Sabbatical (Spring 2008) Report

Kakkala Mohanan Purpose of the Sabbatical Leave Main purpose of my sabbatical leave was to investigate the feasibility of the installation of a Lidar system at the Leeward Community College and work with the research faculty at the University of Hawaii, Manoa, to learn more about the operations of Lidar systems. This report contains a brief description of Lidar telescopes and its operations, the work that has been accomplished on/or related to this project, and its future plans. Lidar Project Description Lidar (LIght Detection and Ranging) is a technique by which a laser beam of known wavelength is fired into the distant atmospheric medium and then the scattered light, by the same medium, is collected to study the physical and chemical properties of it. In 2005, through the effort of the Leeward Community College Chancellor, the Leeward campus accquired a Multilens telescope that was under the supervision of Dr. Sharma, from the SOEST, UH Manoa (Attachment A). This Multilens telescope was used as an astronomical telescope to study the Moon at the top of Haleakala, Maui. This telescope has a total of eighty lenses with an effective optical aperture diameter of 1.7 meters (Attachment B). To use it as a Lidar instrument the telescope has to be modified first for its purpose. Leeward campus is an ideal choice to install a large Lidar system because of two main reasons: a) the readily available space and support facilities required to operate such a large and complex system, and b) the dry atmospheric conditions on the Leeward side of the island, highly desirable criteria for Lidar operations, compared to Windward side. Furthermore, the availability of such a facility, along with the existing observatory facilities on Leeward campus will give an added benefit to start new educational program in electro-optics to support the growing demand for entry level support personal, engineers and scientists in the growing tech-workforce-field in the state of Hawaii. The goal of my sabbatical was to investigate in detail all the necessities for starting the Lidar program along with all the requirements for starting a Certificate or a Diploma or a degree program in Electro-Optics on LCC campus. After bringing the telescope to LCC, it was safely moved and stored in the DA basement on the campus. First, priority was given to cleaning and testing the equipment for its normal operations. Dr. John Porter, a research associate in Lidar system from the UH Campus was hired to properly clean the optical system, and then design and modify to use it as a Lidar System. He successfully completed this task. In order to test the newly modified Lidar, a laser source has to be fired into the atmosphere. From the beginning, we were aware of the sensitivity of firing a laser beam into the open atmosphere, and yet we also knew that with adequate safety measures in place and obtaining a permit from proper channels, it is possible to use the laser to conduct Lidar experiments. Since Leeward observatory is located close to the international airport and busy Hickam Military Air Force, it was absolutely necessary to contact Federal Aviation

Administration (FAA) to get the permit required to use the laser. Upon contacting them, the local FAA office referred to the main office in Seattle, Washington. They suggested employing a well trained dedicated personal at the site at all time to physically watch for approaching aircrafts during the operation and informed us that an automatic-shut off radar technique was not adequate at this point in time, as we previously thought. The FAA offers training/operation information and it is available upon request. (For contact details see attachment C.) At present the Lidar system is ready for test run, however due to sensitive operational procedure, it has not been done yet (Please see the attachment D for the final report from Dr. John Porter on the update of the telescope modifications). Any operational mishap has serious consequence to the all individuals operating the Lidar system as well as for the college. Therefore, initial testing and continued operation of the Lidar system has to be done carefully and methodologically which requires much planning and takes time. Recently finished Master Plan for the Observatory Park includes a building structure for this Lidar system. However, funding is not available for its construction at the present time. Therefore, the telescope is stored in the DA basement. In the mean time, demand for the DA basement has prompted to move the Lidar telescope off LCC campus and Dr. Sharma is exploring various locations to store it. Electro-Optics Program In Hawaii there is already a need for qualified expertise in electrical/electronic and optical engineering to work in the filed of astronomy, bio-tech, environmental, and remote sensing. Furthermore, there are many small, less than ten employees, high-tech companies in the state of Hawaii looking for qualified workers also, and in time they are growing. Thus, there is an added demand for engineers and scientists, from beginner's level to advanced research level, in the state of Hawaii. Most of the larger firms are bringing engineers from the US Mainland to fill many of these positions. However, few firms remarked that their average turn around time is less than eighteen months and further commented that they rather fill these positions with qualified candidates from Hawaii if they are available. Therefore, given the growing demand for engineers from entry level to research level, it is only natural to initiate an educational program to support such a growing demand. Currently there is no special certificate/degree program offered by the University of Hawaii system. Even though the existing astronomical observatory and future Lidar program will be an added resources for hands-on field experiences, the current optics program offered at LCC do not have adequate supply of instrument and equipment to train students in the field of electro-optics. Therefore, new lab has to be set up for such a program and it is very expensive. Also, upon enquiry about the need for future work force, less than anticipated response was received from some of these firms which indicate that initiating a new and expensive educational program must be proceeded with much caution. With the same goals in mind universities in U.S. mainland has started similar programs. An ideal program that suits our system will be a 2+2+2 program in electro-optics to support

