DRI / DIRECTORY / DAVID MITCHELL
David Mitchell Profile Photo
Dr. David Mitchell
Associate Research Professor Emeritus

Professional Interests

Dr. Mitchell’s research has focused on the following areas: (1) theoretical understanding and modeling of the microphysical evolution within cirrus and frontal clouds, especially with regard to particle size spectra and crystal concentrations; (2) understanding and modeling the radiative properties of ice clouds; (3) remote sensing of cloud properties; (4) understanding and predicting the onset, strength and extent of the North American monsoon; (5) modification of cirrus clouds to reduce global warming.

Accomplishments regarding (1) include the development of two models successfully predicting the evolution of ice particle size spectra. The input for one model consists of the ice water content and temperature profiles, while the other is driven by changes in super-saturation. These models are computationally efficient, utilizing analytical solutions for ice particle growth by vapor diffusion and aggregation, and can be easily used to improve radar estimates of precipitation at ground level.

Regarding (2), the optical properties of ice clouds have been successfully described by parameterizing the absorption and scattering processes and rigorously treating their dependence on cloud microphysics. This treatment, the Modified Anomalous Diffraction Approximation (MADA), was formulated in terms of the size distribution and ice particle shape, and agrees with explicit electrodynamic solutions of ice crystal single scattering properties within 15%. These developments, along with parameterizing the asymmetry parameter for various crystal shapes, have led to a new treatment of ice cloud radiative properties which is used in (i) the Community Atmosphere Model version 5 (CAM5) global climate model (GCM), (ii) in the Colorado State University GCM, (iv) in the Regional Atmospheric Modeling System (RAMS) at CIRES and (v) in the Rapid Radiation Transfer Model (RRTM) and the Paleoclimate version of RRTM developed at Atmospheric and Environmental Research (AER).

Regarding (3), the MADA scheme (noted above) resolves the two main processes responsible for the absorption of thermal radiation in ice particles; Beers law and wave resonance absorption. This led to two satellite retrieval algorithms that have been developed that estimate (1) the ice particle size distribution including the number concentration of small (D < 60 m) ice crystals and (2) the percentage of liquid water relative to the total (ice + liquid) condensate in mixed phase clouds. Method (1) is of value due to the difficulty in measuring small ice crystal concentrations from aircraft (which help determine cirrus cloud optical properties) and method (2) is important since ice cloud optical properties strongly depend on the fraction of liquid water when present. Both methods were the first to retrieve the indicated cloud properties. This improved understanding of thermal radiation absorption by ice has also enabled the satellite retrieval of the N/IWC ratio, where N is ice particle number concentration and IWC is the cloud ice water content. This retrieval may allow us to identify whether cirrus clouds have been primarily formed through homo- or heterogeneous ice nucleation.

Regarding (4), a new approach to understanding the North American monsoon (NAM) has been pursued in terms of sea surface temperatures (SSTs) in the eastern tropical Pacific and the Gulf of California (GC). Results from nine monsoon seasons show that relatively heavy rainfall in Arizona commences once the SST in the northern GC exceeds 29oC. Both observational and modeling research indicates that humid air overlying the GC is trapped by an inversion that breaks when SSTs exceed 29C. Once the marine inversion is removed, the warm SSTs humidify a deep layer of free tropospheric air that can be advected over land to often produce thunderstorms. In addition, this mechanism along with climatological and reanalysis data suggest that NAM convection is initiated in central Mexico through the poleward propagation of warm tropical surface water along the Pacific coast, and that this convection contributes to the poleward propagation of the NAM anticyclone that eventually steers mid-level moisture into the NAM region, augmenting the NAM rainfall.

Regarding (5), it is generally accepted that the mean increase in global surface temperatures (relative to pre-industrial times) should not exceed 2C if mankind is to avoid unacceptable consequences of climate change. Recent research has led some scientists to conclude that exceeding this threshold may be unavoidable unless some type of climate intervention (CI) is invoked to remove CO2 from the atmosphere and/or cool the planet (e.g. by reflecting more sunlight) while simultaneously and very rapidly converting to non-carbon based energy systems. A new type of CI has been proposed, based on the aircraft seeding of the coldest cirrus clouds to reduce their coverage and optical thickness, resulting in a significant global cooling by releasing more thermal radiation to space (instead of reflecting more sunlight). GCM simulations of this approach by others show that it has reduced or no side-effects (e.g. the hydrological cycle and ozone perturbation) relative to the most studied solar radiation management (SRM) CI approach (the injection of sulfate aerosols into the stratosphere to reflect more sunlight). Moreover, this cirrus CI method preferentially cools the Polar Regions where climate change is most severe, which is less easily achieved by the SRM methods.

Research Areas

  • Cloud Microphysics
  • Cloud Radiative Properties (especially ice clouds)
  • Remote Sensing of Cloud Physical Properties
  • Climate Dynamics
  • Large-Scale and Mesoscale Dynamic Meteorology
  • Precipitation Scavenging
  • North American Monsoon Research

 

Education

Degree Year Institution Area
Ph.D.. 1995 University of Nevada, Reno Atmospheric Science
M.S. 1986 University of Nevada, Reno Atmospheric Science
B.Sc. 1981 California Polytechnical State, University, San Luis Obispo Chemistry

Selected Publications

Erfani, E. and D. L. Mitchell, 2015: Developing and bounding ice particle mass- and area-dimension expressions for use in atmospheric models and remote sensing. Atmos. Chem. Phys. Discuss., 15, 2851728573, doi:10.5194/acpd-15-28517-2015.

Erfani, E., and D. L. Mitchell, 2014: A Partial Mechanistic Understanding of the North American Monsoon. J. Geophys. Res. Atmos., 119, 13,09613,115, doi:10.1002/2014JD022038.

