Quantitative assessment of surf-produced sea spray aerosol

The first results are presented from a quantitative model describing the aerosol production in the surf zone. A comparison is made with aerosol produced in the surf zone as measured during EOPACE experiments in La Jolla and Monterey. The surf aerosol production was derived from aerosol concentration gradients measured downwind from the surf zone...

Aerosol transport in the coastal environment and effects on extinction

The aerosol in the coastal environment consists of a complicated mixture of anthropogenic and rural aerosol generated over land, and sea spray aerosol. Also, particles are generate dover sea by physical and chemical processes and the chemical composition may change due to condensation/evaporation of gaseous materials. The actual composition is a...

Characterizing large aerosols in the lowest level of the marine atmosphere

This paper discusses techniques to describe the aerosol and the electro optical properties of the marine atmosphere from 15 meters down to the tops of the highest wave. Emphasis is placed on the experimental Rotorod technique to measure the concentrations of giant sea salt droplets. Data from these devices are parameterized using a lognormal...

Aerosol concentration and fetch

On the basis of a comprehensive series of measurements on the Irish Atlantic coast, an extension of the Navy Aerosol Model (NAM) for the coastal zone is proposed. As in NAM, the dependence of the aerosol concentration on meteorological parameters is parameterized using empirical coefficients. The effect of continental aerosols present in the...

Scintillation measurements during the EOPACE Novenber '96 and August '97 campaigns

Following scintillation experiments during EOPACE measurement campaigns in the spring of 1996, a new set of experiments was designed in November 1996 and August/September 1997 over San Diego Bay. The main purpose was to further investigate the discrepancy between measured scintillation data and values predicted from turbulence models. One simple...

An Extensive Analysis of Low-Level IR Transmission Measurements taken over a 15km Path during EOPACE with IRBLEM

Results of over 300 far IR and mid IR transmission measurements taken during several EOPACE intensive operational periods over the low-level 15 km transmission path across San Diego bay are presented. A thorough comparison with calculations obtained using simultaneously measured bulk meteorological parameters with the IR Boundary Layer Model,...

Low elevation transmission measurements at EOPACE; Part III: Scintillation effects

This paper concerns the effect of scintillation on the detection range of infrared sensors, where frame rate appears to play an important role. During EOPACE scintillation measurements were carried out over the Monterey and San Diego Bay. For this purpose 2 kinds of sources were used, either a source, modulated with 1000 Hz, or a DC searchlight...

Atmospheric effects on low elevation transmission measurements at EOPACE

An analysis is presented showing the effects of refraction, aerosol extinction, and molecular extinction on transmission measurements obtained during the EO Propagation Assessment in Coastal Environments (EOPACE) campaign carried out in San Diego during March and April 1996. Infrared transmission measurements were made over both a 7 km path (mid...

Low Elevation Transmission Measurements at EOPACE Part I: Molecular and Aerosol Effects

An analysis is presented showing the effects of molecules and aerosols on atmospheric transmission data obtained during the Electro-Optical Propagation Assessment in Coastal Environments (EOPACE) campaign carried out in San Diego during March and April, 1996. Mid wave infrared transmission was measured over San Diego Bay along a 14.9 km path and...

Point Target Extinction and Scintillation as function of range at LAPTEX, Crete

The range performance of IRST sensors is partly determined by the propagation of the atmosphere. For low altitude targets the boundary layer of the atmosphere introduces a variety of effects due to inhomogeneities, for which model predictions are not yet well validated. For this reason NATO Research Study Group 5 on "Maritime Infrared Target and...

Marine aerosol properties and thermal imager performance (MAPTIP): an overview

The MAPTIP (marine aerosol properties and thermal imager performance) experiment was organized as part of a project to assess atmospheric effects on the detection and identification of targets using thermal imagers in coastal areas. The experiment took place at the North Sea from 11 October - 5 November 1993 and was centered around Meetpost...

Comparison of MAPTIP FLIR Detection Ranges to the EOTDA Prediction Model

The 1993 marine aerosol properties and thermal imager performance (MAPTIP) exercise conducted in the North Sea off the Dutch coast provided data for evaluating the electro- optical tactical decision aid Mark III (EOTDA) in a littoral environment. The EOTDA is a strike-warfare planning tool that is installed in the Navy's tactical environmental...

Lateral Variations of aerosols and meteorological properties in off-shore winds

Aerosol particle size distributions and meteorological parameters were measured during the MAPTIP experiment in the fall of 1993 in the vicinity of MeetPost Noordwijk (MPN), a platform at 9 km from the Dutch coast. One data set was collected at MPN, the other on board of a ship that sailed down and cross wind trajectories. from MPN to a distance...

Lidar measurements of atmospgeric extinction during the MAPTIP trial

During the MAPTIP experiment, that was organized by NATO AC/243 (Panel 4)/RSG.8, the marine atmosphere was characterized, among others, with lidar (optical radar). The investigations were carried out both in horizontal planes (PPI scans), in vertical planes (RHI scans) and combinations of those two. In addition, the temporal variability of the...

Transmission of 10 micron radiation over coastal waters; comparison of point source image intensities with aerosol extinction and MODTRAN calculations

During the MAPTIP experiments in the Dutch coastal waters, 11 October - 5 November 1993, transmission curves were determined from the intensities of the image of a point source suspended from a helicopter at ranges between 0.5 and 6 NMi. The images were recorded with a 10 micrometer USFA 9092 camera from the MeetPost Noordwijk, a research tower...

Comparison of lidar and transmissometer measurements through clouds

A lidar-transmissometer intercomparison was made during an international experiment held in the German Alps to characterize the vertical structure of aerosols and clouds. The transmission path was 2325-m long and inclined at 30 degrees along the slope of a steep mountain ridge. the transmissometer consisted of a Nd:YAG and a CO2 laser located in...

Validation of a bulk turbulence model with therman images of a point source

A model was developed for the prediction of turbulence in the marine surface layer. The model requires standard meteorological values of air temperature, air humidity, wind speed each from any given height from within the surface layer and the sea surface temperature. Internally, the model is controlled by the exchange coefficients for momentum,...