the local work force. Such a program will give students a choice of seeking an entry level position with the completion of a Certificate Program to higher level position with BS degree in electro-optics. However, an informal discussion with the head of a 2+2+2 program commented that after spending millions of dollars on developing a new lab and a program, the enrollment was far less than anticipated. Even after spending $250K on advertisement and recruiting, they still did not meet satisfactory enrollment to call the program successful. The advice given was not to spend money developing a new program and setting up expensive labs unless there is clear indication for strong demand for such work-force, which in my initial research was not substantiated. It is my thought that if LCC is contemplating on a program in electro-optics it is better to partnership with other community college campuses and UH Manoa to the make program cost effective and successful. Conclusion. During my sabbatical leave I worked on the following projects. i) Worked with Dr. John Porter and completed the modification the Multi-lens telescope to a Lidar system. ii) Investigated in depth the operational procedure of Lidar systems. I learned that it is very risky to operate a laser source needed to conduct Lidar research from the Leeward campus, for its proximity to the International Airport and Hickam Air Force filed. Extra or added security measures needed to be taken, such as employing a dedicated trained person to watch for approaching aircraft at all times during the operation of the laser beam. iii) Explored the need to start a new electro-optics program to fill the demand of engineers and scientist in Hawaii. My research indicates that it is not cost effective to start a new program at this point in time due to the lack of response I received from the firms, even though an apparent demand for entry level to research level engineers and scientists exits. iv) Worked with Mr. Christopher Smith, The CJS Group Architects Ltd in finishing up design phase of the Leeward Community College Astronomical and Hawaiian Garden Park. v) Conducted educational out reach programs by having students visit the LCC observatory park and learn astronomy. vi) Participated in an out reach educational program with Kamaile Elementary school on the Waianae coast.

Attachment A

Lidar Applications in Environmental Sciences (LAES) Research Center

A Proposal for a Cooperative Research Center for environmental Research

We propose to establish a Cooperative Research Center at the Leeward Community College in collaboration with the University of Hawaii at Manoa for developing active (laser) remote sensing of the atmosphere and the environment. The research programs at LAES research center will be fundamental molecular-level studies of atmospheric problems of marine and tropical ecosystems of special importance to Hawaii and the Pacific Basin. The center will employ and improve upon the most advanced lidar technologies, and become a Center of Excellence for applications of lidar technologies in environmental science and education for the Pacific region.

The purpose of the LAES center would be to build a foundation for fundamental understanding at molecular level of environmental processes using advance lidar technology, provide educational opportunity for the next generation of scientists and engineers, and disseminate the knowledge to the public. The vision is to understand source and transport of chemical, biological and toxic pollutants and their fate and effects on marine and tropical ecosystems at molecular level and to issue real time information on the environmental issues. We would also expect to provide a real test and evaluation of the integrated optical technologies and identify areas where this technology needs improvement or modification. In addition, we would also address several key atmospheric issues of interest to NASA.

LAES Research Center will also emphasize a systematic approach in the

following three research areas:

(1) Long term measurement of marine and volcanic aerosols with lidar system to be established at Leeward community College using existing 1.6 meter telescope and existing lasers.

(2) We will collaborate with NASA Research Centers to develop a number of techniques that will characterize the spatial and temporal distribution of water vapor over Hawaii and their radiative impacts using a scanning DIAL system that will be located at Leeward Community College. Other techniques will include satellite, GPS and sun photometers. Leeward Community College has strong program in astronomy and has two

astronomical observatories. We propose to argument these facilities by installing 1.6 m telescope that we received from Haleakala Observatory for remote sensing applications. The proposed cooperative LAES center is based on collaboration with the Leeward Community College and upon the past accomplishment and current research efforts at the University of Hawaii at Manoa. This collaboration between two Institutions of the

University of Hawaii System will offer research and educational opportunities to our students, and will benefit the State of Hawaii, the nation, and the Pacific Region.