Mishra, S., D. L. Mitchell, D. D. Turner and R. P. Lawson, 2014: Parameterization of ice fall speeds in mid-latitude cirrus: Results from SPartICus. J. Geophys. Res. Atmospheres, 119, 3857-3876, doi:10.1002/2013JD020602.

Mitchell, D. L., S. Mishra, and R. P. Lawson, 2011: Representing the ice fall speed in climate models: Results from Tropical Composition, Cloud and Climate Coupling (TC4) and the Indirect and Semi-Direct Aerosol Campaign (ISDAC), J. Geophys. Res., 116, D00T03, doi:10.1029/2010JD015433.

Mitchell, D.L., R.P. Lawson, and B. Baker, 2011: Understanding effective diameter and its application to terrestrial radiation in ice clouds. Atmos. Chem. Phys., 11, 3417-3429, doi:10.5194/acp-11-3417-2011.

Mitchell, D. L., and R. P. dEntremont, 2012: Satellite retrieval of the liquid water fraction in tropical clouds between -20 and -38C. Atmos. Meas. Tech. Discuss., 4, 1-42, doi:10.5194/amtd-4-1-2011.

Gettelman, A., X. Liu, S.J. Ghan, H. Morrison, S. Park, A.J. Conley, S.A. Klein, J. Boyle, D.L. Mitchell, and J.-L.F. Li, 2010: Global simulations of ice nucleation and ice supersaturation with an improved cloud scheme in the Community Atmosphere Model. J. Geophys. Res., 115, D18216, doi:10.1029/2009JD013797.

Mitchell, D.L., R.P. D’Entremont, and R.P. Lawson, 2010: Inferring cirrus size distributions through satellite remote sensing and microphysical databases. J. Atmos. Sci., 67, 1106-1125, doi:10.1175/2009JAS3150.1.

Mitchell, D.L. and W. Finnegan, 2009: Modification of cirrus clouds to reduce global warming. Environ. Res. Lett., 4, 045102 (8 pp), doi:10.1088/1748-9326/4/4/045102.

Mitchell, D.L., P.J. Rasch, D. Ivanova, G.M. McFarquhar, T. Nousiainen, 2008: Impact of small ice crystal assumptions on ice sedimentation rates in cirrus clouds and GCM simulations.Geophys. Res. Lett.,35,doi:10.1029/2008GL033552.

Mishra, S., D.L. Mitchell, and D. DeSlover, 2008: Ground based retrievals of small ice crystals and water phase in Arctic cirrus. American Institute of Physics (AIP), Proceedings of theInternational Radiation Symposium,Foz do Iguassu, Brazil, 3-8 August 2008.

Mitchell, D.L., and R.P. dEntremont, 2008: Satellite remote sensing of small ice crystal concentrations in cirrus clouds. American Institute of Physics (AIP), Proceedings of theInternational Radiation Symposium, Foz do Iguassu, Brazil, 3-8 August 2008.

Mitchell, D.L., A.J. Brown, W.P. Arnott, and C. Schmitt, 2006: Testing and comparing the modified anomalous diffraction approximation. J. Atmos. Sci., 63, 2948-2962.

Mitchell, D.L., A. Huggins and V. Grubisic, 2006: A new snow growth model with application to radar precipitation estimates. Atmos. Res., 82, 2-18.

Mitchell, D.L. and A.J. Heymsfield, 2005: Refinements in the treatment of ice particle terminal velocities, highlighting aggregates. J. Atmos. Sci., 62, 1637-1644.

Mitchell, D.L., R.P. d’Entremont, D.H. DeSlover, and W.P. Arnott, 2003: Multispectral thermal retrievals of size distribution shape, effective size, ice water path, optical depth and photon tunneling contribution. 12th Conf. on Satellite Meteorology and Oceanography, AMS Annual Meeting, Long Beach , California, 9-13 Feb. 2003.

Mitchell, D.L., 2002: Effective diameter in radiation transfer: General definition, applications and limitations. J. Atmos. Sci., 59, 2330-2346.

Mitchell, D.L., D. Ivanova, R. Rabin, K. Redmond, and T.J. Brown, 2002: Gulf of California sea surface temperatures and the North American monsoon: Mechanistic implications from observations. J. Climate, 15, 2261-2281.

Ivanova, D.C., D.L. Mitchell, W. Patrick Arnott and M. Poellot, 2001: A GCM parameterization for bimodal size spectra and ice mass removal rates in mid-latitude cirrus clouds.Atmos. Res., 59, 89-113.

Mitchell, D.L., 2000: Parameterization of the Mie extinction and absorption coefficients for water clouds. J. Atmos. Sci., 57, 1311-1326.

Mitchell, D.L., 1996: Use of mass- and area-dimensional power laws for determining precipitation particle terminal velocities. J. Atmos. Sci., 53, 1710-1723.

Mitchell, D.L., A. Macke, and Y. Liu, 1996: Modeling cirrus clouds. Part II: Treatment of radiative properties. J. Atmos. Sci., 53, 2967-2988.

Mitchell, D.L., 1994: A model predicting the evolution of ice particle size spectra and the radiative properties of cirrus clouds. Part I: Microphysics. J. Atmos. Sci., 51, 797-816.

Mitchell, D.L. and W.P. Arnott, 1994: A model predicting the evolution of ice particle size spectra and the radiative properties of cirrus clouds. Part II: Dependence of absorption and extinction on ice crystal morphology. J. Atmos. Sci., 51, 817-832.

Book Reviews and Book Chapters

Mitchell, D. L., 2011: Book review of Geo-engineering Climate Change: Environmental Necessity or Pandoras Box?, Brian Launder and J. Michael T. Thompson (Eds.), 2010, 332 pp., Cambridge Univ. Press, ISBN 978-0-521-19803-5. Bull. Amer. Meteorol. Soc., 92, 1503-1504.

