer, K. Sinclair, et al. B. van Diedenhoven, S. Gupta, G. McFarquhar, J. R. O'Brien, B. Cairns, A. P. Wasilewski, and M. Alexandrov. 2020. Joint Cloud Water Path and Rain Water Path Retrievals from ORACLES Observations [10.5194/acp-2020-849]

Gao, M., P.-W. Zhai, B. A. Franz, et al. K. Knobelspiesse, A. Ibrahim, B. Cairns, S. E. Craig, G. Fu, O. Hasekamp, Y. Hu, and P. J. Werdell. 2020. Inversion of multiangular polarimetric measurements from the ACEPOL campaign: an application of improving aerosol property and hyperspectral ocean color retrievals Atmospheric Measurement Techniques 13 3939–3956 [10.5194/amt-13-3939-2020]

Alexandrov, M. D., D. J. Miller, C. Rajapakshe, et al. A. Fridlind, B. van Diedenhoven, B. Cairns, A. S. Ackerman, and Z. Zhang. 2020. Vertical profiles of droplet size distributions derived from cloud-side observations by the research scanning polarimeter: Tests on simulated data Atmospheric Research 239 104924 [10.1016/j.atmosres.2020.104924]

Miller, D. J., M. Segal-Rozenhaimer, K. Knobelspiesse, et al. J. Redemann, B. Cairns, M. Alexandrov, B. van Diedenhoven, and A. Wasilewski. 2020. Low-level liquid cloud properties during ORACLES retrieved using airborne polarimetric measurements and a neural network algorithm Atmospheric Measurement Techniques 13 3447-3470 [10.5194/amt-13-3447-2020]

Van Diedenhoven, B., A. S. Ackerman, A. M. Fridlind, B. Cairns, and J. Riedi. 2020. Global Statistics of Ice Microphysical and Optical Properties at Tops of Optically Thick Ice Clouds Journal of Geophysical Research: Atmospheres 125 (6): e2019JD031811 [10.1029/2019jd031811]

Sorooshian, A., A. F. Corral, R. A. Braun, et al. B. Cairns, E. Crosbie, R. Ferrare, J. Hair, M. M. Kleb, A. Hossein Mardi, H. Maring, A. McComiskey, R. Moore, D. Painemal, A. J. Scarino, J. Schlosser, T. Shingler, M. Shook, H. Wang, X. Zeng, L. Ziemba, and P. Zuidema. 2020. Atmospheric Research Over the Western North Atlantic Ocean Region and North American East Coast: A Review of Past Work and Challenges Ahead Journal of Geophysical Research: Atmospheres 125 (6): [10.1029/2019jd031626]

van Diedenhoven, B., and B. Cairns. 2020. A Flexible Parameterization for Shortwave and Longwave Optical Properties of Ice Crystals and Derived Bulk Optical Properties for Climate Models Journal of the Atmospheric Sciences 77 (4): 1245-1260 [10.1175/jas-d-19-0193.1]

Sinclair, K., B. Diedenhoven, B. Cairns, et al. M. Alexandrov, R. Moore, L. D. Ziemba, and E. Crosbie. 2020. Observations of Aerosol‐Cloud Interactions During the North Atlantic Aerosol and Marine Ecosystem Study Geophysical Research Letters 47 (3): [10.1029/2019gl085851]

Fu, G., O. Hasekamp, J. Rietjens, et al. M. Smit, A. Di Noia, D. Diner, F. Xu, M. Gao, S. Burton, C. Hostetler, J. Hair, R. Ferrare, K. D. Knobelspiesse, B. Cairns, A. P. Wasilewski, and A. M. Da Silva. 2020. Aerosol retrievals from different polarimeters during the ACEPOL campaign using a common retrieval algorithm Atmospheric Measurement Techniques 13 553-573 [10.5194/amt-13-553-2020]

Frouin, R. J., B. A. Franz, A. Ibrahim, et al. K. Knobelspiesse, Z. Ahmad, B. Cairns, J. Chowdhary, H. M. Dierssen, J. Tan, O. Dubovik, X. Huang, A. B. Davis, O. Kalashnikova, D. R. Thompson, L. A. Remer, E. Boss, O. Coddington, P.-Y. Deschamps, B.-C. Gao, L. Gross, O. Hasekamp, A. Omar, B. Pelletier, D. Ramon, F. Steinmetz, and P.-W. Zhai. 2019. Atmospheric Correction of Satellite Ocean-Color Imagery During the PACE Era Frontiers in Earth Science 7 [10.3389/feart.2019.00145]

Remer, L. A., K. Knobelspiesse, P.-W. Zhai, et al. F. Xu, O. V. Kalashnikova, J. Chowdhary, O. Hasekamp, O. Dubovik, L. Wu, Z. Ahmad, E. Boss, B. Cairns, O. Coddington, A. B. Davis, H. M. Dierssen, D. J. Diner, B. Franz, R. Frouin, B.-C. Gao, A. Ibrahim, R. C. Levy, J. V. Martins, A. H. Omar, and O. Torres. 2019. Retrieving Aerosol Characteristics From the PACE Mission, Part 2: Multi-Angle and Polarimetry Frontiers in Environmental Science 7 [10.3389/fenvs.2019.00094]

Remer, L. A., A. B. Davis, S. Mattoo, et al. R. C. Levy, O. V. Kalashnikova, O. Coddington, J. Chowdhary, K. Knobelspiesse, X. Xu, Z. Ahmad, E. Boss, B. Cairns, H. M. Dierssen, D. J. Diner, B. Franz, R. Frouin, B.-C. Gao, A. Ibrahim, J. V. Martins, A. H. Omar, O. Torres, F. Xu, and P.-W. Zhai. 2019. Retrieving Aerosol Characteristics From the PACE Mission, Part 1: Ocean Color Instrument Frontiers in Earth Science 7 [10.3389/feart.2019.00152]

Smit, J. M., J. H. Rietjens, G. van Harten, et al. A. Di Noia, W. Laauwen, B. E. Rheingans, D. J. Diner, B. Cairns, A. Wasilewski, K. D. Knobelspiesse, R. Ferrare, and O. P. Hasekamp. 2019. SPEX airborne spectropolarimeter calibration and performance Applied Optics 58 (21): 5695 [10.1364/ao.58.005695]