Attachment B Multi-Lens Telescope (MLT) 1.7 meter receiver: The MLT that we propose to upgrade and install was originally constructed for lunar ranging program. This instrument was evolve out of the necessity for a relatively inexpensive (cost ~ $500K in early sixties) light gathering instrument of moderate aperture, which was extremely stable at the arc-second level. The 1.7 meter (effective optical aperture diameter) telescope is consisting of 80 achromatic lenses, each 7.5” (19 cm) in diameter, mounted in a very rigid hollow cubes placed at azimuth-altitude mount. For the sight of this size and f/10, spherical aberration would limit the resolution and hence the minimum operation stop size to about 14 sec of arc rather than 3 or 4 seconds of arc stop, which this instrument is capable of employing. The 80 f/10 achromatics constitute a clear equivalent to that of a single 67-inch (1.7 cm) diameter optical element. The effective “equivalent aperture” of this telescope in the visible region of the spectrum, considering its high 75-80% transmission efficiency and taking into account the obscuration necessary in a conventional telescope, is about 80” (2 meters). The MLT instrument is extremely stable and has been made to point. The light collected by individual lenses is brought to a common focus with the help of folding mirrors, and optical components have been used in the MLT to compensate for the path differences in the light from various lenses.

Attachment C Federal Aviation Administration contact Information 1. Flight Standards District Office 135 Nakolo Plcae Room 215 Phone 837-8300 2. FAA Honolulu Tower Honolulu Control Facility Bob Rabideau, Manager Debbie Saito, Assistant Manager Phone 840-6100 2. Dr. Larry Tonish Federal Aviation Administration Seattle, Washington 425-917-67766 larry.tonish@faa.gov

Attachment D

Progress Report On The Leeward Community College Lure Telescope Lidar

July 1, 2007 by John Porter

Researcher at UH, Hawaii Institute of Geophysics and Planetology johnport@hawaii.edu

Abstract

Two months of work were spent on preparing the Lure telescope for use as a Lidar system. Although it was not possible actually test the telescope as a lidar, this was for safety reasons and not due to any technical problems. Here I describe the preparations, problems, solutions, and possible applications in using the Lure telescope as a modern atmospheric lidar. 1) Introduction This report describes the efforts I have carried out to convert the Lure telescope into a lidar system for atmospheric measurements. Two months of my time were supported for this effort. The Lure telescope was initially designed to measure the range to the moon by shining a laser at the moon and measuring the light reflected back to earth by a retro-reflector left on the moon during the Apollo 11 mission. It was used on Maui for many years (see Figure 1) and was decommissioned in the 80s. It is now at Leeward Community College (LCC) where plans are to use it as a ground based lidar for atmospheric studies. Figure 1. Right figure shows Lure telescope as used on Maui.

Figure 2. Example of mold on one of the 7.5 inch Lure telescope lens.

Until recently, the Lure telescope was in storage (within a custom box) for many years. When I unpacked it I found it was in good structural and mechanical condition but that mold had grown on all of the lenses significantly reducing their quality (see Figure 2). After testing a variety of home made and commercial solutions, it was found that “Mold Avenger”, a commercial product, worked the best at removing the mold. Here the approach was to employ a solution which required minimal rubbing of the lens. After numerous applications and rinsing, the mold was removed from all the lens and they are now in fairly good condition and will work well for the lidar application.

2) Original Telescope Design The Lure telescope employs a unique design with 80 collection lenses and special mirrors and a lens to bring all the light sources to a single detector. The motivation behind the design was to create a large collection area at a fraction of the cost of a single mirror of equal size (James Faller designer of Lure telescope unpublished paper). This was possible because the objective was not to form an actual image, but to simply collect as much light as practical. Each lens has a diameter of 0.19 m (7.48 in.). Adding all the lens together is equivalent in area to a telescope with a diameter of 1.44 m (4.7 ft). The use of achromatic lens produces reduced spherical aberration resulting in near diffraction limit performance from 400nm to 1000nm. Behind each lens is a 2 mm pin hole at the lens focal point (~1.9 m away). Each pin hole has an adjusting mechanism which allows for a small amount of tuning of the distance between the lens and the pin hole. The pin hole size, lens focal length, and lens diameter result in an full acceptance angle of 2 mrad and an F-number of f/10. After passing through the pin hole the light is collimated with a small lens (focal length = 98mm) resulting in a collimated beam with a diameter of 9.8mm. The light beams from each lens system is brought to a single detector point using a series of mirrors and lenses. These remaining optics are not described here as they will be replaced by fiber optics greatly simplifying the alignment and maintenance of the new lidar system. 3) Preliminary Test of the Lure Telescope-Lidar At LCC At the beginning of my effort I was planning to collect lidar data using the Lure telescope to demonstrate its use. The telescope is located in a storage room with a door which opens southward. Although I have added wheels which can lift and move the 5000 pound telescope, it can only be moved over smooth ground and it is not possible to move out to the street without a forklift. In its current location, a small gap exist where some of the lenses could measure a laser beam pointed southward. Using a single lens fiber coupled to the detector, I had planned to test the system using a centrally mounted laser. Figure 3 shows the location of the Honolulu airport and the LCC. Based on this figure, it is highly likely that the laser beam pointed south from LCC could intercept aircraft as they descend into the Honolulu airport. For this reason the demonstration has been canceled and the system will require more preparation (discussed below) before the initial testing of the lidar system can be carried out. Despite this setback, it is useful to discuss the preparations which went into the preliminary test of the Lure lidar system. Figure 4 shows the configuration of the test setup where a laser beam is sent out from the center area of the Lure telescope and a single lens (of the 80 available) is used to collect the scattered light. Prior to sending the laser beam out it is expanded by passing through a telescope. This approach employs a

LCC

Figure 3. Location of LCC and airport. LCC is slightly above sea level therefore a laser beam headed south could be at the same height as an aircraft descending into the airport.

Figure 4. Basic setup to for initial lidar test with Lure telescope.

Airport

Figure 5 Image of custom telescope beam expander fabricated for testing the LCC lidar. The design includes a fine positioning adjustments as well as a novel way to adjust the position of the concave lens without disassembling the tube mounting. Although the design is now working well and appears simple, considerable time went into trials and failures before an ideal design could be achieved. concave lens to cause the laser beam to expand to fill the secondary. In this case the focal length of the lens was carefully selected and the lens was placed at the focal point of the telescope. After significant effort, a custom threaded slide was built which allowed the lens position to be adjusted without removing the overall tubing. Adjusting the telescope focus changes the position of the primary and causes the divergence of the outgoing beam to vary. This system was constructed specifically for this experiment and is shown in Figure 5. In addition to control of the laser beam divergence, the use of an expanded beam causes it to be invisible from side views drawing less attention to the lidar from the public. The detector system which was available for this initial tests consists of a photo-multiplier tube, a narrow band interference filter, a fast digitizer (12 or 14 bit) with USB computer connection, and software to collect the lidar traces. The laser for the test consists of a Big Sky Laser with a pulse length of ~10 nsec, ~20mJ/pulse and a repetition

LaserFine Tread Adjustment

Laser Power Supply

rate of 20 Hz. This setup was recently tested with a function generator and was ready to use in the experiment. All of these components were available from my previous lidar efforts (Porter et al., 2000;2002;2003). In order to bring light from the back of the Lure telescope to the detector an optical fiber with a modified collimating lens was designed and assembled. 4) Summary Of Work Carried Out

1) Unpack the telescope, 2) Clean mold on all lens, 3) Design and build wheel system to lift and allow Lure telescope to be moved, 4) Design and build setup for telescope beam expander, 5) Design and build fine alignment setup for laser launch system, 6) Design and build fiber detector to bring light to detector, 7) Modeling studies of expected lidar signal.

5) Design Suggestions For The Lure Telescope-Lidar System Due to the design of the Lure telescope it can be configured in a variety of ways. Here I suggest several possibilities, A) Telescope configured as single detector: - Laser beam expanded or not expanded, - Laser beam collimated or allowed to diverge at 2 mrad (same as telescope), - Laser pointed manually or under computer control, - Light from each lens brought to a single detector (80 light collimators, 80 fibers). This configuration is conceptually the simplest but requires effort to correctly align the laser beam. This problem occurs due to temperatures changes and thermal expansion of mechanical parts which misalign the outgoing beam and the telescope receiver. In the past we have always manually corrected the alignment but this is not the optimal approach. Automatic control of the beam alignment is more reliable and accurate. For instance the lidar at the Atmospheric Radiation Measurement (ARM) facility carry out alignment (under computer control) every 30 minutes. A similar approach should be implemented here if possible. Figure 6 shows a model of the lidar signal when the Lure telescope is configured as a single detector. This model assumes a telescope with a radius of 0.85 m (the size of the outer lens on the Lure telescope) and a central obstruction radius of 0.25 m (equal to the central region on the Lure telescope where there is are no lenses). Although the Lure telescope is not one large telescope, as modeled here, this difference will only change the amplitude of the signal and not the time dependent shape which is of concern here. The laser beam is assumed to be 3 mm wide (an unexpanded beam in this case). The green line corresponds to an atmosphere with no aerosols (molecular scatter only) while the blue line is for both molecular and aerosols (true condition). The modeled results show that up to 40 m range there is no signal as the beam is not within the field of view of the telescope (similar to figure 5). At ~350 m range the signal becomes the largest then decreases with range following the standard 1/range2 profile. For measurements out to 10 km range the signal covers a range of ~3.5 orders of magnitude which is acceptable for

the more expensive lidar detector systems. Several issues related to detectors are discussed below.

Figure 6. Modeling study of the Lure telescope configured as a single detector. Green lines is for molecular atmosphere, blue for true atmosphere. B) Telescope configured as multiple detectors: - Laser beam expanded or not expanded, - Laser beam collimated or allowed to diverge at 2 mrad (same as telescope), - Laser pointing controlled by motorized system to account for thermal effects, - Light from each lens brought to different detectors. Designing the Lure lidar system as a multi-detector system allows for some unique configurations. In each configuration, the detector gain is optimized for the expected dynamic range of the signal. In this case the inner ring of the lenses can be setup for short range (say 25-1000 m) while intermediate ring of lenses could be configured for long range (say 750-30,000 m). By adjusting the size of each pin hole the acceptance angle of each lens can be varied. Wide fields of view are optimal for short range but pick up too much ambient light for long range measurements. On the other hand narrow field of views are ideal for long range but cannot measure signal close in. A separate advantage of having multiple detectors is the possibility of investigating multiple scattering processes. In this case the laser beam and the lens are designed with narrow field of views so that light cannot enter the detector unless it enters through multiple scattering processes. The outer ring of lenses would be optimal for this configuration. The field of multiple scatter research is now providing exciting results for a variety of applications such as deriving cloud effective drop size (important for Climate

Change) to searching for skin cancer in humans. We now have a custom Monte Carlo model which is ideal for multiple scattering studies of various complex medium (Bates et al., 2007; Porter et al., 2007). C) Sending The Outgoing Laser Beam Through the Lure Lens: Another approach is to send the laser beam out through some of the Lure lenses and use the remaining lenses to collect the lidar light. This has the advantage that the diverging laser beam and the receiving lens have the same divergence, which are presumably co-aligned already. This approach has the advantage that alignment may be less difficult and the acceptance angle of the receiving lens is the same as the divergence angle of the transmitting lens. The disadvantage of this approach is that light scattered from within the main body of the telescope can find its way back to the detector and the initial pulse can blind the detector. Building baffles could remove this problem. A second challenge with this design is bringing the laser beam into the fibers without burning the fiber. Both problems are challenging but we have various solutions which I believe will work. 6) Lidar Detector System As shown in Figure 6, the lidar signal covers a large dynamic range. Two types of detectors are commonly used and include photo-multiplier tubes and avalanche photo-diodes. In order to measure the output signal from these detectors either an Analog to Digital (A/D) converter can be used when the lidar signal is large (close range) or photon counting can be used when the signal is small and long time integration is possible. Fast A/D systems typically have 12 or 14 bit digitization resolution. This corresponds to 3.6 and 4.2 orders of magnitude. But when one considers that the digitizer has an uncertainty of ±1 count then these values are reduced to 2.6 and 3.2 orders of magnitude if one requires less than 10% error in the measurement. For lidar we actually want less than 1% error. Several approaches have been employed to alleviate this problem from custom logarithmic amplifiers (Lienert et al., 2002) to Time Variable Gain for the pmt (Porter unpublished work). Photon counting requires that the high voltage on the detector be large making the photo-multiplier tube (pmt) very sensitive. In this condition the pmt is likely to saturate from large light levels from short range. Once the detector saturates it is not likely to recover in time to accurately measure the remaining light from larger ranges. In order to address this problem the pmt can be gated off until the laser pulse is far away from the laser. This approach works well once the ringing induced by changing the pmt high voltage has passed. Commercial detector packages exist with these features in the $10k price range. Alternatively this problem can be minimized by setting up separate near and far detector systems. In this case the far range receiver has a large central obstruction and does not see the laser beam from short range where the signal would be large. 7) Lure Telescope As A Training Tool The availability of 80 different lenses on the Lure telescope provides an excellent tool for training students. Students would be allowed to test different configurations by simply modifying the collector design using different fiber and detector arrangements. The availability of modern state of the art ocean-atmosphere radiative transfer modeling tools

(i.e. custom Monte Carlo code, Modtrans, High Trans) can allow for training in the complex field of active and passive remote sensing for environmental, military and commercial interests. 8) Mobile Telescope While the Lure telescope will make an excellent training facility at LCC, it will not be put to optimal use if it remains stationary at Leeward Community College. There are a variety of climate and environmental issues which could be addressed if the Lure telescope was mobile. Issues such as cloud properties, trace gasses, local pollution emissions, and atmospheric optics studies for military applications. Adding wheels to the Lure structure should be possible allowing it to be a trailer which can be easily towed to different locations. It is envisioned that it would be moved to a particular location for some field campaign during the summer (1-2 months). Having the Lure telescope mobile would make it very attractive for field experiments carried out by various funding agencies (NASA, NOAA, NSF). Involving the students in funded research projects will provide them with hands on field experience and allow interaction with other scientist. This type of training and experience would give the students an advantage in securing jobs within the electro-optics industry. 9) Use Of Radar To Shut Down Lidar Using the Lure telescope near the Honolulu airport (or anywhere) requires care to not shine the laser beam onto an aircraft. In order to address this problem, several research groups have employed a small radar to detect aircraft in the region where the laser is pointed. Under automatic control the laser is shut down if the aircraft becomes too close. This radar is likely to cost ~$20k along with further cost to implement the system. Acknowledgement This work benefited greatly from long discussions with Dave Harris (Engineer at the Hawaii Institute of Geophysics and Planetology, Engineering Support Facility). Dave has many years of electrical and optical experience and took a keen interest in this effort donating time and energy. Barry Lienert (HIGP Researcher) allowed me to use his near field modeling code and Shiv Sharma (HIGP Associate Director) was instrumental in bringing the Lure telescope to the University of Hawaii and has been very supportive of and in this effort. References Bates, D., J. Porter, S. Sharma, and J. Bowles, Atmosphere-Ocean 3-Dimensional (AO3D) Monte Carlo Radiative Transfer Model, Pacific Congress on Marine Science and Technology (PACON), Honolulu, Hawaii, 2007. Lienert, B, J.N. Porter, N. Ahlquist, D. Harris, S.Sharma, A 50 MHz Logarithmic Amplifier for use in Lidar Measurements, J. of Atmospheric and Oceanic Technology, 19, 654-657, 2002.

Porter, J.N., Lienert, B., S.K. Sharma, Using the Horizontal and Slant Lidar Calibration Methods To Obtain Aerosol Scattering Coefficients From A Coastal Lidar In Hawaii, Journal of Atmospheric and Oceanic Technology, 17, 1445-1454, 2000. Porter, J.N., B. Lienert, S. K. Sharma, and H. W. Hubble, A Small Portable Mie-Rayleigh Lidar System to Measure Aerosol Optical and Spatial Properties, J. of Atmospheric and Oceanic Tech., 19, 11, 1873-1877, 2002. Porter, J.N., K. Horton, P. Mouginis-Mark, B. Lienert, E. Lau, S.K. Sharma, J. Sutton, T. Elias, and C. Oppenheimer, Lidar and Sun Photometer Measurements of The Hawaii Pu’u O’o Volcano Plume: Estimates of SO2 and Aerosol Flux Rates and SO2 Lifetimes, Geo. Res. Let., 29, 2002GL014744, 2002. Porter, J.N., S.K. Sharma, B. R. Lienert, E. Lau and K. Horton, Vertical and Horizontal Aerosol Scattering Fields Over Bellows Beach, Oahu During the SEAS Experiment, J. Atmos. Oceanic Technol., 20, 1375-1387, 2003. Porter, J., D. Bates, S. Sharma, and J. Bowles, Application of the AO3D Monte Carlo Radiative Transfer Model To Various Environmental Problems, Pacific Congress on Marine Science and Technology (PACON), Honolulu, Hawaii, 2007.

Attachment E Sample Websites for the Electro Optics Program 1. http://old.www.iup.edu/armstrong/222/index.shtm 2. http://www.ihcc.cc.ia.us/ihcc/Learn/advtech/laser.asp 3. http://www.isu.edu/academic-info/prev-isu-cat/ugrad99/sat/99slaser.htm