Mitchell, D. L., S. Mishra and R. P. Lawson, 2011:Cirrus clouds and climate engineering: New findings on ice nucleation and theoretical basis.In: Planet Earth 2011 – Global Warming Challenges and Opportunities for Policy and Practice, Prof. Elias Carayannis (Ed.), ISBN 978-953-307-733-8, InTech, Available from

Keywords

cloud microphysics, cirrus clouds, cloud optical properties, remote sensing, climate engineering, global climate modeling, climate change, North American monsoon

 

Program(s)

 

Publications
2020
Shan, Y., Wilcox, E.M., Gao, L., Lin, L., Mitchell, D. L., Yin, Y., Zhang, L., Shi, H., Gao, M. (2020). Evaluating errors in gamma function representations of the rain drop size distribution: A method for determining the optimal parameter set for use in bulk microphysics schemes, J. Atmos. Sci., 77 (2), 513-529, American Meteorological Society, 10.1175/JAS-D-18-0259.1

Mitchell, D. L., Mejia, J. F., Garnier, A., Tomii, Y., Krämer, M., Hosseinpour, F. E. (2020). An Estimate of Global, Regional and Seasonal Cirrus Cloud Radiative Effects Contributed by Homogeneous Ice Nucleation, Atmos. Chem. Phys. Discuss., Preprint. 10.5194/acp-2020-846

2018
Mitchell, D. L., Garnier, A., Pelon, J., Erfani, E. (2018). CALIPSO (IIR-CALIOP) retrievals of cirrus cloud ice particle concentrations, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2018-526

Mitchell, D. L., Garnier, A., Pelon, J., Erfani, E. (2018). CALIPSO (IIR-CALIOP) retrievals of cirrus cloud ice-particle concentrations, Atmos. Chem. Phys., 18, 17325-17354, 10.5194/acp-18-17325-2018

Penner, J., Zhou, C., Garnier, A., Mitchell, D. L. (2018). Anthropogenic aerosol indirect effects in cirrus clouds, J. Geophys. Res., 123 (20), 11,652-11,677, 10.1029/2018JD029204

2017
Eidhammer, T., Morrison, H., Mitchell, D. L., Gettelman, A., Erfani, E. (2017). Improvements in Global Climate Model Microphysics Using a Consistent Representation of Ice Particle Properties, J. Climate, 30 (2), 609-629, 10.1175/JCLI-D-16-0050.1

Erfani, E., Mitchell, D. L. (2017). Growth of ice particle mass and projected area during riming, Atmos. Chem. Phys., 17 (2), 1241-1257, 10.5194/acp-17-1241-2017

2016
Erfani, E., Mitchell, D. L. (2016). Developing and Bounding Ice Particle Mass- and Area-Dimension Expressions for Use in Atmospheric Models and Remote Sensing, Atmos. Chem. Phys., 16, 4379-4400, https://doi.org/10.5194/acp-16-4379-2016

Mlawer, E. J., Iacono, M. J., Pincus, R., Barker, H. W., Oreopoulos, L., Mitchell, D. L. (2016). Contributions of the ARM Program to Radiative Transfer Modeling for Climate and Weather Applications, In The Atmospheric Radiation Measurement (ARM) Program: The First 20 Years, Meteor. Monogr. No. 57, 10.1175/AMSMONOGRAPHS-D-15-0041.1

Mitchell, D. L., Garnier, A., Avery, M., Erfani, E. (2016). CALIPSO Observations of the Dependence of Homo- and Heterogeneous Ice Nucleation in Cirrus Clouds on Latitude, Season and Surface Condition, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2016-1062

2015
Erfani, E., Mitchell, D. L. (2015). Developing and bounding ice particle mass- and area-dimension expressions for use in atmospheric models and remote sensing, Atmos. Chem. Phys. Discuss., 15, 2828517-28573, https://doi.org/10.5194/acpd-15-28517-2015

2014
Mishra, S., Mitchell, D. L., Turner, D. D., Lawson, R. P. (2014). Parameterization of ice fall speeds in mid-latitude cirrus: Results from SPartICus, J. Geophys. Res., 119, 3857-3876, 10.1002/2013JD020602

Erfani, E., Mitchell, D. L. (2014). A Partial Mechanistic Understanding of the North American Monsoon, J. Geophys. Res., 119, 13,096–13,115, 10.1002/2014JD022038

2013
Zhang, K., Liu, X., Wang, M., Comstock, J. M., Mitchell, D. L., Mishra, S., Mace, G. (2013). Evaluating and constraining ice cloud parameterization in CAM5 using aircraft measurements from the SPARTICUS campaign, Atmos. Chem. Phys. Discuss., 13, 1201-1246

2012
Liu, X., Easter, C., Ghan, S. J., Zaveri, R., Rasch, P., Shi, X., Lamarque, J. F., Gettelman, A., Morrison, H., Vitt, F., Conley, A., Park, S., Neale, R., Hannay, C., Ekman, A., Hess, P., Mahowald, N., Collins, W., Iacono, M. J., Bretherton, C. S., Flanner, M. G., Mitchell, D. L. (2012). Toward a minimal representation of aerosols in climate models: Description and evaluation in the Community Atmospheric Model CAM5, Geosci. Model Develop., 5 (3), 709-739

Mitchell, D. L., d’Entremont, R. P. (2012). Satellite retrieval of the liquid water fraction in tropical clouds between &#8722;20 and &#8722;38 C, Atmos. Meas. Tech., 5 (7), 1683-1698
http://www.atmos-meas-tech.net/5/1683/2012/amt-5-1683-2012.pdf

2011
Casalegno, D., Carayannis, P. (Eds.) Mitchell, D. L., Mishra, S., Lawson, R. P. (2011). Cirrus clouds and climate engineering: New findings on ice nucleation and theoretical basisCirrus clouds and climate engineering: New findings on ice nucleation and theoretical basis, In Global Warming

