Mark Z. Jacobson

Model Testing, Scientific Findings, and Model Developments

(Last update, June 2, 2005)

Please submit suggested corrections or clarifications to jacobson@stanford.edu

I. Model Testing

Since 1990, M. Z. Jacobson has developed and applied numerical models to study atmospheric pollution on the urban through global scales.

(Click here for a summary of the evolution of the models Jacobson works with and processes unique to them)

The models have been tested in several ways:

• Over 450 researchers have obtained codes for testing or use. The codes include SMVGEAR/SMVGEAR II, EQUISOLV/EQUISOLV II, and COAGSOLV. In addition, the APC and APD growth schemes and the hybrid and moving-center size structures have been coded and tested by several researchers.

• Individual algorithms have been tested against exact solutions, high-resolution numerical solutions, and/or other model solutions (Jacobson and Turco, 1994, 1995, Jacobson et al., 1994, 1996a; Jacobson, 1995a, 1997a, 1997c, 1998a, 1999c, 2001c, 2002a, 2003, 2004b, 2004d; Ketefian and Jacobson, 2004).

• Individual model processes have been compared with those from other models (Zhang et al., 1999, 2000; Liang and Jacobson, 2000; Barth et al., 2002, Kreidenweis et al., 2002).

• Three-dimensional simulation results have been compared with regional field-campaign and/or globally distributed gas, aerosol, radiative, and/or meteorological data (often paired-in-time-and-space), and/or other model results (Jacobson, 1994; 1997b, 1998b, 1999a, 1999b, 2000, 2001a, 2001b, 2001d, 2002b; 2004a,b; Jacobson et al., 2003; 2004, 2005b,e,f).

Below is a list of scientific findings and model developments since 1990.

II. Scientific Findings

A. Discoveries of Physical Phenomena

1. Aerosol particles reduce wind speeds below them (Jacobson, 2002b; 2005e).

2. Evaporative freezing is a new method of liquid drop freezing in the atmosphere. Evaporation of a drop as it falls through subsaturated air cools the drop surface, enhancing the drop's freezing rate (Jacobson, 2003).

3. Evaporation enhances the coagulation rate of an aerosol particle (Jacobson et al., 2005a).

4. Certain aerosol components, including nitrated aromatics, polycyclic aromatic hydrocarbons, benzaldehydes, benzoic acids, aromatic polycarboxylic acids, phenols, and the nitrate ion, as well as nitrated aromatic gases (such as nitrocresol, nitrophenol, and others) preferentially reduce UV radiation more than total solar radiation in the atmosphere, a phenomenon that helps to explain observed preferential UV radiation relative to total solar reductions at the surface (Jacobson, 1999a).

5. Absorbing aerosol particles and gases decrease boundary-layer ozone by decreasing photolysis (Jacobson, 1997b, 1998b).

6. Coagulation among multiple aerosol size distributions internally mixes particles of all size, thereby affecting the composition at all sizes, contradicting the long-held belief that coagulation affects only small particles. Instead, coagulation affects only small particles in terms of particle number and total mass, but not in terms of composition (Jacobson, 2002a).

7. Coagulation internally mixes a greater fraction of large particles than smaller particles (Jacobson, 2002a).

8. Van der Waals forces and fractal geometry enhance the rate ofthe evolution of the aerosol size distribution near the point of emission (Jacobson and Seinfeld, 2004).

9. Dilution is more important than coagulation at reducing the total number concentration of particles near the emission source (Jacobson and Seinfeld, 2004).

10. Heteorcoagulation of emitted particles with background particles produces new mixtures in increasing concentration with increasing distance from the emission source (Jacobson and Seinfeld, 2004).

11. Self-coagulation of emitted particles reduces particle number concentration by an order of magnitude more than does heterocoagulation of emitted particles with background particles in the first few minutes after emission. Heterocoagulation increases in importance as particles age (Jacobson and Seinfeld, 2004).

12. Close-in-diameter dual peaks in observed cloud distributions appear to be due in part to different activation characteristics of different aerosol size distributions (Jacobson, 2003).

13. Soil moisture changes air pollution concentrations through its effects on temperature profiles and wind speeds in an urban airshed. A decrease in soil moisture increases the concentration of primary gases and particles by increasing surface temperatures, which increase boundary layer heights and near-surface winds. An increase in soil moisture has the opposite effect. (Jacobson, 1999b).

14. Small quantities of calcium and magnesium in large particles affect the chemistry of those particles, shifting the flux of gases between small and large particles, changing the composition of the entire aerosol size distribution (Jacobson, 1999c).

15. The average mixing state of aerosol particles in the global atmosphere is closer to an internal mixture than to an external mixture (Jacobson, 2001b).

B. Discoveries of New Aerosol Feedbacks to Climate

1. "Rainout effect." Reduced precipitation due to the second indirect aerosol effect reduces rainout and washout rates of aerosol particles, increasing their atmospheric concentration (Jacobson, 2002b; 2005f).

