ESSL LAR

Andrew Heymsfield

 

Senior Scientist
TIIMES - MMM
UTLS

 

Contact Information:
PO Box 3000, Boulder, CO 80307-3000
Office: FL3 - 3035
Telephone: 303-497-8943
Email: heyms1@ucar.edu
Home Page

Andrew Heymsfield
 

Project Summary:

ICE-L

Click on picture to view the entire figure.


Figure 1. During ICE-L, researchers will study ice formation processes in lenticlar clouds (such as the one pictured here) along the Front Range.

Our efforts this year have centered on the analysis of in-situ microphysical measurements collected in cirrus clouds in the upper troposphere and lower stratosphere during several experiments in low latitudes (tropics). This work is guided by our efforts in the NCAR UTLS initiative, which are to improve the representation of UTLS cirrus in climate models. The thrust of our effort has been to characterize the properties of ice particle populations in thin to subvisual cirrus, focusing on the population-mean fallspeeds.

The central finding from this research is the sensitivity of the ensemble-mean fallspeeds to the properties of the ice crystals, most importantly the ice crystal masses and indirectly the ice crystal shape(s) We are calculating ice particle fallspeeds that are two to four times lower than previously calculated (for size distributions dominated by small crystals). The implications for the radiative and water budget estimates from climate models may be significant.

Our goal is to participate in the START-08 GV aircraft project for the goal of adding to our body of data in UTLS ice clouds and to refine our estimates of ice particle fallspeeds by directly collecting small ice crystals in-situ. With this additional data, we expect to acquire a sufficient body of data to publish our results and to develop reliable parameterizations to represent them.

 

Community Service:

  • Editor - Journal of Atmospheric Sciences
  • PI - Aircraft effects on climate change: Microphysics, Federal Aviation Administration (FAA)
  • Thesis Committee: Bhaskar, PhD, MIT, Boston, Ma USA
  • Thesis Committee: Carl Schmitt, PhD, University of Colorado`, Boulder, Co USA
  • Thesis Committee: Matthew Shupe, PhD, University of Colorado`, Boulder, Co USA
  • Thesis Committee: Sean Davis, PhD, University of Colorado`, Boulder, Co USA
 

Presentations:

  • Evaluation of radar retrieval algorithms, Hilo USA, October 2006
  • Ice clouds, Kuaui USA, October 2006
  • The role of dust on cloud properties, Baltimore USA, May 2007
  • Tropical Cirrus, Vienna AUS, April 2007
 

TIIMES External Collaborators:

Ken Beard, University of Illinois & Illinois State Water Survey
Wiliam Brune, Pennsylvania State University
Owen Cooper, University of Colorado
James Crawford, Langley Research Center (LARC) - NASA
Paul DeMott, Colorado State University
Paul Krehbiel, New Mexico Institute of Technology
Kenneth Pickering, Goddard Space Flight Center (GSFC) - NASA
Graeme Stephens, Colorado State University
Cynthia Twohy, Oregon State University
Gerd-Jan van Zadelhoff, Koninklijk Nederlands Meteorologisch Instituut (KNMI)
 

Publications:

Field, P. R., A. J. Heymsfield, A. Bansemer, C. H. Twohy, 2007: Determination of the combined ventilation factor and capacitance for ice crystal aggregates from airborne observations in a tropical anvil cloud. J. Atmos. Sci.. (In Press)

Seifert, P., A. Ansmann, D.-J. Muller, U. Wandinger, D. Althausen, A. J. Heymsfield, S. T. Massie, C. Schmitt, 2007: Cirrus optical properties observed with lidar, radiosonde, and satellite over the tropical Indian Ocean during the aerosol-polluted northeast and clean maritime southwest monsoon. J. Geophys. Res., 112, D17205, doi: 10.1029/2006JD008352.

vanZadelhoff, G.-J., A. J. Heymsfield, D.-J. P. Donovan, M. J. McGill, 2007: Evaluating lidar-radar microphysics retrieval using in situ measurements. J. Geophys. Res., 112, D09213, doi: 10.1029/2006JD007202.3

Prenni, A. J., P. J. DeMott, C. Twohy, M. R. Poellot, S. M. Kreidenweis, D. C. Rogers, S. D. Brooks, M. S. Richardson, A. J. Heymsfield, 2007: Examinations of ice formation processes in Florida cumuli using ice nuclei measurements of anvil ice crystal particle residues. J. Geophys. Res., 112, D10221, doi: 10.1029/2006JD007549.