Mishra, S., Mitchell, D. L., Lawson, R. P. (2011). Representing the ice fall speed in climate models: Results from Tropical Composition, Cloud and Climate Coupling (TC4) and the Indirect and Semi-Direct Aerosol Campaign (ISDAC), J Geophys Res, 116 (D1), 10.1029/2010JD015433

Mitchell, D. L., d’Entremont, R. P. (2011). Satellite Retrieval of Percent Liquid Water in Tropical Clouds Between -20 [deg] and -38 [degC]. Hyperspectral Imaging and Sensing of the Environment (HISE), Technical Digest, Optical Society of America

Mitchell, D. L., Lawson, R. P., Baker, B. (2011). Understanding effective diameter and its application to terrestrial radiation in ice clouds, Atmos Chem Phys, 11, 3417-3429, 10.5194/acp-11-3417-2011

2010
Gettelman, A., Liu, X., Ghan, S. J., Morrison, H., Park, S., Conley, A. J., Klein, S. A., Boyle, J., Mitchell, D. L., Li, J. F. (2010). Global simulations of ice nucleation and ice supersaturation with an improved cloud scheme in the Community Atmosphere Model, J Geophys Res, 115, 10.1029/2009JD013797

Lawson, R. P., Jensen, E. J., Mitchell, D. L., Baker, B., Mo, Q., Pilson, B. (2010). Microphysical and Radiative Properties of Tropical Clouds Investigated in TC4 and NAMMA, J Geophys Res, 115, 10.1029/2009JD013017

Mitchell, D. L., d’Entremont, R. P., Lawson, R. P. (2010). Inferring Cirrus Size Distributions through Satellite Remote Sensing and Microphysical Databases, J Atmos Sci, 67, 1106-1125, 10.1175/2009JAS3150.1

Mitchell, D. L., Lawson, R. P., Baker, B. (2010). Understanding effective diameter and its application to terrestrial radiation in ice clouds, Atmos Chem Phys Discuss, 10, 29405-29447, 10.5194/acpd-10-29405-2010

2009
Mitchell, D. L., Finnegan, W. G. (2009). Modification of cirrus clouds to reduce global warming, Environ Res Lett, 4, 10.1088/1748-9326/4/4/045102

Mitchell, D. L., d’Entremont, R. P., Lawson, R. P. (2009). Inferring cirrus size distributions through satellite remote sensing and microphysical databases, J Atmos Sci, 67, 1106-1125, 10.1175/2009JAS3150.1

2008
Mitchell, D. L., Rasch, P. J., Ivanova, D., McFarquhar, G. M., Nousiainen, T. (2008). Impact of small ice crystal assumptions on ice sedimentation rates in cirrus clouds and GCM simulations, Geophys. Res. Lett., 35, 10.1029/2008GL033552

2007
Comstock, J. M., d’Entremont, R., DeSlover, D., Mace, G. G., Matrosov, S. Y., McFarlane, S. A., Minnis, P., Mitchell, D. L., Sassen, K., Shupe, M. D., Turner, D. D., Wang, Z. (2007). An intercomparison of microphysical retrieval algorithms for upper-tropospheric ice clouds, Bull. Amer. Meteorol. Soc., 88 (2), 191-+

2006
Mitchell, D. L., Huggins, A. W., Grubisic, V. (2006). A new snow growth model with application to radar precipitation estimates, Atmos Res, 82, 2-18

Mitchell, D. L., Baran, A. J., Arnott, W. P., Schmitt, C. G. (2006). Testing and comparing the modified anomalous diffraction approximation, J Atmos Sci, 63, 2948-2962

2005
Mitchell, D. L., Heymsfield, A. J. (2005). Refinements in the Treatment of Ice Particle Terminal Velocities, Highlighting Aggregates, J. Atmos. Sci., 62, 1637-1644

Mitchell, D. L., Heymsfield, A. J. (2005). Refinements in the treatment of ice particle terminal velocities, highlighting aggregates, J Atmos Sci, 62, 1637-1644

2003
Iacobellis, S. F., McFarquhar, G. M., Mitchell, D. L., Somerville, R. C. (2003). On the sensitivity of radiative fluxes to parameterized cloud microphysics, J. Climate, 16, 2979-2996

Radel, G., Stubenrauch, C. J., Holz, R., Mitchell, D. L. (2003). Retrieval of effective ice crystal size in the infrared: Sensitivity study and global measurements from TIROS-N Operational Vertical Sounder, J. Geophys. Res. Atmos., 108 (D9), Article No. 4281, 10.1029/2002JD002801

2002
Mitchell, D. L. (2002). Effective diameter in radiation transfer: General definition, applications and limitations, J. Atmos. Sci., 59 , 2330-2346

Mitchell, D. L., Ivanova, D., Rabin, R., Brown, T. J., Redmond, K. T. (2002). Gulf of California Sea Surface Temperatures and the North American Monsoon: Mechanistic Implications from Observations, J. Climate, 15 (17), 2261-2281

Mitchell, D. L., d’Entremont, R. P., DeSlover, D. H., Arnott, W. P. (2002). Remote Sensing Answers for Ice Cloud Questions, Bull. Amer. Meteor. Soc., 83, 845-846

2001
Ivanova, D., Mitchell, D. L., Arnott, W. P., Poellot, M. (2001). A GCM parameterization for bimodal size spectra and ice mass removal rates in mid-latitude cirrus clouds, Atmos. Res., 59-60, 89-113

Mitchell, D. L., Arnott, W. P., Schmitt, C., Baran, A. J., Havermann, S., Fu, Q. (2001). Photon tunneling contributions to extinction for laboratory grown hexagonal columns, J. Quant. Spectroscopy & Radiative Transfer, 70, 761-776