2. "First self-feedback effect." Emission of anthropogenic aerosol particles increases total particle surface area, increasing the rate of gas-to-particle conversion, enhancing the size of aerosol particles further, enhancing the magnitude of the radiative effect of aerosol particles on climate (Jacobson, 2002b; 2005f).

3. "Second self-feedback effect." The emission of absorbing anthropogenic aerosol particles heats the air, decreasing the relative humidity, decreasing aerosol liquid water content and the dissolution rates of soluble aerosol components, affecting radiative transfer and, thus, climate (Jacobson, 2002b; 2005f).

4. "Photochemistry effect." Changes in gas concentration due to aerosol reduction or increase in photolysis coefficients, affect heating rates, which feed back to air temperatures (Jacobson, 2002b, 2005f).

5. "Wind-stability effect." The reduction in wind speed due to aerosol particles reduces the emission rates of wind-blown pollutants, such as soil dust and sea spray (Jacobson, 2002b; 2005f).

6. "BC-water vapor feedback." When black carbon (BC) warms the air, it warms the surface to a lesser extent, but still increasing the evaporation rate of soil or ocean water, a greenhouse gas (Jacobson, 2002b).

C. Policy-Relevant Findings Demonstrated by Cause and Effect

1. Black carbon may be the second-leading cause of global warming after carbon dioxide in terms of direct forcing. A portion of its strong direct forcing arises because its absorption of sunlight increases as it obtains a coating in the atmosphere during aging (Jacobson, 2000, 2001b).

2. Due to the short lifetime and strong heating effect of black carbon, control of fossil-fuel particulate black carbon plus organic matter may be the most effective method of slowing global warming in terms of the speed and magnitude of its effect (Jacobson, 2002b).

3. Aerosol particles enhance extreme local warming and cooling climate trends in comparison with greenhouse gases alone (Jacobson, 2005g).

4. Biomass-burning causes short-term cooling but long-term warming of global climate (Jacobson, 2004a).

5. Absorbing aerosol particles have two major indirect effects on health: they reduce UV radiation and slightly reduce ozone (Jacobson, 1998b). These "benefits," though come at the cost of high aerosol concentrations, and aerosol particles are the most unhealthful component of air pollution.

6. Converting the U.S. fleet of gasoline vehicles to modern diesel vehicles may increase ozone over the U.S. unless the diesel NO₂:NO ratio and total NO_x are reduced to those of gasoline (Jacobson et al., 2004).

7. Converting the U.S. vehicle fleet to hydrogen fuel cell vehicles should improve air quality, health, and climate, regardless of whether the hydrogen is produced by wind-electrolysis, steam-reforming of natural gas, or coal gasification (Jacobson et al., 2005b).

8. Vehicle NO_x controls may be more effective than vehicle NO₂:NO ratio controls at reducing ozone (Jacobson et al., 2004).

9. The reduction in wind speed due to aerosol particles may reduce wind energy availability in California by a few percent (Jacobson, 2005e).

10. Aerosol particles may reduce precipitation in California by several (~6.5) percent (Jacobson, 2005e).

D. Demonstration of Physical Phenomena by Cause and Effect

1. Demonstrated for first time, by cause and effect with a 3-D model compared with paired-in-time-and space data, that pollutant aerosol particles and gases are together responsible for observed reductions in surface solar radiation (Jacobson, 1997b, 1998b). This phenomenon is a major factor in what is widely referred to as "global dimming."

Previous measurement studies had found reductions of surface radiation in "polluted" versus "clean" air, suggesting this phenomena by correlation, but not cause and effect. Previous 1-D studies had suggested cause and effect by showing that a slab of aerosol particles could reduce surface radiation, but had not shown this phenomenon in a realistic air pollution event in which emission and meteorology played a role. Previous 3-D studies had not compared model predictions of aerosol reduction of sunlight with paired-in-time-and-space data, nor had they treated discrete size- and composition-resolved aerosol particles or the transport of particles by online modeled winds affected by the aerosol particles and gases.

In Los Angeles, aerosol particles were found to reduce peak solar radiation on average by 6-8% (55 W/m²) (Jacobson, 1997b, Table 6 and figures). Jacobson (1998b, Table 4) showed that observed peak reductions at Riverside of 13.6% (134 W/m²) were due to aerosol particles and gases.

2. Demonstrated for first time, by cause and effect through comparing 3-D model results with paired-in-time-and space data, that aerosol particles increase nighttime air temperatures and decrease daytime temperatures (Jacobson, 1997b).

3. Demonstrated for first time, by cause and effect through comparing 3-D model results with paired-in-time-and space data, that pollutant aerosol particles and gases are together responsible for observed reductions in surface ultraviolet (UV) radiation. Aerosols particles and gases reduced peak UV radiation by 22-48% (up to 27 W/m² in Riverside) in the Los Angeles basin in 1987 (Jacobson, 1998b).

