Sequoia Scientific


B&W picture of Ole Aarup MikkelsenOle Aarup Mikkelsen, President & CEO

My initial life plan was to become a theoretical physicist, Stephen Hawking was an early idol. But in high school I had a phenomenal geography teacher, so that’s what I ended up studying in college instead. My Ph.D. thesis (2001) dealt with suspended particle dynamics in Danish coastal waters, and had lots of LISST results in it. One of Sequoia’s very first customers was my supervisor, Professor Morten Pejrup at University of Copenhagen, and to a large extent my life and career has been intertwined with Sequoia since he bought LISST-100 s/n 1019 from Sequoia in 1997. (That unit, btw, is still going strong today (2019), and despite decades of use it has only been back for service once in 22 years).

A series of early visits to Sequoia during my Ph.D. (1998-2001) and subsequent postdocs in Canada and the UK (2002-2007) led me to being hired by Sequoia and relocating to Seattle in November 2007. During my Ph.D. I used a LISST to study the dynamics sedimentology of suspended particles in Danish coastal waters, leading to some of the first papers on in-situ estimates of flocculation time scales, the influence of flocculation on remote sensing estimates of particle concentration, and a new settling velocity model. During my 2001 visit to Sequoia I started working on the randomly shape particle studies, which culminated in 2008 with the JGR publication of the randomly shaped particle matrices. Sequoia is still the only company in the world to have done this. During my post doc in Canada I developed the INSSECT sampling platform for studying dynamic sedimentology in coastal areas, deployed in a number of locations in Canada and the Adriatic Sea 2002-2005. My work on Schlieren, which can potentially affect all optical instruments, also was initiated during my Canadian postdoc, and finalized during my postdoc in the UK (2005-2007). Upon relocating to Seattle work continued on the randomly shaped particle topic, leading to a couple of papers in Applied Optics with published phase functions for randomly shaped particles.

I left Sequoia in 2013 but was brought back as President 1/1/2019 as Yogi retired.


Chuck_PottsmithChuck Pottsmith, VP, Operations

All of my life I have been fascinated by what makes things work. My whole career as a mechanical engineer has just been an extension of the curiosity I had as a kid. I think I have the best job in the world…I get paid to invent, build, and make work a wide variety of interesting things.

I started my career as a fluid dynamics laboratory technician at Flow Research while going to school at the University of Washington. I learned many things about experimental science and fluid mechanics. In addition to learning the science I also learned the art of machining. My hours spent working with and talking to the “elders” of the machine shop taught me how to be a much better mechanical engineer.

In 1988 I met Dr. Yogi Agrawal. After graduating I started working with Yogi full time and I have been working with him ever since. We have built many unique instruments for our oceanographic research. Most, if not all, included some kind of optics and electronics. Some examples are Laser Doppler Velocimeters, Laser particle size analyzers, and underwater cameras. All of which were in-situ instruments that required close coupling of electronics, optics and mechanical components.

Yogi and I started Sequoia in early 1995 on the idea that we could build a better science and technology company. We wanted to work at a place that could do both high caliber contract science and manufacture state of the art research equipment. We feel that we have achieved that goal.


DRD portrait croppedDavid R. Dana, VP, Engineering & Production

At about the age of six, I was excited to discover that I could make my fingers tingle by pulling a 110-Volt plug partly from a socket and touching both blades. Surprisingly, I survived childhood, with all my fingers, and with enough working neurons to learn more sophisticated ways of handling electrons. Eventually, with the help of professors, mentors and colleagues, I expanded my skills to include all facets of electronic and software design, and project management, with a smattering of mechanical engineering, optics, space physics and oceanography.

I have devoted my career to the design, development and deployment of sophisticated instrumentation to support scientific research. That has often involved equipment working in hostile and inaccessible places, from the deep ocean to low Earth orbit. After deployment, I’ve usually been the first interpreter of the data returned from these exotic places. But what keeps me going is the thrill of helping a design go from a concept to the real world. I’m happy to be part of a team that does that all the time.


slade_0aea574Wayne H. Slade, VP, Science & Technology

My research focuses on characterization of oceanic particles and their dynamics using optical methods, especially using multi-spectral, multi-angle, and polarized measurements of inherent optical properties. As a research scientist at Sequoia Scientific, one of my primary aims is the development of instrumentation and methods for measuring particle optical properties and the deployment of these technologies in observing systems, ship-based flowthrough systems, and on autonomous and other challenging platforms. I received a Ph.D. in Oceanography in 2011 focused on ocean particle optics. I am experienced in deploying optical sensors in coastal and open ocean environments, in design and execution of laboratory studies using these same sensors, in the analysis of data from field and laboratory experiments, and in computer modeling of the optical properties of particles. I have additional research experience in signal and image processing and intelligent algorithm design.

Current Research Interests

Improving understanding of the links between optical properties and particle size

Measurement of the volume scattering function and polarization properties of natural waters and links to particle properties

Developing algorithms and validation methods for remote sensing algorithms for estimating biogeochemical quantities such as particulate organic carbon and particle size distribution


Yogi_website150x150 Yogesh C. Agrawal, President (Emeritus)

Yogi received a PhD in the mechanics of fluids from the Univ of California, Berkeley in 1975. His Bachelor’s degree was from IIT, Bombay, India. In the course of his PhD, he became interested in lasers, first for Doppler velocimetry (LDV), applying it to measuring blood flow in a model human aorta. Later he developed LDV’s for combustion research, and then shifting to ocean science, he built autonomous systems for use on deep ocean bottom, in shallow seas, and lakes. This interest in sediment transport in coastal and ocean boundary layers introduced him to laser diffraction technology for particle size measurements. This became the basis of the company, Sequoia Scientific, that he founded with partner Chuck Pottsmith in 1995. The company has produced a series of laser diffraction instruments under the trade name LISST for use in coasts, ports, harbors, rivers etc. Yogi’s most recent interest is in high-frequency acoustic backscatter measurement of particles. This technology underlies Sequoia’s LISST-ABS series instruments. Yogi continues to publish and contribute to technology development at Sequoia.


Curtis MobleyCurtis Mobley, Emeritus Vice President and Senior Scientist

Although my background is physics and meteorology, most of my career has been devoted to research in radiative transfer theory applied to problems in optical oceanography and ocean color radiometry. The widely-used HydroLight computer program, the textbook Light and Water: Radiative Transfer in Natural Waters, and the Ocean Optics Web Book ( are the best-known products of my efforts.

Early in my career, I was a Fulbright Fellow to Germany, and I have held both regular (at the NOAA Pacific Marine Environmental Lab) and senior (at the Jet Propulsion Lab) National Research Council Resident Research Associateships. I was an oceanographer with the University of Washington Joint Institute for the Study of the Atmosphere and Ocean during the 1980s. From 1989-1991, I was the Program Manager of the Ocean Optics program at the Office of Naval Research.  I have also been an associate professor of physics at Pacific Lutheran University, an Affiliate Professor in the School of Oceanography at the University of Washington, and an External Faculty member of the School of Marine Sciences at the University of Maine.  I was the 2012 Distinguished Alumnus for the School of Atmospheric and Oceanic Sciences at the University of Maryland.  I received the 2016 Jerlov Award, in part for “applications of radiative transfer theory to problems in optical oceanography.”   According to Google Scholar Citations, my papers and books have been cited over 10,000 times.  I have an H index of 37 (37 papers cited 37 or more times), and 70 papers with ten or more citations.   I have been Vice President for Science and Senior Scientist at Sequoia since 1997.

Research Interests

Much of my early research at Sequoia sought to improve remote sensing of optically shallow water. That work involved the development and evaluation of spectrum-matching methods for retrieval of bathymetry, bottom classification, and water inherent optical properties from airborne hyperspectral imagery.  More recent work has been on improving ocean ecosystem models by improving their light calculations (the light both heats the water and drives photosynthesis).  One result of that work is the extremely fast EcoLight-S(ubroutine) radiative transfer code, which is designed for use as the optical component of coupled physical-biological-optical ocean ecosystem models.

I also have a fondness for teaching, and I have taught many intensive week-long courses and summer classes (twice at the Univ. of Washington, 7 times at the Univ. of Maine, 3 times in France, twice in Brazil, 3 times in China, and also in Singapore and Sweden).  I enjoy figuring out something and then explaining it to others, so much of my time is now spend adding new material to the Ocean Optics Web Book.


Starting in graduate school, my wife, Ann Kruse, and I devoted all weekends and vacations to climbing — ice in New England in the winter, rock in California, mountaineering in Alaska, and everything in between. But after 20 years of playing on vertical terrain, all of the climbs started to feel the same. This serious mid-life crisis was resolved when we discovered sea kayaking. Our vacations now find us paddling in exotic locations around the world.  Our kayaking expeditions have included Alaska, Greece, arctic Norway, eastern Greenland, Panama, and Fiji.  Thoughts of Antarctica are now becoming more frequent.  You can see photos from recent trips at our Smugmug site.

For almost 20 years I led trips for Wilderness Volunteers, a non-profit organization that does trail maintenance, habitat restoration, archaeological surveys, and similar work in National Parks, wilderness areas, wildlife refuges, and other public lands.  I now serve on the Wilderness Volunteers Board of Directors.  For many years I also led white-water rafting and sea kayaking, and cultural trips in China, for the Sierra Club

I think everyone should have an ongoing project for which failure is guaranteed but which will leave you a better person.  For that last few years, my project has been learning a bit of Mandarin Chinese.