2000
Kristjansson, J. E., Edwards, J. M., Mitchell, D. L. (2000). The impact of a new scheme for the optical properties of ice crystals on the climates of two GCMs, J. Geophys. Res., 105, 10,063-10,079

Yang, P., Liou, K. N., Wyser, K., Mitchell, D. L. (2000). Parameterization of the scattering and absorption properties of individual ice crystals, J. Geophys. Res., 105, 4699-4718

Borys, R. D., Lowenthal, D. H., Mitchell, D. L. (2000). The relationships among cloud microphysics, chemistry, and precipitation rate in cold mountain clouds, Atmos. Environ., 34, 2593-2602

Mitchell, D. L. (2000). Parameterization of the Mie Extinction and Absorption Coefficients for Water Clouds, J. Atmos. Sci., 57, 1311-1326

1999
Baran, A. J., Brown, S. J., Foot, J. S., Mitchell, D. L. (1999). Retrieval of tropical cirrus thermal optical depth, crystal size and shape using a dual-view instrument at 3.7 and 10.8 um, J. Atmos. Sci., 56, 92-110

Macke, A., Mitchell, D. L., Bremen, L. V. (1999). Monte Carlo radiative transfer calculations for inhomogeneous mixed phase clouds, Phys. Chem. Earth (B), 24 (3), 237-241

Kristjansson, J. E., Edwards, J. M., Mitchell, D. L. (1999). A new parameterization scheme for the optical properties of ice crystals for use in general circulation models of the atmosphere, Phys. Chem. Earth (B), 24, 231-236

1998
Baran, A. J., Foot, J. S., Mitchell, D. L. (1998). The question of ice crystal absorption: A comparison between T-matrix, Mie and anomalous diffraction theory and implications for remote sensing, Appl. Opt., 37, 2207-2215

Conference Proceedings
2022
Dmitruk, G., Garnier, A., Mitchell, D. L. (2022). Reigniting CCT: Satellite Retrieval-Model Integration, Gordon Research Conference on Climate Engineering: Sunday River, Maine, June 26, 2022-July 1, 2022

Mitchell, D. L., Mejia, J. F., Garnier, A. (2022). How realistic are explicit CCT simulations in climate models?, Gordon Research Conference on Climate Engineering: Sunday River, Maine, June 26, 2022-July 1, 2022

Mitchell, D. L., Ivanova, D., Simpson, R., Arnold, R. (2022). Lower Colorado River Basin issues: modeling of region. Can precipitation in the Colorado Basin be increased? Conference titled ?Increasing the Water Supply in the Colorado Basin?, sponsored by the International Water Holdings Corp. (IWH) in conjunction with American Ground Water Trust (AGWT): Las Vegas, NV, July 20, 2022-July 21, 2022

Mitchell, D. L., Garnier, A., Mejia, J. F. (2022). Evidence of relatively high contributions of homogeneous ice nucleation over land during winter at mid-to-high latitudes, with comparisons against global climate model predictions, AMS Collective Madison Meeting, 16th Conference on Cloud Physics: Madison, WI, August 8, 2022-August 12, 2022

Mitchell, D. L., Garnier, A. (2022). An improved CALIPSO (IIR-CALIOP) cirrus cloud retrieval of ice particle number concentration, effective size and ice water content with observations relevant to extreme weather, AMS Collective Madison Meeting, 17th Conference on Polar Meteorology and Oceanography: Madison, WI, August 8, 2022-August 12, 2022

Mitchell, D. L., Garnier, A. (2022). A Reformulated CALIPSO (IIR-CALIOP) retrieval for cirrus cloud ice particle number concentration, effective diameter, and ice water content, NASA CloudSat-CALIPSO Science Team Meeting: Fort Collins, CO, September 12, 2022-September 14, 2022

2021
Mitchell, D. L., Mejia, J. F., Garnier, A. (2021). How realistic are explicit CCT simulations in climate models?, Climate Engineering in Context Conference: Potsdam, Germany, October 4, 2021-October 8, 2021

2020
Tomii, Y., Hosseinpour, F. E., Mejia, J. F., Mitchell, D. L. (2020). An evaluation of cirrus cloud thinning through improved integration of satellite retrievals and climate modeling, American Meteorological Society Annual Meeting (100th anniversary): Boston, MA, January 12, 2020-January 17, 2020

Mitchell, D. L., Mejia, J. F., Tomii, Y., Hosseinpour, F. E. (2020). Combining measurements by satellite and aircraft with climate modeling to evaluate the efficacy of cirrus cloud thinning, American Geophysical Union Fall Meeting: [Virtual]

2019
Mitchell, D. L., Mejia, J. F., Tomii, Y., Garnier, A. (2019). On the potential role of Arctic cirrus clouds in producing anomalous mid-latitude weather and climate, CESM Atmosphere Model Working Group (AMWG) Meeting, National Center for Atmospheric Research (NCAR): Boulder, CO, February 19, 2019-February 21, 2019

Mitchell, D. L., Tomii, Y., Mejia, J. F., Garnier, A. (2019). Constraining WACCM6 cirrus cloud microphysics with CALIPSO (IIR-CALIOP) effective diameter retrievals, American Geophysical Union Fall Meeting: San Francisco, CA, December 9, 2019-December 13, 2019

Mitchell, D. L., Mejia, J. F., Tomii, Y., Hosseinpour, F. E. (2019). Evaluating cirrus cloud thinning using CALIPSO retrievals and the Whole Atmosphere Community Climate Model v. 6, Invited presentation, Geoengineering Modeling Research Consortium (GMRC), Harvard University, School of Engineering and Applied Sciences (SEAS): Cambridge, MA, September 30, 2019