Gao, M., P.-W. Zhai, B. A. Franz, et al. Y. Hu, K. Knobelspiesse, P. J. Werdell, A. Ibrahim, B. Cairns, and A. Chase. 2019. Inversion of multi-angular polarimetric measurements over open and coastal ocean waters: a joint retrieval algorithm for aerosol and water leaving radiance properties Atmospheric Measurement Techniques 12 (7): 3921–3941 [10.5194/amt-12-3921-2019]

Sinclair, K., B. van Diedenhoven, B. Cairns, et al. M. Alexandrov, R. Moore, E. Crosbie, and L. Ziemba. 2019. Polarimetric retrievals of cloud droplet number concentrations Remote Sensing of Environment 228 227-240 [10.1016/j.rse.2019.04.008]

Jamet, C., A. Ibrahim, Z. Ahmad, et al. F. Angelini, M. Babin, M. J. Behrenfeld, E. Boss, B. Cairns, J. Churnside, J. Chowdhary, A. B. Davis, D. Dionisi, L. Duforêt-Gaurier, B. Franz, R. Frouin, M. Gao, D. Gray, O. Hasekamp, X. He, C. Hostetler, O. V. Kalashnikova, K. Knobelspiesse, L. Lacour, H. Loisel, V. Martins, E. Rehm, L. Remer, I. Sanhaj, K. Stamnes, S. Stamnes, S. Victori, J. Werdell, and P.-W. Zhai. 2019. Going Beyond Standard Ocean Color Observations: Lidar and Polarimetry Frontiers in Marine Science 6 [10.3389/fmars.2019.00251]

Werdell, P. J., M. J. Behrenfeld, P. S. Bontempi, et al. E. Boss, B. Cairns, G. T. Davis, B. A. Franz, U. B. Gliese, E. T. Gorman, O. Hasekamp, K. D. Knobelspiesse, A. Mannino, J. V. Martins, C. R. McClain, G. Meister, and L. A. Remer. 2019. The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission: Status, science, advances Bulletin of the American Meteorological Society 100 (9): 1775–1794 [10.1175/bams-d-18-0056.1]

Behrenfeld, M. J., R. H. Moore, C. A. Hostetler, et al. J. Graff, P. Gaube, L. M. Russell, G. Chen, S. C. Doney, S. Giovannoni, H. Liu, C. Proctor, L. M. Bolaños, N. Baetge, C. Davie-Martin, T. K. Westberry, T. S. Bates, T. G. Bell, K. D. Bidle, E. S. Boss, S. D. Brooks, B. Cairns, C. Carlson, K. Halsey, E. L. Harvey, C. Hu, L. Karp-Boss, M. Kleb, S. Menden-Deuer, F. Morison, P. K. Quinn, A. J. Scarino, B. Anderson, J. Chowdhary, E. Crosbie, R. Ferrare, J. W. Hair, Y. Hu, S. Janz, J. Redemann, E. Saltzman, M. Shook, D. A. Siegel, A. Wisthaler, M. Y. Martin, and L. Ziemba. 2019. The North Atlantic Aerosol and Marine Ecosystem Study (NAAMES): Science Motive and Mission Overview Frontiers in Marine Science 6 (122): 25 [10.3389/fmars.2019.00122]

Dubovik, O., Z. Li, M. I. Mishchenko, et al. D. Tanré, Y. Karol, B. Bojkov, B. Cairns, D. J. Diner, W. R. Espinosa, P. Goloub, X. Gu, O. Hasekamp, J. Hong, W. Hou, K. D. Knobelspiesse, J. Landgraf, L. Li, P. Litvinov, Y. Liu, A. Lopatin, T. Marbach, H. Maring, V. Martins, Y. Meijer, G. Milinevsky, S. Mukai, F. Parol, Y. Qiao, L. Remer, J. Rietjens, I. Sano, P. Stammes, S. Stamnes, X. Sun, P. Tabary, L. D. Travis, F. Waquet, F. Xu, C. Yan, and D. Yin. 2019. Polarimetric remote sensing of atmospheric aerosols: Instruments, methodologies, results, and perspectives Journal of Quantitative Spectroscopy and Radiative Transfer 224 474-511 [10.1016/j.jqsrt.2018.11.024]

Knobelspiesse, K., Q. Tan, C. Bruegge, et al. B. Cairns, J. Chowdhary, B. van Diedenhoven, D. Diner, R. Ferrare, G. van Harten, V. Jovanovic, M. Ottaviani, J. Redemann, F. Seidel, and K. Sinclair. 2019. Intercomparison of airborne multi-angle polarimeter observations from the Polarimeter Definition Experiment Applied Optics 58 (3): 650 [10.1364/ao.58.000650]

Segal-Rozenhaimer, M., D. J. Miller, K. Knobelspiesse, et al. J. Redemann, B. Cairns, and M. D. Alexandrov. 2018. Development of neural network retrievals of liquid cloud properties from multi-angle polarimetric observations Journal of Quantitative Spectroscopy and Radiative Transfer 220 39-51 [10.1016/j.jqsrt.2018.08.030]

Alexandrov, M. D., B. Cairns, K. Sinclair, et al. A. P. Wasilewski, L. Ziemba, E. Crosbie, R. Moore, J. Hair, A. J. Scarino, Y. Hu, S. Stamnes, M. A. Shook, and G. Chen. 2018. Retrievals of cloud droplet size from the research scanning polarimeter data: Validation using in situ measurements Remote Sensing of Environment 210 76-95 [10.1016/j.rse.2018.03.005]

Grosvenor, D. P., O. Sourdeval, P. Zuidema, et al. A. Ackerman, M. D. Alexandrov, R. Bennartz, R. Boers, B. Cairns, J. C. Chiu, M. Christensen, H. Deneke, M. Diamond, G. Feingold, A. Fridlind, A. Hünerbein, C. Knist, P. Kollias, A. Marshak, D. McCoy, D. Merk, D. Painemal, J. Rausch, D. Rosenfeld, H. Russchenberg, P. Seifert, K. Sinclair, P. Stier, B. van Diedenhoven, M. Wendisch, F. Werner, R. Wood, Z. Zhang, and J. Quaas. 2018. Remote Sensing of Droplet Number Concentration in Warm Clouds: A Review of the Current State of Knowledge and Perspectives Reviews of Geophysics 56 (2): 409-453 [10.1029/2017rg000593]

