There is not only one type of clouds, but many of them, with diverse properties leading to various ways to visualize them when looking at our satellite measurements. Here an example with the Copernicus Sentinel-3 (S3) A Sea & Land Surface Temperature Radiometer (SLSTR) over Amazonia.
SLSTR has a special channel at 1.3 um in which water vapor (H2O) so much absorbs that no signal at the top of the atmosphere may be measured. Unless clouds at a very high altitude are present, shielding then a large fraction of the H2O column in the atmosphere. Consequently, a bright signal spikes up and elevated clouds shine!
From the picture above, snow & ice clouds are primary the highest one! Anything else lower, such as surface and fractional low clouds, seems “invisible”. They cannot be “seen”.
No doubt winter has come in Europe! The Earth inclination has changed.
As observed last Winter with GOME-2 UltraViolet (UV) measurements, a big change in the effective UV irradiance reaching the Earth surface is also seen over the day between last July and nowadays.
Here below is an example with the estimated reduced Vitamine D production in our skin as a direct consequence. These pictures are from the ESA / KNMI Tropospheric Emission Monitoring Internet Service (TEMIS). Satellite UV dose is computed from the assimilated global O3 – ozone field at local solar noon, and with surface downwelling solar (SDS) radiation & cloud information measured by the Meteosat Second Generation (MSG) satellites led by the EUMETSAT agency.
A recent work achieved by my colleagues of the National Observatory of Athens (NOA): 9 years of observations acquired by the CALIOP space-borne instrument were combined with EARLINET ground-based measurements to provide a climatology of desert dust particles over South and East Asia.
Having such a knowledge is important for many research studies focused on atmospheric transport and climate effect of dust.
You can see more details on my webpage here, and the paper of Proestakis et al. (2018) published in the Atmospheric Chemistry and Physics (ACP) journal here.
Why are we (I and my colleagues) that excited this week? Why is TROPOMI so much important for the new coming era in air quality & climate satellite era?
Throughout the week, we will post more information on our GRS TU Delft website and also be using the #GRS_TROPOMI on social media (Twitter and Instagram) as we explain more about the mission, its goals, and how it all works in relation to the goals and work being done in our department. The week will culminate with the Sentinel-5P launch event taking place at the Space Expo in Noordwijk.
Despite its quite advance age for a satellite mission (13 years old!), OMI is still delivering remarkable measurements about our atmospheric composition and air quality. So many talks and discussions on the aerosol global record over cloud-free scenes and above clouds, decade global volcanic SO2 – Sulfur dioxide missions, the use of OMI data by air quality model simulations to inform air quality policy, the case studies on emissions monitoring and to support authorities and clean-tech industry, the new generation of the Quality Assurance For Essential Climate Variables (QA4ECV), the evolution in the ozone trends and related mechanisms, and of course the future with the forthcoming TROPOMI (Sentinel-5 Precursor) mission, TEMPO (NASA Geostationary) and TROPOLITE.
In spite of being glad of having been part of this adventure, I cannot stop myself thinking this may have been my very last OMI conference, before finishing my current research project and starting new professional & personal adventures (still in satellite & atmospheric community of course!). But this last point will be specifically mentioned later in future weeks. Stay tuned!
All volcanoes are on satellite watch due to their continuous gas emissions, in particular SO2 – Sulphur dioxide, and their impacts after eruptions on air quality and landslide risks. A new study, from University of Leeds (Ilyinska et al., 2017), has found a previously undetected potential health risk from the high concentration of small particles – aerosols – found in a boomerang-like return of a volcanic plume.
This study focused on the evolution of the plume chemistry from the 2014-2015 Icelandic Holuhraun lava field eruption and found a second type of plume that impacts air quality. This second plume had circled back to Icelandic cities and towns long after the health warning about the initial plume had been lifted.
The 2014–2015 Holuhraun eruption in Iceland, emitted ∼11 Tg of SO2 into the troposphere over 6 months, and caused one of the most intense and widespread volcanogenic air pollution events in centuries, exceeding hourly air quality standards (350 μg/m3) for SO2 on 88 occasions in Reykjahlíð town (100 km distance), and 34 occasions in Reykjavík capital area (250 km distance). Average daily concentration of volcanogenic sulphate particles exceeded 5μg/m3 on 30 days in Reykjavík capital area.
2 types of plume impacted the downwind populated areas:
The first type was characterised by high concentrations of both SO2 gas and fine particles,
The second type had a low SO2 gas concentration.
Ilyinska et al. (2017) suggest that this second type was a mature plume where sulphur had undergone significant gas-to-aerosol conversion in the atmosphere. This second plume had circled back to Icelandic cities and towns long after the health warning about the initial plume had been lifted. The return of this second mature plume, named as a ‘plumerang’, meant that the sulphur dioxide (SO2) levels were reduced and within the European Commission air quality standards and, therefore, there were no health advisory messages in place.
However, both types of plume were rich in fine aerosol, sulphate (on average ∼90% of the aerosol mass) and various trace species, including heavy metals. The fine size of the volcanic aerosol mass (~75–80%), combined with chemical components, have potential adverse implications for environmental and health impacts (e.g. exacerbating asthma attacks). The concentrations of these trace metals did not reduce as the plume matured and included heavy metals found in human-made air pollution that are linked to negative health effects. But, only the dispersion of volcanic SO2 gas was forecast in public warnings and operationally monitored during the eruption.
