Exploring Your Environment with Arduino Microcontrollers
(See IESRE home page for ordering information and additional information about this book.)
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| Brooks, David R. Exploring Your Environment with Arduino Microcontrollers (See IESRE home page for ordering information and additional information about this book.) |
The paper referenced in the Aura Science Team Meeting presentation
Forrest M. Mims III, LED Sun Photometry
Niepold, F., D. Brooks, B. Lefer, A. Linsley, K. Duckenfield, Climate Literacy Through Student-Teacher-Scientist Research Partnerships,
E.J. Brinksma, T. Vlemmix, I. de Haan, N. van der Hoeven,
J. de Vroom, K.F. Boersma, D. Brooks, S. Stockman, P.F. Levelt, Satellite Aerosol Validation using KNMI-GLOBE data,
Aura Science Team Meeting, 11-15 September, 2006, Boulder, Colorado.
In the previous years, more than 400 measurements over
12 locations were performed. These data were
compared with MODIS and Aeronet data, and shown to be
sufficiently sound for validation of MODIS data over five
Dutch locations. We conclude that MODIS overestimates AOT at
low values, and underestimates AOT at high values over
land, while in coastal areas, MODIS overestimated AOT
in general (Boersma and De Vroom, accepted for publication
in JGR).
Starting in September 2006, the GLOBE efforts in the
Netherlands will increase substantially. They are
part of an educational module on Aerosols and UV, which
will be offered as option to all 670 secondary schools by
September 2007, within the framework of the official curriculum
for the high school exams. We expect that the number of
schools measuring aerosols will increase over the next 1.5 years
to about 100.
The module teaches school children about
aerosols in general, the importance of UV radiation, the
underlying physics, and satellite observations. Part of
the module is that students measure with the sun photometer.
KNMI provides the scientific input, including instrument
calibration and quality control, and trains teachers
in doing the measurements, so they can teach their pupils.
We also maintain a website with the AOT results, based on
an improved algorithm that also corrects for actual ozone
columns (from SCIAMACHY).
The GLOBE data from the coming years will be used for validation
of OMI AOT over the Netherlands. With data from about
70 schools over a country of about 200 x 300 km, we expect
to have a dense network of regular measurements, which is not
available from more professional instruments.
Besides the educational task, the GLOBE-KNMI programme also
addresses outreach, by promoting science to students,
and indirectly by generating press interest for GLOBE and thus
also for satellite research.
Rebecca A. Boger, David Brooks, Albert Rafalimanana, The GLOBE Malaria Project: A Unique Student/Teacher/Scientist Partnership. Seventh International Conference on School and Popular
Meteorological and Oceanographic Education, 3-7 July 2006, Boulder, Colorado, USA.
The GLOBE Madagascar Malaria Project is a new initiative whose objective is to involve students, teachers, and the community in learning more about malaria, collecting environmental data relevant to malaria, and educating the community to assist in combating this mosquito-borne disease. Madagascar schools, scientists, health department officials, government officials including the Minister of Education, and others, have given their support to this project that links GLOBE hydrology and atmospheric data with mosquito larval occurrence and identification. In the context of environmental/Earth science education, the issues related to malaria can be viewed as a unique opportunity for developing scientist/teacher/student partnerships that attack a real-world problem with the resources that only a widely dispersed network of participants, such as GLOBE educators, students and scientists can provide. Local identification of mosquito breeding/hatching sites is critical because mosquitoes tend to stay within a few kilometers of their hatching sites. In developing countries such as Madagascar, it is entirely possible that GLOBE schools in remote locations could provide the only regular source of these kinds of data. Once the Madagascar pilot study is complete, this project can be expanded to the continent of Africa and to other parts of the world.
To date, Madagascar scientists and educators have drafted and field tested science and education materials for teachers and students. The materials are currently under revision based on the initial evaluations gleaned from field testing. The larval collection and identification protocols will be implemented in schools the next school year along with other GLOBE protocols that provide a more complete picture of the environmental conditions controlling mosquito breeding. The data collected will be made available to the scientific and public health community and used to promote student research. Results from this project can be used to increase public awareness of malaria in participants’ communities and to provide better information for guiding effective mitigation strategies.