Harten, G. V., D. J. Diner, B. J. Daugherty, et al. B. E. Rheingans, M. A. Bull, F. C. Seidel, R. A. Chipman, B. Cairns, A. P. Wasilewski, and K. D. Knobelspiesse. 2018. Calibration and validation of Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) polarization measurements Applied Optics 57 (16): 4499 [10.1364/ao.57.004499]

Gao, M., P.-W. Zhai, B. Franz, et al. Y. Hu, K. Knobelspiesse, P. J. Werdell, A. Ibrahim, F. Xu, and B. Cairns. 2018. Retrieval of aerosol properties and water-leaving reflectance from multi-angular polarimetric measurements over coastal waters Optics Express 26 (7): 8968 [10.1364/oe.26.008968]

Stamnes, S., C. Hostetler, R. Ferrare, et al. S. Burton, X. Liu, J. Hair, Y. Hu, A. Wasilewski, W. Martin, B. van Diedenhoven, J. Chowdhary, I. Cetinić, L. K. Berg, K. Stamnes, and B. Cairns. 2018. Simultaneous polarimeter retrievals of microphysical aerosol and ocean color parameters from the “MAPP” algorithm with comparison to high-spectral-resolution lidar aerosol and ocean products Applied Optics 57 (10): 2394 [10.1364/ao.57.002394]

Ottaviani, M., R. Foster, A. Gilerson, et al. A. Ibrahim, C. Carrizo, A. El-Habashi, B. Cairns, J. Chowdhary, C. Hostetler, J. Hair, S. Burton, Y. Hu, M. Twardowski, N. Stockley, D. Gray, W. Slade, and I. Cetinic. 2018. Airborne and shipborne polarimetric measurements over open ocean and coastal waters: Intercomparisons and implications for spaceborne observations Remote Sensing of Environment 206 375-390 [10.1016/j.rse.2017.12.015]

Sinclair, K., B. van Diedenhoven, B. Cairns, et al. J. Yorks, A. Wasilewski, and M. McGill. 2017. Remote Sensing of Multiple Cloud Layer Heights using Multi-Angular Measurements Atmospheric Measurement Techniques Discussions 1-23 [10.5194/amt-10-2361-2017]

Mishchenko, M. I., M. D. Alexandrov, B. Cairns, and L. D. Travis. 2016. Multistatic aerosol–cloud lidar in space: A theoretical perspective Journal of Quantitative Spectroscopy and Radiative Transfer 184 180-192 [10.1016/j.jqsrt.2016.07.015]

Wu, L., O. Hasekamp, B. van Diedenhoven, et al. B. Cairns, J. E. Yorks, and J. Chowdhary. 2016. Passive remote sensing of aerosol layer height using near-UV multiangle polarization measurements Geophysical Research Letters 43 (16): 8783-8790 [10.1002/2016gl069848]

Alexandrov, M. D., B. Cairns, B. van Diedenhoven, et al. A. S. Ackerman, A. P. Wasilewski, M. J. McGill, J. E. Yorks, D. L. Hlavka, S. E. Platnick, and G. T. Arnold. 2016. Polarized view of supercooled liquid water clouds Remote Sensing of Environment 181 96-110 [10.1016/j.rse.2016.04.002]

Mishchenko, M. I., J. A. Lock, A. A. Lacis, L. D. Travis, and B. Cairns. 2016. First-principles definition and measurement of planetary electromagnetic-energy budget J. Opt. Soc. Am. A 33 (6): 1126 [10.1364/josaa.33.001126]

van Diedenhoven, B., A. M. Fridlind, B. Cairns, A. S. Ackerman, and J. E. Yorks. 2016. Vertical variation of ice particle size in convective cloud tops Geophysical Research Letters 43 (9): 4586-4593 [10.1002/2016gl068548]

Mishchenko, M. I., J. M. Dlugach, M. A. Yurkin, et al. L. Bi, B. Cairns, L. Liu, R. L. Panetta, L. D. Travis, P. Yang, and N. T. Zakharova. 2016. First-principles modeling of electromagnetic scattering by discrete and discretely heterogeneous random media Physics Reports 632 1-75 [10.1016/j.physrep.2016.04.002]

McCorkel, J., B. Cairns, and A. Wasilewski. 2016. Imager-to-radiometer in-flight cross calibration: RSP radiometric comparison with airborne and satellite sensors Atmospheric Measurement Techniques 9 (3): 955-962 [10.5194/amt-9-955-2016]

Alexandrov, M. D., B. Cairns, C. Emde, et al. A. S. Ackerman, M. Ottaviani, and A. P. Wasilewski. 2016. Derivation of cumulus cloud dimensions and shape from the airborne measurements by the Research Scanning Polarimeter Remote Sensing of Environment 177 144-152 [10.1016/j.rse.2016.02.032]

van Diedenhoven, B., A. S. Ackerman, A. M. Fridlind, and B. Cairns. 2016. On averaging aspect ratios and distortion parameters over ice crystal population ensembles for estimating effective scattering asymmetry parameters Journal of the Atmospheric Sciences 73 (2): 775-787 [10.1175/jas-d-15-0150.1]

Alexandrov, M. D., I. V. Geogdzhayev, K. Tsigaridis, et al. A. Marshak, R. Levy, and B. Cairns. 2016. New statistical model for variability of aerosol optical thickness: Theory and application to MODIS data over ocean Journal of the Atmospheric Sciences 73 (2): 821-837 [10.1175/jas-d-15-0130.1]

Berg, L. K., J. D. Fast, J. C. Barnard, et al. S. P. Burton, B. Cairns, D. Chand, J. M. Comstock, S. Dunagan, R. A. Ferrare, C. J. Flynn, J. W. Hair, C. A. Hostetler, J. Hubbe, A. Jefferson, R. Johnson, E. I. Kassianov, C. D. Kluzek, P. Kollias, K. Lamer, K. Lantz, F. Mei, M. A. Miller, J. Michalsky, I. Ortega, M. Pekour, R. R. Rogers, P. B. Russell, J. Redemann, A. J. Sedlacek, M. Segal-Rosenheimer, B. Schmid, J. E. Shilling, Y. Shinozuka, S. R. Springston, J. M. Tomlinson, M. Tyrrell, J. M. Wilson, R. Volkamer, A. Zelenyuk, and C. M. Berkowitz. 2016. The Two-Column Aerosol Project: Phase I-Overview and impact of elevated aerosol layers on aerosol optical depth J. Geophys. Res. Atmos. 121 (1): 336-361 [10.1002/2015jd023848]