4. Demonstrated for first time, by cause and effect through comparing 3-D model results with paired-in-time-and space data, that pollutant aerosol particles increase the downward infrared flux of radiation to the surface, and absorbing aerosol particles increase the heating rate of the boundary layer (Jacobson, 1997b, Table 6).

5. Aerosol particles containing black carbon are capable of causing a net short-term day-night average near-surface temperature increase in a polluted urban region (Jacobson, 1997b, Table 6).

7. Chloride and its associated liquid water in sea spray and natural sulfate may be the two most important natural aerosol constituents in the atmosphere in terms of their global direct radiative forcing (Jacobson, 2001a).

8. Solid formation in aerosols affects global direct radiative forcing (Jacobson, 2001a).

9. UV absorption by organics from fossil fuels and biomass burning affects surface and tropopause global direct forcing (Jacobson, 2001a).

10. Hydrometeor-hydrometeor coagulation plays a role in controlling aerosol-particle number globally (Jacobson, 2003).

11. Washout (aerosol-hydrometeor coagulation) may be a more important in-plus-below-cloud removal mechanism of aerosol number than rainout (the opposite is true for aerosol mass) (Jacobson, 2003).

12. Heterogeneous-homogeneous freezing may freeze more upper-tropospheric drops than contact freezing, but neither appears to affect warm-cloud hydrometeor distributions or aerosol scavenging substantially (Jacobson, 2003).

III. Model Developments

A. Coupled Air Quality-Meteorological Models

1. Developed and applied the first online-coupled (with feedback in both directions) meteorological-air quality model on a regional scale (GATORM - Jacobson, 1994; 1997a; Jacobson et al., 1996a). This feature has now been copied by numerous models, including MODELS-3, CMAQ-MM5, WRF-CHEM. An air quality model solves chemical equation, treats aerosol microphysics/chemistry, and transports gases and aerosol particles.

2. Developed the first online-coupled meteorological-air quality model on a global scale (GATORG, Jacobson, 1995b, 2001b,c). This feature has now been copied by numerous models including HadSM4 and various models coupled with CCM3.

3. Developed and applied the first three-dimensional atmospheric model to simulate the stratospheric ozone layer with an online-coupled chemical, radiative, meteorological model that treats wavelength-resolved UV photochemistry and feedback of wavelength-resolved heating rates from UV, visible, and infrared absorbing gases to dynamical meteorology through radiative transfer (GATORG, Jacobson, 1995b).

B. Nesting

1. Developed and applied the first three-dimensional atmospheric model that nests gas, aerosol, radiative, and meteorological variables simultaneously from the global down to the urban scale (GATOR-GCMM, Jacobson, 2001c,d). The technique of global-through-urban nesting of air quality and meteorological parameters has now been copied by several models.

C. Comparisons With Data

1. Developed and applied the first 3-D atmospheric model whose predictions of gas, size-resolved aerosol, radiative, and meteorological parameters have been compared simultaneously with paired-in-time-and-space data from a comprehensive field-program database (GATORM, Jacobson, 1994; 1997b).

2. Developed and applied the first 3-D atmospheric model whose predictions have been compared with paired-in-time-and-space data for at least 20 gases simultaneously (Jacobson, 2001d).

3. Developed and applied the first 3-D model whose predictions of gas, meteorological, radiative, and aerosol (in some cases) parameters have been compared with paired-in-time-and space data at a time resolution of an hour for at least 30 consecutive days, without model spinup or data assimilation (Jacobson et al., 2004; Jacobson et al., 2005b; Jacobson, 2005e).

4. Developed the first model to predict specific weather parameters accurately at several locations for 30 days without model spinup or data assimilation (Jacobson et al., 2004; Jacobson et al., 2005b; Jacobson, 2005e).

D. Aerosol Climate Response

1. Developed and applied the first 3-D model to calculate the regional scale climate response of discrete size- and composition-resolved aerosol particles of any type (GATORM, Jacobson, 1997b).

2. Developed and applied the first 3-D model to calculate the regional-scale evolution and climate response of discrete size-resolved aerosol particles containing black carbon and organic matter (Jacobson, 1997b).

3. Developed and applied the first 3-D model to calculate the global-scale evolution and climate response of discrete size- and composition-resolved aerosol particles containing black carbon and organic matter (GATOR-GCMOM, Jacobson, 2002b).

4. Developed and applied the first 3-D global model to calculate the climate response of discrete size- and composition-resolved aerosol particles containing sulfate (GATOR-GCMOM, Jacobson, 2002b).

5. Developed and applied the first 3-D global model to calculate the climate response of discrete size- and composition-resolved biomass-burning particles and gases (Jacobson, 2004a).