David Brooks, Rebecca A. Boger, Albert Rafalimanana,
The GLOBE/Madagascar Malaria Project: Creating Student/Educator/Scientist Partnerships with Regional Impact. 2006 Joint Assembly of the AGU, GS, MAS, MSA, SEG, and UGM, 23-26 May 2006, Baltimore, MD, USA.
The GLOBE Program is currently collaborating with students, educators, scientists, health department officials, and government officials in Madagascar to develop a program that combines existing GLOBE protocols for measuring atmospheric and water quality parameters with a new protocol for collecting and identifying mosquito larvae at the genus (Anopheles and non-Anopheles) level. There are dozens of Anopheles species and sub-species that are adapted to a wide range of micro-environmental conditions encountered in Madagascar’s variable climate. Local data collection is essential because mosquitoes typically spend their entire lives within a few kilometers of their breeding sites. The GLOBE Program provides an ideal framework for such a project because it offers a highly structured system for defining experiment protocols that ensure consistent procedures, a widely dispersed network of observing sites, and a centralized data collection and reporting system.
Following a series of training activities in 2005, students in Madagascar are now beginning to collect data. Basic environmental parameters and first attempts at larvae collection and identification are presented. Results from this project can be used to increase public awareness of malaria, to provide new scientific data concerning environmental impacts on mosquito breeding, and to provide better information for guiding effective mitigation strategies. Problems encountered include difficulties in visiting and communicating with remote school sites. These are typical problems in developing tropical countries where malaria is endemic and their solution benefits the entire scientific and educational infrastructure in those countries. Joris de Vroom, Boersma, K.F., Brooks, D.R.:
Undergraduate student measurements to validate satellite-derived aerosol
optical thickness. Abstract submitted to European Geosciences Union, General Assembly 2005,
Vienna, Austria, 24-29 April, 2005.
K. F. Boersma and J. P. de Vroom, Validation of MODIS aerosol observations over the
Netherlands with GLOBE student measurements, in press, J. Geophys. Res., 2006.
ABSTRACT
We have established a network of secondary schools in the Netherlands with students routinely
measuring aerosol optical thickness (AOT) at two wavelengths with a hand-held Sun photometer.
As the Dutch contribution to Global Learning and Observations to Benefit the Environment (GLOBE),
more than 400 measurements have been performed on different days over more than 12 locations within
the Netherlands. We have developed an improved AOT retrieval algorithm that accounts for the effective
wavelength of the broadband GLOBE detectors, and for the spatiotemporal variation of ozone. Results
from a theoretical error analysis indicate that GLOBE Sun photometer measurements achieve a
precision better
than 0.02 AOT for both channels. A comparison of measurements over The Hague shows that students and
AERONET, 4 km apart and with sampling time differences up to 30 minutes, observe the same AOT within
0.04 AOT. From these tests, we conclude that student data is scientifically valid and may be used to
validate MODIS AOT retrievals over the Netherlands. We find that, over land, MODIS overestimates AOT
at low values, and underestimates AOT at high values. Over coastal areas, MODIS overestimates AOT.
Seasonally
averaged MODIS observations over Northwestern Europe show relatively highest AOT values over the
region of Flanders and the Netherlands, with a seasonal cycle peaking in Spring/Summer. Our study
shows the potential of secondary school-based networks in addition to existing, professional networks
that have much less spatial coverage.
Go to Papers and Other Publications of Interest by Other Authors.
Recent Papers and Other Publications with Brooks and/or Mims as Principal or
Co-authors
Twenty years ago, amateur scientist Forrest Mims revolutionized the field of sun
photometry by devising an inexpensive filterless method of detecting sunlight that uses LEDs as
spectrally selective photodiodes. He has been working ever since to develop improved instruments and
collect measurements of atmospheric aerosols and water vapor. His story highlights that good science
requires neither a big budget nor an advanced degree—just an active, engaged mind.
Eos Trans. AGU,
87(52), Fall Meet. Suppl., Abstract ED11C-03, 2006
ABSTRACT
Expanding on the GLOBE Program's Atmosphere and Aerosol investigations, high school students can conduct Earth System
scientific research that promotes scientific literacy in both content and the science process. Through the use of Student-Teacher-Scientist
partnerships, Earth system scientific investigations can be conducted that serve the needs of the classroom as well as participating scientific
investigators. During the proof-of-concept phase of this partnership model, teachers and their students developed science plans, through consultation
with scientists, and began collecting atmospheric and aerosol data in support of the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS)
campaign in Houston Texas. This effort uses some pre-existing GLOBE materials, but draws on a variety of other resources to tailor the teacher development
activities and intended student participation in a way that addresses local and regional problems. Students and teachers have learned about best practices
in scientific inquiry and they also helped to expand the pipeline of potential future scientists and researchers for industry, academia, and government.
