Description of NAAPS (Navy Aerosol Analysis and Prediction System) Global Aerosol Model
Last updated May 14, 2009
A description of the NAAPS plots can be found
The Naval Research Laboratory (NRL) in Monterey, CA, has developed a near-operational
system for predicting the distribution of tropospheric aerosols.
The model is a modified form of that developed by Christensen (1997).
The NRL version uses global meteorological fields from
the Navy Operational Global Atmospheric Prediction System
(Hogan and Rosmond, 1991; Hogan and Brody 1993)
analyses and forecasts
on a 1 X 1 degree grid, at 6-hour
intervals and 24 vertical levels reaching 100 mb
(12 levels for initial runs then 18 levels beginning 1998062412 and
24 levels beginning 2002091700.)
The original model used northern hemispheric,
12-hourly ECMWF fields on a 2.5 X 2.5 degree grid.
Current strengths of the model are:
1. the use of operational dynamics, eg. 'REAL' weather
2. 120-hour forecasts
3. operated in near-real-time
4. global coverage
5. Dust simulations
5. Smoke simulations
Our current work:
1. Improve the dust source function
2. Verify the sulfate simulations
3. Improve the microphysics and chemistry.
sulfur dioxide emission
is based on the
inventory, version 1A, for the
year 1985 with a seasonal variation and two-level vertical distribution
(Benkovitz, 1996). The anthropogenic emissions are converted to
95% sulfur dioxide and 5% sulfate.
Of the total DMS emission, 43% is converted to sulfur dioxide and 5% to sulfate.
The current smoke emission algorithm is described
From September 1 through December 31, 1999, the 1993
ESA ESRIN IONIA AVHRR daily fire product was used to specify
smoke sources in Central Africa and the Sahel.
The daily 1993 data were used in liu of a realtime daily product.
Starting January 1, 2000, the 1993 ESA ESRIN IONIA AVHRR monthly fire product was used to specify fire locations in Australia, Central Africa and the Sahel. The monthly 1993 data were used in lieu of a real-time daily product.
Beginning June 9, 2000, the
fire product was used again to specify smoke sources in South America.
Beginning May 22, 2001, the
fire product is used to specify fire locations in the western hemisphere
based on GEOS-8, -10, and -12.
Beginning September 2001, the
fire product (via U. Md, C. Justice) is used to specify fire locations in the western hemisphere,
based on MODIS-Terra. MODIS-Aqua data became available December 10, 2002.
The smoke sources (whether analyzed by ABBA or from IONIA climatology)
from the previous 24 hours are used for the 5-day NAAPS smoke forecasts.
The emission for today is shown
Dust emission occurs whenever the friction velocity exceeds a threshold value,
snow depth is less than a critical value,
and the surface moisture is less than a critical value.
The flux is taken from Westphal et. al. (1988) and scaled to include only particles
with radii smaller than 5 microns.
The flux is injected into the lowest two layers of the model.
The threshold friction velocity is set to infinity except in known dust-emission areas.
These areas originally were defined as areas covered by eight of the
94 land-use types
used in the
USGS Land Cover Characteristics Database.
The USGS dataset was developed from AVHRR data and has 1-km resolution.
NRL/MRY has interpolated the USGS dataset to 0.01-degree resolution.
High-resolution (0.02-degree) plots
show the six most common landuse
types within 10x10 degree areas of the world.
(Some areas of the world, particularly Europe and North America, have over 30 land use
types within a single 10x10 degree area. These plots have limited use in those areas.)
The eight presumed dust-producing categories, and their USGS number classification, are:
Low sparse grassland (2)
Bare desert (8)
Sand desert (50)
Semi-desert shrubs (51)
Semi-desert sage (52)
Polar and alpine desert (69)
Salt playas (71)
Sparse dunes and ridges (82)
An example of the distribution of erodible areas for a 10x10 degree areas
centered over Senegal and over Northern India and western China are
High-resolution (0.01-degree) plots for other 10x10 degree areas of the world can be found
Based on observational evidence,
we made subjective modifications to the land use database when determining the
dust source regions.
(1) Low sparse grassland is a source region only in China and Mongolia.
This excludes areas of the Steppes, Turkey, New Zealand, and N. America
(2) Bare desert and Semi-desert shrubs north of 60N are excluded.
The resolution has been reduced for use with the global aerosol model.
For each 1X1-degree grid box, we have derived the fraction
covered by erodible land types and the predominant land type.
The erodible fraction for the same two regions are shown in
Figure 3 and
Plots for other 10x10 degree areas of the world can be found
The surface flux is scaled by the erodible fraction for each grid box.
