Saharan dust outbreak often occurs across the Atlantic. Here, a big #aerosol plume was captured by the Sentinel-3 Ocean & Land Colour Instrument (OLCI) from the Copernicus programme led by the European Union (EU). A big fraction of it usually travels across-Atlantic and one may think it doesn’t come back to us…
But the forecast of Aerosol Optical Depth (AOD) for Friday 1st November 2019, computed by the Copernicus Atmospheric Service (CAMS)& depicted by the Windy on-line application, shows a striking dust “boomerang”-like pattern. After travelling a large distance, a heavy dust load eventually comes back to South Europe. Wind is a key factor explaining such aerosol long-range transport.
My colleague, Dr. Antti Lipponen, researcher at the Finnish Meteorological Institue (FMI), evaluated this transport phenomenon in a fancy unit. “Based on NASA’s GEOS-FP analysis the area of the dust over the Atlantic Ocean is about 9.1 million km² and the mass of the dust about 2.6 million tons (2 600 000 000 kg). If a truck would carry 40 tons of dust it would make about 65 000 truckloads!!!“
On 2019.02.05, a remarkable dust outbreak issued from the Western Sahara coast spread over Gran Canaria islands. This thick plume, with heavy load of particles, and larger than 1.000 km width, was well observed via a series of satellite images:
Aerosol Index UVAI retried from TROPOMI Sentinel-5 Precursor over the Saharan dust outbreak of 2019.02.05. Credit SentinelHub.. Source: https://apps.sentinel-hub.com/eo-browser
Several days later, on 2019.03.02, another Saharan dust was transported over Cabo Verde. Similarly, a very large and thick plume was captured in the images from the NASA SUOMI VIIRS sensor, and measured by the aerosol index UVAI from Tropomi.
RGB composite image from SUOMI VIIRS of the Saharan dust transport of 2019.03.02. Credit: NASA EODIS Worldview Source: https://worldview.earthdata.nasa.gov
Aerosol Index UVAI retried from TROPOMI Sentinel-5 Precursor over the Saharan dust transport of 2019.03.02. Credit SentinelHub.. Source: https://apps.sentinel-hub.com/eo-browser
Biomass burning is a major source of trace gases & aerosol particles on a regional and a global scale (Seiler and Crutzen, 1980; Logan et al., 1981; Crutzen and Andreae, 1990; Andreae, 1991). Interannual variations in biomass burning within specific regions of the world can be dramatic, depending on factors such as rainfall and political incentives to clear land. The forest fires in Indonesia during 1997–1998 and those in Mexico during 1998, both related to the El Nino Southern Oscillation (ENSO) induced drought, are well known examples of extreme fire events (e.g. Levine, 1999; Nakajima et al., 1999; Peppler et al., 2000; Cheng and Lin, 2001).
The principal biomass burning areas can be observed in the Amazonian region and in central Africa. Among the trace gases released, NO2 – nitrogen dioxide & CO – carbon monoxide abundances can be very high. Satellite observations are a helpful tool for the identification of these sources in the troposphere and to follow their transport. In addition, these intensive biomass burning episodes release a large quantity of aerosol particles, at fine size and with absorbing properties.
Below are the animations of NO2 and CO columns as observed by the TROPOMI sensor, on-board the Sentinel-5 Precursor mission from the European Copernicus program. These animations cover ~1 month of biomass burning over Central Africa. They are extracted from the SentinelHub Earth Observation (EO) browser.
Animation Tropospheric NO2 vertical column density from TROPOMI Sentinel-5 Precursor from 2019.01.01 to 2019.02.07. Credit SentinelHub. Source: https://apps.sentinel-hub.com/eo-browser/
Additionally, you can visualise here animations based on the NASA SUOMI VIIRS observations showing the fire detected pixels (in red) and the detection of fine absorbing particles in large concentrations. Note that SUOMI and Sentinel-5 P are flying together on the same orbit / same track with only a few minutes apart.