This work began with a Student-Teacher-Scientist partnership started in 2002 during a GLOBE Aerosol Protocol Cross- Ground Validation of AERONET with MODIS
Satellite Aerosol Measurements. Several other GLOBE schools, both national and international, have contributed to this research. The current project support
of the intensive GoMACCS air quality and atmospheric dynamics field campaign during September and October of 2006. This model will be evaluated for wider
use in other project-focused partnerships led by NOAA's Climate Program Office.
ABSTRACT
Within the GLOBE Aerosol Programme, high school students
perform sun photometer measurements of the aerosol optical
thickness (AOT) at two wavelengths as part of their science
curriculum.The Dutch contribution to the GLOBE Aerosol
Programme represents the largest student-based
aerosol monitoring project in the world. This contribution
is a collaboration between KNMI, SME Advies, and the GLOBE Programme.
ABSTRACT
pdf version of paper
ABSTRACT
Malaria is a parasitic disease spread by mosquitoes in the genus Anopheles. It causes more than 300,000,000 acute illnesses and more than one million deaths annually, including the death of one African child every 30 seconds. Recent epidemiological trends include increases in malaria mortality and the emergence of drug-resistant parasites. Some experts believe that predicted climate changes during the 21st century will bring malaria to areas where it is not now common.
AGU PowerPoint Poster. NOTE:
To access this file, your browser must be configured to allow files to be opened, and PowerPoint must be installed on your computer.
The poster is a single slide, 56" x 36". Viewed full-screen, the text
will not be readable. However, you can "zoom in" on parts of the poster.
Brooks, David R., Alan Czarnetzki, Wade Geery, Kelen Panec, Richard Roettger.
Current Scientist/Teacher/Student Collaborations in Atmospheric Science. Ninth Annual
GLOBE Conference, 31 July -- 05 August, 2005, Prague, Czech Republic.
Panec, K., Brooks, D., McLaughlin, J., Seavey, M. M., Grimm, M., Hickman, C., Shepard, N.,
Agbese, Q. Teacher, Student, and Scientist Collaboration for the Benefit of Education and Science: GLOBE ONE. Presentation ED12A-04, 2005 AGU, SEG, NABS and SPD/AAS Joint Assembly,
New Orleans, Lousiana, USA, 23—27 May, 2005.
ABSTRACT
GLOBE is a partnership between students, teachers, and scientists in more than 100 countries designed to benefit science and education. Participating students learn about Earth's systems by collecting atmosphere, soils, hydrology, land cover, and seasonal data at the local level and sharing it. In 2004, GLOBE began an intensive new field campaign in Black Hawk County, Iowa: GLOBE ONE. Students and local volunteer citizens collect a structured data set of environmental measurements that is being used for research and publication. Students participating in the program have multiple opportunities to meet with GLOBE scientists in both large and small group settings. Educators in the program have frequent training opportunities and ongoing support from GLOBE scientists and the local GLOBE partner. Kelen Panec's eighth grade students at Central Middle School, in Waterloo Iowa are working directly with Dr. David Brooks and other GLOBE scientists to study the atmosphere. The students are collecting temperature, precipitation, aerosol, cloud type, cloud cover, and contrail data on a daily basis. Participation in the program provides students with experience doing real science, as evidenced by Kelen's students who are now working on answering atmospheric research questions of their own. GLOBE ONE is a model for partnering students, teachers, local community members, and scientists to benefit science and education.
ABSTRACT
In reference to aerosols and their role in the climate system, the need to measure aerosols with satellite instruments, and
reduced enthousiasm for technical sciences in secondary education, the main question addressed in this talk is:
Can measurements by 15-18 year undergraduate students be used to validate aerosol measurements by satellite instruments?