2018
Mitchell, D. L., Mejia, J. F., Garnier, A., Erfani, E. (2018). On the feasibility of cirrus cloud thinning (CCT): A surprising coincidence, 98th AMS Annual Meeting, 21st Conference on Planned and Inadvertent Weather Modification, joint session with Aerosol-Cloud-Climate Interactions on Climate Engineering and Inadvertent Weather Modification: Austin, TX, January 7, 2018-January 11, 2018

Mitchell, D. L., Mejia, J. F., Garnier, A., Hosseinpour, F. E. (2018). Comparing standard CAM5 against “CALIPSO Cirrus CAM5” and the need for a better cirrus cloud parameterization, CESM Atmosphere Model Working Group (AMWG) Annual Meeting, National Center for Atmospheric Research: Boulder, CO, February 12, 2018-February 14, 2018

Mitchell, D. L., Mejia, J. F., Garnier, A., Hosseinpour, F. E. (2018). Can changes in cirrus cloud ice nucleation affect the jet stream and storm track?, Atmospheric Radiation Conference, American Meteorological Society: Vancouver, BC, Canada, July 9, 2018-July 13, 2018

Mitchell, D. L., Mejia, J. F., Garnier, A., Hosseinpour, F. E. (2018). On the Potential Role of Arctic Cirrus Clouds in Predicting Anomalous Mid-Latitude Weather and Climate, American Geophysical Union Fall Meeting: Washington, DC, December 10, 2018-December 14, 2018

2017
Mitchell, D. L., Mejia, J. F., Garnier, A., Avery, M. (2017). A potential radiative forcing error from the cirrus cloud pre-existing ice assumption, CESM Atmosphere Model Working Group (AMWG) Annual Meeting: National Center for Atmospheric Research, February 27, 2017-March 1, 2017

Mitchell, D. L., Garnier, A., Mejia, J. F., Avery, M. (2017). The seasonal cycle of Arctic cirrus clouds and its possible relevance to jet steam dynamics, Fourth Santa Fe Conference on Global and Regional Climate Change: Santa Fe, NM, February 5, 2017-February 10, 2017

Mitchell, D. L., Garnier, A., Avery, M., Erfani, E. (2017). The latitude and seasonal dependence of cirrus cloud occurrence frequency and formation mechanism, and their potential impact on jet steam dynamics, A-Train Symposium: Pasadena, CA, April 19, 2017-April 21, 2017

Mitchell, D. L., Mejia, J. F., Garnier, A., Hosseinpour, F. E., Avery, M. A. (2017). A potential regulation of jet stream behavior by changes in Arctic cirrus cloud formation mechanism and coverage, Session Proposal: A54G The Dynamics of the Large-Scale Atmospheric Circulation in Present and Future Climates: Jet Streams, Storm Tracks, Stationary Waves, and Monsoons III, American Geophysical Union Fall Meeting: New Orleans, LA, December 11, 2017-December 15, 2017

2016
Mitchell, D. L., Garnier, A., Avery, M., Erfani, E. (2016). Insights on the Feasibility, Modeling and Field Testing of Cirrus Cloud Thinning from Satellite Remote Sensing [invited talk], Sixth GeoMIP Meeting: Norwegian Meteorological Institute, Oslo, Norway, June 21, 2016-June 22, 2016

Mitchell, D. L., Garnier, A., Avery, M., Erfani, E. (2016). The Dependence of Cirrus Cloud Formation Mechanism on Latitude, Season and Surface Type, International Conference on Clouds and Precipitation: Manchester, UK, July 25, 2016-July 29, 2016

Mitchell, D. L., Garnier, A., Avery, M., Erfani, E. (2016). The Dependence of Homo- and Heterogeneously Formed Cirrus Clouds on Latitude, Season and Surface-Type Based on a New CALIPSO Remote Sensing Method [invited talk], AGU Fall Meeting: San Francisco, CA, December 12, 2016-December 16, 2016

Mitchell, D. L., Garnier, A., Mejia, J. F., Avery, M. A., Erfani, E. (2016). Insights on the Feasibility, Modeling and Field Testing of Cirrus Cloud Thinning from Satellite Remote Sensing, Poster, AGU Fall Meeting: San Francisco, CA, December 12, 2016-December 16, 2016

Erfani, E., Mitchell, D. L., Eidhammer, T., Morrison, H., Gettelman, A. (2016). Improving the microphysical characteristics in CAM, Annual CESM Workshop: Breckenridge, CO, 20-23 Jun. 2016

2015
Mitchell, D. L. (2015). On the ethics of climate engineering: An overlooked question?, Joint session on Human Alternation of Climate: Engineering, Ethics, and Politics, 95th AMS Annual Meeting, 20th Conference on Planned and Inadvertent Weather Modification, and the Seventh Symposium on Aerosol: Phoenix, AZ, January 5, 2015
Oral presentation recorded at: https://ams.confex.com/ams/95Annual/videogateway.cgi/id/29788?recordingid=29788

Mitchell, D. L., Avery, M. A., Garnier, A. (2015). Inferred Differences in Ice Crystal Nucleation Rates between Continental and Maritime Deep Convective Clouds., Joint session on Human Alternation of Climate: Engineering, Ethics, and Politics, 95th AMS Annual Meeting and Seventh Symposium on Aerosol, Cloud, Climate Interactions: Phoenix, AZ, January 7, 2015

Erfani, E., Mitchell, D. L. (2015). Evolution of Snow-sized Spectra by the Growth Processes of Vapor Deposition, Aggregation and Riming, Paper, 95th AMS Annual Meeting: Phoenix, AZ, January 5, 2015

Ivanova, D., Mitchell, D. L. (2015). WRF and MM5 Modeling of the 1999 North American Monsoon Onset and the Las Vegas Flood, Paper, 95th AMS Annual Meeting: Phoenix, AZ, January 7, 2015

