Don Lenschow

Senior Scientist
TIIMES - MMM
BEACHON - BGS - UTLS

Contact Information:
PO Box 3000, Boulder, CO 80307-3000
Office: FL3 - 3049
Telephone: 303-497-8903
Email: lenschow@ucar.edu
Home Page

Project Summary:

A Simple Model for Vertical Transport of Reactive Species in the Convective Atmospheric Boundary Layer

Leif Kristensen, David Gurarie and Don Lenschow are jointly developing a model to describe the vertical profiles of trace reactive species concentrations and fluxes in the convective atmospheric boundary layer (CBL).  We have successfully implemented a CBL model that generates profiles of concentrations and fluxes of the NO-NO2-O3 triad.

The model consists of a set of differential equations (ultimately traced back to the Navier-Stokes equations) that incorporate vertical transport by convection (neglecting shear-generated surface-layer turbulence).  The equations are solved by using a relaxation technique implemented with Mathematica after specifying the appropriate boundary conditions at both the surface and the CBL top.

We also initiated work on expanding the model to include VOCs, starting with isoprene, in collaboration with Thomas Karl, Alex Guenther, John Orlando, and Ned Patton. Our goal is to develop a robust and versatile model to describe fluxes and concentrations of trace reactive species throughout the CBL.  One practical application is to be able use the model to estimate surface (and possibly entrainment) fluxes from measurements of a set of fluxes and/or concentrations at several levels in the CBL. Surface fluxes of highly reactive species (reaction time constants of about an hour or less) are needed as boundary conditions in larger-scale models and yet are difficult to measure directly because the reactivity causes departures from Monin-Obukhov and mixed-layer similarity theories, which assume conservation of species.  Another goal, in some cases, may be to estimate species lifetimes within the CBL - particularly when the atmospheric sinks of the species under consideration are not well known.  We plan to continue this work

Additional Comments

Leif Kristensen is now retired from Risoe National Laboratory, but still works there as a consultant.  His research has been in the field of boundary-layer meteorology and theoretical metrology, i.e. analyses of measuring procedures for the turbulent atmosphere. The past ten years his interest has to a large extent been concentrated on chemically active scalars in the atmospheric boundary layer. He has a long history of collaboration with NCAR scientists, beginning in 1979.  From 1983 to 1984 he spent a year at NCAR as a visiting scientist mostly working with Don Lenschow.  He held an Affiliate Scientist  appointment jointly with both MMM and ATD from 1988  to 1993, which included frequent collaborative visits to NCAR.

David Gurarie has been a frequent visitor to NCAR/MMM. In the past five years he has collaborated mainly with Don Lenschow, and also with Ian Faloona (ASP postdoc, now at University of California, Davis) on developing simple models to describe profiles of trace reactive species concentrations and fluxes throughout the atmosphere. He has been a collaborator  with Don Lenschow and Ian Faloona on two proposals submitted to the cross-discipline NSF program Collaborations in Mathematics and Geosciences (CMG) (neither was funded).  His applied mathematics skills are a good complement to the geophysical and chemical expertise at NCAR.

TIIMES External Collaborators:

Wiliam Brune, Pennsylvania State University
Owen Cooper, University of Colorado
James Crawford, Langley Research Center (LARC) - NASA
Joyhn Finnigan, Commonwealth Scientific and Industrial Research Organisation (CSIRO)
Paul Krehbiel, New Mexico Institute of Technology
Siming Liu, Chinese Academy of Sciences
Kenneth Pickering, Goddard Space Flight Center (GSFC) - NASA

Publications:

Lenschow, D. H., J. Sun, 2007: The spectral composition of fluxes and variances over land and sea out to the mesoscale. Bound.-Layer Meteor., 125, 63-84, doi: 10.1007/s10546-007-9191-8.

Gochis, D. J., G. Bonan, E. Brandes, F. Chen, D. Lenschow, M. LeMone, R. Rasmussen, T. T. Warner, M. Ek, K. Mitchell, 2007: A ten-year vision for advancing coupled land-atmosphere prediction. Water Resources Research. (Submitted)

Zhou, M., Z. Zhang, D. H. Lenschow, S. Zhong, H.-M. Hsu, W. Yao, Z. Gao, S. Li, B. Sun, X. Bian, 2007: Properties of the katabatic winds on the eastern Antarctic plateau and its adjacent slopes. Geophys. Res. Lett.. (Submitted)

Rauber, R. M., B. Stevens, H. T. Ochs III, C. Knight, B. A. Albrecht, A. M. Blyth, C. W. Fairall, J. B. Jensen, S. G. Lasher-Trapp, O. L. Mayol-Bracero, G. Vali, J. R. Anderson, B. A. Baker, A. R. Bandy, F. Burnet, J.-L. Brenguier, W. A. Brewer, P. R. A. Brown, P. Chuang, W. R. Cotton, L. Di Girolamo, B. Geert, H. Gerber, S. Goeke, L. Gomes, B. G. Heikes, J. G. Hudson, P. Kollias, R. P. Lawson, P. Jonas, S. K. Krueger, D. H. Lenschow, L. Nuijens, D. W. O'Sullivan, R. A. Rilling, D. C. Rogers, A. P. Siebesma, E. Snodgrass, J. L. Stith, D. C. Thornton, S. Tucker, C. H. Twohy, P. Zuidema, 2007: Rain in (shallow) cumulus over the ocean - the RICO campaign. Bull. Amer. Meteor. Soc.. (In Press)

Lenschow, D. H., V. Savic-Jovcic, B. Stevens, 2007: Divergence and vorticity from aircraft air motion measurements. J. Atmos. Ocean. Technol.. (In Press)

Lothon, M., F. Couvreux, S. Donier, F. Guichard, P. Lacarrere, D. H. Lenschow, J. Noilhan, F. Said, 2007: Impact of coherent eddies on airborne measurements of vertical turbulent fluxes. Bound.-Layer Meteor., 124, 425-447, doi: 10.1007/s10546-007-9182-9.

Sun, J., S. P. Burns, A. C. Delaney, S. P. Oncley, A. A. Turnipseed, B. B. Stephens, D. H. Lenschow, M. A. LeMone, R. K. Monson, D. E. Anderson, 2007: CO2 Transport over Complex Terrain. Agric. For. Meteorol., 145, 1-21, doi: 10.1016/j.agrformet.2007.02.007.

Mayor, S. D., S. M. Spuler, B. M. Morley, S. C. Himmelsbach, R. A. Rilling, T. M. Weckwerth, E. G. Patton, D. H. Lenschow, 2007: Elastic backscatter lidar and in situ observations of sea-breeze fronts in Dixon, California. 7th Conf. on Coastal Atmospheric and Oceanic Prediction and Processes, San Diego, CA, US, AMS.

Lothon, M., D. H. Lenschow, S. Mayor, 2006: Coherence and scale of vertical velocity in the convective boundary layer from a Doppler lidar. Bound.-Layer Meteor., 121, 521-536.

Gao, Z., M. Zhou, D. H. Lenschow, J. Wen, Q. Zeng, L. Wang, 2006: Comparison of two soil temperature algorithms for bare ground soil over the loess plateau in China. J. Appl. Meteor. Climat.. (Submitted)