We have investigated the accuracy of aerosol measurements performed by undergraduate students in the Netherlands within the
GLOBE (Global Learning and Observations to Benefit the Environment) framework. A network of 17 schools equipped with simple, hand-held
Sun photometers is currently operational in the Netherlands. This network has been set up as a cooperation between the Institute for
Environmental Education (SME Milieuadviseurs), The GLOBE Program (www.globe.gov) and KNMI (www.knmi.nl/globe). The students take
measurements, calculate aerosol concentrations, and learn to report their results through the internet. AOT measurements are processed
by GLOBE scientists who also provide comments and feedback to students and teachers. The aim is to generate public outreach for the
OMI and SCIAMACHY satellite instruments and to increase undergraduate student's interest in Science. With this network, the
Netherlands contributes substantially to the worldwide GLOBE aerosol monitoring project. For more information and examples of feedback
to students: www.knmi.nl/globe.
Some of the students measurements have been directly compared to collocated professional measurements of aerosol optical thickness
(AOT). As a proof of concept, we first characterised the LED-based GLOBE Sun photometer's perfomance relative to a full-automatic,
sun-tracking Sun photometer at KNMI. Results from this comparison indicate that collocated measurements by the GLOBE instrument are
within 0.02 AOT of the values retrieved from the SPUV. Subsequently, AOT measurements performed by undergraduate students in The
Hague have been compared to results from the AERONET CIMEL-instrument in The Hague. The encouraging results from this comparison
show that undergraduate students are capable of measuring AOT up to a reasonable degree of precision (0.03 AOT) and with no significantly
large bias.
With these results, the student measurements can be used for qualitative validation of satellite-derived AOT measurements. As a case
study for future SCIAMACHY and OMI validation, we discuss in our paper the results of a comparison between MODIS AOT and undergraduate
student-measured AOT over the Netherlands. We will discuss strategies to overcome the main practical obstacles in getting students to
measure AOT on a regular basis, as well as some important technical aspects of the AOT retrieval and comparison, including the determination
of the extraterrestrial constant and assumptions on spectral interpolation.
Brooks, David R., Forrest M. Mims III, Arlene S. Levine, Dwayne Hinton, The GLOBE/GIFTS Water Vapor
Monitoring Project:An Educator's Guide with Activities in Earth Sciences.
NASA Publication EG-2003-12-06-LARC, 2003. (Copies available from David Brooks or Arlene Levine.)
Link to online version
ABSTRACT
An instrument and experiment protocol for measuring total
atmospheric water vapor from a ground observing site has been developed in support of NASA
Langley Research Center’s Geosynchronous Imaging Fourier Spectrophotometer (GIFTS) instrument,
in cooperation with GLOBE, an international science and education program for K-12 students.
The GLOBE/GIFTS water vapor instrument is a battery-powered, handheld device suitable for use
by middle and secondary school students. It uses the ratio of the outputs from two narrowband
detectors in the near-infrared to determine total atmospheric water vapor.
The measurement protocol described in this report has
been adopted by the GLOBE Program, which provides a worldwide infrastructure for implementing
student-based environmental measurements. Science background, materials for educators and
students, alignment to science education standards, detailed field guides, and data entry
forms are provided in this comprehensive guide to using the GLOBE/GIFTS water vapor instrument.
Supplementary materials include discussions of
geosynchronous orbits, analog-to-digital conversion (for automated collection of water
vapor data), a simple model of Earth’s greenhouse effect, and an experiment for determining
dewpoint temperature.
Mims, Forrest M. III, Five years of photosynthetic radiation measurements using a new kind of LED sensor, Photochemistry and Photobiology 77, 30-33, 2003.
Mims, Forrest M. III, Solar aureoles caused by dust, smoke and haze, Applied Optics 42, 492-496, 2003.
Mims, Sarah A., and Forrest M. Mims III, Fungal spores are transported long distances in smoke from biomass fires, Atmospheric Environment 38, 651-655, 2004.
Brooks, D., Holzer, M., Ledley, T. S.,
Atmospheric Aerosols Project: A GLOBE Student-Teacher-Scientist Partnership, AGU Fall Meeting,
San Francisco, CA, 8-12 December, 2003.
ABSTRACT
The National Science Education Standards (NSES) emphasize that students should learn science
through inquiry and should understand the concepts and processes that shape our natural world.
One method of accomplishing these goals is to provide students and teachers with opportunities to
participate in scientists' ongoing research. The GLOBE program has done this to an extent through
the involvement of students in taking environmental observations and reporting them in a useful way.