Ottaviani, M., B. van Diedenhoven, and B. Cairns. 2015. Photopolarimetric retrievals of snow properties The Cryosphere 9 1933-1942 [10.5194/tc-9-1933-2015]

Alexandrov, M. D., B. Cairns, A. P. Wasilewski, et al. A. S. Ackerman, M. J. McGill, J. E. Yorks, J. E. Hlavka, S. E. Platnick, G. T. Arnold, B. van Diedenhoven, J. Chowdhary, M. Ottaviani, and K. D. Knobelspiesse. 2015. Liquid water cloud properties during the Polarimeter Definition Experiment (PODEX) Remote Sens. Environ. 169 20-36 [doi:10.1016/j.rse.2015.07.029]

Geogdzhayev, I. V., M. I. Mishchenko, J. Li, et al. W. B. Rossow, L. Liu, and B. Cairns. 2015. Extension and statistical analysis of the GACP aerosol optical thickness record Atmos. Res. 164-165 268-277 [doi:10.1016/j.atmosres.2015.05.013]

Wu, L., O. Hasekamp, B. van Diedenhoven, and B. Cairns. 2015. Aerosol retrieval from multiangle, multispectral photopolarimetric measurements: Importance of spectral range and angular resolution Atmos. Meas. Tech. 8 2625-2638 [doi:10.5194/amt-8-2625-2015]

Kokhanovsky, A. A., A. B. Davis, B. Cairns, et al. O. Dubovik, O. P. Hasekamp, I. Sano, S. Mukai, V. V. Rozanov, P. Litvinov, T. Lapyonok, I. S. Kolomiets, Y. A. Oberemok, S. Savenkov, W. G. Martin, A. P. Wasilewski, A. di Noia, A. Stap, J. Rietjens, F. Xu, V. Natraj, M. Duan, T. Cheng, and R. Munro. 2015. Space-based remote sensing of atmospheric aerosols: The multi-angle spectro-polarimetric frontier Earth-Sci. Rev. 145 85-116 [doi:10.1016/j.earscirev.2015.01.012]

Knobelspiesse, K., B. Cairns, H. T. Jethva, et al. M. Kacenelenbogen, M. Segal-Rosenheimer, and O. Torres. 2014. Remote sensing of above cloud aerosols Light Scattering Reviews 9 167-210

Martin, W., B. Cairns, and G. Bal. 2014. Adjoint methods for adjusting three-dimensional atmosphere and surface properties to fit multi-angle/multi-pixel polarimetric measurements J. Quant. Spectrosc. Radiat. Transfer 144 68-85 [10.1016/j.jqsrt.2014.03.030]

van Diedenhoven, B., A. M. Fridlind, B. Cairns, and A. S. Ackerman. 2014. Variation of ice crystal size, shape and asymmetry parameter in tops of tropical deep convective clouds J. Geophys. Res. Atmos. 119 (20): 11809-11825 [doi:10.1002/2014JD022385]

Mishchenko, M. I., L. Liu, B. Cairns, and D. W. Mackowski. 2014. Optics of water cloud droplets mixed with black-carbon aerosols Opt. Lett. 39 (9): 2607 [10.1364/OL.39.002607]

Van Diedenhoven, B., A. S. Ackerman, B. Cairns, and A. M. Fridlind. 2014. A Flexible Parameterization for Shortwave Optical Properties of Ice Crystals J. Atmos. Sci. 71 (5): 1763-1782 [10.1175/JAS-D-13-0205.1]

Remer, L., C. Brogniez, B. Cairns, and N.-Y. C. Hsu. 2013. Recent instruments and algorithms for passive shortwave remote sensing Aerosol Remote Sensing, Springer 185-221

Geogdzhayev, I., B. Cairns, M. Alexandrov, and M. I. Mishchenko. 2013. Statistical analysis of single-track instrument sampling in spaceborne aerosol remote sensing for climate research J. Quant. Spectrosc. Radiat. Transfer 121 69-77 [10.1016/j.jqsrt.2013.02.003]

Ottaviani, M., K. Knobelspiesse, B. Cairns, and M. Mishchenko. 2013. Information content of aerosol retrievals in the sunglint region Geophys. Res. Lett. 40 (3): 631-634 [10.1002/grl.50148]

Ryerson, T. B., A. E. Andrews, W. M. Angevine, et al. T. S. Bates, C. A. Brock, B. Cairns, R. C. Cohen, O. R. Cooper, J. A. de Gouw, F. C. Fehsenfeld, R. A. Ferrare, M. L. Fischer, R. C. Flagan, A. H. Goldstein, J. W. Hair, R. M. Hardesty, C. A. Hostetler, J. L. Jimenez, A. O. Langford, E. McCauley, S. A. McKeen, L. T. Molina, A. Nenes, S. J. Oltmans, D. D. Parrish, J. R. Pederson, R. B. Pierce, K. Prather, P. K. Quinn, J. H. Seinfeld, C. J. Senff, A. Sorooshian, J. Stutz, J. D. Surratt, M. Trainer, R. Volkamer, E. J. Williams, and S. C. Wofsy. 2013. The 2010 California Research at the Nexus of Air Quality and Climate Change (CalNex) field study J. Geophys. Res. Atmos. 118 (11): 5830-5866 [10.1002/jgrd.50331]

van Diedenhoven, B., B. Cairns, A. M. Fridlind, A. S. Ackerman, and T. J. Garrett. 2013. Remote sensing of ice crystal asymmetry parameter using multi-directional polarization measurements – Part 2: Application to the Research Scanning Polarimeter Atmos. Chem. Phys. 13 (6): 3185-3203 [10.5194/acp-13-3185-2013]

Zhai, P., Y. Hu, C. A. Hostetler, et al. B. Cairns, R. A. Ferrare, K. D. Knobelspiesse, D. B. Josset, C. R. Trepte, P. L. Lucker, and J. Chowdhary. 2013. Uncertainty and interpretation of aerosol remote sensing due to vertical inhomogeneity J Quant Spectrosc Radiat Transfer 114 91-100 [10.1016/j.jqsrt.2012.08.006]

van Diedenhoven, B., A. M. Fridlind, A. S. Ackerman, and B. Cairns. 2012. Evaluation of Hydrometeor Phase and Ice Properties in Cloud-Resolving Model Simulations of Tropical Deep Convection Using Radiance and Polarization Measurements J Atmos Sci 69 (11): 3290-3314 [10.1175/JAS-D-11-0314.1]