Animation RGB image composite from SUOMI VIIRS from 2019.01.01 to 2019.02.07. Credit NASA EODIS WorldView. Source: https://worldview.earthdata.nasa.gov/?p=geographic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor,MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor(hidden),VIIRS_SNPP_Thermal_Anomalies_375m_Day,OMPS_Aerosol_Index(hidden),AIRS_CO_Total_Column_Day(hidden),OMI_Nitrogen_Dioxide_Tropo_Column(hidden),MODIS_Terra_Thermal_Anomalies_All(hidden),MODIS_Terra_Aerosol_Optical_Depth_3km(hidden),Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2019-01-25-T00%3A00%3A00Z&z=3&v=-80.65378411193339,-57.40841307238665,84.29515205827931,42.15408692761331&ab=on&as=2019-01-01T00%3A00%3A00Z&ae=2019-02-07T00%3A00%3A00Z&av=3&al=false
Animation UV Absorbing Aerosol Index (UVAI – Red = absorbing aerosols detected in large amounts) from SUOMI VIIRS from 2019.01.01 to 2019.02.07. Credit NASA EODIS WorldView. Source: https://worldview.earthdata.nasa.gov/?p=geographic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor,MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor(hidden),VIIRS_SNPP_Thermal_Anomalies_375m_Day,OMPS_Aerosol_Index(hidden),AIRS_CO_Total_Column_Day(hidden),OMI_Nitrogen_Dioxide_Tropo_Column(hidden),MODIS_Terra_Thermal_Anomalies_All(hidden),MODIS_Terra_Aerosol_Optical_Depth_3km(hidden),Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2019-01-25-T00%3A00%3A00Z&z=3&v=-80.65378411193339,-57.40841307238665,84.29515205827931,42.15408692761331&ab=on&as=2019-01-01T00%3A00%3A00Z&ae=2019-02-07T00%3A00%3A00Z&av=3&al=false
More information?
TROPOMI, on-board the Copernicus Sentinel-5 Precursor satellite, here
Research Thesis book cover – Julien Chimot – July 2018
Almost 3 months ago, on 2018.09.10, I had the privilege to defend my research thesis at Delft University of Technology. A big moment after 4 years of intensive collaboration with my colleagues of the Geoscience & Remote Sensing Department and KNMI and in the presence of several friends and relatives. An very strict protocol to follow according to the Dutch rules and tradition.
My thesis book is now available online as an Ebook here! Feel free to have a look if you are interested by aerosol layer height retrieval, UV-Vis satellite measurements such as OMI, troposphericNO2, air quality and climate observations. My main papers are concatenated there.
While the last Intergovernmental Panel on Climate Change (IPPC) report just got released, and stresses the urgency to act extremely quickly for limiting the global warming close to 1.5 deg, one should keep in mind that the worldwide electricity sector is one of the highest source of CO2 – Carbon dioxide released in the atmosphere. Do we want to keep our lights on? Let’s ban then coal gas & use electricity sources with low CO2 – Carbon dioxide emissions (including nuclear!).
Atmosphericaerosol are particles suspended in the air. Their sources are very mixed. Aerosol can be man-made or natural: e.g. smoke, desert dust, sea spray, nitrates and sulfates. The aerosol effects on the sunlight modify the shortwave radiation field in the atmosphere. This directly impacts the climate and the satellite observations devoted to ocean surface, land surface, vegetation, and atmospheric gases. Furthermore, heavy load of aerosols affects our air quality.
In spite of many progresses during the last 10-20 years, aerosol observations from space-borne instruments remain incredibly complex. One of the main reasons is their heterogeneity: aerosols are everywhere, but with very variable quantities spatially (horizontally and vertically!), and temporally. And, as highlighted by this NASA picture, aerosol types are also very heterogeneous! Retrieving all these parameters from single satellite measurements, without ambiguity with respect to surface characteristics and clouds, is the difficult task of the scientists working with atmospheric satellite measurements. Many works to continue to do…
More information
NASA WebPage “Just another Day on Aerosol Earth” here
As part of the Copernicus programme, Sentinel-3 is a very important mission for ocean colour, sea and land surface, fire, atmosphere and climate purposes. With the two platforms, Sentinel-3 A and B, an optimal global coverage will be now obtained. The next observations and related products are promising!