Mitchell, D. L., Garnier, A., Avery, M. (2015). Evidence of More Frequent Homogeneous Ice Nucleation During Arctic Winter, ASR Annual Meeting: Vienna, VA, March 16, 2015

Mitchell, D. L., Garnier, A., Avery, M. (2015). New Physical Understanding of Satellite Retrieved Effective Absorption Optical Depth Ratios, ASR Annual Meeting: Vienna, VA, March 16, 2015

Erfani, E., Mitchell, D. L. (2015). Progress in representing microphysical processes in a mixed-phase snow growth model, International Union of Geophysics and Geodesy (IUGG), 26th IUGG General Assembly: Prague, Czech Republic, June 22, 2015-July 2, 2015

Erfani, E., Mitchell, D. L., Avery, M. (2015). A partial mechanistic understanding of the North American monsoon, International Union of Geophysics and Geodesy (IUGG), 26th IUGG General Assembly: Prague, Czech Republic, June 22, 2015-July 2, 2015

Erfani, E., Mitchell, D. L., Avery, M. (2015). The role of coastal mid-latitude air-sea interactions in exporting tropical energy to N. America during summer, International Union of Geophysics and Geodesy (IUGG), 26th IUGG General Assembly: Prague, Czech Republic, June 22, 2015-July 2, 2015

Mitchell, D. L., Garnier, A., Avery, M. (2015). On the feasibility of cirrus cloud thinning: Dependence of homo- and heterogeneous ice nucleation as a function of latitude and season, Climate engineering: new insights from (Solar) Radiation Management studies, European Geosciences Union General Assembly: Vienna, Austria, April 12, 2015

Mitchell, D. L., Garnier, A., Avery, M. (2015). The seasonal dependence of climate on high latitude cirrus clouds, International Union of Geophysics and Geodesy (IUGG), 26th IUGG General Assembly: Prague, Czech Republic, June 22, 2015-July 2, 2015

Mitchell, D. L. (2015). What do the models need to get right?, Invited talk, Panelist. 3rd Annual Regional Climate and Meteorology Meeting for Northwest Mexico and the Southwest U.S.: Centro de Ciencias de la Atmósfera, UNAM, Mexico City, June 4, 2015

Mitchell, D. L., Erfani, E., Ivanova, D., Avery, M. (2015). Observational and Modeling Evidence for both Local- and Large-scale NAM Mechanisms, Invited talk. 3rd Annual Regional Climate and Meteorology Meeting for Northwest Mexico and the Southwest U.S.: Centro de Ciencias de la Atmósfera, UNAM, Mexico City, June 4, 2015

Mitchell, D. L., Garnier, A., Avery, M., Erfani, E. (2015). Satellite remote sensing of the dependence of homogeneous ice nucleation on latitude and season, 2015 AGU Fall Meeting: San Francisco, CA, December 14, 2015

Mitchell, D. L., Garnier, A., Avery, M. (2015). Cirrus cloud thinning: Do the right conditions exist, and how can it be tested with observations?, Our Common Future Under Climate Change International Scientific Conference: Paris, France, July 7, 2015

2014
Erfani, E., Mitchell, D. L. (2014). Mechanisms for the onset and evolution of North American monsoon, Proceedings, Climate Prediction S&T Digest (February 2014), pp. 13-15, 38th NOAA Climate Diagnostics and Prediction Workshop Special Issue, Climate Prediction S & T Digest, NWS Science & Technology Infusion Climate Bulletin Supplement: College Park, MD, October 21, 2013

Mitchell, D. L., Erfani, E. (2014). Parameterizing Ice Particle Mass and Area in Ice Clouds: Towards a Self-consistent Treatment of Ice Microphysics and Radiation, Atmospheric Model Working Group, NCAR: Boulder, CO, February 10, 2014

Mitchell, D. L., Erfani, E., Mishra, S. (2014). Developing and bounding ice particle mass- and area-dimensional expressions for use in atmospheric models and remote sensing, ASR Annual Meeting: Potomac, MD, March 10, 2014

Mitchell, D. L. (2014). Globally mapping regions of homo- and heterogenous nucleation as a function of latitude and season: A potential strategy using CALIPSO, ASR Annual Meeting: Potomac, MD, March 10, 2014

Mitchell, D. L. (2014). An overview of cirrus cloud thinning and determining its scientific feasibility, Invited talk. Climate Engineering Conference 2014, Critical Global Discussions: Berlin, Germany, August 18, 2014

Erfani, E., Mitchell, D. L. (2014). Improving a Snow Growth Model with Application to Radar Quantitative Precipitation Estimates, AMS Conference on Cloud Physics: Boston, MA, July 6, 2014

Mitchell, D. L., Avery, M. A., Garnier, A. (2014). Inferred Differences in Ice Crystal Nucleation Rates between Continental and Maritime Deep Convective Clouds, Presentation, 2014 AGU Fall Meeting: San Francisco, CA, December 15, 2014

Mitchell, D. L. (2014). Evolution of the North American monsoon: Potential large- and small-scale mechanism, Invited talk, Pennsylvania State University, Dept. of Meteorology seminar series: University Park, PA, December 10, 2014

Mitchell, D. L., Erfani, E. (2014). Ice particle mass- and area-dimensional expressions for cirrus clouds: A proposed strategy, ASR Annual Meeting: Potomac, MD, March 10, 2014

Mitchell, D. L., Mishra, S., Comstock, J., Lohmann, U., Kuebbeler, M., Mejia, J. F., Turner, D., Rasch, P. (2014). Relevance of the negative Twomey effect for cirrus clouds, 94th Annual Meeting of the American Meteorological Society: Atlanta, GA, February 6, 2015

2013
Mitchell, D. L., Mejia, J. F., Kuebbeler, M., Lohmann, U., Xiao, M. (2013). Seeding of Cirrus Clouds to Reduce Global Warming, Applications of Numerical Models to Weather and Climate Modification,, 19th Conference on Planned and Inadvertent Weather Modification, 93rd American Meteorological Society Annual Meeting: Austin, TX, January 6, 2013