Alexandrov, M. D., B. Cairns, and M. I. Mishchenko. 2012. Rainbow Fourier transform J Quant Spectrosc Radiat Transfer 113 (18): 2521-2535 [10.1016/j.jqsrt.2012.03.025]

Zaveri, R. A., W. J. Shaw, D. J. Cziczo, et al. B. Schmid, R. A. Ferrare, M. L. Alexander, M. Alexandrov, R. J. Alvarez, W. P. Arnott, D. B. Atkinson, S. Baidar, R. M. Banta, J. C. Barnard, J. Beranek, L. K. Berg, F. Brechtel, W. A. Brewer, J. F. Cahill, B. Cairns, C. D. Cappa, D. Chand, S. China, J. M. Comstock, M. K. Dubey, R. C. Easter, M. H. Erickson, J. D. Fast, C. Floerchinger, B. A. Flowers, E. Fortner, J. S. Gaffney, M. K. Gilles, K. Gorkowski, W. I. Gustafson, M. Gyawali, J. Hair, R. M. Hardesty, J. W. Harworth, S. Herndon, N. Hiranuma, C. Hostetler, J. M. Hubbe, J. T. Jayne, H. Jeong, B. T. Jobson, E. I. Kassianov, L. I. Kleinman, C. Kluzek, B. Knighton, K. R. Kolesar, C. Kuang, A. Kubátová, A. O. Langford, A. Laskin, N. Laulainen, R. D. Marchbanks, C. Mazzoleni, F. Mei, R. C. Moffet, D. Nelson, M. D. Obland, H. Oetjen, T. B. Onasch, I. Ortega, M. Ottaviani, M. Pekour, K. A. Prather, J. G. Radney, R. R. Rogers, S. P. Sandberg, A. Sedlacek, C. J. Senff, G. Senum, A. Setyan, J. E. Shilling, M. Shrivastava, C. Song, S. R. Springston, R. Subramanian, K. Suski, J. Tomlinson, R. Volkamer, H. W. Wallace, J. Wang, A. M. Weickmann, D. R. Worsnop, X. Y. Yu, A. Zelenyuk, and Q. Zhang. 2012. Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) Atmos. Chem. Phys. 12 (16): 7647-7687 [10.5194/acp-12-7647-2012]

van Diedenhoven, B., B. Cairns, I. V. Geogdzhayev, et al. A. M. Fridlind, A. S. Ackerman, P. Yang, and B. A. Baum. 2012. Remote sensing of ice crystal asymmetry parameter using multi-directional polarization measurements. Part I: Methodology and evaluation with simulated measurements Atmos Meas Tech 5 (10): 2361-2374 [10.5194/amt-5-2361-2012]

Ottaviani, M., B. Cairns, J. Chowdhary, et al. B. van Diedenhoven, K. Knobelspiesse, C. Hostetler, R. Ferrare, S. Burton, J. Hair, M. D. Obland, and R. Rogers. 2012. Polarimetric retrievals of surface and cirrus clouds properties in the region affected by the Deepwater Horizon oil spill Remote Sens Environ 121 389-403 [10.1016/j.rse.2012.02.016]

Ottaviani, M., B. Cairns, R. R. Rogers, and R. Ferrare. 2012. Iterative atmospheric correction scheme and the polarization color of alpine snow J Quant Spectrosc Radiat Transfer 113 (10): 789-804 [10.1016/j.jqsrt.2012.03.014]

Litvinov, P., O. Hasekamp, O. Dubovik, and B. Cairns. 2012. Model for land surface reflectance treatment: Physical derivation, application for bare soil and evaluation on airborne and satellite measurements J Quant Spectrosc Radiat Transfer 113 (16): 2023-2039 [10.1016/j.jqsrt.2012.06.027]

Knobelspiesse, K. D., B. Cairns, M. I. Mishchenko, et al. J. Chowdhary, K. Tsigaridis, B. Van Diedenhoven, W. Martin, M. Ottaviani, and M. D. Alexandrov. 2012. Analysis of fine-mode aerosol retrieval capabilities by different passive remote sensing instrument designs Opt. Express 20 (19): 21,457-21,484 [10.1364/OE.20.021457]

Chowdhary, J., B. Cairns, F. Waquet, et al. K. Knobelspiesse, M. Ottaviani, J. Redemann, L. Travis, and M. Mishchenko. 2012. Sensitivity of multiangle, multispectral polarimetric remote sensing over open oceans to water-leaving radiance: Analyses of RSP data acquired during the MILAGRO campaign Remote Sens Environ 118 284-308 [10.1016/j.rse.2011.11.003]

Alexandrov, M. D., B. Cairns, C. Emde, A. S. Ackerman, and B. van Diedenhoven. 2012. Accuracy assessments of cloud droplet size retrievals from polarized reflectance measurements by the research scanning polarimeter Remote Sens Environ 125 92-111 [10.1016/j.rse.2012.07.012]

Litvinov, P., O. Hasekamp, and B. Cairns. 2011. Models for surface reflection of radiance and polarized radiance: Comparison with airborne multi-angle photopolarimetric measurements and implications for modeling top-of-atmosphere measurements Remote Sensing of Environment 115 (2): 781-792 [10.1016/j.rse.2010.11.005]

Knobelspiesse, K. D., B. Cairns, M. Ottaviani, et al. R. Ferrare, J. Hair, C. Hostetler, M. Obland, R. Rogers, J. Redemann, Y. Shinozuka, A. Clarke, S. Freitag, S. Howell, V. Kapustin, and C. McNaughton. 2011. Combined retrievals of boreal forest fire aerosol properties with a polarimeter and lidar Atmos. Chem. Phys. 11 (14): 7045-7067 [10.5194/acp-11-7045-2011]

Knobelspiesse, K. D., B. Cairns, J. Redemann, R. W. Bergstrom, and A. Stohl. 2011. Simultaneous retrieval of aerosol and cloud properties during the MILAGRO field campaign Atmos. Chem. Phys. 11 (13): 6245-6263 [10.5194/acp-11-6245-2011]

