Good morning and welcome to the NASA hyperwall presentation this morning.
We are going to be talking about aerosols.
Aerosols are one of the most important
and as yet still uncertain elements of the climate system
and the best estimates that we have
of both the distribution and composition
and the impact they have on clouds and climate
and air quality come from a series of a set of measurements
that are run through this project called AERONET.
You are going to be hearing from Brent Holben
who's the principal investigator for AERONET
at NASA's Goddard Space Flight Center
and so over to Brent. (Introduction by Dr. Gavin Schmidt who is NASA’s Senior Climate Advisor)
Hello, my name is Brent Holben.
I'm the project scientist for the AERONET project
and I'd like to welcome you all to Mount AERONET
here on the top of building 33 where we provide calibration for all of our instruments
that are in the network. AERONET is a relatively small program
that is designed to measure aerosol concentrations
and properties from a ground-based network of sun photometers,
these guys here,
for primarily for validation of satellite retrievals of aerosols.
We know the energy at the top of the atmosphere.
We're measuring it at the bottom of the atmosphere with these guys.
We can actually point it at the sun.
It has a filter wheel here that, uh,
looks at nine spectral channels and
we use that difference between the top and the bottom of the atmosphere
to characterize the properties,
as well as to measure the concentration of those aerosols.
Also, there is a very large land surface community
that doesn't care anything about aerosols,
but they want to see what's going on with the
vegetation and surface characteristics.
So, they need to remove the atmosphere.
So, the data from this basically provides
that information to correct the satellite imagery
so you can get a better view of the surface characterization.
There's also the ocean community which is interested in ocean color
and the concentration of chlorophyll and particulates in the water.
And aerosols contributed approximately 90% of the signals,
so it's very important to very accurately remove t
he aerosol signal from that satellite ocean color signal.
All together, there are about 450 sites worldwide and
they're very well distributed.
In all kinds of ecosystems
and all kinds of aerosol environments.
And as satellites come and go,
this project is simple enough and robust enough
that it keeps producing more and more information
at a higher and higher data rate, at a higher and higher distribution.
So, I suspect that in the long term, we're going to grow
to several thousand instruments. And because
it's a relatively inexpensive program,
I think that the future bodes very well for providing more data
for not just NASA, but the entire globe.
Okay I'm down for Mt. AERONET now.
I'd like to make a point before we move forward.
Consider AERONET measurements this way,
humans tend to look horizontally.
We appreciate visibility,
and we have a notion of what haze is,
but it's really transmissivity of the atmosphere.
AERONET looks up through the atmosphere
to measure a similar transmissivity parameter.
AERONET has been growing and
improving for 28 years, and in 2021,
this year approximately 500 ground stations
have contributed to our database.
It's effectively an aerosol climatology.
The map in the upper left shows
the contributing sites this year.
This is a Federated network with
partner collaborations in all continents,
97 countries and territories.
The network functions because
scientists and technicians working in Partnership
share their data in a public domain database
for the community.
It takes Global Village to make this work.
Okay, but still, why does NASA It takes Global Village to make this work.
Okay, but still, why does NASA
or anybody need AERONET?
Why ask AERONET?
Let's go to the satellite and models.
My favorite animation, GMAO.
They do everything.
They ingest the satellite data,
in this case MODIS,
combine it with meteorology sources,
microphysics of the aerosols.
Then it transports and modifies aerosols
around the planet as a very realistic representation
of the aerosol environment.
Note, dust blowing off West Africa
and transported across the Atlantic.
Smoke from wildfires in the US and Canada.
Sea salt, all modified by meteorology and physics
embedded in the code and nudged by
new data from the satellites.
We will see an additional clip showing transport later.
The question is how accurate are the data
from the satellites and model simulations?
We need error bars put on the retrievals,
so how do we do that?
Let's go to the next slide. so how do we do that?
Let's go to the next slide.
We need to go to where the aerosols are.
We need to kind of get dirty.
The upper left-hand Corner shows an
active fire in the Forest Clearing.
It’s man made.
Notice the dark smoke plume generating a cumulous cloud.
Clearly a chaotic and a massive aerosol cloud interaction.
It is very difficult to measure.
The very hot fire the panel below,
well I don't want to get in that,
but some people do, to get the ground truth data.
We send planes in on challenging sampling missions
to measure and ultimately understand the processes for the models.
How about the picture of the container ship idling in a harbor on a hazy afternoon –
fossil-fuel aerosols.
Then, there's the dust storm about to overtake suburbia.
The melon vendor is sampling dust with his eyes and his nose and skin,
not exactly scientific, but he knows what it is.
It works for him. AERONET takes easy street.
Robots sit and wait for aerosols to come to them.
Measurements every five minutes.
No weekends off. No holidays allowed - 24/7.
Let’s go on a global tour of AERONET.
Here we are in Europe.
It is not just NASA doing AERONET.
Our calibration partners in Lille and Valladolid
maintain the European Network
and the result has been a great gift to the aerosol community.
Check out the map - the density of observations often shows connectivity
between the adjacent instruments. The validation scientists,
we have statistics. The breadth of the science sites from Iceland to Poland,
Scandinavia to the Iberian Peninsula,
Turkey to Glasgow. UKMET has one here.
Rural, urban, over water, mountains -
that diversity and density of the Relentless routine observations
make AERONET Europe exceptional!
You have aerosol transport.
Check out the GMAO simulation!
We must credit the scientists,
the governmental and University institutions
that have recognized the importance of these measurements.
Okay, let’s do something a little different.
Let's transport ourselves to Southeast Asia and warm up.
Southeast Asia - another GMAO simulation –
zoomed into southeast Asia.
Note that indonesian fires light up in September
on the satellite image shows thousands of hotspots likely ag fires
in Thailand, Laos, and Myanmar in March and April.
Aerosols don't respect country boundary, country regulations,
and are transported to the East!
Seven Seas is a long-running bootstrap international program
established by host country scientists in 7 Southeast Asian countries.
The mission - characterize aerosol meteorological interactions across
southeast Asia and establish a multinational collaborative
database of regional ground-based observations.
Provide space space retrieval algorithms
and modeling datasets and
AERONET is the validation anchor in all of this.
Collaboration continues. The network continues to expand adding to our regional aerosol climatology.
Ladies and gentlemen, I give you topography. Beautiful Japanese Alps - spectacular, but topography messes up our simple view of the Earth.
It is difficult to do remote sensing of any type in steep Mountainous settings. Inversions trap Aerosols upslope, and downslope winds make a mockery of our global models.
The Amazon - everybody knows what's going on in the Amazon.
And everybody is an expert.
Forest conversion, land cover change.
Look at the animation –
burning monoculture in a river of smoke pours south.
The issues are climate affects, ecosystem function,
and health effects on 20 million people that live in the Amazon.
AERONET has been measuring in the Amazon since 1992.
First with Brazilian space agency (aeb),
and later with University of San Paulo,
and other agencies and university scientists.
Aerosol climatology is emerging and
note the annual 3 month pulse.
Year-by-year AERONET sites in
Brazil, Bolivia, Paraguay, Argentina, and Uruguay
capture those pulses as they exit over the South Atlantic.
AERONET further compliments detailed
meteorological in situ measurements at the
300 m ATTO tower near Manaus
to chronicle the effects of a changing atmosphere
on a pristine part of the Amazon basin.
Next slide please.
Africa looms large in every facet of the earth's climate system,
and for aerosols it is easily depicted in the GMAO animation.
We know that vast quantities of mineral dust are transported
over the Atlantic, Mediterranean, Caribbean,
South America, and Europe. AERONET is there to spot check
the satellites and models.
We are there in the Sahara, and Sahel,
including islands surrounding the continent.
Likewise, the largest area of biomass burning
on the planet occur every year in a north to south migration
of anthropogenic biomass burning.
Check out the animation on the upper right.
AERONET began observations in Zambia in 1997
and greatly expanded observations during the 1990s during
NASA and University of the Witwatersrand (Wits), Safari 2000
airborne campaign to understand the processes and magnitude
of the burning. That ushered in the Eos era of validation
for the Terra satellite. Antonio Queface a young graduate student at Wits
volunteered to man an AERONET site in southern Mozambique,
his home country for the campaign.
Today, he is a professor of physics at University
and is leading his students in measurements and
assessments of AERONET data.
Last slide please.
There are five hundred stories, and
stories within stories to be told.
I’ve nearly run out of time.
I'd like to show you two historic science results
from AERONET.
The upper left-hand panel is a figure showing
the first published MODIS/Terra versus AERONET
comparisons over land and water.
Validation with Statistics, and it was good!
This analysis is now routine.
The upper right is a published figure showing the AERONET climate parameter.
Single scattering albedo for 3 aerosol types.
All values above the blue line which we superimposed
on the figure would contribute to cooling the atmosphere
and those below the red line would likely warm the atmosphere.
In conclusion, we have aerosol climatology, validation and
research owing to the hard work and dedication of the
science community working together.
On behalf of the research and technical staff at Goddard,
Lille, Valladolid, Boulder, and Beijing,
and the calibration sites at Mauna Loa and Izaña,
and the hundreds of scientists and technicians at 500 sites
in 97 countries and territories,
we wish COP26 every success.
Remember, if you're not sure ask AERONET.
thank you