The predominant land use type for the same two regions are shown in
1X1-degree plots for other 10x10 degree areas of the world can be found
Variable threshold friction velocities will eventually be assigned to each of the different land
Currently it is set to 0.6 m s^-1 for all land types.
1X1-degree plots for 10x10 degree areas of the world can be found
The erodible fraction and predominant land types for the world are shown in
Plots for other regions of the world can be found
In June, 2000, we used an analysis of TOMS AI data to further refine the
source regions in the Sahara, Middle East, Arabia, and Australia.
Our method bases the erodibility fraction on the frequency that high TOMS AI values are observed
for a 1-degree grid box.
Prospero, et. al. have conducted a thorough study of dust source regions using the TOMS data,
terrain data, and other information.
The landuse type is arbitrarily set to (8) Bare desert (for plots) and
the threshold friction velocity is set to 0.6 m/s.
Plots of NAAPS erodibility fraction, surface types, and threshold friction velocity (based on
USGS and TOMS AI) may be found
The critical surface moisture is set to 0.3.
The critical snow depth value is set to 0.4 cm.
These choices are based on a qualitative analysis of these NOGAPS fields
and synoptic dust observations.
The forecasted friction velocities are used for the NAAPS dust forecasts.
A description of the NAAPS plots can be found
Benkovitz, C. M., T. Scholtz, L. Pacyna, L. Tarrson, J. Dignon, E. Voldner,
P. A. Spiro, and T. E. Graedel, 1996: Global gridded inventories of
anthropogenic emissions of sulphur and nitrogen.
J. Geophys. Res., 101, 29239-29253.
Christensen, J. H., 1997: The Danish eulerian hemispheric model - A three-dimensional
air pollution model used for the Arctic. Atm. Env., 31, 4169-4191.
Hogan, T. F., and T. E. Rosmond, 1991: The description of the Navy operational global atmospheric prediction
system's spectral forecast model.
Mon. Wea. Rev., 119, 1786-1815.
Hogan, T. F., and L. R. Brody, 1991: Sensitivity studies of the Navy's global forecast model
parameterizations and evaluation of improvements to NOGAPS.
Mon. Wea. Rev., 121, 2373-2395.
Prospero, J.M., P. Ginoux, O. Torres, S. Nicholson, and T. Gill, 2002: Environmental characterization of global
sources of atmospheric soil dust identified with the NIMBUS 7 Total Ozone Mapping Spectrometer
(TOMS) absorbing aerosol product. Reviews of Geophysics, 10.1029/2000RG000095, 04 September.
Westphal, D. L., O. B. Toon, and T. N. Carlson, 1987: A two-dimensional numerical
investigation of the dynamics and microphysics of Saharan dust storms. J.
Geophys. Res., 92, 3027-3049.
Westphal, D. L., O. B. Toon, and T. N. Carlson, 1988: A case study of mobilization and
transport of Saharan dust. J. Atmos. Sci., 45, 2145-2175.
Papers Utilizing NAAPS data for analyses:
2004, Jaffe, D., I. Bertschi, L. Jaegl, P. Novelli, J. S. Reid, H. Tanimoto,
R. Vingarzan, and D. L. Westphal: Long-range transport of Siberian
biomass burning emissions and impact on surface ozone in western North
America, Geophys. Res. Lett., 31, L16106, doi:10.1029/2004GL020093.
2003, Schollaert, S. E., J. A. Yoder, D. L. Westphal, and J. E. O'Reilly: The influence of
dust and sulfate aerosols on ocean color spectra and chlorophyll-a concentrations
derived from SeaWiFS off the U.S. Coast. J. Geophys. Res., 108 (C6), 3191,
2003, Johnson, K. S., V. A. Elrod, S. E. Fitzwater, J. N. Plant, F. P. Chavez, S. J. Tanner,
R. M. Gordon, D. L. Westphal, K. D. Perry, J. Wu, D. M. Karl: Surface Ocean-
Lower Atmosphere Interactions in the Northeast Pacific Ocean Gyre: Aerosols,
Iron and the Ecosystem Response. Global Biogeochem. Cycles, 17(2), 1063,
doi:10.1029/ 2002GB002004, 2003.
2003, Bucholtz, A., J. H. Bowles, C. Carrico, W. Chen, D. Collins, C. O. Davis, J. Eilers,
P. Flatau, H. Jonsson, D. Korwan, S. M. Kreidenweis, J. M. Livingston, M.
Montes, B. Provencal, E. A. Reid, J. S. Reid, J. Redemann, B. Schmid, W.
Snyder, A. Strawa, A. L. Walker, D. L. Westphal, M. Witek: Properties and
Effects of Asian Aerosols Over the Central California Coast During the ADAM-
2003 (Asian Dust Above Monterey-2003) Field Study, 22nd Annual AAAR
Conference, Anaheim, CA, Oct 20-24, American Association For Aerosol
Research, P3B3, 23.