E. Ordinary Differential Equation Solvers

1. Developed the fastest ordinary differential equation solver in history for a given level of accuracy (<1 % error for all parameters) in three dimensions on a single processor (SMVGEAR, SMVGEAR II) (Jacobson and Turco, 1994; Jacobson, 1995a, 1998a, 1999d)

2. Developed the first Gear-type chemical ordinary differential equation solver usable in a 3-D regional or global atmospheric model. (SMVGEAR, SMVGEAR II) (Jacobson and Turco, 1994; Jacobson, 1995a, 1998a, 1999d).

3. Developed a new technique of reordering matrices of partial derivatives to take advantage of their sparsity during the solution of ordinary differential equations (Jacobson and Turco, 1994).

4. Developed a new technique of vectorizing 3-D atmospheric models around the grid cell dimension for improving the speed of all physical and chemical processes within them on vector, scalar, and parallel computers. With this technique, a 3-D grid domain is divided into blocks of grid cells, and equations are vectorized around the grid cell dimension (Jacobson and Turco, 1994). On scalar machines, the technique minimizes computational overhead, speeding solutions (Jacobson, 1998a). On parallel machines, the technique allows blocks of grid cells to be sent to different processors.

5. Developed a new technique of predicting the stiffness of chemical equations and reordering grid cells according to stiffness to speed solutions of chemistry in a 3-D atmospheric model (Jacobson, 1995a).

6. Developed the Multistep-Implicit-Explicit (MIE) ordinary differential equation solver, which solves equations by iterating forward Euler equations and linearized backward Euler equations until they converge to each other (Jacobson and Turco, 1994; Jacobson 1999d, 2005d).

7. Discovered that the forward the Euler solution to ordinary differential equations converges to the linearized backward Euler solution upon iteration and, upon convergence, both solutions conserve mass and are positive definite (MIE, Jacobson and Turco, 1994; Jacobson 1999).

F. Aerosol Number and Mass/Moles

1. Developed and applied the first three-dimensional regional model (GATORM) and global model (GATORG) to solve for both size-resolved aerosol number concentration and aerosol mass/mole concentration prognostically (Jacobson, 1994; 1997a,b; 2001b,c).

G. Aerosol Size Structures

1. Developed the hybrid aerosol size bin structure, which controls how aerosol sizes change in a model during coagulation, growth, transport, and other processes (Jacobson and Turco, 1995, Jacobson, 1999d)

2. Developed the moving-center aerosol size bin structure, which controls how aerosol sizes change in a model during coagulation, growth, transport, and other processes (Jacobson, 1997a, Jacobson, 1999d).

H. Multiple Aerosol Size Distributions

1. Developed and applied the first three-dimensional model that treats time-dependent feedback of multiple aerosol size distributions to meteorology through radiative transfer (Jacobson, 2001b; 2002a).

2. Developed the first 3-D atmospheric model to examine the mixing state of aerosols among multiple size distributions near the point of emission (Jacobson and Seinfeld, 2004).

I. Aerosol Nucleation, Condensation, Dissolutio

1. Developed the first unconditionally stable, noniterative, positive-definite, mass-conserving (between the gas and aerosol), and number conserving scheme to solve condensational growth between the gas phase and multiple aerosol or hydrometeor size bins (Analytical Predictor for Condensation – APC scheme) (Jacobson, 1997c, 1999d, 2002a).

2. Developed the first unconditionally stable, noniterative, mass-conserving (between the gas and aerosol), and number-conserving scheme to solve dissolutional growth between the gas phase and multiple aerosol size bins (Analytical Predictor for Dissolution – APD scheme) (Jacobson, 1997c, 1999d, 2002a).

3. Developed and applied the first noniterative, unconditionally stable, mass (between the gas and size-resolved aerosol), and number-conserving scheme that solves nucleation simultaneously with size-resolved condensation (Jacobson, 2001b, 2002a).

J. Aerosol Chemical Equilibrium, Equilibrium/Nonequilibrium Growth

1. Developed and applied the first three-dimensional atmospheric model to treat diffusion-limited mass-transfer to size-resolved particles together with equilibrium chemistry within such particles (GATORM, Jacobson 1997a,b,c).

2. Developed two mass- and charge-conserving, positive-definite, unconditionally stable chemical equilibrium solvers (EQUISOLV, EQUISOLV II) (Jacobson et al. 1996a; Jacobson 1999c, d).

3. Developed a method (Analytical Equilibrium Iteration – AEI method) of solving chemical equilibrium equations (Jacobson 1999c).

4. Developed a new, nonoscillatory method of solving nonequilibrium growth of acids and equilibrium growth of the base ammonia simultaneously among multiple size bins and size distributions, at long time step (Jacobson, 2005a).

K. Aerosol-Aerosol Coagulation

1. Developed the first three-dimensional atmospheric model that treats size-resolved aerosol-aerosol coagulation, size-resolved coagulation among multiple aerosol size distributions, and size-resolved coagulation among multiple components within a size distribution. (GATORM, GATORG, GATOR-GCMOM, Jacobson, 1994, 1997a,b, 2001b, 2002a,c; Jacobson et al., 1994).