“On at least 18 days during the 6-month long eruption the plumerang was in the capital city of Reykjavík, while the official forecast showed ‘no plume’.” (said lead author, Dr Ilyinskaya from the Institute of Geophysics and Tectonics at Leeds). “We spoke to people living in Reykjavik who described a burning sensation in the throat and eyes when the SO2 levels would have been well within air quality standards but the particle-rich plumerang would have been over the city.”
For the future, Ilyinska et al. (2017) strongly recommends that in future gas-rich eruptions both the young and mature plumes should be considered when forecasting air pollution and the dispersion and transport pattern of the plume.
Previous WebPost on “Volcanoes on Sentinel-2 and OMI satellites watch – First global emission maps!” here
Ilyinska et al. (2017): Evgenia Ilyinskaya, Anja Schmidt, Tamsin A. Mather, Francis D. Pope, Claire Witham, Peter Baxter, Thorsteinn Jóhannsson, Melissa Pfeffer, Sara Barsotti, Ajit Singh, Paul Sanderson, Baldur Bergsson, Brendan McCormick Kilbride, Amy Donovan, Nial Peters, Clive Oppenheimer, Marie Edmonds. Understanding the environmental impacts of large fissure eruptions: Aerosol and gas emissions from the 2014–2015 Holuhraun eruption (Iceland). Earth and Planetary Science Letters, 2017; DOI: 10.1016/j.epsl.2017.05.025here
“Volcanic ‘plumerang’ could impact human health” on geology page here
A new book that I strongly recommend to my French fellows (or anyone speaking French)!
Written by Dr. Francois-Marie Breon, and Gilles Luneau, it greatly explains the climate system, its past story and what we know (with high certainty) about its warming future and the consequences. Nicely illustrated, it also summarizes the planned and potential worldwide initiatives to face the on-going changes.
For the first time, a University of Maryland-led team (Warmer et al.) revealed, in Geophysical Research Letters, a global atmospheric NH3 — Ammonia from 2002 to 2016 over four of the world’s more productive agricultural regions: United States, Europes, China and India. All these countries show increased NH3 concentrations!
NH3 concentrations are estimated from the NASA’s Atmospheric Infrared Sounder (AIRS) instrument on NASA’s Aqua satellite. Like NO2 – Nitrogen dioxide, NH3 is part of the nitrogen cycle and a precursor of ammonium and nitrate aerosols. Excess reactive nitrogen reduces biodiversity and causes harmful algal blooms and anoxic conditions. Dry deposition of gaseous ammonia may have substantially greater adverse impacts on ecosystem health than deposition of ammonium in aerosols or precipitation. The main sources of atmospheric NH3 are farming and animal husbandry involving reactive nitrogen ultimately derived from fertilizer use. The rate of these emissions is also sensitive to climate change.
In the abstract, Warmer et al., (2017) says: “Significant increasing trends are seen over the U.S. (2.61% yr-1 ), the European Union (EU) (1.83% yr-1 ), and China (2.27% yr-1 ). Over the EU, the trend results from decreased scavenging by acid aerosols. Over the U.S., the increase results from a combination of decreased chemical loss and increased soil temperatures. Over China, decreased chemical loss, increasing temperatures, and increased fertilizer use all play a role. Over South Asia, increased NH3 emissions are masked by increased SO2 – Sulphur dioxide and NOx – Nitrogen oxides emissions, leading to increased aerosol loading and adverse health effects”.
Warner, J. X., R. R. Dickerson, Z. Wei, L. L. Strow, Y. Wang, and Q. Liang (2017), Increased atmospheric ammonia over the world’s major agricultural areas detected from space, Geophys. Res. Lett., 44, doi:10.1002/2016GL072305 here
Atmospheric SO2 is not only emitted by humans (such this plume in Iraq) but also by volcanoes…
Volcanoes are on watch by satellite observations. This is of high importance as, about 22 volcanoes are active, and 1500 potentially active, around the world.
Optical sensors, such as Sentinel-2, are exploited to track their continuous eruptions (through thermal anomalies at the surface) and to assess the health of plant life and agriculture around the volcanoes. The knowledge of the extent of eruptive deposits is crucial for assessing a volcanic event and any follow-on landslide risk and the size of the affected area.
Furthermore, volcanoes do not only affect the land surfaces but also the atmosphere! They are responsible of continuous gas emissions such as water vapour laced with heavy metals, CO2 – Carbon dioxode, hydrogen sulfide and SO2 – Sulfure dioxide, among many other gases. Cumulative daily and big eruption emissions can be very significant.
The Dutch-Finnish OMI satellite missions provides with high values of atmospheric SO2 measurements. A research team from Michigan Technological University created the first, truly global inventory for volcanic SO2 emissions using OMI data. The publication in Scientific reports mentions that each year volcanoes collectively emit 20 to 25 million tons of SO2 into the atmosphere
The data set will help refine climate and atmospheric chemistry models and provide more insight into human and environmental health risks.