2003, Lerner, J.A., R. Passi, D.L. Westphal, J.S. Reid: Producing A Quality-Controlled
Surface Visibility Dataset for Predictive Model Validation Purposes. Battlespace
Atmospheric and Cloud Impacts on Military Operations (BACIMO), Monterey,
CA, Sept. 9-11. CD ROM, P3-08
2003, Reid ,J. S., D. L. Westphal, M. Liu, K. A. Richardson, C. O. Justice, E. M. Prins, J.
Descloitres, S. D. Miller; Detection, Modeling, and Impacts of Biomass and Oil
Fires, Battlespace Atmospheric and Cloud Impacts on Military Operations
(BACIMO), Sept. 9-11, Monterey, CA, P3-11
2002, Thulasiraman, S., N. T. O'Neill, A. Royer, B. N. Holben, D. L. Westphal, and L. J.
B. McArthur: Sunphotometric observations of the 2001 Asian dust storm over
Canada and the U.S. Geophys. Res. Lett., 29, 96-1 - 96-4.
2002, Reid, J. S., D. L. Westphal, , J. M. Livingston, D. L. Savoie, H. B. Maring, H. H.
Jonsson, D. P. Eleuterio, and J. E. Kinney: Dust Vertical Distribution in the
Caribbean during the Puerto Rico Dust Experiment, Geophys. Res. Lett., 29, 55-
1 - 55-4.
2002, Bucholtz, A., M. V., Ramana, P. J. Flatau, D. L. Westphal, and V. Ramanathan,
Atmospheric Aerosol Conditions Over the Central California Coast During ITCT-2K2
Eos Trans. AGU, 83(47), Fall Meet. Suppl., Abstract A62B-0174, 2002.
2001, Tratt, D. M., R. J. Frouin, D. L. Westphal: The April 1998 Asian dust event: a
Southern California perspective. J. Geophys. Res, 106, 18,371-18,379.
2001, Husar, R. B., D. Tratt, B. A. Schichtel, S. R. Falke, F. Li, D. Jaffe, S. Gasso, T.
Gill, N. S. Laulainen, F. Lu. M Reheis, Y. Chun, D. Westphal, B. N. Holben, C.
Geymard, I. McKendry, N. Kuring, G. C. Feldman, C. McClain, R. J. Frouin, J.
Merrill, D. DuBois, F. Vignola, T. Murayama, S. Nickovic, W. E. Wilson, K.
Sassen, N. Sugimoto: The Asian Dust Events of April 1998. J. Geophys. Res.,
2001, Reid, J. S., E. M. Prins, D. L. Westphal, K. Richardson, S. Christopher, C.
Schmidt. M. Theisen, T. Eck, E. A. Reid: The Fire Locating and Modeling of
Biomass Emissions (FLAMBE) Project. Presented at the 2001 Fall A.G.U.
Meeting, 10-14 December, San Francisco.
2000, Westphal, D. L., J. S. Reid, B. N. Holben, O. Torres: Validation of Real-time Dust
Forecasting during the Puerto Rico Dust Experiment (PRIDE). Presented at the
2000 Fall A.G.U. Meeting, 15-19 December, San Francisco
2000, Reid, J. S., D. L. Westphal, S. Tsay, L. A. Remer, Pl. A. Pilewskie, H. B. Maring,
J. M. Livingston, B. M. Holben, R. J. Ferek, D. P. Eleuterio: The Puerto Rico
Dust Experiment - PRIDE: Mission Overview. Presented at the 2000 Fall
A.G.U. Meeting, 15-19 December, San Francisco.
2000, Eleuterio, D. P., D. L. Westphal, J. S. Reid: The Puerto Rico Dust Experiment -
PRIDE: Summary of synoptic conditions. Presented at the 2000 Fall A.G.U.
Meeting, 15-19 December, San Francisco.
1999, Westphal, D. L.: Recent dust events as simulated by NAAPS: Navy aerosol
analysis and prediction system. Presented at the Workshop on Mineral Dust,
Boulder, June 9-11.
1999, Prospero, J., D. L. Westphal, and R. Poirot: The great northeastern United States
haze event of 16-17 July 1999: A comparison of chemical transport models and
measurements. Presented at the Amer. Geophys. Union Fall Meeting, San
Francisco, Dec 6-11.
1999, Tratt, D. M., R. J. Frouin, and D. L. Westphal: A southern California perspective of
the April, 1998 trans-Pacific Asian dust event. Presented at the 10th Conference
on Coherent Laser Radar, Mt. Hood, OR, June 28 - July 2.