2. Developed a numerical method of adapting the semiimplicit coagulation solution (which is noniterative, volume conserving, volume-concentration conserving, positive definite, and unconditionally stable) to cases where the volume ratio of adjacent size bins is <2 (Jacobson et al., 1994).

3. Generalized the semiimplicit coagulation solution to any number of external mixtures >2 and a single internal mixture (Jacobson et al., 1994).

4. Generalized the semiimplicit coagulation solution to any combination of interactions among multiple aerosol distributions (thus any number of external mixtures and any number of binary pairs or higher combinations of mixtures) (Jacobson, 2001b, 2002a, 2003).

5. Developed the first 3-D atmospheric model to treat size-resolved coagulation enhancement due to van der Waals forces (Jacobson and Seinfeld, 2004).

6. Developed the first 3-D atmospheric model to treat size-resolved coagulation enhancement due to fractal geometry (Jacobson and Seinfeld, 2004).

L. Clouds and Their Interactions With Aerosol Particles

1. Developed and applied the first 3-D global model to treat cloud and precipitation microphysics (including condensation, evaporation, deposition, sublimation, freezing, melting, coagulation, bounceoff, etc.) with discrete size resolution (Jacobson, 2002b; 2003, 2004a,b).

2. Developed and applied the first global 3-D model to treat the evolution of discrete size- and composition-resolved liquid, ice, and graupel hydrometeor particles from discrete size- and composition-resolved aerosol particles (GATOR-GCMOM, Jacobson, 2002b, 2003, 2004a,b).

3. Developed and applied the first regional model to treat the 3-D evolution (including thermodynamics, microphysics, and transport) of discrete size- and composition- resolved liquid, ice, and mixed-phase clouds/precipitation from discrete size-and-composition-resolved aerosol particles, where multicomponent aerosol inclusions are accounted for in the liquid, ice, and graupel hydrometeor particles (2005e,f).

4. Developed the first 3-D global and regional models to treat contact freezing between discrete size-resolved aerosol particles and size-resolved hydrometeor particles (Jacobson, 2002b, 2003, 2005e,f; Jacobson et al., 2004).

5. Generalized the semiimplicit coagulation solution to treat interactions among multiple-distribution hydrometeors and between multiple-distribution aerosols and multiple-distribution hydrometeors (Jacobson, 2003).

6. Developed the first 3-D atmospheric model to treat size-resolved coagulation by diffusiophoresis, thermophoresis, and electric charge (Jacobson, 2002b, 2003).

7. Developed the first 3-D global and regional models to treat coagulation between discrete size-resolved aerosol particles and size-resolved cloud and precipitation hydrometeor particles (within and below clouds) (Jacobson, 2002b, 2003, 2005e,f; Jacobson et al., 2004).

8. Developed the first 3-D global and regional models to calculate lightning and the resulting NO emission by considering collisions and bounceoffs among discrete size-resolved solid hydrometeor particles (Jacobson, 2002b, 2003, 2005e,f; Jacobson et al., 2004).

9. Developed the first atmospheric model to treat water condensation/deposition simultaneously onto multiple discrete aerosol size distributions to form hydrometeor particles (Jacobson, 2003).

10. Developed the first atmospheric model to treat water condensation/deposition onto pre-existing hydrometeor particles and unactivated aerosol particles simultaneously (Jacobson, 2005f).

11. Developed and applied the first 3-D model to calculate the surface temperature of discrete, size-resolved liquid, ice, and graupel particles (Jacobson, 2002b, 2003).

12. Developed and applied the first 3-D global model to treat subcloud evaporation/sublimation of discrete size-resolved hydrometeor particles (Jacobson, 2002b, 2003).

13. Developed and applied the first 3-D global model to treat drop breakup of discrete size-resolved hydrometeor particles (Jacobson, 2002b, 2003).

14. Developed and applied the first 3-D global model to treat melting/freezing of discrete size-resolved hydrometeor particles (Jacobson, 2002b, 2003).

M. Radiation

1. Developed and applied the first 3-D regional or global atmospheric model to solve for photolysis with a spectral radiative transfer module affected by both gas and discrete size- and composition-resolved aerosol optical properties (GATORM – Jacobson, 1994; 1997a).

2. Developed and applied the first 3-D regional or global atmospheric module to solve for heating rates with a spectral radiative transfer model affected by both gas and discrete size- and composition-resolved aerosol optical properties (GATORM – Jacobson, 1994; 1997a).

3. Developed and applied the first 3-D model to study the impacts of discrete size-resolved aerosols containing black carbon and other components on heating rates, irradiances, and temperature profiles (Jacobson, 1997b, 1998b, 1999a).

4. Developed and applied the first 3-D model to calculate the effects of size-resolved aerosols on UV radiation, photolysis, and ozone (Jacobson, 1997b).