Heymsfield, A. J., C. Schmitt, A. Bansemer, G.-J. vanZadelhoff, M. J. McGill, C. Twohy, D. Baumgardner, 2007: Responses to comments on "Effective radius of ice cloud particle populations derived from aircraft probes" by Heymsfield et al, 2006. J. Atmos. Ocean. Technol., 24, 1511-1518, doi: 10.1175/JTECH2077.1.

Field, P. R., A. J. Heymsfield, A. Bansemer, 2007: Snow size distribution parameterization for midlatitude and tropical ice clouds. J. Atmos. Sci.. (In Press)

Schmitt, C. G., A. J. Heymsfield, 2007: On the occurrence of hollow bullet rosette and column shaped ice crystals in mid-latitude cirrus. J. Atmos. Sci.. (In Press)

Protat, A., D. Bouniol, A. J. Heymsfield, A. Bansemer, P. Brown, 2007: Evaluation of ice water content retrievals from cloud radar reflectivity and temperature using a large airborne in situ microphysical database. J. Appl. Meteor. Climat., 46, 557-572, doi: 10.1175/JAM2488.1.

Baum, B., P. Yang, S. Nasiri, A. K. Heidinger, A. J. Heymsfield, J. Li, 2007: Bulk scattering properties for the remote sensing of ice clouds. Part III: High-resolution spectral models from 100 to 3250 cm-1. J. Appl. Meteor. Climat., 46, 423-434, doi: 10.1175/JAM2473.1.

Heymsfield, A. J., A. Bansemer, C. Twohy, 2007: Refinements to ice particle mass dimensional and terminal velocity relationships for ice clouds: Part I: Temperature dependence. J. Atmos. Sci., 64(4), 1047-1067.

Heymsfield, A. J., A. Bansemer, C. Twohy, 2007: Refinements to ice particle mass dimensional and terminal velocity relationships for ice clouds: Part II: Evaluation and parameterizations of ensemble ice particle sedimentation velocities. J. Atmos. Sci., 64(4), 1068-1088.

vanZadelhoff, G.-J., G. P. Donovan, A. J. Heymsfield, 2007: An effective radius parameterization for ice clouds using cloud thickness. Geophys. Res. Lett.. (Submitted)

Massie, S. T., A. Heymsfield, C. Schmitt, D. Mueller, P. Seifert, 2007: Aerosol indirect effects as a function of cloud top pressure. J. Geophys. Res., 112, D06202, doi: 10.1029/2006JD007383.

Heymsfield, A. J., P. R. Field, A. Bansemer, C. Schmitt, 2007: FSSP ice particle shattering: Relationship to total ice water content and extinction. J. Atmos. Ocean. Technol.. (Submitted)

Comstock, J. M., D. G. Baumgardner, H. Gerber, A. J. Heymsfield, P. Minnis, M. R. Poellot, C. H. Twohy, 2007: Investigation of anvil microphysics and evolution using ground-based, in situ, and satellite measurements during CRYSTAL-FACE. J. Geophys. Res.. (Submitted)

Halverson, J., M. Black, S. Braun, D. Cecil, M. Goodman, A. J. Heymsfield, G. Heymsfield, R. Hood, T. Krishnamurti, G. McFarquhar, M. J. Mahoney, J. Molinari, R. Rogers, J. Turk, C. Velden, D.-L. Zhang, E. Zipser, R. Kahar, 2007: NASA's tropical cloud systems and processes (TCSP) experiment: Investigating tropical cyclogenesis and hurricane intensity change. Bull. Amer. Meteor. Soc.. (Submitted)

Heymsfield, A. J., A. Protat, R. T. Austin, D. Bouniol, R. J. Hogan, J. Delanoe, H. Okamoto, K. Sato, G.-J. vanZadelhoff, D. P. Donovan, Z. Wang, 2007: Testing IWC retrieval methods using radar and ancillary measurements with in-situ data. J. Appl. Meteor. Climat.. (In Press)