Meteorological Instrumentation

To properly test military material's vulnerabilities to weather effects in the real world as a complement to virtual testing requires a complete spectrum of meteorological services. Meteorology in support of military testing, therefore, is more diversified than usual civilian meteorological services such as National Weather Service and focuses on very specific locations, time periods, and types of meteorological phenomena. The instrumentation used to measure such phenomena is extensive.

After its review of US Army meteorological instrumentation, the National Center for Atmospheric Research (NCAR) noted in their final report (1996) that it was "quite good" and "provides a data-rich environment." (NCAR is the international center for scientific excellence in meteorology supported largely by the National Science Foundation.)

The following examples of instrumentation are available at Aberdeen Test Center. This instrumentation (NIST-traceable) is used to support extensive and complex outdoor testing in a very active weather location:

Test Support Required	Instrumentation Available
Acoustic Propagation	Meso-scale network and SODAR for continuous input to model predictions and verification of sound sensor network.
Background general meteorology conditions	Meso-scale network for entire APG area, continuous record.
Ballistic direct fire corrections	In-situ range crosswind measurement for Main Front and Trench Warfare II ranges. New in 1997-optical crosswind sensor for any site, any range, very accurate.
Ballistic indirect fire corrections	Upper-air suite of techniques for any time or height scale.
Infrared signature met effects	Complete suite of sensors--Airport Range 8, portable platforms with infrared irradiance, visual irradiance, rainrate, etc.
Smoke permits	Meso-scale network, SODAR-derived stability for input to smoke dispersion model
Special measurements for smart sensors	Raindrop spectra, rainrate, new (1997) transmission sensor
Water levels in Bay for safe access to UNDEX	National Ocean Service surveyed tide sensor, pressure and wind sensors

1. Meso-Scale and Micro-Scale Networks

Meso-scale and micro scale networks of surface data-collection platforms featuring standard and non-standard sensors as well as standard and non-standard sampling strategies (ATC has approximately 30--a compromise between test requirements and maintenance costs).

CLASSIC 10 METER DCP / DCP ENCLOSURE

Specially-outfitted test ranges can monitor atmospheric drag forces on projectiles in flight for verifying their performance for ballistic testing. Portable platforms can also be deployed anywhere to collect many different parameters needed to detect electro-optical, infrared, millimeter-wave, optical turbulence, rain, snow, stability, and transmissivity effects on test article performance.

RANGE POSITION / REMOTE SENSING TRAILER

2. Upper-air measuring equipment

Standard rawinsonde (weather balloon) systems (fixed and portable) sample from the surface layers up to the stratosphere for ballistic tests and for running models to characterize smoke dispersion, sound propagation, and atmospheric stability. Data routinely shared with the National Weather Service. Used recently in a study to measure transport of air pollution along the Atlantic seaboard cities.

BALLOON LAUNCH / DIGICORA SYSTEM

Acoustic Doppler SODARS sample the wind and air density field in the lower atmospheric boundary layer from the surface up to 500 meters every 15 minutes. Used for measuring atmospheric turbulence and small-scale changes in the low level wind field for smoke dispersion, sound propagation, air-drops, and spraying operations.

SODARS

Tethersonde samples wind, temperature, and humidity in the small-scale from the surface to over 500 meters to continuously monitor these parameters during tests that require calibrated measurements in the surface boundary layer.

Tethersonde

3. WSR88D NEXRAD Weather Radar

The Principle-User-Processor (PUP) workstation acquires real-time reflectivity and Doppler-derived wind velocity data from the U.S. NEXRAD network and generates dozens of products for application to test programs such as rainfall over a kilometer square grid, wind direction and speed every 15 minutes from the surface to over 10,000 feet out to 100 miles surrounding Aberdeen Proving Ground. This information is used to support ballistic and tests that require certain rainrates or no rain events for go/no-go decisions to save tests costs.

Mr. Kaiser working at NEXRAD PUP Workstation

Mr. Mitchell Working at NEXRAD PUP Processor

4. Special Non-Standard Instrumentation

Specialized instrumentation is constantly researched and maintained for tests involving specialized parameters by ATC. Rain-rate sensors and particle-measurement systems are necessary to help specify millimeter-wave and infrared weather effects.

MINI-ORG / PMS SYSTEM

Optical Anemometer

Infrared effects are also investigated with the use of special radiometers that measure irradiance in the visible and infrared spectra. For determining atmospheric transmissivity by actual measurement (instead of relying on computer models like LOWTRAN and MODTRAN) in the visible and infrared, an expensive multiband tranmissometer is available to ATC (summer of 1997).

HSS Visibility

Small Portable Transmissometer (SPOT)
Measures Transmissivity Over a 0-5,000 Meter Range

Source/Receiver

ATC provides this instrument for transmissivity
measurements. This unit is one of only seven in the world.