5. Developed the first 3-D model to predict rather than to diagnose the albedo of snow and sea ice from a radiative transfer solution (Jacobson, 2004b).

6. Developed a new method of parameterizing absorption coefficients among all important gases in the atmosphere from line by-line spectral data for use in atmospheric models (Jacobson, 2004c).

N. Ocean-Atmosphere Exchange, Ocean Chemistry

1. Developed the first noniterative, unconditionally-stable, positive-definite, mass-conserving technique for solving ocean-atmosphere exchange of any trace gas (Jacobson, 2005c).

2. Developed the first mass- and charge-conserving, positive-definite, unconditionally stable chemical equilibrium solvers for the ocean that treats any number of reactions (EQUISOLV O, Jacobson, 2005c).

O. Soil Moisture

1. Developed and applied the first model to study the effects of soil moisture on gas and aerosol pollution (Jacobson, 1999b).

P. Subgrid Soil Treatment

1. Developed and applied the first 3-D model to calculate surface fluxes of latent heat, sensible heat, and moisture by tracking the temperature/moisture of multiple subgrid soil surfaces, each with multiple subsurface soil layers, and averaging fluxes over all surfaces (Jacobson, 2001c,d). Previous 3-D subgrid models averaged soil parameters, rather than fluxes, over subgrid surfaces.

2. Developed and applied the first 3-D model to calculate subgrid road and rooftop temperatures on the regional or global scale (Jacobson, 2001c,d)

3. Developed and applied the first 3-D model to solve for vegetation temperature, and in-canopy temperature iteratively and for each of several subgrid soil classes (Jacobson, 2001c,d)

Q. Evolution of Aerosol Composition

1. Developed and applied the first 3-D model to calculate the regional-scale evolution of discrete size- and composition-resolved aerosol particles containing black carbon, organic matter, sulfate, nitrate, ammonium, sodium, and chloride when gases and aerosols fed back to meteorology through radiative transfer (Jacobson, 1997b) (earlier studies were driven by offline meteorology).

2. Developed and applied the first 3-D model to calculate the global-scale evolution of discrete size- and composition-resolved aerosols containing black carbon, organic matter, sulfate, nitrate, ammonium, sodium, chloride, and soil dust simultaneously (GATOR-GCMOM, Jacobson, 2002b).

R. Direct Radiative Forcing

1. Developed and applied the first model to quantify the global direct radiative forcing due to size-resolved, multicomponent aerosols containing calcium, magnesium, potassium, sodium, chloride, carbonate, silicon, aluminum, or iron (Jacobson, 2000, 2001a). The direct forcings of sulfate, nitrate, ammonium, organic carbon, and black carbon were also calculated.

4. Developed and applied the first model to calculate the direct forcing of black carbon as a core component in an internal mixture (Jacobson, 2000, 2001a,b).

IV. References

Click here to find PDF Files of most of the references given below.

Barth, M. C., S. Sillman, R. Hudman, M. Z. Jacobson, C.-H. Kim, A. Monod, and J. Liang, Summary of the cloud chemistry modeling intercomparison: Photochemical box model simulation, J. Geophys. Res., 108 (D7) doi: 10.1029/2002JD002673, 2003.

Jacobson, M. Z., Developing, coupling, and applying a gas, aerosol, transport, and radiation model to study urban and regional air pollution. Ph. D. Thesis, Dept. of Atmospheric Sciences, University of California, Los Angeles, 436 pp., 1994.

Jacobson, M. Z., Computation of global photochemistry with SMVGEAR II. Atmos. Environ., 29A, 2541-2546, 1995a, www.stanford.edu/group/efmh/jacobson/impSMVGEAR.html.

Jacobson, M. Z., Simulations of the rates of regeneration of the global ozone layer upon reduction or removal of ozone-destroying compounds. EOS Supplement, Fall, 1995, p. F119, 1995b.

See also, "Closing the hole," Geotimes Magazine (American Geological Institute), April, 1996, p. 9; "Simulations on C90 Predict Rapid Regeneration of Earth's Ozone Layer -- With Caveats," NAS News, July - August 1996, Vol. 2, No. 18, p. 5., 1996.

Jacobson, M. Z., Development and application of a new air pollution modeling system. Part II: Aerosol module structure and design, Atmos. Environ., 31A, 131 – 144, 1997a, www.stanford.edu/group/efmh/jacobson/IIb.html.

Jacobson, M. Z., Development and application of a new air pollution modeling system. Part III: Aerosol-phase simulations, Atmos. Environ., 31A, 587 – 608, 1997b, www.stanford.edu/group/efmh/jacobson/IIa.html.

Jacobson, M. Z., Numerical techniques to solve condensational and dissolutional growth equations when growth is coupled to reversible reactions, Aerosol Sci. Technol., 27, 491–498, 1997c, www.stanford.edu/group/efmh/jacobson/numTech.html.