However, in this project we move the teachers and students beyond the collection of data, to engage
them in an interesting scientific question that they have formulated on their own, perhaps with the
help of a teacher and a participating scientist. In collaboration with a scientist and their teacher,
the students address their question by collecting the necessary data, performing an analysis of the
data, drawing conclusions, and reporting the results. In this way, the ideal of real scientific
inquiry is pursued through more formal relationships among scientists, teachers and students.
David Brooks, a GLOBE Science PI, has been conducting research to learn more about how the
concentration of atmospheric aerosols varies in time and space, and how those variations may
be related to other changes on the planet. Students can support Dr. Brooks' research while
engaging in a research project of their own. A description of the project provided for teachers
and students can be found at the following
url http://essn.terc.edu/projects/proj_brooks01/ovrvw_01.cfm. In this presentation we will
describe our activities from the 2002-2003 school year during which we involved three schools
(two in New Jersey and one in North Carolina) in the atmospheric aerosols research project; and
our plans for the 2003-2004 school year with possibly more than six schools.
Brooks, D. R., F. Niepold, G. D'Emilio, J. Glist, G. Hatterscheid, S. Martin, K. Dede, I. Neumann. Scientist-Teacher-Student
Partnerships for Aerosol Optical Thickness Measurements in Support of Ground Validation Programs for Remote
Sensing Spacecraft. IAC-03-P.4.07,
International Astronautical Federation,
54th International Astronautical Congress, Bremen, Germany,
Sept. 28 - Oct. 3, 2003.
ABSTRACT
Satellite-based retrievals
of aerosol optical thickness (AOT) depend on mathematical models that interpret sunlight reflected
from the Earth/atmosphere system. The best way to assess the performance of aerosol retrievals is to
compare space-based data with ground-based data that include not just measurements of AOT, but also
descriptions of sky and meteorological conditions (metadata). Automated systems such as AERONET
provide the former, but not the latter. The GLOBE Program Aerosol Monitoring Project provides AOT at
505 nm and 625 nm, using handheld sun photometers developed especially for this program. The project
protocol also requires reporting of air temperature, barometric pressure, relative humidity, cloud
type and amount, and sky color and haziness. The paper presents a series of aerosol measurements
made by GLOBE students during spring and summer, 2003, in Washington, DC, USA, and Cuxhaven,
Germany. Measurements are timed to coincide with overflights of NASA’s Terra and Aqua spacecraft.
Comparisons between GLOBE measurements and aerosol
retrievals from the MODIS instrument are strikingly similar to comparisons of MODIS data with
other ground-based aerosol measurements, demonstrating that working partnerships among scientists,
teachers, and students provide opportunities for geographically dispersed research that is
impractical for scientists to undertake by themselves.
Ledley, T. S., N. Haddad, J. Lockwood, D. Brooks. Developing Meaningful Student-Teacher-Scientist
Partnerships. J. Geoscience Education, 51, 91-95, 2003.
pdf of this paper
Brooks, D. R., and Mims, F. M. III. Development of an inexpensive handheld LED-based Sun photometer
for the GLOBE program. J. Geophys. Res., 106, D5, 4733-4740, 2001.
ABSTRACT
Sun photometers that use light-emitting diode (LED) detectors in
place of optical interference filters and photo diodes have significant potential advantages,
including low cost, durabaility, and long-term optical stability. However, their relatively wide
specdtral response bandwidth poses some challenges in calibration and interpretation. Analysis of
LED-based Sun photometers developed for the Global Learning and Observations to Benefit the
Environment (GLOBE) program has demonstrated
that such instruments can, in fact, be calibrated using the standard Langley plot method and that
their performance can be described in terms of effective response wavelengths. Several GLOBE Sun
photometers have been calibrated at Mauna Loa Observatory on two separate occasions. The derived
extraterrestrial constants are essentially the same in spite of the fact
that the calibrations were performed under significantly different atmospheric conditions. These
reference
instruments have been used to transfer calibrations to other optically and electronically
identical Sun photometers, thereby making it possible to establish a large network
of inexpensive LED-based Sun photometers. Data collected by students at a GLOBE high school near
NASA's Goddard Space Flight Center (GSFC) and compared against aerosol optical thickness measurements
from Sun photometers at GSFC demonstrate both that students can reliably make the required
measurements and that LED-based Sun photometers give results that compare favorably with
conventional filter-based instruments, even though their optical properties are significantly different.