Mishchenko, M. I., V. P. Tishkovets, L. D. Travis, et al. B. Cairns, J. M. Dlugach, L. Liu, V. K. Rosenbush, and N. N. Kiselev. 2011. Electromagnetic scattering by a morphologically complex object: Fundamental concepts and common misconceptions J. Quant. Spectrosc. Radiat. Transfer 112 (4): 671-692 [10.1016/j.jqsrt.2010.03.016]

Mishchenko, M. I., L. Liu, L. D. Travis, B. Cairns, and A. A. Lacis. 2010. Toward unified satellite climatology of aerosol properties: 3 MODIS versus MISR versus AERONET J Quant Spectrosc Radiat Transfer 111 (4): 540-552 [10.1016/j.jqsrt.2009.11.003]

Litvinov, P., O. Hasekamp, B. Cairns, and M. I. Mishchenko. 2010. Reflection models for soil and vegetation surfaces from multiple-viewing angle photopolarimetric measurements J Quant Spectrosc Radiat Transfer 111 (4): 529-539 [10.1016/j.jqsrt.2009.11.001]

Waquet, F., J. Riédi, L. Labonnote, et al. P. Goloub, B. Cairns, J. Deuzé, and D. Tanré. 2009. Aerosol Remote Sensing over Clouds Using A-Train Observations J Atmos Sci 66 (8): 2468-2480 [10.1175/2009JAS3026.1]

Waquet, F., B. Cairns, K. Knobelspiesse, et al. J. Chowdhary, L. D. Travis, B. Schmid, and M. I. Mishchenko. 2009. Polarimetric remote sensing of aerosols over land J. Geophys. Res. 114 (D1): D01206 [10.1029/2008JD010619]

Waquet, F., J. Léon, B. Cairns, et al. P. Goloub, J. Deuzé, and F. Auriol. 2009. Analysis of the spectral and angular response of the vegetated surface polarization for the purpose of aerosol remote sensing over land Applied Optics 48 (6): 1228 [10.1364/AO.48.001228]

Mishchenko, M. I., I. V. Geogdzhayev, L. Liu, et al. A. A. Lacis, B. Cairns, and L. D. Travis. 2009. Toward unified satellite climatology of aerosol properties: What do fully compatible MODIS and MISR aerosol pixels tell us? J Quant Spectrosc Radiat Transfer 110 (6-7): 402-408 [10.1016/j.jqsrt.2009.01.007]

Alexandrov, M. D., B. Schmid, D. D. Turner, et al. B. Cairns, V. Oinas, A. A. Lacis, S. I. Gutman, E. R. Westwater, A. Smirnov, and J. Eilers. 2009. Columnar water vapor retrievals from multifilter rotating shadowband radiometer data J. Geophys. Res. 114 (D2): D02306 [10.1029/2008JD010543]

Knobelspiesse, K. D., B. Cairns, B. Schmid, M. O. Román, and C. B. Schaaf. 2008. Surface BRDF estimation from an aircraft compared to MODIS and ground estimates at the Southern Great Plains site J. Geophys. Res. 113 (D20): D20105 [10.1029/2008JD010062]

Alexandrov, M. D., A. A. Lacis, B. E. Carlson, and B. Cairns. 2008. Characterization of atmospheric aerosols using MFRSR measurements J. Geophys. Res. 113 (D8): D08204 [10.1029/2007JD009388]

Mishchenko, M. I., L. Liu, D. W. Mackowski, B. Cairns, and G. Videen. 2007. Multiple scattering by random particulate media: exact 3D results Opt. Express 15 (6): 2822-2836 [10.1364/OE.15.002822]

Mishchenko, M. I., I. V. Geogdzhayev, W. B. Rossow, et al. B. Cairns, B. E. Carlson, A. A. Lacis, L. Liu, and L. D. Travis. 2007. Long-Term Satellite Record Reveals Likely Recent Aerosol Trend Science 315 (5818): 1543-1543 [10.1126/science.1136709]

Mishchenko, M. I., B. Cairns, G. Kopp, et al. C. F. Schueler, B. A. Fafaul, J. E. Hansen, R. J. Hooker, T. Itchkawich, H. B. Maring, and L. D. Travis. 2007. Accurate Monitoring of Terrestrial Aerosols and Total Solar Irradiance: Introducing the Glory Mission Bulletin of the American Meteorological Society 88 (5): 677-691 [10.1175/BAMS-88-5-677]

Hansen, J. E., M. Sato, R. A. Ruedy, et al. P. A. Kharecha, A. A. Lacis, R. L. Miller, L. S. Nazarenko, K.-W. Lo, G. A. Schmidt, G. L. Russell, I. Aleinov, S. E. Bauer, E. Baum, B. Cairns, V. M. Canuto, M. A. Chandler, Y.-B. Cheng, A. Cohen, A. D. Del Genio, G. S. Faluvegi, E. Fleming, A. Friend, T. M. Hall, C. H. Jackman, J. A. Jonas, M. Kelley, N. Y. Kiang, D. Koch, G. Labow, J. Lerner, S. Menon, T. Novakov, V. Oinas, J. P. Perlwitz, J. Perlwitz, D. H. Rind, A. Romanou, R. B. Schmunk, D. T. Shindell, P. Stone, S. Sun, D. Streets, N. L. Tausnev, D. Thresher, N. Unger, M.-S. Yao, and S. Zhang. 2007. Dangerous human-made interference with climate: a GISS modelE study Atmos. Chem. Phys. 7 (9): 2287-2312 [10.5194/acp-7-2287-2007]

Hansen, J. E., M. Sato, R. A. Ruedy, et al. P. A. Kharecha, A. A. Lacis, R. L. Miller, L. S. Nazarenko, K.-W. Lo, G. A. Schmidt, G. L. Russell, I. Aleinov, S. E. Bauer, E. Baum, B. Cairns, V. M. Canuto, M. A. Chandler, Y.-B. Cheng, A. Cohen, A. D. Del Genio, G. S. Faluvegi, E. Fleming, A. Friend, T. M. Hall, C. H. Jackman, J. A. Jonas, M. Kelley, N. Y. Kiang, D. Koch, G. Labow, J. Lerner, S. Menon, T. Novakov, V. Oinas, J. P. Perlwitz, J. Perlwitz, D. H. Rind, A. Romanou, R. B. Schmunk, D. T. Shindell, P. Stone, S. Sun, D. Streets, N. L. Tausnev, D. Thresher, N. Unger, M.-S. Yao, and S. Zhang. 2007. Climate simulations for 1880–2003 with GISS modelE Clim Dyn 29 (7-8): 661-696 [10.1007/s00382-007-0255-8]

Diner, D. J., A. Davis, B. Hancock, et al. G. Gutt, R. A. Chipman, and B. Cairns. 2007. Dual-photoelastic-modulator-based polarimetric imaging concept for aerosol remote sensing Applied Optics 46 (35): 8428 [10.1364/AO.46.008428]

Mishchenko, M. I., I. V. Geogdzhayev, B. Cairns, et al. B. E. Carlson, J. Chowdhary, A. A. Lacis, L. Liu, W. B. Rossow, and L. D. Travis. 2007. Past, present, and future of global aerosol climatologies derived from satellite observations: A perspective J Quant Spectrosc Radiat Transfer 106 (1-3): 325-347 [10.1016/j.jqsrt.2007.01.007]

Schmidt, G. A., R. A. Ruedy, J. E. Hansen, et al. I. Aleinov, N. Bell, M. P. Bauer, S. E. Bauer, B. Cairns, V. M. Canuto, Y.-B. Cheng, A. Del Genio, G. S. Faluvegi, A. D. Friend, T. M. Hall, Y. Hu, M. Kelley, N. Y. Kiang, D. Koch, A. A. Lacis, J. Lerner, K.-W. Lo, R. L. Miller, L. S. Nazarenko, V. Oinas, J. Perlwitz, D. Rind, A. Romanou, G. L. Russell, M. Sato, D. T. Shindell, P. H. Stone, S. Sun, N. L. Tausnev, D. Thresher, and M.-S. Yao. 2006. Present-Day Atmospheric Simulations Using GISS ModelE: Comparison to In Situ, Satellite, and Reanalysis Data J. Climate 19 (2): 153-192 [10.1175/JCLI3612.1]

Liu, L., M. I. Mishchenko, B. Cairns, B. E. Carlson, and L. D. Travis. 2006. Modeling single-scattering properties of small cirrus particles by use of a size-shape distribution of ice spheroids and cylinders J Quant Spectrosc Radiat Transfer 101 (3): 488-497 [10.1016/j.jqsrt.2006.02.040]

Liu, L., A. A. Lacis, B. E. Carlson, et al. I. V. Geogdzhayev, M. I. Mishchenko, and B. Cairns. 2006. Assessing Goddard Institute for Space Studies ModelE aerosol climatology using satellite and ground-based measurements: A comparison study J. Geophys. Res. 111 (D20): D20212 [10.1029/2006JD007334]

Mishchenko, M. I., B. Cairns, J. Chowdhary, et al. I. V. Geogdzhayev, L. Liu, and L. D. Travis. 2005. Remote sensing of terrestrial tropospheric aerosols from aircraft and satellites J Phys Conf Series 6 73-89 [10.1088/1742-6596/6/1/005]

Hansen, J. E., M. Sato, R. A. Ruedy, et al. L. S. Nazarenko, A. A. Lacis, G. A. Schmidt, G. L. Russell, I. Aleinov, M. P. Bauer, S. E. Bauer, N. Bell, B. Cairns, V. M. Canuto, M. A. Chandler, Y.-B. Cheng, A. Del Genio, G. S. Faluvegi, E. Fleming, A. Friend, T. M. Hall, C. Jackman, M. Kelley, N. Y. Kiang, D. Koch, J. Lean, J. Lerner, K.-W. Lo, S. Menon, R. L. Miller, P. Minnis, T. Novakov, V. Oinas, J. Perlwitz, D. Rind, A. Romanou, D. T. Shindell, P. Stone, S. Sun, N. L. Tausnev, D. Thresher, B. Wielicki, T. Wong, M.-S. Yao, and S. Zhang. 2005. Efficacy of climate forcings J. Geophys. Res. 110 (D18): D18104 [10.1029/2005JD005776]

Chowdhary, J., B. Cairns, M. I. Mishchenko, et al. P. V. Hobbs, G. F. Cota, J. Redemann, K. Rutledge, B. Holben, and E. Russell. 2005. Retrieval of Aerosol Scattering and Absorption Properties from Photopolarimetric Observations over the Ocean during the CLAMS Experiment J. Atmos. Sci. 62 (4): 1093-1117 [10.1175/JAS3389.1]

Alexandrov, M. D., B. E. Carlson, A. A. Lacis, and B. Cairns. 2005. Separation of fine and coarse aerosol modes in MFRSR data sets J. Geophys. Res. 110 (D13): D13204 [10.1029/2004JD005226]

Hansen, J. E., T. Bond, B. Cairns, et al. H. Gaeggler, B. Liepert, T. Novakov, and B. Schichtel. 2004. Carbonaceous aerosols in the industrial era Eos, Trans Amer Geophys Union 85 (25): 241-244 [10.1029/2004EO250001]

Mishchenko, M. I., B. Cairns, J. E. Hansen, et al. L. D. Travis, R. Burg, Y. J. Kaufman, J. V. Martins, and E. P. Shettle. 2004. Monitoring of aerosol forcing of climate from space: Analysis of measurement requirements J Quant Spectrosc Radiat Transfer 88 (1-3): 149-161 [10.1016/j.jqsrt.2004.03.030]

Alexandrov, M. D., A. Marshak, B. Cairns, A. A. Lacis, and B. E. Carlson. 2004. Automated cloud screening algorithm for MFRSR data Geophys Res Lett 31 (4): L04118 [10.1029/2003GL019105]

Alexandrov, M. D., A. Marshak, B. Cairns, A. A. Lacis, and B. E. Carlson. 2004. Scaling properties of aerosol optical thickness retrieved from ground-based measurements J Atmos Sci 61 1024-1039.

Mishchenko, M., B. Cairns, J. Hansen, et al. L. Travis, R. Burg, Y. Kaufman, J. Martins, and E. Shettle. 2004. Monitoring of aerosol forcing from space: analysis of measurement requirements J Quant Spectros& Rad Trans 88 149-161

Cairns, B., B. E. Carlson, R. Ying, A. A. Lacis, and V. Oinas. 2003. Atmospheric correction and its application to an analysis of Hyperion data IEEE Trans Geosci Remote Sens 41 (6): 1232-1245 [10.1109/TGRS.2003.813134]

Chowdhary, J., B. Cairns, and L. D. Travis. 2002. Case studies of aerosol retrievals over the ocean from multiangle, multispectral photopolarimetric remote sensing data J Atmos Sci 59 (3): 383-397 [10.1175/1520-0469(2002)059<0383:CSOARO>2.0.CO;2]

Geogdzhayev, I. V., M. I. Mishchenko, W. B. Rossow, B. Cairns, and A. A. Lacis. 2002. Global two-channel AVHRR retrievals of aerosol properties over the ocean for the period of NOAA-9 observations and preliminary retrievals using NOAA-7 and NOAA-11 data J Atmos Sci 59 262-278.

Rossow, W. B., C. Delo, and B. Cairns. 2002. Implications of the observed mesoscale variations of clouds for the Earth's radiation budget J Climate 15 557-585.

Alexandrov, M. D., A. A. Lacis, B. E. Carlson, and B. Cairns. 2002. Remote sensing of atmospheric aerosols and trace gases by means of multifilter rotating shadowband radiometer. Part I: Retrieval algorithms J Atmos Sci 59 524-543.

Alexandrov, M. D., A. A. Lacis, B. E. Carlson, and B. Cairns. 2002. Remote sensing of atmospheric aerosols and trace gases by means of multifilter rotating shadowband radiometer. Part II: Climatological applications J Atmos Sci 59 544-566.

Chowdhary, J., B. Cairns, M. Mishchenko, and L. Travis. 2001. Retrieval of aerosol properties over the ocean using multispectral and multiangle Photopolarimetric measurements from the Research Scanning Polarimeter Geophys. Res. Lett. 28 (2): 243-246 [10.1029/2000GL011783]

Cairns, B., A. A. Lacis, and B. E. Carlson. 2000. Absorption within inhomogeneous clouds and its parameterization in general circulation models J Atmos Sci 57 (5): 700-714 [10.1175/1520-0469(2000)057<0700:AWICAI>2.0.CO;2]

Mishchenko, M. I., I. V. Geogdzhayev, B. Cairns, W. B. Rossow, and A. A. Lacis. 1999. Aerosol retrievals over the ocean by use of channels 1 and 2 AVHRR data: sensitivity analysis and preliminary results Applied Optics 38 (36): 7325-7341 [10.1364/AO.38.007325]

Lacis, A. A., J. Chowdhary, M. I. Mishchenko, and B. Cairns. 1998. Modeling errors in diffuse-sky radiation: Vector <i>vs</i> scalar treatment Geophysical Research Letters 25 (2): 135-138 [10.1029/97GL03613]

Mishchenko, M. I., L. D. Travis, W. B. Rossow, et al. B. Cairns, B. E. Carlson, and Q. Han. 1997. Retrieving CCN column density from single-channel measurements of reflected sunlight over the ocean: A sensitivity study Geophysical Research Letters 24 (21): 2655-2658 [10.1029/97GL02783]

Hansen, J., M. Sato, R. Ruedy, et al. A. Lacis, K. Asamoah, K. Beckford, S. Borenstein, E. Brown, B. Cairns, B. Carlson, B. Curran, S. de Castro, L. Druyan, P. Etwarrow, T. Ferede, M. Fox, D. Gaffen, J. Glascoe, H. Gordon, S. Hollandsworth, X. Jiang, C. Johnson, N. Lawrence, J. Lean, J. Lerner, K. Lo, J. Logan, A. Luckett, M. P. McCormick, R. McPeters, R. L. Miller, P. Minnis, I. Ramberran, G. Russell, P. Russell, P. Stone, I. Tegen, S. Thomas, L. Thomason, A. Thompson, J. Wilder, R. Willson, and J. Zawodny. 1997. Forcings and chaos in interannual to decadal climate change J. Geophys. Res. 102 (D22): 25679-25720 [10.1029/97JD01495]

Macke, A., M. I. Mishchenko, and B. Cairns. 1996. The influence of inclusions on light scattering by large ice particles J. Geophys. Res. 101 (D18): 23311-23316 [10.1029/96JD02364]

Rossow, W. B., and B. Cairns. 1995. Monitoring changes of clouds Climatic Change 31 (2-4): 305-347 [10.1007/BF01095151]

Hansen, J., W. Rossow, B. Carlson, et al. A. Lacis, L. Travis, A. Del Genio, I. Fung, B. Cairns, M. Mishchenko, and I. Sato. 1995. Low-cost long-term monitoring of global climate forcings and feedbacks Climatic Change 31 (2-4): 247-271 [10.1007/BF01095149]

Fischer, D. G., and B. Cairns. 1995. Inverse Problems with Quasihomogeneous Random Media Utilizing Scattered Pulses Journal of Modern Optics 42 (3): 655-666 [10.1080/09500349514550601]

Cairns, B. 1995. Diurnal variations of cloud from ISCCP data Atmospheric Research 37 (1-3): 133-146 [10.1016/0169-8095(94)00074-N]

Cairns, B., and J. T. Foley. 1993. Contribution of the second-order Born approximation to the scattered intensity Opt Comm 101 (3–4): 144-150 [10.1016/0030-4018(93)90356-A]

Talks, Presentations and Posters


Invited

Polarimetric Remote Sensing of Aerosols and Clouds

August 3, 2014

EUMETSAT is currently developing a polarimetric sensor for the Meteosat Second Generation platform called 3MI.  Dr. Cairns was invited to talk about his experience with the airborne Research Scanning Polarimeter and any lessons learned in the development of the Aerosol Polarimetry Sensor that might have value in their acquistion of 3MI.

Other

Selected Public Outreach


Glory Project Outreach Team

April 2007 - 2009

RHG Exceptional Achievement Outreach Team award.

A Polarizing View of Clouds and Aerosols

2011 - 2011

Spoke at Desert Research Institute and Pyramid Lake High School on climate and what we can learn from polarimetric remote sensing.

A handheld polarimeter for aerosol remote sensing

April 2007 - Present

Work with Professor Jame Frost of Laguardia Community College to develop and build hand held polarimeters and analyse the measurements obtained with the hand held instruments.  Students build the instruments, take the measurements and perform the analysis giving them a complete view of what is required of a scientific measurement.