Jacobson, M. Z., Improvement of SMVGEAR II on vector and scalar machines through absolute error tolerance control. Atmos. Environ., 32, 791 – 796, 1998a, www.stanford.edu/group/efmh/jacobson/impSMVGEAR.html.

Jacobson, M. Z., Studying the effects of aerosols on vertical photolysis rate coefficient and temperature profiles over an urban airshed, J. Geophys. Res., 103, 10,593 - 10,604, 1998b, www.stanford.edu/group/efmh/jacobson/IIc.html.

Jacobson, M. Z., Isolating nitrated and aromatic aerosols and nitrated aromatic gases as sources of ultraviolet light absorption, J. Geophys. Res., 104, 3527-3542, 1999a, www.stanford.edu/group/efmh/jacobson/IId.html.

Jacobson, M. Z., Studying the effects of soil moisture on ozone, temperatures, and winds in Los Angeles, J. Appl. Meteorol., 38, 607-616, 1999b, www.stanford.edu/group/efmh/jacobson/IIIa.html.

Jacobson, M. Z., Studying The effects of calcium and magnesium on size-distributed nitrate and ammonium with EQUISOLV II, Atmos. Environ., 33, 3635-3649, 1999c, www.stanford.edu/group/efmh/jacobson/studyEff.html.

Jacobson, M. Z., Fundamentals of Atmospheric Modeling. Cambridge University Press, New York, 656 pp., 1999d.

Jacobson, M. Z., A physically-based treatment of elemental carbon optics: Implications for global direct forcing of aerosols, Geophys. Res. Lett., 27, 217-220, 2000.

Jacobson, M. Z., Global direct radiative forcing due to multicomponent anthropogenic and natural aerosols, J. Geophys. Res., 106, 1551-1568, 2001a.

Jacobson, M. Z., Strong radiative heating due to the mixing state of black carbon in atmospheric aerosols, Nature, 409, 695-697, 2001b, http://www.nature.com/nature/fow/010208.html.

Jacobson, M. Z., GATOR-GCMM: A global through urban scale air pollution and weather forecast model. 1. Model design and treatment of subgrid soil, vegetation, roads, rooftops, water, sea ice, and snow., J. Geophys. Res., 106, 5385-5402, 2001c, http://www.stanford.edu/group/efmh/jacobson/GATORglob.html.

Jacobson, M. Z., GATOR-GCMM: 2. A study of day- and nighttime ozone layers aloft, ozone in national parks, and weather during the SARMAP Field Campaign, J. Geophys. Res., 106, 5403-5420, 2001d, http://www.stanford.edu/group/efmh/jacobson/GATORstudy.html.

Jacobson, M. Z., Analysis of aerosol interactions with numerical techniques for solving coagulation, nucleation, condensation, dissolution, and reversible chemistry among multiple size distributions, J. Geophys. Res., 107 (D19), 4366, doi:10.1029/ 2001JD002044, 2002a, http://www.stanford.edu/group/efmh/multdist/multdist.html.

Jacobson, M. Z., Control of fossil-fuel particulate black carbon plus organic matter, possibly the most effective method of slowing global warming, J. Geophys. Res., 107, 10.1029/ 2001JD001376, 2002b, http://www.stanford.edu/group/efmh/fossil/fossil.html.

Jacobson, M. Z., Development of mixed-phase clouds from multiple aerosol size distributions and the effect of the clouds on aerosol removal, J. Geophys. Res., 108 (D8), 4245, doi:10.1029/2002JD002691, 2003, http://www.stanford.edu/group/efmh/cloudaer/cloudaer.html.

Jacobson, M. Z., The short-term cooling but long-term global warming due to biomass burning, J. Clim., 17 (15), 2909-2926, 2004a, www.stanford.edu/group/efmh/bioburn/index.html.

Jacobson, M.Z., The climate response of fossil-fuel and biofuel soot, accounting for soot’s feedback to snow and sea ice albedo and emissivity, J. Geophys. Res., 109, D21201, doi:10.1029/2004JD004945, 2004b, www.stanford.edu/group/efmh/jacobson/VIIIc.html.

Jacobson, M.Z., A solution to the problem of nonequilibrium acid/base gas-particle transfer at long time step, Aerosol Sci. Technol, 39, 92-103, 2005a, www.stanford.edu/group/efmh/jacobson/nonequilAcid.html.

Jacobson, M.Z., A refined method of parameterizing absorption coefficients among multiple gases simultaneously from line-by-line data, J. Atmos. Sci., 62, 506-517, 2005b, www.stanford.edu/group/efmh/jacobson/radAbsPap.html.

Jacobson, M.Z., Studying ocean acidification with conservative, stable numerical schemes for nonequilibrium air-ocean exchange and ocean equilibrium chemistry, J. Geophys. Res., 110, D07302, doi:10.1029/2004JD005220, 2005c, www.stanford.edu/group/efmh/jacobson/oceanAcidif.html.