Brooks, David R., and Mims, Forrest M. III: The GLOBE Aerosol Monitoring Project:
Where Are We Now and Where Do We Go From Here? GLOBE Seventh Annual Meeting,
July 22-26, 2002, Chicago, Illinois, USA
1. How can we expand the application of the basic GLOBE sun photometer concept (using LEDs as spectrally selective light detectors) to remain responsive to real science needs?
2. How can we increase the level and sophistication of teacher and student participation in this area of environmental science?
online version here
(from the Introduction)
During the last few years, as reported regularly at these meetings, we have developed the GLOBE sun photometer to its current operational status. At the same time, there has been a surge of scientific interest in aerosol research that surpassed even our own expectations at the time we wrote our original proposal in 1997. This level of scientific interest provides many opportunities, but also presents new challenges. We are starting to accumulate interesting aerosol data from a few sites. Now, at the start of a new 3-year project, we need to address two challenges:
Mims, Forrest M. III and Brooks, David R.: Validation of Satellite Derived Aerosol
Optical Depth Using the GLOBE Sun Photometer. GLOBE Seventh Annual
Meeting, July 22-26, 2002, Chicago, Illinois, USA.
online version here
ABSTRACT
Various satellites measure the atmosphere’s aerosol optical depth (AOD). Because of
instrumental degradation and calibration drift, it is important to regularly validate data
provided by satellite remote sensing instruments. Serious students can use GLOBE Sun photometers
to play an important role in such comparisons by making observations during satellite overpasses
when the solar disk is unobscured by clouds. Here we report that on 5 clear days a carefully
calibrated GLOBE Sun photometer has precisely validated AOD measurements by the MODIS instrument
aboard NASA’s Terra satellite. The correlations of the green AOD measured by GLOBE and MODIS within
35 and 10 minutes of the MODIS overpass are, respectively, good (r2 = 0.89) and remarkably high
(r2 = 0.99). Similarly, the correlations of the red AOD measured within 35 and 10 minutes of the
MODIS overpass are, respectively, good (r2 = 0.80) and remarkably high
(r2 = 0.997). These findings
compare well with the results of a comparison of MODIS and some 30 automated Cimel Sun photometers in
the AERONET network (Chu et al., 2000). Very similar biases in the MODIS AOD were
identified by the
NASA study and the work reported here.
Brooks, David R., 2001: The GLOBE Sun Photometer is Operational. Sixth Annual GLOBE Conference,
Blaine, Washington, USA, July 22-27, 2001.
online version here
Abstract
Last year we reported some results from field-testing the GLOBE sun photometer.
During the past year, the GLOBE office has incorporated all the new atmosphere
protocols into its training and we have presented the aerosol protocols to European
country coordinators in September 2000 and to teachers, country coordinators, and
others from Africa in April 2001. This year we can report that the GLOBE sun photometer
is an operational instrument.
Brooks, David R., Forrest M. Mims III, George Strachan, Susannah Kim, Jean Yeung, Brent Holben, Alexander Smirnov: Calibrating the GLOBE Sun Photometer. AGU Spring Meeting, Boston, Massachusetts, May 31-June 4, 1999.
Brooks, David R., Forrest M. Mims III, Tran Nguyen, and Stephen Bannasch:
Characterization of LED-based sun photometers for use as GLOBE instruments.
Third Annual GLOBE Conference, Snowmass, Colorado, August 3-7, 1998.
Full Report
Mims, Forrest M. III: Sun photometer with light-emitting diodes as spectrally selective detectors.
Appl. Opt., 31, 6965-6967, 1992.
This is the original paper that provided the foundation
for the GLOBE sun photometer, water vapor instrument, and UV-A radiometer.
Mims, Forrest M. III: An Inexpensive and Accurate Student Sun Photometer with Light-Emitting Diodes as Spectrally Selective Detectors
Full Report
Papers and Other Publications of Interest by Other Authors
Geophysical Research Abstracts, Vol. 9, 00563, 2007 SRef-ID: 1607-7962/gra/EGU2007-A-00563 © European Geosciences Union 2007
The GLOBE-Aerosol monitoring Project at KNMI
T. Vlemmix (1), E.J. Brinksma (1), P.F. Levelt (1), R. Braak (1), B. Veihelmann (1), J.P. Veefkind (1)
(1)Royal Netherlands Meteorological Institute (KNMI), de Bilt, the Netherlands (vlemmix@knmi.nl)
Aerosols play a key role in the radiative balance of the Earth's atmosphere, and are therefore linked to global climate change. In the GLOBE-aerosol monitoring project at KNMI1, secondary school students take ground measurements of aerosol optical thickness (AOT) to get hands-on experience with atmospheric remote sensing, and to learn about satellite aerosol remote sensing. KNMI has been actively involved in this project since 2002 and currently about 30 schools participate. Measurements are taken with a simple, hand held Sun photometer that provides AOT in two wavelength bands (508 and 625 nm), at the moment of overpass of the OMI instrument on the NASA-satellite Aura. Students can enter their data and additional meteorological observations on the international GLOBE website. Data are sent to KNMI where an aerosol algorithm is applied which converts the output voltages of the Sun photometer to AOT's. This algorithm also takes satellite observations of ozone into account. Boersma and de Vroom have investigated the reliability and accuracy of the student measurements2 and they found that the degree of precision (0.03 AOT) was similar to that of professional validation instruments. The instrument MODIS on the NASA-satellite Terra compared well with GLOBE AOT's. Furthermore, the GLOBE measurements confirmed that the MODIS aerosol retrieval for pixels over land was better than for pixels over water and that MODIS had difficulties to retrieve the AOT for coastal pixels over half land, half water. In this talk an outline of the project will be given: the cooperation between students, teachers, GLOBE international and KNMI; the algorithm of the Sun photometer; the calibration of the GLOBE photometers by comparison with professional Sun photometers such as CIMEL and SPUV; first results of the validation of the OMI aerosol multi-wavelength product through comparison with the ground measurements by students.
1 The GLOBE aerosol monitoring project at KNMI is a part of the international GLOBE program. See: www.globe.gov. The Dutch GLOBE-project is coordinated by SME-advies (organization for environmental education and counseling).
2Boersma, K. F., and J. P. de Vroom (2006), Validation of MODIS aerosol observations over the Netherlands with GLOBE student measurements, J. Geophys. Res., Vol. III, D20311, doi:10. 1029/2006JD0071 72
Boersma, K.F., and J.P. de Vroom. "Validation of MODIS Aerosol Observations over the Netherlands with GLOBE Student Participation." Journal of Geophysical Research, Vol. III, p. D20311, doi. 10.1029/2006
Joris de Vroom, Folkert Boersma, and Pieternel Levelt. Can Dutch GLOBE schools validate MODIS Aerosol Optical Thickness measurements? KNMI, Presentation at the EOS/Aura Science Team Meeting, October 2003.
Vroom, Joris de. The Contribution of Dutch GLOBE Schools to Validation of Aerosol
Measurements from Space. Master's Thesis, Vrije Universiteit Amsterdam, October 2003.
As far as I know, this is the first science-related
Master's Thesis based primarily on GLOBE student
data. The thesis does not include an abstract. This text is from the Conclusion section.
Conclusion
GLOBE high school student aerosol optical thickness
measurements with the GLOBE Sun photometer are used to validate MODIS AOT measurements. The results
compare reasonably well even when a mean time difference criterion of 2 hours is used.
When the time criterion is set at 10 minutes, the results compare
remarkably well. This shows that it is important to choose an appropriate time criterion
for validation since it is essential that GLOBE and MODIS measure the same air sample...
For coastal pixels,
MODIS AOT results are relatively high compared to GLOBE AOT results. The comparisons of
coastal pixels improve significantly when the GLOBE measurements are compared to the
neighboring (land-) pixel instead of the coastal pixel. This is a strong indication that
MODIS overestimates AOT at pixels that are partly over water. The results confirm the
high potential for satellite instrument validation of the GLOBE school network, since
similar results were achieved by validation campaigns with professional Sun photometers.
To improve the validation of satellite measurements
with the Dutch GLOBE school network, more measurementes are necessary... GLOBE
measurements within 10 minutes of the satellite overpass time are very useful since the
time difference between GLOBE and satellite instrument measurements has shown to have
great impact on the validation results. A relatively quick and simple action to extend
the validation is comparing GLOBE data with MODIS on Aqua. Furthermore, the current
GLOBE school measurements can be used to validate SCIAMACHY AOT measurements when
SHIAMACHY data is released.