More information?
Check the diverse pictures of this fantastic launch via the Twitter accounts of EUMETSAT and ESA
The current Sentinel-3 services provided by EUMETSAT here
And watch below the movie from EUMETSAT in live in the Sentinel-3 control centre “Sentinel-3: Operating satellites” with Hillary Wilson, EUMETSAT’s Sentinel-3 manager, and Kevin Marston, EUMETSAT’s System operation manager.
25 years ago, in 1992, 1700 independent scientists already told us in their “World Scientists – Warning to Humanity – 1st Notice”. And yet, it seems that was not sufficient. This month, a second notice was submitted, this time by about 15,000 worldwide scientists. And the message is still quite clear: “the world is going toward catastrophic biodiversity loss and untold amounts of human misery” and we have little time to act before avoiding this.
This may sound like an unrealistic, even irrational alarmist message. But it is worth reminding that, since its beginning, science work (and scientists) is beforehand based on observations, facts, interpretations with evaluation of uncertainties, implementing models that are then continuously and thoroughly evaluated by confronting with observations.
This article is relatively short and very simple to read. No need to be an expert, every citizen can easily understand all the messages. I think this is the duty to each of us to take some minutes for reviewing it, and then thinking about our actions. Especially, the causes are nowadays well identified: rapid population growth, deforestation, agricultural production, and rising greenhouse gases from burning fossil fuels that has triggered and driven our climate change.
For this last one, in spite of continuous denial and unjustified claims (especially in the USA), the odds from IPCC and COP23 are pretty clear: CO2 – Carbon dioxide and CH4 – Methane amount in the atmosphere are historically unique, and the emissions keep increasing. Some of these increases are also even observable from space.
Atmospheric levels of CH4 – Methane from 2003 to 2005 and 2008 to 2010, showing increased concentrations in the latter dataset (in red). The newly released ‘Climate Research Data Package No. 3’ covers more than one decade (2003–14) of atmospheric data products used to get information on the sources and sinks of carbon dioxide and methane. The data products are available through the website: http://www.esa-ghg-cci.org/ (Source ESA: http://www.esa.int/Our_Activities/Observing_the_Earth/Methane_and_carbon_dioxide_on_the_rise).
A positive sign: stratospheric O3 – Ozone hole over Antarctic is recovering. If our actions have allowed to create and then solved this problem, then we can still do something, at every level, about the greenhouse gases.
Several journals and websites forwarded this article. But I have the feeling yet it could reach more and more people and lead to further discussions and actions in our societies. Hope this is not too late…
More information?
Ripple et al., 2017: Full articles World Scientists’ Warning to Humanity, 1st and 2nd notices here. You can also endorse the 2017 article here
European Space Agency (ESA): CO2 – Carbon dioxide and CH4 – Methane on the rise here
Finally, that’s official! TROPOMI, on-board Sentinel-5 Precursor, the 1st European operational satellite mission devoted to air quality, ozone & climate monitoring, should be launched within the next weeks. And this looks very impressive!
What are the new signs? The Sentinel-5P campaign kicked off, the satellite left UK to Russia some days ago, and several media allow to follow it (through ESA blogs and Twitter accounts). All of these new elements have appeared just some days before our very soon 20th OMI Science Team Meeting focused on the last 13-year developments and data sets.
Let’s keep the fingers crossed that OMI can continue to fly and acquire new observations together with its successor TROPOMI. Autumn 2017 promises to be a very exciting season for our community!
The 20th OMI Science Team Meeting will be held at NASA Goddard in Greenbelt MD, USA from Tuesday September 12 through Thursday September 14, 2017. With nearly 14 years of data and the impending launch of TROPOMI on board-Sentinel-5 Precursor, there is much to discuss within the OMI (& TROPOMI) team and user community regarding the current state of OMI, trends and longer-terms records, comparisons with (satellite) data sets, and the validation of OMI data. This meeting will highlight recent OMI results as well as address research plans and program goals for the coming year.
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