Jacobson, M.Z., Fundamentals of Atmospheric Modeling, Second Edition, Cambridge University Press, New York, 813 pp., 2005d, www.stanford.edu/group/efmh/FAMbook2dEd/index.html.

Jacobson, M.Z., Wind reduction by aerosol particles, Nature, in review, 2005e.

Jacobson, M.Z., Simulating the 3-D evolution of size- and composition-resolved mixed-phase clouds and precipitation from size-resolved aerosol particles and the resulting feedbacks to regional climate, in preparation, 2005f.

Jacobson, M.Z., Enhancement of extreme warming and cooling of local climate by anthropogenic aerosol particles, in preparation, 2005g.

Jacobson, M. Z., and R. P. Turco, SMVGEAR: A sparse-matrix, vectorized Gear code for atmospheric models, Atmos. Environ., 28A, 273-284, 1994, www.stanford.edu/group/efmh/jacobson/smvgear.html.

Jacobson, M. Z., R. P. Turco, E. J. Jensen, and O. B. Toon, Modeling coagulation among particles of different composition and size, Atmos. Environ., 28A, 1327–1338, 1994, www.stanford.edu/group/efmh/jacobson/VIa.html.

Jacobson, M. Z., and R. P. Turco, Simulating condensational growth, evaporation, and coagulation of aerosols using a combined moving and stationary size grid, Aerosol Sci. and Technol., 22, 73 – 92, 1995, www.stanford.edu/group/efmh/jacobson/simCond.html.

Jacobson, M. Z., A. Tabazadeh, and R. P. Turco, Simulating equilibrium within aerosols and non-equilibrium between gases and aerosols, J. Geophys. Res., 101, 9079–9091, 1996a, www.stanford.edu/group/efmh/jacobson/simEqui.html.

Jacobson, M. Z., R. Lu, R. P. Turco, and O. B. Toon, Development and application of a new air pollution modeling system. Part I: Gas-phase simulations, Atmos. Environ., 30B, 1939 – 1963, 1996b, www.stanford.edu/group/efmh/jacobson/devAppI.html.

Jacobson, M. Z., and G. M. Masters, Exploiting wind versus coal, Science, 293, 1438-1438, 2001, http://www.sciencemag.org/cgi/content/summary/293/5534/1438.

Jacobson, M. Z., J. H. Seinfeld, G. R. Carmichael, and D.G. Streets, The effect on photochemical smog of converting the U.S. fleet of gasoline vehicles to modern diesel vehicles, Geophys. Res. Lett., 31, L02116, doi:10.1029/2003GL018448, 2004, www.stanford.edu/group/efmh/jacobson/effPhoto.html.

Jacobson, M.Z., and J.H. Seinfeld, Evolution of nanoparticle size and mixing state near the point of emission, Atmos. Environ., 38, 1839-1850, 2004, www.stanford.edu/group/efmh/jacobson/hiRes_a.html.

Jacobson, M.Z., D.B. Kittelson, and W.F. Watts, Enhanced coagulation due to evaporation and its effect on nanoparticle evolution, Environmental Science and Technology, in review, 2005a.

Jacobson, M.Z., W.C. Colella, and D.M. Golden, Cleaning the air and improving health with hydrogen fuel cell vehicles, Science, in press, 2005b, www.stanford.edu/group/efmh/jacobson/fuelcellhybrid.html.

Ketefian G., and M.Z. Jacobson, Development and application of a 2-D potential-enstrophy-, energy-, and mass-conserving mixed-layer ocean model with arbitrary boundaries, Mon. Weath. Rev., in review, 2005.

Liang, J., and M. Z. Jacobson, Comparison of a 4000-reaction chemical mechanism with the Carbon Bond IV and an adjusted Carbon Bond IV-EX mechanism using SMVGEAR II., Atmos. Environ., 34, 3015-3026, 2000.

Kreidenweis, S. M., C. Walcek, G. Feingold, W. Gong, M. Z. Jacobson, C.-H. Kim, X. Liu, J. E. Penner, A. Nenes and J. H. Seinfeld, Modification of aerosol mass and size distribution due to aqueous-phase SO₂ oxidation in clouds: Comparisons of several models, J. Geophys. Res., 108 (D7) doi:10.1029/2002JD002697, 2003.

Zhang, Y., C. Seigneur, J. H. Seinfeld, M. Z. Jacobson, and F. Binkowski, Simulation of aerosol dynamics: A comparative review of algorithms used in air quality models, Aerosol Sci. Technol., 31, 487-514, 1999.

Zhang, Y., C. Seigneur, J. H. Seinfeld, M. Jacobson, S. L. Clegg, and F. Binkowski, A comparative review of inorganic aerosol thermodynamic equilibrium modules: Similarities, differences, and their likely causes, Atmos. Environ., 34, 117-137, 2000.

Number of visitors to this site since 12/19/02: