NASA Scientific and Technical Aerospace Reports

forecasting weather in the vast, data denied region of Southwest Asia in support of daily military and humanitarian operations.
As a result, the 28th OWS requests a simplified forecasting tool to help predict mesoscale dust events that affect coalition
operations at Al Udeid AB, Qatar. This research satisfies the 28th OWS request through an extensive statistical analysis of
observational data depicting seasonal dust events over the past 2 years. The resultant multiple linear regression best fit model
combines 28 easily attainable model outputs, satellite imagery, surface and upper air observations, and applies a linear
transformation equation. The best fit model derived provides the end user with a numerical visibility prediction tool for Al
Udeid AB that is verified against a seasonally divided and independent validation data set that yields an R2 of 0.79 while
maintaining < 800 m accuracy.
DTIC
Dust Storms; Forecasting; Weather Forecasting
20040073767 Army Research Lab., Adelphi, MD
Toward Improving the Efficiency and Realism of Coupled Meteorological Acoustic Computer Models for the Forest
Canopy
Arnold, Tunick; Apr. 2004; 24 pp.; In English
Report No.(s): AD-A422715; ARL-MR-586; No Copyright; Avail: CASI; A03, Hardcopy
Several physics-based computer models have been developed to calculate one-and two-dimensional forest canopy
micrometeorology and turbulence for future U. S. Army acoustic application research. Individual computer codes have
incorporated various computational methods on a uniform grid to solve the meteorological fields. However, it may be possible
to improve the efficiency and realism of the coupled meteorological acoustic computer models by introducing variable grid.
Variable grid will allow for better distribution of grid points and will extend calculations higher into the boundary layer above
the forest. A finer grid inside the forest and a coarser grid above the forest will help to resolve important meteorological (and
acoustic) scales and processes. Therefore, the following report presents results from some preliminary tests to incorporate this
important feature into numerical codes. First, several simpler physics-based diffusion models are developed to benchmark
fundamental (numerical) techniques. Both explicit and implicit differencing schemes are examined. In addition, numerical
stability criteria for these calculations are demonstrated. Then, successful preliminary tests on these codes are extended to
more complicated meteorological acoustic models for the forest canopy.
DTIC
Acoustic Properties; Acoustics; Canopies (Vegetation); Computer Programs; Computerized Simulation; Forests;
Meteorological Parameters
20040073770 Army Research Lab., White Sands Missile Range, NM
Forecast Model Uncertainty; MM5 Accuracy Over Utah
Sauter, Barbara; Mar. 2004; 46 pp.; In English; Original contains color illustrations
Report No.(s): AD-A422720; ARL-TR-3170; No Copyright; Avail: CASI; A03, Hardcopy
Researchers are investigating various approaches to determine and portray weather forecast uncertainty. Methods
requiring extensive computing power on the battlefield or massive data communications to the end user will not be
implemented in the near future. This study investigated weather forecast uncertainty through a compilation of forecast errors
in the Penn State/National Center for Atmospheric Research fifth-generation Mesoscale Model (MM5) over 50 winter days
in Utah. The percentage of forecasts meeting the Army s stated accuracy requirements for temperature, dew-point temperature,
wind speed, and wind direction is highlighted.
DTIC
Data Transmission; Forecasting; Weather Forecasting
20040074154 National Defense Univ., Washington, DC
Global Warming Could Have a Chilling Effect on the Military (Defense Horizons, Number 33, October 2003)
Pittenger, Richard F.; Gagosian, Robert B.; Dec. 2003; 9 pp.; In English; Original contains color illustrations
Report No.(s): AD-A422382; No Copyright; Avail: CASI; A02, Hardcopy
Most debates and studies addressing potential climate change have focused on the buildup of industrial greenhouse gases
in the atmosphere and a gradual increase in global temperatures. But this "slow ramp" climate change scenario
ignores recent and rapidly advancing evidence that Earth’s climate repeatedly has become much colder, warmer, wetter, or
drier-in time spans as short as three to 10 years. Earth’s climate system appears to have sensitive thresholds, the crossing of
which shifts the system into different modes of operation and triggers rapid, non-linear, and not necessarily global changes.
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