Erfani, E., Mitchell, D. L., Ivanova, D. (2013). A Mechanism for the Impact of Gulf of California Sea Surface Temperature on North American Monsoon, Poster presentation, Atmospheric System Research (ASR) 2013 Science Team Meeting: Potomac, MD, March 18, 2013

Erfani, E., Mitchell, D. L., Ivanova, D. (2013). North American Monsoon: Progress Toward a Mechanistic Understanding, Poster presentation, 18th Annual CESM Workshop: Breckenridge, CO, June 17, 2013

Erfani, E., Mitchell, D. L., Ivanova, D. (2013). Mechanisms Governing the Onset, Extent and Strength of the North American Monsoon, Poster presentation, 14th Annual WRF Workshop: Boulder, CO, June 24, 2013

Erfani, E., Mitchell, D. L., Ivanova, D. (2013). Toward a Mechanistic Understanding of the Onset and Extent of the North American Monsoon, Poster presentation, Gordon Research Conference and Gordon Research Seminar on Radiation and Climat: New London, NH, July 6, 2013

Erfani, E., Mitchell, D. L. (2013). Mechanisms for the onset and evolution of North American monsoon, 38th NOAA Climate Diagnostics and Prediction Workshop Special Issue, Climate Prediction S & T Digest, NWS Science & Technology Infusion Climate Bulletin Suppleme: College Park, MD, October 21, 2013

Erfani, E., Mitchell, D. L. (2013). Air-sea interaction in the Gulf of California and its effect on the North American Monsoon, Oral presentation, Atmospheric System Research (ASR) 2013 Fall Meeting: Rockville, MD, November 4, 2013

Erfani, E., Mitchell, D. L., Ivanova, D., Lavin, M. (2013). Partial validation of the onset mechanism for the North American monsoon, Poster presentation, AGU Fall Meeting: San Francisco, CA, December 9, 2013

Mitchell, D. L., Mejia, J. F., Lohmann, U., Kuebbeler, M., Mishra, S., Comstock, J., Rasch, P. (2013). Microphysical and radiative impacts of the cirrus cloud negative Twomey effect in two GCMs based on SPARTICUS data, Oral presentation, Atmospheric System Research (ASR) 2013 Fall Working Groups,: Washington, D.C., November 4, 2013

Mitchell, D. L., Mejia, J. F., Kuebbeler, M., Xiao, M., Rasch, P. (2013). Cirrus Cloud Climate Engineering, Oral presentation at the AMS Annual Meeting: Austin, TX, January 6, 2013

Mitchell, D. L., Lance, S., Lawson, R. P. (2013). Improving the Ice Optics in CAM5: Treatment of the Asymmetry Parameter, Oral presentation, Atmosphere Model Working Group, NCAR: Boulder, CO, February 10, 2013

Mitchell, D. L., Mishra, S., Comstock, J., Mejia, J. F., Kuebbeler, M., Lohmann, U. (2013). Relevance of the negative Twomey effect for ice clouds, Poster presentation, Gordon Research Conference: Radiation and Climate: New London, NH, July 6, 2013

Mitchell, D. L., Mejia, J. F., Kuebbeler, M., Lohmann, U., Mishra, S., Comstock, J. (2013). Constraining the Negative Twomey Effect for Cirrus Clouds, Poster presentation, Gordon Research Conference: Radiation and Climate: New London, NH, July 6, 2013

Mitchell, D. L., Erfani, E., Mishra, S. (2013). Convergence on ice particle mass- and area-dimensional expressions for ice clouds, Poster presentation, AGU Fall Meeting: San Francisco, CA, December 9, 2013

2012
Erfani, E., Mitchell, D. L., Ivanova, D. C., Lavin, M. (2012). Dependence of the North American monsoon on Pacific Ocean eastern boundary currents, Paper presented: AGU 2012 Fall Meeting: San Francisco, CA, December 3, 2012

Mitchell, D. L., Mejia, J. F., Xiao, M., Rasch, P. J., Kuebbeler, M. (2012). Cirrus Cloud Climate Engineering, International Conference on Clouds and Precipitation (ICCP): Leipzig, Germany, July 30, 2012-August 3, 2012

Other
2016
Mitchell, D. L. (2016). Participant in the Workshop on Low Environmental Impact Solar Radiation Management Field Experiments, Institute of Advanced Sustainability Studies: Potsdam, Germany, September 7, 2016-September 8, 2016

2015
Mitchell, D. L., Garnier, A., Avery, M. (2015). On the feasibility of cirrus cloud thinning: Dependence of homo- and heterogeneous ice nucleation on latitude and season, Invited talk. International Union of Geophysics and Geodesy (IUGG), 26th IUGG General Assembly: Prague, Czech Republic, June 22, 2015-July 2, 2015

Mitchell, D. L. (2015). Dependence of global sustainability on the degree of fear and aspiration. A Mindset for the Anthropocene project, Invited talk. Institute for Advanced Sustainability Studies (IASS): Potsdam, Germany, July 14, 2015

Mitchell, D. L. (2015). Local vs Large-Scale Forcing and NAM Variability, Invited talk, Panelist. 3rd Annual Regional Climate and Meteorology Meeting for Northwest Mexico and the Southwest U.S.: Centro de Ciencias de la Atmósfera, UNAM, Mexico City, June 4, 2015

Mitchell, D. L., Garnier, A., Avery, M. (2015). Cirrus cloud thinning: Do the right conditions exist, and how can it be tested with observations?, Invited talk. Workshop 1. Solar Radiation Management: Foresight for Governance (SRM4G): Institute for Advanced Sustainability Studies (IASS), Potsdam, Germany, July 13, 2015